Spring 4 MVC, Hibernate: many to many association

This post shows the many-to-many relationship in Hibernate, by the example of joining tables in the Spring 4 MVC web application. We will discuss the management of many-to-many relationships in representations and back-end'ah. We will perform create, update, delete and query operations through the web interface.

This application uses the org.springframework.core.convert.converter.Converter interface, which helps us to display the ID 'of objects in real subjects in the database.

The following technologies were used:
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Spring 4.1.7.RELEASE
Hibernate Core 4.3.10.Final
validation-api 1.1.0.Final
hibernate-validator 5.1.3.Final
MySQL Server 5.6
Maven 3
JDK 1.7
NetBeans 8.0.2

Let's get started

Step 1: Create a schema for a many-to-many relationship using the JOIN table

APP_USER : Contains users. A user can have multiple profiles [USER, ADMIN, DBA].
USER_PROFILE : Contains user profiles. A profile can be associated with multiple users.
APP_USER_USER_PROFILE : This is a join table that links the APP_USER and USER_PROFILE tables with a many-to-many relationship.

For demonstration purposes, we will discuss the many-to-many relationship in a unidirectional setting [user with user profile] in this example.

Creating tables and adding data

 create table APP_USER ( id BIGINT NOT NULL AUTO_INCREMENT, sso_id VARCHAR(30) NOT NULL, password VARCHAR(100) NOT NULL, first_name VARCHAR(30) NOT NULL, last_name VARCHAR(30) NOT NULL, email VARCHAR(30) NOT NULL, PRIMARY KEY (id), UNIQUE (sso_id) ); create table USER_PROFILE( id BIGINT NOT NULL AUTO_INCREMENT, type VARCHAR(30) NOT NULL, PRIMARY KEY (id), UNIQUE (type) ); CREATE TABLE APP_USER_USER_PROFILE ( user_id BIGINT NOT NULL, user_profile_id BIGINT NOT NULL, PRIMARY KEY (user_id, user_profile_id), CONSTRAINT FK_APP_USER FOREIGN KEY (user_id) REFERENCES APP_USER (id), CONSTRAINT FK_USER_PROFILE FOREIGN KEY (user_profile_id) REFERENCES USER_PROFILE (id) ); /* Populate USER_PROFILE Table */ INSERT INTO USER_PROFILE(type) VALUES ('USER'); INSERT INTO USER_PROFILE(type) VALUES ('ADMIN'); INSERT INTO USER_PROFILE(type) VALUES ('DBA'); commit;

Step 2: Create the directory structure

The final structure of the project will be as follows.

Step 3: Update pom.xml to enable dependencies.

pom.xml

 <project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <modelVersion>4.0.0</modelVersion> <groupId>com.websystique.springmvc</groupId> <artifactId>SpringMVCHibernateManyToManyCRUDExample</artifactId> <packaging>war</packaging> <version>1.0.0</version> <name>SpringMVCHibernateManyToManyCRUDExample</name> <properties> <springframework.version>4.1.7.RELEASE</springframework.version> <hibernate.version>4.3.10.Final</hibernate.version> <mysql.connector.version>5.1.31</mysql.connector.version> </properties> <dependencies> <!-- Spring --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>${springframework.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> <version>${springframework.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>${springframework.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-tx</artifactId> <version>${springframework.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-orm</artifactId> <version>${springframework.version}</version> </dependency> <!-- Hibernate --> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-core</artifactId> <version>${hibernate.version}</version> </dependency> <!-- jsr303 validation --> <dependency> <groupId>javax.validation</groupId> <artifactId>validation-api</artifactId> <version>1.1.0.Final</version> </dependency> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-validator</artifactId> <version>5.1.3.Final</version> </dependency> <!-- MySQL --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>${mysql.connector.version}</version> </dependency> <!-- Servlet+JSP+JSTL --> <dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>3.1.0</version> </dependency> <dependency> <groupId>javax.servlet.jsp</groupId> <artifactId>javax.servlet.jsp-api</artifactId> <version>2.3.1</version> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>jstl</artifactId> <version>1.2</version> </dependency> </dependencies> <build> <pluginManagement> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-war-plugin</artifactId> <version>2.4</version> <configuration> <warSourceDirectory>src/main/webapp</warSourceDirectory> <warName>SpringMVCHibernateManyToManyCRUDExample</warName> <failOnMissingWebXml>false</failOnMissingWebXml> </configuration> </plugin> </plugins> </pluginManagement> <finalName>SpringMVCHibernateManyToManyCRUDExample</finalName> </build> </project>

Step 4: Preparing Model Classes

User class

 package com.websystique.springmvc.model; import java.util.HashSet; import java.util.Set; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.FetchType; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.JoinColumn; import javax.persistence.JoinTable; import javax.persistence.ManyToMany; import javax.persistence.Table; import org.hibernate.validator.constraints.NotEmpty; @Entity @Table(name="APP_USER") public class User { @Id @GeneratedValue(strategy=GenerationType.IDENTITY) private Integer id; @NotEmpty @Column(name="SSO_ID", unique=true, nullable=false) private String ssoId; @NotEmpty @Column(name="PASSWORD", nullable=false) private String password; @NotEmpty @Column(name="FIRST_NAME", nullable=false) private String firstName; @NotEmpty @Column(name="LAST_NAME", nullable=false) private String lastName; @NotEmpty @Column(name="EMAIL", nullable=false) private String email; @NotEmpty @ManyToMany(fetch = FetchType.LAZY) @JoinTable(name = "APP_USER_USER_PROFILE", joinColumns = { @JoinColumn(name = "USER_ID") }, inverseJoinColumns = { @JoinColumn(name = "USER_PROFILE_ID") }) private Set<UserProfile> userProfiles = new HashSet<UserProfile>(); public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getSsoId() { return ssoId; } public void setSsoId(String ssoId) { this.ssoId = ssoId; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public Set<UserProfile> getUserProfiles() { return userProfiles; } public void setUserProfiles(Set<UserProfile> userProfiles) { this.userProfiles = userProfiles; } @Override public int hashCode() { final int prime = 31; int result = 1; result = prime * result + ((id == null) ? 0 : id.hashCode()); result = prime * result + ((ssoId == null) ? 0 : ssoId.hashCode()); return result; } @Override public boolean equals(Object obj) { if (this == obj) return true; if (obj == null) return false; if (!(obj instanceof User)) return false; User other = (User) obj; if (id == null) { if (other.id != null) return false; } else if (!id.equals(other.id)) return false; if (ssoId == null) { if (other.ssoId != null) return false; } else if (!ssoId.equals(other.ssoId)) return false; return true; } @Override public String toString() { return "User [id=" + id + ", ssoId=" + ssoId + ", password=" + password + ", firstName=" + firstName + ", lastName=" + lastName + ", email=" + email + "]"; } }

See how the userProfiles property is annotated with many-to-many.

@ManyToMany indicates that there is a many-to-many relationship between the user and the user profile. A user may have multiple profiles [USER, ADMIN, DBA], while a profile may belong to several users. @JoinTable shows that there is a reference table that joins two tables using the foreign key constraints to their primary keys. This annotation is mainly used on the side of owning relationships joinColumns refers to the column name on the owning side (user ID), and the reverse joinColumns refers to the column on the reverse side of the relationship (ID and user profile). The primary key of this connecting table is a combination of USER_ID and USER_PROFILE_ID.

"Lazy loading"

Pay particular attention to fetch = FetchType.LAZY . Here we inform Hibernate about the “lazy” loading of the userProfile collection. This behavior is basic. With such an installation, the request to download the collection will be deleted as soon as it is first applied. This is a good way to avoid retrieving all connections of objects to a graph, which is an “expensive” operation. When you are in a transaction / active session and you try to access the collection, Hibernate will separate the requests to get them.

But if you are out of an active session (for example, the session has been closed / no transactions: you are on the JSP page), and have tried to access the collection, you will encounter org.hibernate.LazyInitializationException – could not initialize proxy – no Session . To avoid this, you must initialize the on-demand collection of Hibernate.initialize(user.getUserProfiles()); calls Hibernate.initialize(user.getUserProfiles()); in active session.

Also note that we do not use cascade. This is because the user profile does not depend on the user and can exist separately.

One important note : In cases of "many" associations, always override the hashCode () and equals () methods that Hibernate observes when holding entities in a collection.

Class UserProfile

 package com.websystique.springmvc.model; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.Table; @Entity @Table(name="USER_PROFILE") public class UserProfile { @Id @GeneratedValue(strategy=GenerationType.IDENTITY) private Integer id; @Column(name="TYPE", length=15, unique=true, nullable=false) private String type = UserProfileType.USER.getUserProfileType(); public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getType() { return type; } public void setType(String type) { this.type = type; } @Override public int hashCode() { final int prime = 31; int result = 1; result = prime * result + ((id == null) ? 0 : id.hashCode()); result = prime * result + ((type == null) ? 0 : type.hashCode()); return result; } @Override public boolean equals(Object obj) { if (this == obj) return true; if (obj == null) return false; if (!(obj instanceof UserProfile)) return false; UserProfile other = (UserProfile) obj; if (id == null) { if (other.id != null) return false; } else if (!id.equals(other.id)) return false; if (type == null) { if (other.type != null) return false; } else if (!type.equals(other.type)) return false; return true; } @Override public String toString() { return "UserProfile [id=" + id + ", type=" + type + "]"; } }

Since we show a one-way relationship (user to user profile), there is no need to refer to the user in the user profile.

UserProfileType

 package com.websystique.springmvc.model; public enum UserProfileType { USER("USER"), DBA("DBA"), ADMIN("ADMIN"); String userProfileType; private UserProfileType(String userProfileType){ this.userProfileType = userProfileType; } public String getUserProfileType(){ return userProfileType; } }

Step 5: Creating the DAO Layer

UserDao interface

 package com.websystique.springmvc.dao; import java.util.List; import com.websystique.springmvc.model.User; public interface UserDao { User findById(int id); User findBySSO(String sso); void save(User user); void deleteBySSO(String sso); List<User> findAllUsers(); }

UserProfileDao interface

 package com.websystique.springmvc.dao; import java.util.List; import com.websystique.springmvc.model.UserProfile; public interface UserProfileDao { List<UserProfile> findAll(); UserProfile findByType(String type); UserProfile findById(int id); }

Abstract class AbstractDao

 package com.websystique.springmvc.dao; import java.io.Serializable; import java.lang.reflect.ParameterizedType; import org.hibernate.Criteria; import org.hibernate.Session; import org.hibernate.SessionFactory; import org.springframework.beans.factory.annotation.Autowired; public abstract class AbstractDao<PK extends Serializable, T> { private final Class<T> persistentClass; @SuppressWarnings("unchecked") public AbstractDao(){ this.persistentClass =(Class<T>) ((ParameterizedType) this.getClass().getGenericSuperclass ()).getActualTypeArguments()[1]; } @Autowired private SessionFactory sessionFactory; protected Session getSession(){ return sessionFactory.getCurrentSession(); } @SuppressWarnings("unchecked") public T getByKey(PK key) { return (T) getSession().get(persistentClass, key); } public void persist(T entity) { getSession().persist(entity); } public void delete(T entity) { getSession().delete(entity); } protected Criteria createEntityCriteria(){ return getSession().createCriteria(persistentClass); } }

Class UserDaoImpl

 package com.websystique.springmvc.dao; import java.util.List; import org.hibernate.Criteria; import org.hibernate.Hibernate; import org.hibernate.criterion.Order; import org.hibernate.criterion.Restrictions; import org.springframework.stereotype.Repository; import com.websystique.springmvc.model.User; @Repository("userDao") public class UserDaoImpl extends AbstractDao<Integer, User> implements UserDao { public User findById(int id) { User user = getByKey(id); if(user!=null){ Hibernate.initialize(user.getUserProfiles()); } return user; } public User findBySSO(String sso) { System.out.println("SSO : "+sso); Criteria crit = createEntityCriteria(); crit.add(Restrictions.eq("ssoId", sso)); User user = (User)crit.uniqueResult(); if(user!=null){ Hibernate.initialize(user.getUserProfiles()); } return user; } @SuppressWarnings("unchecked") public List<User> findAllUsers() { Criteria criteria = createEntityCriteria().addOrder(Order.asc("firstName")); criteria.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY);//To avoid duplicates. List<User> users = (List<User>) criteria.list(); return users; } public void save(User user) { persist(user); } public void deleteBySSO(String sso) { Criteria crit = createEntityCriteria(); crit.add(Restrictions.eq("ssoId", sso)); User user = (User)crit.uniqueResult(); delete(user); } }

Class UserProfileDaoImpl

 package com.websystique.springmvc.dao; import java.util.List; import org.hibernate.Criteria; import org.hibernate.criterion.Order; import org.hibernate.criterion.Restrictions; import org.springframework.stereotype.Repository; import com.websystique.springmvc.model.UserProfile; @Repository("userProfileDao") public class UserProfileDaoImpl extends AbstractDao<Integer, UserProfile>implements UserProfileDao{ public UserProfile findById(int id) { return getByKey(id); } public UserProfile findByType(String type) { Criteria crit = createEntityCriteria(); crit.add(Restrictions.eq("type", type)); return (UserProfile) crit.uniqueResult(); } @SuppressWarnings("unchecked") public List<UserProfile> findAll(){ Criteria crit = createEntityCriteria(); crit.addOrder(Order.asc("type")); return (List<UserProfile>)crit.list(); } }

Step 6: Create Service Layer

UserProfileService interface

 package com.websystique.springmvc.service; import java.util.List; import com.websystique.springmvc.model.UserProfile; public interface UserProfileService { UserProfile findById(int id); UserProfile findByType(String type); List<UserProfile> findAll(); }

UserService interface

 package com.websystique.springmvc.service; import java.util.List; import com.websystique.springmvc.model.User; public interface UserService { User findById(int id); User findBySSO(String sso); void saveUser(User user); void updateUser(User user); void deleteUserBySSO(String sso); List<User> findAllUsers(); boolean isUserSSOUnique(Integer id, String sso); }

Class UserProfileServiceImpl

 package com.websystique.springmvc.service; import java.util.List; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import org.springframework.transaction.annotation.Transactional; import com.websystique.springmvc.dao.UserProfileDao; import com.websystique.springmvc.model.UserProfile; @Service("userProfileService") @Transactional public class UserProfileServiceImpl implements UserProfileService{ @Autowired UserProfileDao dao; public UserProfile findById(int id) { return dao.findById(id); } public UserProfile findByType(String type){ return dao.findByType(type); } public List<UserProfile> findAll() { return dao.findAll(); } }

Class UserServiceImpl

 package com.websystique.springmvc.service; import java.util.List; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import org.springframework.transaction.annotation.Transactional; import com.websystique.springmvc.dao.UserDao; import com.websystique.springmvc.model.User; @Service("userService") @Transactional public class UserServiceImpl implements UserService{ @Autowired private UserDao dao; public User findById(int id) { return dao.findById(id); } public User findBySSO(String sso) { User user = dao.findBySSO(sso); return user; } public void saveUser(User user) { dao.save(user); } /* * Since the method is running with Transaction, No need to call hibernate update explicitly. * Just fetch the entity from db and update it with proper values within transaction. * It will be updated in db once transaction ends. */ public void updateUser(User user) { User entity = dao.findById(user.getId()); if(entity!=null){ entity.setSsoId(user.getSsoId()); entity.setPassword(user.getPassword()); entity.setFirstName(user.getFirstName()); entity.setLastName(user.getLastName()); entity.setEmail(user.getEmail()); entity.setUserProfiles(user.getUserProfiles()); } } public void deleteUserBySSO(String sso) { dao.deleteBySSO(sso); } public List<User> findAllUsers() { return dao.findAllUsers(); } public boolean isUserSSOUnique(Integer id, String sso) { User user = findBySSO(sso); return ( user == null || ((id != null) && (user.getId() == id))); } }

Step 7: Create Hibernate Settings

HibernateConfiguration class

 package com.websystique.springmvc.configuration; import java.util.Properties; import javax.sql.DataSource; import org.hibernate.SessionFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.ComponentScan; import org.springframework.context.annotation.Configuration; import org.springframework.context.annotation.PropertySource; import org.springframework.core.env.Environment; import org.springframework.jdbc.datasource.DriverManagerDataSource; import org.springframework.orm.hibernate4.HibernateTransactionManager; import org.springframework.orm.hibernate4.LocalSessionFactoryBean; import org.springframework.transaction.annotation.EnableTransactionManagement; @Configuration @EnableTransactionManagement @ComponentScan({ "com.websystique.springmvc.configuration" }) @PropertySource(value = { "classpath:application.properties" }) public class HibernateConfiguration { @Autowired private Environment environment; @Bean public LocalSessionFactoryBean sessionFactory() { LocalSessionFactoryBean sessionFactory = new LocalSessionFactoryBean(); sessionFactory.setDataSource(dataSource()); sessionFactory.setPackagesToScan(new String[] { "com.websystique.springmvc.model" }); sessionFactory.setHibernateProperties(hibernateProperties()); return sessionFactory; } @Bean public DataSource dataSource() { DriverManagerDataSource dataSource = new DriverManagerDataSource(); dataSource.setDriverClassName(environment.getRequiredProperty("jdbc.driverClassName")); dataSource.setUrl(environment.getRequiredProperty("jdbc.url")); dataSource.setUsername(environment.getRequiredProperty("jdbc.username")); dataSource.setPassword(environment.getRequiredProperty("jdbc.password")); return dataSource; } private Properties hibernateProperties() { Properties properties = new Properties(); properties.put("hibernate.dialect", environment.getRequiredProperty("hibernate.dialect")); properties.put("hibernate.show_sql", environment.getRequiredProperty("hibernate.show_sql")); properties.put("hibernate.format_sql", environment.getRequiredProperty("hibernate.format_sql")); return properties; } @Bean @Autowired public HibernateTransactionManager transactionManager(SessionFactory s) { HibernateTransactionManager txManager = new HibernateTransactionManager(); txManager.setSessionFactory(s); return txManager; } }

Settings for Hibernate:

jdbc.driverClassName = com.mysql.jdbc.Driver
jdbc.url = jdbc:mysql://localhost:3306/
jdbc.username =
jdbc.password =
hibernate.dialect = org.hibernate.dialect.MySQLDialect
hibernate.show_sql = true
hibernate.format_sql = true

Step 8: Creating the Controller

Class AppController

 package com.websystique.springmvc.controller; import java.util.List; import java.util.Locale; import javax.validation.Valid; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.context.MessageSource; import org.springframework.stereotype.Controller; import org.springframework.ui.ModelMap; import org.springframework.validation.BindingResult; import org.springframework.validation.FieldError; import org.springframework.web.bind.annotation.ModelAttribute; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.SessionAttributes; import com.websystique.springmvc.model.User; import com.websystique.springmvc.model.UserProfile; import com.websystique.springmvc.service.UserProfileService; import com.websystique.springmvc.service.UserService; @Controller @RequestMapping("/") @SessionAttributes("roles") public class AppController { @Autowired UserService userService; @Autowired UserProfileService userProfileService; @Autowired MessageSource messageSource; /** * This method will list all existing users. */ @RequestMapping(value = { "/", "/list" }, method = RequestMethod.GET) public String listUsers(ModelMap model) { List<User> users = userService.findAllUsers(); model.addAttribute("users", users); return "userslist"; } /** * This method will provide the medium to add a new user. */ @RequestMapping(value = { "/newuser" }, method = RequestMethod.GET) public String newUser(ModelMap model) { User user = new User(); model.addAttribute("user", user); model.addAttribute("edit", false); return "registration"; } /** * This method will be called on form submission, handling POST request for * saving user in database. It also validates the user input */ @RequestMapping(value = { "/newuser" }, method = RequestMethod.POST) public String saveUser(@Valid User user, BindingResult result, ModelMap model) { if (result.hasErrors()) { return "registration"; } /* * Preferred way to achieve uniqueness of field [sso] should be implementing custom @Unique annotation * and applying it on field [sso] of Model class [User]. * * Below mentioned peace of code [if block] is to demonstrate that you can fill custom errors outside the validation * framework as well while still using internationalized messages. * */ if(!userService.isUserSSOUnique(user.getId(), user.getSsoId())){ FieldError ssoError =new FieldError("user","ssoId",messageSource.getMessage("non.unique.ssoId", new String[]{user.getSsoId()}, Locale.getDefault())); result.addError(ssoError); return "registration"; } userService.saveUser(user); model.addAttribute("success", "User " + user.getFirstName() + " "+ user.getLastName() + " registered successfully"); //return "success"; return "registrationsuccess"; } /** * This method will provide the medium to update an existing user. */ @RequestMapping(value = { "/edit-user-{ssoId}" }, method = RequestMethod.GET) public String editUser(@PathVariable String ssoId, ModelMap model) { User user = userService.findBySSO(ssoId); model.addAttribute("user", user); model.addAttribute("edit", true); return "registration"; } /** * This method will be called on form submission, handling POST request for * updating user in database. It also validates the user input */ @RequestMapping(value = { "/edit-user-{ssoId}" }, method = RequestMethod.POST) public String updateUser(@Valid User user, BindingResult result, ModelMap model, @PathVariable String ssoId) { if (result.hasErrors()) { return "registration"; } /*//Uncomment below 'if block' if you WANT TO ALLOW UPDATING SSO_ID in UI which is a unique key to a User. if(!userService.isUserSSOUnique(user.getId(), user.getSsoId())){ FieldError ssoError =new FieldError("user","ssoId",messageSource.getMessage("non.unique.ssoId", new String[]{user.getSsoId()}, Locale.getDefault())); result.addError(ssoError); return "registration"; }*/ userService.updateUser(user); model.addAttribute("success", "User " + user.getFirstName() + " "+ user.getLastName() + " updated successfully"); return "registrationsuccess"; } /** * This method will delete an user by it's SSOID value. */ @RequestMapping(value = { "/delete-user-{ssoId}" }, method = RequestMethod.GET) public String deleteUser(@PathVariable String ssoId) { userService.deleteUserBySSO(ssoId); return "redirect:/list"; } /** * This method will provide UserProfile list to views */ @ModelAttribute("roles") public List<UserProfile> initializeProfiles() { return userProfileService.findAll(); } }

The messages that are used above are described in the messages.properties file:

NotEmpty.user.firstName= .
NotEmpty.user.lastName= .
NotEmpty.user.email= .
NotEmpty.user.password= .
NotEmpty.user.ssoId= SSO ID .
NotEmpty.user.userProfiles= .
non.unique.ssoId=SSO ID {0} . , .

Step 9: Creating a Converter

This heart is a post. This takes care of mapping individual user profile IDs to actual user profile entities in the database.

Class RoleToUserProfileConverter

 package com.websystique.springmvc.converter; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.core.convert.converter.Converter; import org.springframework.stereotype.Component; import com.websystique.springmvc.model.UserProfile; import com.websystique.springmvc.service.UserProfileService; /** * A converter class used in views to map id's to actual userProfile objects. */ @Component public class RoleToUserProfileConverter implements Converter<Object, UserProfile>{ @Autowired UserProfileService userProfileService; /** * Gets UserProfile by Id * @see org.springframework.core.convert.converter.Converter#convert(java.lang.Object) */ public UserProfile convert(Object element) { Integer id = Integer.parseInt((String)element); UserProfile profile= userProfileService.findById(id); System.out.println("Profile : "+profile); return profile; } }

Step 10: Creating Spring Settings

AppConfig class

 package com.websystique.springmvc.configuration; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.context.MessageSource; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.ComponentScan; import org.springframework.context.annotation.Configuration; import org.springframework.context.support.ResourceBundleMessageSource; import org.springframework.format.FormatterRegistry; import org.springframework.web.servlet.config.annotation.EnableWebMvc; import org.springframework.web.servlet.config.annotation.PathMatchConfigurer; import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry; import org.springframework.web.servlet.config.annotation.ViewResolverRegistry; import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter; import org.springframework.web.servlet.view.InternalResourceViewResolver; import org.springframework.web.servlet.view.JstlView; import com.websystique.springmvc.converter.RoleToUserProfileConverter; @Configuration @EnableWebMvc @ComponentScan(basePackages = "com.websystique.springmvc") public class AppConfig extends WebMvcConfigurerAdapter{ @Autowired RoleToUserProfileConverter roleToUserProfileConverter; /** * Configure ViewResolvers to deliver preferred views. */ @Override public void configureViewResolvers(ViewResolverRegistry registry) { InternalResourceViewResolver viewResolver = new InternalResourceViewResolver(); viewResolver.setViewClass(JstlView.class); viewResolver.setPrefix("/WEB-INF/views/"); viewResolver.setSuffix(".jsp"); registry.viewResolver(viewResolver); } /** * Configure ResourceHandlers to serve static resources like CSS/ Javascript etc... */ @Override public void addResourceHandlers(ResourceHandlerRegistry registry) { registry.addResourceHandler("/static/**").addResourceLocations("/static/"); } /** * Configure Converter to be used. * In our example, we need a converter to convert string values[Roles] to UserProfiles in newUser.jsp */ @Override public void addFormatters(FormatterRegistry registry) { registry.addConverter(roleToUserProfileConverter); } /** * Configure MessageSource to lookup any validation/error message in internationalized property files */ @Bean public MessageSource messageSource() { ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource(); messageSource.setBasename("messages"); return messageSource; } /**Optional. It's only required when handling '.' in @PathVariables which otherwise ignore everything after last '.' in @PathVaidables argument. * It's a known bug in Spring [https://jira.spring.io/browse/SPR-6164], still present in Spring 4.1.7. * This is a workaround for this issue. */ @Override public void configurePathMatch(PathMatchConfigurer matcher) { matcher.setUseRegisteredSuffixPatternMatch(true); } }

First of all, the interesting thing is the registration converter that we created in previous lessons with configuring Spring using addFormatters . The following configurePathMatch method that provides a workaround (although there are other workarounds) for the well-known bug in Spring, which is also present in Spring 4.1.7.RELEASE.

Installing the converter in the XML configuration will look like this:

 <mvc:annotation-driven conversion-service="conversionService"/> <bean id="conversionService" class="org.springframework.format.support.FormattingConversionServiceFactoryBean"> <property name="converters"> <list> <bean id="roleToUserProfile" class="com.websystique.springsecurity.configuration.RoleToUserProfileConverter" /> </list> </property> </bean>

Add an initializing class:

 package com.websystique.springmvc.configuration; import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer; public class AppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer { @Override protected Class<?>[] getRootConfigClasses() { return new Class[] { AppConfig.class }; } @Override protected Class<?>[] getServletConfigClasses() { return null; } @Override protected String[] getServletMappings() { return new String[] { "/" }; } }

11: /JSP

, Bootstrap JSP.

userslist.jsp

 <%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%> <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Users List</title> <link href="<c:url value='/static/css/bootstrap.css' />" rel="stylesheet"></link> <link href="<c:url value='/static/css/app.css' />" rel="stylesheet"></link> </head> <body> <div class="generic-container"> <div class="panel panel-default"> <!-- Default panel contents --> <div class="panel-heading"><span class="lead">List of Users </span></div> <table class="table table-hover"> <thead> <tr> <th>Firstname</th> <th>Lastname</th> <th>Email</th> <th>SSO ID</th> <th width="100"></th> <th width="100"></th> </tr> </thead> <tbody> <c:forEach items="${users}" var="user"> <tr> <td>${user.firstName}</td> <td>${user.lastName}</td> <td>${user.email}</td> <td>${user.ssoId}</td> <td><a href="<c:url value='/edit-user-${user.ssoId}' />" class="btn btn-success custom-width">edit</a></td> <td><a href="<c:url value='/delete-user-${user.ssoId}' />" class="btn btn-danger custom-width">delete</a></td> </tr> </c:forEach> </tbody> </table> </div> <div class="well"> <a href="<c:url value='/newuser' />">Add New User</a> </div> </div> </body> </html>

registration.jsp

 <%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%> <%@ taglib prefix="form" uri="http://www.springframework.org/tags/form"%> <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>User Registration Form</title> <link href="<c:url value='/static/css/bootstrap.css' />" rel="stylesheet"></link> <link href="<c:url value='/static/css/app.css' />" rel="stylesheet"></link> </head> <body> <div class="generic-container"> <div class="well lead">User Registration Form</div> <form:form method="POST" modelAttribute="user" class="form-horizontal"> <form:input type="hidden" path="id" id="id"/> <div class="row"> <div class="form-group col-md-12"> <label class="col-md-3 control-lable" for="firstName">First Name</label> <div class="col-md-7"> <form:input type="text" path="firstName" id="firstName" class="form-control input-sm"/> <div class="has-error"> <form:errors path="firstName" class="help-inline"/> </div> </div> </div> </div> <div class="row"> <div class="form-group col-md-12"> <label class="col-md-3 control-lable" for="lastName">Last Name</label> <div class="col-md-7"> <form:input type="text" path="lastName" id="lastName" class="form-control input-sm" /> <div class="has-error"> <form:errors path="lastName" class="help-inline"/> </div> </div> </div> </div> <div class="row"> <div class="form-group col-md-12"> <label class="col-md-3 control-lable" for="ssoId">SSO ID</label> <div class="col-md-7"> <c:choose> <c:when test="${edit}"> <form:input type="text" path="ssoId" id="ssoId" class="form-control input-sm" disabled="true"/> </c:when> <c:otherwise> <form:input type="text" path="ssoId" id="ssoId" class="form-control input-sm" /> <div class="has-error"> <form:errors path="ssoId" class="help-inline"/> </div> </c:otherwise> </c:choose> </div> </div> </div> <div class="row"> <div class="form-group col-md-12"> <label class="col-md-3 control-lable" for="password">Password</label> <div class="col-md-7"> <form:input type="password" path="password" id="password" class="form-control input-sm" /> <div class="has-error"> <form:errors path="password" class="help-inline"/> </div> </div> </div> </div> <div class="row"> <div class="form-group col-md-12"> <label class="col-md-3 control-lable" for="email">Email</label> <div class="col-md-7"> <form:input type="text" path="email" id="email" class="form-control input-sm" /> <div class="has-error"> <form:errors path="email" class="help-inline"/> </div> </div> </div> </div> <div class="row"> <div class="form-group col-md-12"> <label class="col-md-3 control-lable" for="userProfiles">Roles</label> <div class="col-md-7"> <form:select path="userProfiles" items="${roles}" multiple="true" itemValue="id" itemLabel="type" class="form-control input-sm" /> <div class="has-error"> <form:errors path="userProfiles" class="help-inline"/> </div> </div> </div> </div> <div class="row"> <div class="form-actions floatRight"> <c:choose> <c:when test="${edit}"> <input type="submit" value="Update" class="btn btn-primary btn-sm"/> or <a href="<c:url value='/list' />">Cancel</a> </c:when> <c:otherwise> <input type="submit" value="Register" class="btn btn-primary btn-sm"/> or <a href="<c:url value='/list' />">Cancel</a> </c:otherwise> </c:choose> </div> </div> </form:form> </div> </body> </html>

registrationsuccess.jsp

 <%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%> <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Registration Confirmation Page</title> <link href="<c:url value='/static/css/bootstrap.css' />" rel="stylesheet"></link> <link href="<c:url value='/static/css/app.css' />" rel="stylesheet"></link> </head> <body> <div class="generic-container"> <div class="alert alert-success lead"> ${success} </div> <span class="well floatRight"> Go to <a href="<c:url value='/list' />">Users List</a> </span> </div> </body> </html>

:

app.css

 body, #mainWrapper { height: 100%; background-color:rgb(245, 245, 245); } body, .form-control{ font-size:12px!important; } .floatRight{ float:right; margin-right: 18px; } .has-error{ color:red; } .generic-container { position:fixed; width:80%; margin-left: 20px; margin-top: 20px; margin-bottom: 20px; padding: 20px; background-color: #EAE7E7; border: 1px solid #ddd; border-radius: 4px; box-shadow: 0 0 30px black; } .custom-width { width: 80px !important; }