The last post outlined how to use Spring MVC to kick-start a RESTful web-services application. This post will build upon what we learned from last lesson by building persistence mechanism using Spring Data JPA. Download the code of this project from Github.
WHAT TECHNOLOGIES WILL BE USED?
- MySQL
- Spring Data JPA
- BoneCP (JDBC Connection Pool)
- Hibernate (as JPA Vendor)
- Ehcache
DEPendancies
In Persistence/pom.xml we will need to add the dependancies required for Spring Data JPA.
4.3.5.Final
org.springframework.boot
spring-boot-starter-data-jpa
1.8.1.RELEASE
org.hibernate
hibernate-entitymanager
${hibernate}
org.hibernate
hibernate-ehcache
${hibernate}
net.sf.ehcache
ehcache-core
net.sf.ehcache
ehcache
2.7.0
mysql
mysql-connector-java
5.1.22
runtime
com.jolbox
bonecp
0.7.1.RELEASE
Now, what did all that mean? These dependancies instruct the application to use:
- Spring Data JPA module.
- Hibernate as JPA vendor. The usage of HibernateJpaVendorAdapter ensure that our application will not require persistence.xml among many other benefits like support for supports the detection of annotated packages
- Hibernate Ehcache module but excludes the core module as hibernate uses version and no Ehcache has newer versions
- BoneCP as connection pool, I personally find it fast. However, it seems that the project is discontinued. So, it may be time to think about an alternative Maybe Tomcat JDBC.
- mysql database (You may delete this dependancy and place the connector in <%CATALINA_HOME%>/lib)
Configuration
To configure Spring in persistence we will need to define a new java config file, and register this config class to root context in com.coffeebeans.initializer.WebAppInitializer
Config Class
package com.coffeebeans.config;
import com.coffeebeans.utils.Constants;
import com.jolbox.bonecp.BoneCPDataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import org.springframework.core.env.Environment;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.JpaVendorAdapter;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import javax.persistence.EntityManagerFactory;
import javax.sql.DataSource;
import java.util.Properties;
/**
* Created by muhamadto on 12/07/2015.
*/
@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(basePackages = "com.coffeebeans.repository")
@PropertySource("classpath:default.properties")
public class PersistenceConfig {
@Autowired
Environment env;
@Bean(destroyMethod = "close")
public DataSource dataSource() {
BoneCPDataSource dataSource = new BoneCPDataSource();
dataSource.setJdbcUrl(System.getProperty(Constants.DB_URL, Constants.LOCALHOST));
dataSource.setUsername(System.getProperty(Constants.DB_USERNAME));
dataSource.setPassword(System.getProperty(Constants.DB_PASSWORD));
dataSource.setIdleConnectionTestPeriodInMinutes(Integer.parseInt(env.getProperty(Constants.BONECP_IDLE_CONNECTION_TEST_PERIOD_IN_MINUTES)));
dataSource.setIdleMaxAgeInMinutes(Integer.parseInt(env.getProperty(Constants.BONECP_IDLE_MAX_AGE_IN_MINUTES)));
dataSource.setMaxConnectionsPerPartition(Integer.parseInt(env.getProperty(Constants.BONECP_MAX_CONNECTIONS_PER_PARTITION)));
dataSource.setMinConnectionsPerPartition(Integer.parseInt(env.getProperty(Constants.BONECP_MIN_CONNECTIONS_PER_PARTITION)));
dataSource.setPartitionCount(Integer.parseInt(env.getProperty(Constants.BONECP_PARTITION_COUNT)));
dataSource.setAcquireIncrement(Integer.parseInt(env.getProperty(Constants.BONECP_ACQUIRE_INCREMENT))) ;
dataSource.setStatementsCacheSize( Integer.parseInt(env.getProperty(Constants.BONECP_STATEMENTS_CACHE_SIZE)));
return dataSource;
}
@Bean
public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
em.setDataSource(dataSource());
em.setPackagesToScan(env.getProperty(Constants.COFFEEBEANS_MODEL_PACKAGE));
JpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
em.setJpaVendorAdapter(vendorAdapter);
em.setJpaProperties(additionalProperties());
return em;
}
@Bean
public PlatformTransactionManager transactionManager(EntityManagerFactory emf){
JpaTransactionManager transactionManager = new JpaTransactionManager();
transactionManager.setEntityManagerFactory(emf);
return transactionManager;
}
private Properties additionalProperties() {
Properties prop = new Properties();
prop.setProperty(Constants.HIBERNATE_CACHE_USE_SECOND_LEVEL_CACHE, env.getProperty(Constants.HIBERNATE_CACHE_USE_SECOND_LEVEL_CACHE));
prop.setProperty(Constants.HIBERNATE_CACHE_REGION_FACTORY_CLASS, env.getProperty(Constants.HIBERNATE_CACHE_REGION_FACTORY_CLASS));
prop.setProperty(Constants.HIBERNATE_CACHE_USE_QUERY_CACHE, env.getProperty(Constants.HIBERNATE_CACHE_USE_QUERY_CACHE));
prop.setProperty(Constants.HIBERNATE_GENERATE_STATISTICS, env.getProperty(Constants.HIBERNATE_DIALECT));
prop.setProperty(Constants.HIBERNATE_DIALECT, env.getProperty(Constants.HIBERNATE_DIALECT));
return prop;
}
}
Notice that DB_URL, DB_USERNAME, and DB_PASSWORD are jvm variables
Register The Config Class With The Root Context
In com.coffeebeans.initializer.WebAppInitializer change onStartUp
@Override
public void onStartup(ServletContext servletContext) throws ServletException {
AnnotationConfigWebApplicationContext rootContext = new AnnotationConfigWebApplicationContext();
rootContext.register(ServicesConfig.class,PersistenceConfig.class);
servletContext.addListener(new ContextLoaderListener(rootContext));
AnnotationConfigWebApplicationContext dispatcherServlet = new AnnotationConfigWebApplicationContext();
dispatcherServlet.register(MvcConfig.class);
ServletRegistration.Dynamic dispatcher = servletContext.addServlet("mvc-dispatcher", new DispatcherServlet(dispatcherServlet));
dispatcher.setLoadOnStartup(1);
dispatcher.addMapping("/1/*");
FilterRegistration charEncodingFilterReg = servletContext.addFilter("CharacterEncodingFilter", CharacterEncodingFilter.class);
charEncodingFilterReg.setInitParameter("encoding", "UTF-8");
charEncodingFilterReg.setInitParameter("forceEncoding", "true");
charEncodingFilterReg.addMappingForUrlPatterns(EnumSet.allOf(DispatcherType.class), false, "/*");
}
PersistenceConfig is annotated with:
- org.springframework.context.annotation.Configuration, which signals that this class is a Spring config class
- org.springframework.transaction.annotation.EnableTransactionManagement, to enable Spring's annotation-driven transaction management capability, similar to the support found in Spring's <tx:*> XML namespace
- org.springframework.data.jpa.repository.config.EnableJpaRepositories, to enable and activate Spring Data JPA repositories as the name suggests and to provide information on which base package will contain the repositories, in our example basePackages = "com.coffeebeans.repository".If no base package is configured it will use the one the configuration class resides in. In other work, Spring will scan for JPA repositories in the provided package to sire them later in a client that might depend on them.
- org.springframework.context.annotation.PropertySource, declarative way for adding properties to Spring environment. In our case these properties define in default.properties file.
It defines the following beans:
- DataSource bean of type BoneCPDataSource. It uses a connection pool to the data base. In this example we use DB url, username and password. In a production environment it would be better to create a data source in the container (e.g. tomcat -> contaxt.xml) and look it up using JNDI. However, this will need web.xml to be define because Servlet 3 Java API does not have replacement for <resource-ref/>.
- EntityManagerFactory bean of type LocalContainerEntityManagerFactoryBean. It creates JPA EntityManagerFactory and provide ability to pass it to JPA-based DAOs using dependancy injection. This FactoryBean is more flexible in that you can override the location of the
persistence.xml
file. However, in Spring 4 we can instruct the code to use Spring-based scanning for entity classes in the classpath instead of JPA's approach which uses persistence.xml. This can be done by calling setPackagesToScan() on the LocalContainerEntityManagerFactoryBean.
- TransactionManager bean of type PlatformTransactionManager, for controlling transactions.
Remember default.properties?! Here's it. In Persistence module add default.properties in src/main/resources
################### DataSource Configuration ##########################
jdbc.driverClass=com.mysql.jdbc.Driver
jdbc.dataSource=java:comp/env/jdbc/Rest
init-db=false
################### Hibernate Configuration ##########################
hibernate.show_sql=false
hibernate.hbm2ddl.auto=update
hibernate.generateDdl=false
hibernate.cache.use_second_level_cache=true
hibernate.cache.region.factory_class=org.hibernate.cache.ehcache.EhCacheRegionFactory
hibernate.cache.use_query_cache=true
hibernate.generate_statistics=true
hibernate.dialect=org.hibernate.dialect.MySQL5Dialect
############################### BoneCP ##############################
bonecp.driverClass=com.mysql.jdbc.Driver
bonecp.dataSource=java:comp/env/jdbc/Rest
bonecp.idleMaxAgeInMinutes=240
bonecp.idleConnectionTestPeriodInMinutes=60
bonecp.maxConnectionsPerPartition=10
bonecp.minConnectionsPerPartition=1
bonecp.partitionCount=2
bonecp.acquireIncrement=5
bonecp.statementsCacheSize=100
############################ Persistence ###########################
repository.package=com.coffeebeans.repository
model.package=com.coffeebeans.domain.model
and add com.coffeebeans.utils.Constants, to define the identifiers of the properties as java constants.
package com.coffeebeans.utils;
/**
* Created by muhamadto on 12/07/2015.
*/
public class Constants {
public static final String COFFEEBEANS_REPOSITORY_PACKAGE = "repository.package";
public static final String COFFEEBEANS_MODEL_PACKAGE = "model.package";
public static final String LOCALHOST = "localhost";
public static final String JDBC_DRIVER_CLASS = "jdbc.driverClass";
public static final String DB_URL = "DB_URL";
public static final String DB_USERNAME = "DB_USERNAME";
public static final String DB_PASSWORD = "DB_PASSWORD";
public static final String BONECP_IDLE_CONNECTION_TEST_PERIOD_IN_MINUTES = "bonecp.idleConnectionTestPeriodInMinutes";
public static final String BONECP_IDLE_MAX_AGE_IN_MINUTES = "bonecp.idleMaxAgeInMinutes";
public static final String BONECP_MAX_CONNECTIONS_PER_PARTITION = "bonecp.maxConnectionsPerPartition";
public static final String BONECP_MIN_CONNECTIONS_PER_PARTITION = "bonecp.minConnectionsPerPartition";
public static final String BONECP_PARTITION_COUNT = "bonecp.partitionCount";
public static final String BONECP_ACQUIRE_INCREMENT = "bonecp.acquireIncrement";
public static final String BONECP_STATEMENTS_CACHE_SIZE = "bonecp.statementsCacheSize";
public static final String HIBERNATE_CACHE_USE_SECOND_LEVEL_CACHE = "hibernate.cache.use_second_level_cache";
public static final String HIBERNATE_CACHE_REGION_FACTORY_CLASS = "hibernate.cache.region.factory_class";
public static final String HIBERNATE_CACHE_USE_QUERY_CACHE = "hibernate.cache.use_query_cache";
public static final String HIBERNATE_GENERATE_STATISTICS = "hibernate.generate_statistics";
public static final String HIBERNATE_DIALECT = "hibernate.dialect";
}
By registering PersistenceConfig with rootContext in com.coffeebeans.initializer.WebAppInitializer#onStartup(), Spring Data JPA is component is fully configured. Now, lets add entities and repositories.
Entity Classes
Entity class are in com.coffeebeans.domain.model package as we previously specified using LocalContainerEntityManagerFactoryBean#setPackagesToScan() in com.coffeebeans.config.PersistenceConfig.
Define a super class for entity classes
import lombok.Data;
import org.springframework.data.annotation.CreatedDate;
import org.springframework.data.annotation.LastModifiedDate;
import org.springframework.data.jpa.domain.AbstractPersistable;
import org.springframework.util.Assert;
import javax.persistence.*;
import java.util.Date;
import java.util.UUID;
/**
* Created by muhamadto on 12/07/2015.
*/
@MappedSuperclass
@Data
public class DomainObject extends AbstractPersistable <long > {
@Version
protected int version;
@Column(length = 36, unique = true, nullable = false)
protected String uuid;
@CreatedDate
protected Date insertDate;
@LastModifiedDate
protected Date lastModified;
public DomainObject() {
this(UUID.randomUUID());
}
public DomainObject(UUID uuid) {
Assert.notNull(uuid, "UUID is required");
this.uuid = uuid.toString();
this.insertDate = new Date();
}
}
Let's inspect this class closely:
- DomainObject class inherts from org.springframework.data.jpa.domain.AbstractPersistable which ultimitly inherets Serializable and add mapping for id property.
- DomainObject class is annotate with javax.persistence.MappedSuperclass, which means
that the mappings for its fields apply only to its subclasses.
Another annotation also is
lombok.Data, This saves us from writing boilerplate code for setters, getters, default constructor, ... etc.
- It contains the general fields that all entity classes must have, like inserDate, id (which it inherits from AbstractPersistable) and version.
Define User entity class
package com.coffeebeans.domain.model.user;
import com.coffeebeans.domain.model.base.DomainObject;
import com.coffeebeans.domain.request.user.UserSignupRequest;
import lombok.Data;
import org.hibernate.annotations.CacheConcurrencyStrategy;
import org.hibernate.annotations.Type;
import org.hibernate.annotations.Cache;
import javax.persistence.*;
import java.util.UUID;
/**
* Created by mohamedhamtou on 28/12/14.
*/
@Entity
@Table(name="USER")
@Cache(usage = CacheConcurrencyStrategy.READ_WRITE, region = "user")
@Data
public class User extends DomainObject {
@Column(length = 36, unique = true, nullable = false)
protected String username;
@Column(length = 36, unique = true, nullable = false)
protected String email;
@Column(length = 16, nullable = false)
protected String password;
@Type(type = "numeric_boolean")
protected boolean enabled;
@Type(type = "numeric_boolean")
protected boolean verified = false;
@Enumerated(EnumType.STRING)
protected Role role;
public User() {
this(UUID.randomUUID());
}
public User(UUID uuid) {
super(uuid);
}
public User(String username, String email, String encryptedPassword) {
super(UUID.randomUUID());
this.username = username.toLowerCase();
this.email = email.toLowerCase();
this.password = encryptedPassword;
}
public User(UserSignupRequest userSignupRequest) {
super(UUID.randomUUID());
this.username = userSignupRequest.getUsername().toLowerCase();
this.email = userSignupRequest.getEmail().toLowerCase();
this.password = userSignupRequest.getPassword();
}
}
Important things to notice:
- It's annotated with javax.persistence.Entity
- Its corresponding table called USER, we know that through the annotation javax.persistence.Table
- org.hibernate.annotations.Cache, to add caching strategy, region attribute refers to cache in ehcache.xml
The user role is define in com.coffeebeans.domain.model.user.Role
package com.coffeebeans.domain.model.user;
/**
* Created by muhamadto on 5/07/2015.
*/
public enum Role {
ROLE_ANONYMOUS("ROLE_ANONYMOUS"),
ROLE_USER("ROLE_USER"),
ROLE_ADMIN("ROLE_ADMIN");
private String userAuthorityType;
private Role(String userAuthorityType){
this.userAuthorityType= userAuthorityType;
}
public String toString() {
return userAuthorityType;
}
}
DataBase
CREATE DATABASE `Rest`;
USE `Rest`;
CREATE TABLE `USER` (
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`insertDate` datetime NOT NULL,
`lastModified` datetime NOT NULL,
`uuid` varchar(36) NOT NULL,
`version` int(11) NOT NULL,
`email` varchar(36) NOT NULL,
`enabled` bit(1) NOT NULL,
`verified` bit(1) NOT NULL,
`password` varchar(16) NOT NULL,
`role` varchar(25) NOT NULL,
`username` varchar(36) NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `uuid` (`uuid`),
UNIQUE KEY `username_UNIQUE` (`username`),
UNIQUE KEY `email_UNIQUE` (`email`),
UNIQUE KEY `id_UNIQUE` (`id`)
);
CACHING
For now we will focus on 2nd level caching of hibernate. This can be done by:
- Add src/main/resources/ehcache.xml in Persistence module.
- Annotating entity classes (e.g. User) with org.hibernate.annotations.Cache
- Adding the following properties to the EntityManagerFactory (please revisit PersistenceConfig#additionalProperties())
- hibernate.cache.use_second_level_cache=true
- hibernate.cache.region.factory_class=org.hibernate.cache.ehcache.EhCacheRegionFactory
- hibernate.cache.use_query_cache=true
Defining Repositories
- Repositories live in com.coffeebeans.repository package as we previously specified using @EnableJpaRepositories(basePackages = "com.coffeebeans.repository") in com.coffeebeans.config.PersistenceConfig.
- In Spring Data JPA, Repository interface is the central interface. It takes the the domain class (e.g. User) to manage as well as the id type of the domain class as type arguments (e.g. Long as we passed Long to AbstractPersistable while defining DomainObject super class). This Repository interface acts as a marker interface to capture the types to work with.
- The
CrudRepository
that inserts Repository adds sophisticated CRUD functionality for the entity class that is being managed.
PagingAndSortingRepository
adds methods to facilitate paginated access to entities.
- Then persistence technology specific sub-interfaces to include additional technology specific methods like JpaRepository in our example.
Define User repository interface
package com.coffeebeans.repository.user;
import com.coffeebeans.domain.model.user.User;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
/**
* Created by muhamadto on 12/07/2015.
*/
@Repository("userRepository")
public interface UserRepository extends JpaRepository<User, Long> {
User findByUsername(String username);
User findByEmail(String email);
User findByUuid(String uuid);
User findById(Long id);
}
Before we go and build a service to use our repository we will add two additional types of classes.
- Request class: which a client of a service will provide in the request
- Response class: which will be returned to the service caller.
Request Class
package com.coffeebeans.domain.request.user;
import lombok.Data;
/**
* Created by muhamadto on 12/07/2015.
*/
@Data
public class UserSignupRequest {
private String email;
private String username;
private String password;
}
Response Class
package com.coffeebeans.domain.response;
import lombok.Data;
import java.net.URI;
/**
* Created by mohamedhamtou on 20/02/15.
*/
@Data
public class BaseResponse {
protected URI location;
}
package com.coffeebeans.domain.response;
import com.coffeebeans.domain.model.user.User;
import com.coffeebeans.domain.response.base.BaseResponse;
import lombok.Data;
/**
* Created by mohamedhamtou on 20/02/15.
*/
@Data
public class UserResponse extends BaseResponse{
protected boolean enabled;
protected boolean verified;
protected String username;
protected String email;
public static UserResponse convert(User user){
UserResponse userResponse = new UserResponse();
userResponse.setUsername(user.getUsername());
userResponse.setEmail(user.getEmail());
userResponse.setVerified(user.isVerified());
userResponse.setEnabled(user.isEnabled());
return userResponse;
}
}
Now persistence module is ready to be used. So, let's build a service to use it.
BUILDING THE CLIENT
In Services module
Define A User Controller
import com.coffeebeans.controller.base.BaseController;
import com.coffeebeans.domain.model.user.Role;
import com.coffeebeans.domain.request.user.UserSignupRequest;
import com.coffeebeans.domain.response.UserResponse;
import com.coffeebeans.service.user.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.*;
import java.net.URI;
/**
* Created by muhamadto on 12/07/2015.
*/
@RestController
@RequestMapping(value = "user", produces = MediaType.APPLICATION_JSON_VALUE)
public class UserController extends BaseController {
@Autowired
private UserService userService;
@ResponseBody
@RequestMapping(method = RequestMethod.POST)
public UserResponse signupUser(@RequestBody final UserSignupRequest userSignupRequest){
UserResponse userResponse = this.userService.createUser(userSignupRequest, Role.ROLE_ANONYMOUS);
URI location = this.buildLocationFromCurrentRequestUri(userResponse.getUsername());
userResponse.setLocation(location);
return userResponse;
}
@ResponseBody
@RequestMapping(method = RequestMethod.GET, value = "/{username}")
public UserResponse getMyUserDetails(@PathVariable String username) {
UserResponse userResponse = this.userService.getUserByUsername(username);
URI location = this.buildLocationFromCurrentServletMapping("user", userResponse.getUsername());
userResponse.setLocation(location);
return userResponse;
}
}
This controllers defines to RESTful calls.
- One to create a user
- Another to get that user by name
Both methods in this controller return UserResponse to their clients. signupUser()requires that the client of to JSON representation of UserSignupRequest class (Curtesy of RequestBody annotation).
Define A User Service
import com.coffeebeans.domain.model.user.Role;
import com.coffeebeans.domain.request.user.UserSignupRequest;
import com.coffeebeans.domain.response.UserResponse;
/**
* Created by muhamadto on 12/07/2015.
*/
public interface UserService {
UserResponse createUser(final UserSignupRequest userSignupRequest, Role role);
UserResponse getUserByUsername(String username);
}
and a class to implement this interface
package com.coffeebeans.service.user;
import com.coffeebeans.exception.general.NotFoundException;
import com.coffeebeans.repository.user.UserRepository;
import com.coffeebeans.domain.model.user.Role;
import com.coffeebeans.domain.model.user.User;
import com.coffeebeans.domain.request.user.UserSignupRequest;
import com.coffeebeans.domain.response.UserResponse;
import com.coffeebeans.exception.general.DuplicateEntryException;
import com.coffeebeans.service.base.BaseService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import java.util.Date;
/**
* Created by muhamadto on 12/07/2015.
*/
@Service("userService")
public class UserServiceImpl extends BaseService implements UserService{
public static Logger LOGGER = LoggerFactory.getLogger(UserServiceImpl.class);
@Autowired
private UserRepository userRepository;
@Override
@Transactional
public UserResponse createUser(UserSignupRequest userSignupRequest, Role role) {
UserResponse newUser;
final String email = userSignupRequest.getEmail().toLowerCase();
if(this.userRepository.findByEmail(email) == null){
LOGGER.info("User does not exist - creating a new user [{}].", userSignupRequest.getUsername());
User user = new User(userSignupRequest);
user.setRole(role);
Date now = new Date();
user.setInsertDate(now);
user.setLastModified(now);
user = this.userRepository.save(user);
newUser = UserResponse.convert(user);
LOGGER.debug("Created new user [{}].", user);
} else{
LOGGER.error("Duplicate user located [{}], exception raised with appropriate HTTP response code.", email);
throw new DuplicateEntryException("User already exists.");
}
return newUser;
}
@Override
public UserResponse getUserByUsername(String username) {
UserResponse userResponse;
User user = this.userRepository.findByUsername(username);
if(user != null){
LOGGER.debug("User has been found [{}].", user);
userResponse = UserResponse.convert(user);
} else{
LOGGER.error("Could not find a user for search criteria [{}]", username);
throw new NotFoundException(String.format("Could not find a user for search criteria [username = %s]", username));
}
return userResponse;
}
}
- UserServiceImpl uses gets instance of UserRepository using dependancy injection. It uses this instance to save, update, and query User. UserRepository can be autowired no because of EnableJpaRepositories in PersistenceConfig class.
Exception Handling
As we saw in the UserServiceImpl, their are two exception:
- createUser() throws com.coffeebeans.exception.general.DuplicateEntryException if the added user already exist
- getUserByUsername() throws com.coffeebeans.exception.general.NotFoundException if the username search did not find that user.
- Both exceptions are subclasses from RuntimeException
package com.coffeebeans.exception.general;
/**
* Created by mohamedhamtou on 26/01/15.
*/
public class NotFoundException extends RuntimeException {
public NotFoundException(){
super();
}
public NotFoundException(String message){
super(message);
}
public NotFoundException(String message, Throwable cause) {
super(message, cause);
}
public NotFoundException(Throwable cause) {
super(cause);
}
protected NotFoundException(String message, Throwable cause,
boolean enableSuppression,
boolean writableStackTrace) {
super(message, cause, enableSuppression, writableStackTrace);
}
}
package com.coffeebeans.exception.general;
/**
* Created by muhamadto on 12/07/2015.
*/
public class DuplicateEntryException extends RuntimeException {
public DuplicateEntryException() {
super();
}
public DuplicateEntryException(String message) {
super(message);
}
public DuplicateEntryException(String message, Throwable cause) {
super(message, cause);
}
public DuplicateEntryException(Throwable cause) {
super(cause);
}
protected DuplicateEntryException(String message, Throwable cause,
boolean enableSuppression,
boolean writableStackTrace) {
super(message, cause, enableSuppression, writableStackTrace);
}
}
So how can we handle these, add the following methods to com.coffeebeans.controller.base.BaseController
@ResponseBody
@ExceptionHandler(DuplicateEntryException.class)
@ResponseStatus(value = HttpStatus.CONFLICT)
ErrorResponse handleException(DuplicateEntryException e){
return new ErrorResponse(HttpStatus.CONFLICT.toString(), e.getMessage(), "Duplicated User");
}
@ResponseBody
@ExceptionHandler(NotFoundException.class)
@ResponseStatus(value = HttpStatus.NOT_FOUND)
ErrorResponse handleException(NotFoundException e){
return new ErrorResponse(HttpStatus.NOT_FOUND.toString(), e.getMessage(), "NOT FOUND (aka Huh?)");
}
- com.coffeebeans.api.error.ErrorResponse is a custom error class. The usefulness of this class will be clear once we start the JSR 303: Bean Validation lesson.
- specific message such as throw new NotFoundException(String.format("Could not find a user for search criteria [username = %s]", username));
- General message such as NOT FOUND (aka Huh?)
import lombok.Data;
import java.util.ArrayList;
import java.util.List;
/**
* Created by muhamadto on 12/07/2015.
*/
@Data
public class ErrorResponse {
private String errorCode;
private String consumerMessage;
private String applicationMessage;
public ErrorResponse(){}
public ErrorResponse(String errorCode, String consumerMessage, String applicationMessage){
this.errorCode = errorCode;
this.consumerMessage = consumerMessage;
this.applicationMessage = applicationMessage;
}
}
Now run mvn clean install on the persistence module, then mvn clean package on Services module then depoly the war file in tomcat.
Using CURL To TEST
- Signup user
- Request:
curl -H "Content-Type: application/json; charset=utf-8" --data '{"email":"post@domain.com","username":"example", "password":"password"}' http://localhost:8080/services/1/user
-
Response:
{
"location": "http://localhost:8080/services/1/user/example1"
"enabled": false
"verified": false
"username": "example1"
"email": "example1@domain.com"
}
- Retrieve User by Name
- Request:
curl http://localhost:8080/services/1/user/example1
- Response:
{
"location": "http://localhost:8080/services/1/user/example1"
"enabled": false
"verified": false
"username": "example1"
"email": "example1@domain.com"
}
The location property in the response is coming from the com.coffeebeans.domain.response.BaseResponse location property and been built through one of two methods in com.coffeebeans.controller.base.BaseController. These methods are:
protected URI buildLocationFromCurrentRequestUri(String username){
URI location = ServletUriComponentsBuilder.fromCurrentRequestUri().path("/").path(username).build().toUri();
return location;
}
protected URI buildLocationFromCurrentServletMapping(String mapping, String username){
URI location = ServletUriComponentsBuilder.fromCurrentServletMapping().path("/").path(mapping).path("/").path(username).build().toUri();
return location;
}
Now, we have a working RESTful web-services application that run Spring MVC and supports persistence using Spring Data JPA.
What is Next
Next post we will talk about bean validation.