使用Spring Data REST将Spring Data JPA存储库导出为REST服务

Spring Data模块提供了各种模块，以统一的方式处理各种类型的数据源，如RDBMS，NOSQL存储等。在我以前的文章SpringMVC4 + Spring Data JPA +使用JavaConfig的SpringSecurity配置中，我已经解释了如何使用JavaConfig配置Spring Data JPA。

现在，在这篇文章中，让我们看看如何使用Spring Data JPA存储库以及如何使用Spring Data REST将JPA实体导出为REST端点。

首先，让我们在pom.xml中配置spring-data-jpa和spring-data-rest-webmvc依赖项。

<dependency><groupId>org.springframework.data</groupId><artifactId>spring-data-jpa</artifactId><version>1.5.0.RELEASE</version>
</dependency><dependency><groupId>org.springframework.data</groupId><artifactId>spring-data-rest-webmvc</artifactId><version>2.0.0.RELEASE</version>
</dependency>

确保正确配置了最新发布的版本，否则将遇到以下错误：

java.lang.ClassNotFoundException: org.springframework.data.mapping.SimplePropertyHandler

创建JPA实体。

@Entity
@Table(name = "USERS")
public class User implements Serializable
{private static final long serialVersionUID = 1L;@Id@GeneratedValue(strategy = GenerationType.IDENTITY)@Column(name = "user_id")private Integer id;@Column(name = "username", nullable = false, unique = true, length = 50)private String userName;@Column(name = "password", nullable = false, length = 50)private String password;@Column(name = "firstname", nullable = false, length = 50)private String firstName;@Column(name = "lastname", length = 50)private String lastName;@Column(name = "email", nullable = false, unique = true, length = 50)private String email;@Temporal(TemporalType.DATE)private Date dob;private boolean enabled=true;@OneToMany(fetch=FetchType.EAGER, cascade=CascadeType.ALL)@JoinColumn(name="user_id")private Set<Role> roles = new HashSet<>();@OneToMany(mappedBy = "user")private List<Contact> contacts = new ArrayList<>();//setters and getters}@Entity
@Table(name = "ROLES")
public class Role implements Serializable
{private static final long serialVersionUID = 1L;@Id@GeneratedValue(strategy = GenerationType.IDENTITY)@Column(name = "role_id")private Integer id;@Column(name="role_name",nullable=false)private String roleName;//setters and getters}@Entity
@Table(name = "CONTACTS")
public class Contact implements Serializable
{private static final long serialVersionUID = 1L;@Id@GeneratedValue(strategy = GenerationType.IDENTITY)@Column(name = "contact_id")private Integer id;@Column(name = "firstname", nullable = false, length = 50)private String firstName;@Column(name = "lastname", length = 50)private String lastName;@Column(name = "email", nullable = false, unique = true, length = 50)private String email;@Temporal(TemporalType.DATE)private Date dob;@ManyToOne@JoinColumn(name = "user_id")private User user;//setters and getters}

使用AbstractAnnotationConfigDispatcherServletInitializer配置DispatcherServlet。观察到我们已经将RepositoryRestMvcConfiguration.class添加到getServletConfigClasses（）方法中。 RepositoryRestMvcConfiguration是一个繁重的工作，它寻找Spring Data Repository并将其导出为REST端点。

package com.sivalabs.springdatarest.web.config;import javax.servlet.Filter;
import org.springframework.data.rest.webmvc.config.RepositoryRestMvcConfiguration;
import org.springframework.orm.jpa.support.OpenEntityManagerInViewFilter;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;import com.sivalabs.springdatarest.config.AppConfig;public class SpringWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer
{@Overrideprotected Class<?>[] getRootConfigClasses(){return new Class<?>[] { AppConfig.class};}@Overrideprotected Class<?>[] getServletConfigClasses(){return new Class<?>[] { WebMvcConfig.class, RepositoryRestMvcConfiguration.class };}@Overrideprotected String[] getServletMappings(){		return new String[] { "/rest/*" };}	@Overrideprotected Filter[] getServletFilters() {return new Filter[]{new OpenEntityManagerInViewFilter()};} 
}

为JPA实体创建Spring Data JPA存储库。

public interface UserRepository extends JpaRepository<User, Integer>
{
}public interface RoleRepository extends JpaRepository<Role, Integer>
{
}public interface ContactRepository extends JpaRepository<Contact, Integer>
{
}

而已。 Spring Data REST将负责其余的工作。

您可以使用spring Rest Shell https://github.com/spring-projects/rest-shell或Chrome的Postman插件来测试导出的REST服务。

D:\rest-shell-1.2.1.RELEASE\bin>rest-shell
http://localhost:8080:>

现在我们可以使用baseUri命令更改baseUri，如下所示：

http://localhost:8080:>baseUri http://localhost:8080/spring-data-rest-demo/rest/http://localhost:8080/spring-data-rest-demo/rest/>http://localhost:8080/spring-data-rest-demo/rest/>listrel         href======================================================================================users       http://localhost:8080/spring-data-rest-demo/rest/users{?page,size,sort}roles       http://localhost:8080/spring-data-rest-demo/rest/roles{?page,size,sort}contacts    http://localhost:8080/spring-data-rest-demo/rest/contacts{?page,size,sort}

注意：当DispatcherServlet url映射到“ /”时，rest-shell似乎存在问题，并且它发出的list list命令以“未找到资源”作为响应。

http：// localhost：8080 / spring-data-rest-demo / rest />获取用户/

{"_links": {"self": {"href": "http://localhost:8080/spring-data-rest-demo/rest/users/{?page,size,sort}","templated": true},"search": {"href": "http://localhost:8080/spring-data-rest-demo/rest/users/search"}},"_embedded": {"users": [{"userName": "admin","password": "admin","firstName": "Administrator","lastName": null,"email": "admin@gmail.com","dob": null,"enabled": true,"_links": {"self": {"href": "http://localhost:8080/spring-data-rest-demo/rest/users/1"},"roles": {"href": "http://localhost:8080/spring-data-rest-demo/rest/users/1/roles"},"contacts": {"href": "http://localhost:8080/spring-data-rest-demo/rest/users/1/contacts"}}},{"userName": "siva","password": "siva","firstName": "Siva","lastName": null,"email": "sivaprasadreddy.k@gmail.com","dob": null,"enabled": true,"_links": {"self": {"href": "http://localhost:8080/spring-data-rest-demo/rest/users/2"},"roles": {"href": "http://localhost:8080/spring-data-rest-demo/rest/users/2/roles"},"contacts": {"href": "http://localhost:8080/spring-data-rest-demo/rest/users/2/contacts"}}}]},"page": {"size": 20,"totalElements": 2,"totalPages": 1,"number": 0}
}