SpringBoot整合Spring Data JPA详解
JPA是Java Persistence API的简称,是一套Sun官方提出的Java持久化规范。其设计目标主要是为了简化现有的持久化开发工作和整合ORM技术,它为Java开发人员提供了一种ORM工具来管理Java应用中的关系数据。 简而言之,JPA提供了使用面向对象的方式操作数据库的功能。JPA充分吸收了现有Hibernate,TopLink,JDO等ORM框架的优势,具有易于使用、伸缩性强等优点。
Spring Data JPA是Spring基于Spring Data框架对于JPA规范的一套具体实现方案,使用Spring Data JPA可以极大地简化JPA 的写法,几乎可以在不写具体实现的情况下完成对数据库的操作,并且除了基础的CRUD操作外,Spring Data JPA还提供了诸如分页和排序等常用功能的实现方案。合理的使用Spring Data JPA可以极大的提高我们的日常开发效率和有效的降低项目开发成本。
实现案例
接下来,我们就通过实际案例来讲解Spring Data JPA的整合,以及提供JPA相关操作的一些示例。
生成项目模板
为方便我们初始化项目,Spring Boot给我们提供一个项目模板生成网站。
1. 打开浏览器,访问:https://start.spring.io/
2. 根据页面提示,选择构建工具,开发语言,项目信息等。
3. 点击 Generate the project,生成项目模板,生成之后会将压缩包下载到本地。
4. 使用IDE导入项目,我这里使用Eclipse,通过导入Maven项目的方式导入。
添加相关依赖
清理掉不需要的测试类及测试依赖,添加 Maven 相关依赖,这里需要添加上WEB和Swagger和JPA的依赖,Swagger的添加是为了方便接口测试。
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<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.1.5.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.louis.springboot</groupId> <artifactId>demo</artifactId> <version>0.0.1-SNAPSHOT</version> <name>demo</name> <description>Demo project for Spring Boot</description> <properties> <java.version>1.8</java.version> </properties> <dependencies> <!-- web --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <!-- swagger --> <dependency> <groupId>io.springfox</groupId> <artifactId>springfox-swagger2</artifactId> <version>2.9.2</version> </dependency> <dependency> <groupId>io.springfox</groupId> <artifactId>springfox-swagger-ui</artifactId> <version>2.9.2</version> </dependency> <!-- jpa --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <!-- mysql --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> <!-- 打包时拷贝MyBatis的映射文件 --> <resources> <resource> <directory>src/main/java</directory> <includes> <include>**/sqlmap/*.xml</include> </includes> <filtering>false</filtering> </resource> <resource> <directory>src/main/resources</directory> <includes> <include>**/*.*</include> </includes> <filtering>true</filtering> </resource> </resources> </build> </project> |
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<!-- web -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- swagger -->
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger2</artifactId>
<version>2.9.2</version>
</dependency>
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger-ui</artifactId>
<version>2.9.2</version>
</dependency>
<!-- jpa -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<!-- mysql -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
<!-- 打包时拷贝MyBatis的映射文件 -->
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/sqlmap/*.xml</include>
</includes>
<filtering>false</filtering>
</resource>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.*</include>
</includes>
<filtering>true</filtering>
</resource>
</resources>
</build>
</project>
添加相关配置
1.添加数据源配置
将application.properties文件改名为application.yml ,并在其中添加MySQL数据源连接信息。
注意:
这里需要首先创建一个MySQL数据库,并输入自己的用户名和密码。这里的数据库是springboot。
另外,如果你使用的是MySQL 5.x及以前版本,驱动配置driverClassName是com.mysql.jdbc.Driver。
application.yml
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server: port: 8080 spring: datasource: driverClassName: com.mysql.cj.jdbc.Driver url: jdbc:mysql://localhost:3306/springboot?useUnicode=true&zeroDateTimeBehavior=convertToNull&autoReconnect=true&characterEncoding=utf-8 username: root password: 123456 jpa: show-sql: true # 默认false,在日志里显示执行的sql语句 database: mysql hibernate.ddl-auto: update #指定为update,每次启动项目检测表结构有变化的时候会新增字段,表不存在时会新建,如果指定create,则每次启动项目都会清空数据并删除表,再新建 properties.hibernate.dialect: org.hibernate.dialect.MySQL5Dialect database-platform: org.hibernate.dialect.MySQL5Dialect hibernate: naming: implicit-strategy: org.hibernate.boot.model.naming.ImplicitNamingStrategyLegacyJpaImpl #指定jpa的自动表生成策略,驼峰自动映射为下划线格式 #physical-strategy: org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl |
2. 添加swagger 配置
添加一个swagger 配置类,在工程下新建 config 包并添加一个 SwaggerConfig 配置类。
SwaggerConfig.java
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import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import springfox.documentation.builders.ApiInfoBuilder; import springfox.documentation.builders.PathSelectors; import springfox.documentation.builders.RequestHandlerSelectors; import springfox.documentation.service.ApiInfo; import springfox.documentation.spi.DocumentationType; import springfox.documentation.spring.web.plugins.Docket; import springfox.documentation.swagger2.annotations.EnableSwagger2; @Configuration @EnableSwagger2 public class SwaggerConfig { @Bean public Docket createRestApi(){ return new Docket(DocumentationType.SWAGGER_2).apiInfo(apiInfo()) .select() .apis(RequestHandlerSelectors.any()) .paths(PathSelectors.any()).build(); } private ApiInfo apiInfo(){ return new ApiInfoBuilder() .title("SpringBoot API Doc") .description("This is a restful api document of Spring Boot.") .version("1.0") .build(); } } |
@Configuration
@EnableSwagger2
public class SwaggerConfig {
@Bean
public Docket createRestApi(){
return new Docket(DocumentationType.SWAGGER_2).apiInfo(apiInfo())
.select()
.apis(RequestHandlerSelectors.any())
.paths(PathSelectors.any()).build();
}
private ApiInfo apiInfo(){
return new ApiInfoBuilder()
.title("SpringBoot API Doc")
.description("This is a restful api document of Spring Boot.")
.version("1.0")
.build();
}
}
编写业务代码
首先,编写一个实体类,并添加相关注解,具体注解说明参见代码。
SysUser.java
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package com.louis.springboot.demo.model; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.Index; import javax.persistence.Table; @Entity // @Entity: 实体类, 必须 // @Table: 对应数据库中的表, 必须, name=表名, Indexes是声明表里的索引, columnList是索引的列, 同时声明此索引列是否唯一, 默认false @Table(name = "sys_user", indexes = {@Index(name = "id", columnList = "id", unique = true), @Index(name = "name", columnList = "name", unique = true)}) public class SysUser { @Id // @Id: 指明id列, 必须 @GeneratedValue(strategy = GenerationType.IDENTITY) // @GeneratedValue: 表明是否自动生成, 必须, strategy也是必写, 指明主键生成策略, 默认是Oracle private Long id; @Column(name = "name", nullable = false) // @Column: 对应数据库列名,可选, nullable 是否可以为空, 默认true private String name; private String password; private String email; public Long getId() { return id; } public void setId(Long id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } } |
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Index;
import javax.persistence.Table;
@Entity // @Entity: 实体类, 必须
// @Table: 对应数据库中的表, 必须, name=表名, Indexes是声明表里的索引, columnList是索引的列, 同时声明此索引列是否唯一, 默认false
@Table(name = "sys_user", indexes = {@Index(name = "id", columnList = "id", unique = true), @Index(name = "name", columnList = "name", unique = true)})
public class SysUser {
@Id // @Id: 指明id列, 必须
@GeneratedValue(strategy = GenerationType.IDENTITY) // @GeneratedValue: 表明是否自动生成, 必须, strategy也是必写, 指明主键生成策略, 默认是Oracle
private Long id;
@Column(name = "name", nullable = false) // @Column: 对应数据库列名,可选, nullable 是否可以为空, 默认true
private String name;
private String password;
private String email;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
然后,编写一个SysUserDao并继承JpaRepository,由此我们已经继承了大部分可用的CURD操作,针对基础操作,DAO完全不用写任何方法。
SysUserDao.java
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package com.louis.springboot.demo.dao; import java.io.Serializable; import org.springframework.data.jpa.repository.JpaRepository; import com.louis.springboot.demo.model.SysUser; public interface SysUserDao extends JpaRepository<SysUser, Long>, Serializable { } |
import java.io.Serializable;
import org.springframework.data.jpa.repository.JpaRepository;
import com.louis.springboot.demo.model.SysUser;
public interface SysUserDao extends JpaRepository<SysUser, Long>, Serializable {
}
使用Spring Data JPA,可以通过两种方式使用 JPA 进行数据持久化。
方式一:使用Spring Data JPA 提供的接口默认实现,如上面我们的DAO实现。
方式二:自定义符合Spring Data JPA规则的查询方法,由框架将其自动解析为SQL。
Spring Data JPA提供了一些实现了基本的数据库操作的接口类,这些接口和类的关系如下。
其中CrudRepository是顶层CURD接口,提供了一些简单的增删查改功能,接口定义如下。
CrudRepository.java
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package org.springframework.data.repository; import java.util.Optional; /** * Interface for generic CRUD operations on a repository for a specific type. * @author Oliver Gierke * @author Eberhard Wolff */ @NoRepositoryBean public interface CrudRepository<T, ID> extends Repository<T, ID> { /** * Saves a given entity. Use the returned instance for further operations as the save operation might have changed the * entity instance completely. * * @param entity must not be {@literal null}. * @return the saved entity will never be {@literal null}. */ <S extends T> S save(S entity); /** * Saves all given entities. * * @param entities must not be {@literal null}. * @return the saved entities will never be {@literal null}. * @throws IllegalArgumentException in case the given entity is {@literal null}. */ <S extends T> Iterable<S> saveAll(Iterable<S> entities); /** * Retrieves an entity by its id. * * @param id must not be {@literal null}. * @return the entity with the given id or {@literal Optional#empty()} if none found * @throws IllegalArgumentException if {@code id} is {@literal null}. */ Optional<T> findById(ID id); /** * Returns whether an entity with the given id exists. * * @param id must not be {@literal null}. * @return {@literal true} if an entity with the given id exists, {@literal false} otherwise. * @throws IllegalArgumentException if {@code id} is {@literal null}. */ boolean existsById(ID id); /** * Returns all instances of the type. * * @return all entities */ Iterable<T> findAll(); /** * Returns all instances of the type with the given IDs. * * @param ids * @return */ Iterable<T> findAllById(Iterable<ID> ids); /** * Returns the number of entities available. * * @return the number of entities */ long count(); /** * Deletes the entity with the given id. * * @param id must not be {@literal null}. * @throws IllegalArgumentException in case the given {@code id} is {@literal null} */ void deleteById(ID id); /** * Deletes a given entity. * * @param entity * @throws IllegalArgumentException in case the given entity is {@literal null}. */ void delete(T entity); /** * Deletes the given entities. * * @param entities * @throws IllegalArgumentException in case the given {@link Iterable} is {@literal null}. */ void deleteAll(Iterable<? extends T> entities); /** * Deletes all entities managed by the repository. */ void deleteAll(); } |
import java.util.Optional;
/**
* Interface for generic CRUD operations on a repository for a specific type.
* @author Oliver Gierke
* @author Eberhard Wolff
*/
@NoRepositoryBean
public interface CrudRepository<T, ID> extends Repository<T, ID> {
/**
* Saves a given entity. Use the returned instance for further operations as the save operation might have changed the
* entity instance completely.
*
* @param entity must not be {@literal null}.
* @return the saved entity will never be {@literal null}.
*/
<S extends T> S save(S entity);
/**
* Saves all given entities.
*
* @param entities must not be {@literal null}.
* @return the saved entities will never be {@literal null}.
* @throws IllegalArgumentException in case the given entity is {@literal null}.
*/
<S extends T> Iterable<S> saveAll(Iterable<S> entities);
/**
* Retrieves an entity by its id.
*
* @param id must not be {@literal null}.
* @return the entity with the given id or {@literal Optional#empty()} if none found
* @throws IllegalArgumentException if {@code id} is {@literal null}.
*/
Optional<T> findById(ID id);
/**
* Returns whether an entity with the given id exists.
*
* @param id must not be {@literal null}.
* @return {@literal true} if an entity with the given id exists, {@literal false} otherwise.
* @throws IllegalArgumentException if {@code id} is {@literal null}.
*/
boolean existsById(ID id);
/**
* Returns all instances of the type.
*
* @return all entities
*/
Iterable<T> findAll();
/**
* Returns all instances of the type with the given IDs.
*
* @param ids
* @return
*/
Iterable<T> findAllById(Iterable<ID> ids);
/**
* Returns the number of entities available.
*
* @return the number of entities
*/
long count();
/**
* Deletes the entity with the given id.
*
* @param id must not be {@literal null}.
* @throws IllegalArgumentException in case the given {@code id} is {@literal null}
*/
void deleteById(ID id);
/**
* Deletes a given entity.
*
* @param entity
* @throws IllegalArgumentException in case the given entity is {@literal null}.
*/
void delete(T entity);
/**
* Deletes the given entities.
*
* @param entities
* @throws IllegalArgumentException in case the given {@link Iterable} is {@literal null}.
*/
void deleteAll(Iterable<? extends T> entities);
/**
* Deletes all entities managed by the repository.
*/
void deleteAll();
}
PagingAndSortingRepository在继承了CrudRepository基础上实现了排序和分页的方法。
PagingAndSortingRepository.java
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package org.springframework.data.repository; import org.springframework.data.domain.Page; import org.springframework.data.domain.Pageable; import org.springframework.data.domain.Sort; /** * Extension of {@link CrudRepository} to provide additional methods to retrieve entities using the pagination and * sorting abstraction. * * @author Oliver Gierke * @see Sort * @see Pageable * @see Page */ @NoRepositoryBean public interface PagingAndSortingRepository<T, ID> extends CrudRepository<T, ID> { /** * Returns all entities sorted by the given options. * * @param sort * @return all entities sorted by the given options */ Iterable<T> findAll(Sort sort); /** * Returns a {@link Page} of entities meeting the paging restriction provided in the {@code Pageable} object. * * @param pageable * @return a page of entities */ Page<T> findAll(Pageable pageable); } |
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
/**
* Extension of {@link CrudRepository} to provide additional methods to retrieve entities using the pagination and
* sorting abstraction.
*
* @author Oliver Gierke
* @see Sort
* @see Pageable
* @see Page
*/
@NoRepositoryBean
public interface PagingAndSortingRepository<T, ID> extends CrudRepository<T, ID> {
/**
* Returns all entities sorted by the given options.
*
* @param sort
* @return all entities sorted by the given options
*/
Iterable<T> findAll(Sort sort);
/**
* Returns a {@link Page} of entities meeting the paging restriction provided in the {@code Pageable} object.
*
* @param pageable
* @return a page of entities
*/
Page<T> findAll(Pageable pageable);
}
JpaRepository又在继承PagingAndSortingRepository的基础上,同时继承了QueryByExampleExecutor接口,使其拥有了匹配指定样例查询的能力。
JpaRepository.java
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package org.springframework.data.jpa.repository; import java.util.List; import javax.persistence.EntityManager; import org.springframework.data.domain.Example; import org.springframework.data.domain.Sort; import org.springframework.data.repository.NoRepositoryBean; import org.springframework.data.repository.PagingAndSortingRepository; import org.springframework.data.repository.query.QueryByExampleExecutor; /** * JPA specific extension of {@link org.springframework.data.repository.Repository}. * * @author Oliver Gierke * @author Christoph Strobl * @author Mark Paluch */ @NoRepositoryBean public interface JpaRepository<T, ID> extends PagingAndSortingRepository<T, ID>, QueryByExampleExecutor<T> { /* * (non-Javadoc) * @see org.springframework.data.repository.CrudRepository#findAll() */ List<T> findAll(); /* * (non-Javadoc) * @see org.springframework.data.repository.PagingAndSortingRepository#findAll(org.springframework.data.domain.Sort) */ List<T> findAll(Sort sort); /* * (non-Javadoc) * @see org.springframework.data.repository.CrudRepository#findAll(java.lang.Iterable) */ List<T> findAllById(Iterable<ID> ids); /* * (non-Javadoc) * @see org.springframework.data.repository.CrudRepository#save(java.lang.Iterable) */ <S extends T> List<S> saveAll(Iterable<S> entities); /** * Flushes all pending changes to the database. */ void flush(); /** * Saves an entity and flushes changes instantly. * * @param entity * @return the saved entity */ <S extends T> S saveAndFlush(S entity); /** * Deletes the given entities in a batch which means it will create a single {@link Query}. Assume that we will clear * the {@link javax.persistence.EntityManager} after the call. * * @param entities */ void deleteInBatch(Iterable<T> entities); /** * Deletes all entities in a batch call. */ void deleteAllInBatch(); /** * Returns a reference to the entity with the given identifier. Depending on how the JPA persistence provider is * implemented this is very likely to always return an instance and throw an * {@link javax.persistence.EntityNotFoundException} on first access. Some of them will reject invalid identifiers * immediately. * * @param id must not be {@literal null}. * @return a reference to the entity with the given identifier. * @see EntityManager#getReference(Class, Object) for details on when an exception is thrown. */ T getOne(ID id); /* * (non-Javadoc) * @see org.springframework.data.repository.query.QueryByExampleExecutor#findAll(org.springframework.data.domain.Example) */ @Override <S extends T> List<S> findAll(Example<S> example); /* * (non-Javadoc) * @see org.springframework.data.repository.query.QueryByExampleExecutor#findAll(org.springframework.data.domain.Example, org.springframework.data.domain.Sort) */ @Override <S extends T> List<S> findAll(Example<S> example, Sort sort); } |
import java.util.List;
import javax.persistence.EntityManager;
import org.springframework.data.domain.Example;
import org.springframework.data.domain.Sort;
import org.springframework.data.repository.NoRepositoryBean;
import org.springframework.data.repository.PagingAndSortingRepository;
import org.springframework.data.repository.query.QueryByExampleExecutor;
/**
* JPA specific extension of {@link org.springframework.data.repository.Repository}.
*
* @author Oliver Gierke
* @author Christoph Strobl
* @author Mark Paluch
*/
@NoRepositoryBean
public interface JpaRepository<T, ID> extends PagingAndSortingRepository<T, ID>, QueryByExampleExecutor<T> {
/*
* (non-Javadoc)
* @see org.springframework.data.repository.CrudRepository#findAll()
*/
List<T> findAll();
/*
* (non-Javadoc)
* @see org.springframework.data.repository.PagingAndSortingRepository#findAll(org.springframework.data.domain.Sort)
*/
List<T> findAll(Sort sort);
/*
* (non-Javadoc)
* @see org.springframework.data.repository.CrudRepository#findAll(java.lang.Iterable)
*/
List<T> findAllById(Iterable<ID> ids);
/*
* (non-Javadoc)
* @see org.springframework.data.repository.CrudRepository#save(java.lang.Iterable)
*/
<S extends T> List<S> saveAll(Iterable<S> entities);
/**
* Flushes all pending changes to the database.
*/
void flush();
/**
* Saves an entity and flushes changes instantly.
*
* @param entity
* @return the saved entity
*/
<S extends T> S saveAndFlush(S entity);
/**
* Deletes the given entities in a batch which means it will create a single {@link Query}. Assume that we will clear
* the {@link javax.persistence.EntityManager} after the call.
*
* @param entities
*/
void deleteInBatch(Iterable<T> entities);
/**
* Deletes all entities in a batch call.
*/
void deleteAllInBatch();
/**
* Returns a reference to the entity with the given identifier. Depending on how the JPA persistence provider is
* implemented this is very likely to always return an instance and throw an
* {@link javax.persistence.EntityNotFoundException} on first access. Some of them will reject invalid identifiers
* immediately.
*
* @param id must not be {@literal null}.
* @return a reference to the entity with the given identifier.
* @see EntityManager#getReference(Class, Object) for details on when an exception is thrown.
*/
T getOne(ID id);
/*
* (non-Javadoc)
* @see org.springframework.data.repository.query.QueryByExampleExecutor#findAll(org.springframework.data.domain.Example)
*/
@Override
<S extends T> List<S> findAll(Example<S> example);
/*
* (non-Javadoc)
* @see org.springframework.data.repository.query.QueryByExampleExecutor#findAll(org.springframework.data.domain.Example, org.springframework.data.domain.Sort)
*/
@Override
<S extends T> List<S> findAll(Example<S> example, Sort sort);
}
上面因为我们的SysUserDao直接继承了JpaRepository,所以上述所有的接口SysUserDao都是可以直接使用的,当然,除了可以直接使用默认提供的基础接口外,Spring Data JPA还允许我们自定义查询方法,对于符合以下命名规则的方法,Spring Data JPA能够根据其方法名为其自动生成SQL,除了使用示例中的 find 关键字,还支持的关键字有:query、get、read、count、delete等。
只要按照以下命名规范的定义的方法,Spring Data JPA都能够帮我们自动生成SQL,无需自己实现。
接着编写一个服务接口,添加用户保存、删除、查询全部和分页查询的方法。
SysUserService.java
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package com.louis.springboot.demo.service; import java.util.List; import com.louis.springboot.demo.model.SysUser; import com.louis.springboot.demo.util.PageQuery; public interface SysUserService { /** * 保存用户 * @param user */ public void save(SysUser user); /** * 删除用户 * @param id */ public void delete(SysUser user); /** * 查询全部用户 * @return */ public List<SysUser> findAll(); /** * 查询分页数据 * @return */ public Object findPage(PageQuery pageQuery); } |
public interface SysUserService {
/**
* 保存用户
* @param user
*/
public void save(SysUser user);
/**
* 删除用户
* @param id
*/
public void delete(SysUser user);
/**
* 查询全部用户
* @return
*/
public List<SysUser> findAll();
/**
* 查询分页数据
* @return
*/
public Object findPage(PageQuery pageQuery);
}
继续编写服务实现类并调用DAO实现相应功能,以下DAO方法都是继承而来的,除此之后,JPA还提供了大量的API可用。
SysUserServiceImpl.java
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package com.louis.springboot.demo.service.impl; import java.util.List; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.data.domain.PageRequest; import org.springframework.stereotype.Service; import com.louis.springboot.demo.dao.SysUserDao; import com.louis.springboot.demo.model.SysUser; import com.louis.springboot.demo.service.SysUserService; import com.louis.springboot.demo.util.PageQuery; @Service public class SysUserServiceImpl implements SysUserService { @Autowired private SysUserDao sysUserDao; @Override public void save(SysUser user) { sysUserDao.save(user); } @Override public void delete(SysUser user) { sysUserDao.delete(user); } @Override public List<SysUser> findAll() { return sysUserDao.findAll(); } @Override public Object findPage(PageQuery pageQuery) { return sysUserDao.findAll(PageRequest.of(pageQuery.getPage(), pageQuery.getSize())); } } |
@Service
public class SysUserServiceImpl implements SysUserService {
@Autowired
private SysUserDao sysUserDao;
@Override
public void save(SysUser user) {
sysUserDao.save(user);
}
@Override
public void delete(SysUser user) {
sysUserDao.delete(user);
}
@Override
public List<SysUser> findAll() {
return sysUserDao.findAll();
}
@Override
public Object findPage(PageQuery pageQuery) {
return sysUserDao.findAll(PageRequest.of(pageQuery.getPage(), pageQuery.getSize()));
}
}
接着编写一个用户控制器,调用服务接口实现对应功能。
SysUserController.java
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package com.louis.springboot.demo.controller; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PostMapping; import org.springframework.web.bind.annotation.RequestBody; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import com.louis.springboot.demo.model.SysUser; import com.louis.springboot.demo.service.SysUserService; import com.louis.springboot.demo.util.PageQuery; @RestController @RequestMapping("user") public class SysUserController { @Autowired private SysUserService sysUserService; @PostMapping(value="/save") public Object save(@RequestBody SysUser user) { sysUserService.save(user); return 1; } @PostMapping(value="/delete") public Object delete(@RequestBody SysUser user) { sysUserService.delete(user); return 1; } @GetMapping(value="/findAll") public Object findAll() { return sysUserService.findAll(); } @PostMapping(value="/findPage") public Object findPage(@RequestBody PageQuery pageQuery) { return sysUserService.findPage(pageQuery); } } |
import com.louis.springboot.demo.model.SysUser;
import com.louis.springboot.demo.service.SysUserService;
import com.louis.springboot.demo.util.PageQuery;
@RestController
@RequestMapping("user")
public class SysUserController {
@Autowired
private SysUserService sysUserService;
@PostMapping(value="/save")
public Object save(@RequestBody SysUser user) {
sysUserService.save(user);
return 1;
}
@PostMapping(value="/delete")
public Object delete(@RequestBody SysUser user) {
sysUserService.delete(user);
return 1;
}
@GetMapping(value="/findAll")
public Object findAll() {
return sysUserService.findAll();
}
@PostMapping(value="/findPage")
public Object findPage(@RequestBody PageQuery pageQuery) {
return sysUserService.findPage(pageQuery);
}
}
上面对分页请求进行了简单的封装,主要包含查询页码和每页数量两个属性。
PageQuery.java
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package com.louis.springboot.demo.util; public class PageQuery { private int page; private int size; public int getPage() { return page; } public void setPage(int page) { this.page = page; } public int getSize() { return size; } public void setSize(int size) { this.size = size; } } |
public class PageQuery {
private int page;
private int size;
public int getPage() {
return page;
}
public void setPage(int page) {
this.page = page;
}
public int getSize() {
return size;
}
public void setSize(int size) {
this.size = size;
}
}
编译测试运行
1. 右键项目 -> Run as -> Maven install,开始执行Maven构建,第一次会下载Maven依赖,可能需要点时间,如果出现如下信息,就说明项目编译打包成功了。
2. 打开数据库,创建一个springboot数据库,然后右键文件 DemoApplication.java -> Run as -> Java Application,开始启动应用,如果一开始数据库没有对应的表,在应用启动时会创建,我们可以通过控制台查看到对应的SQL语句。
3. 打开浏览器,访问:http://localhost:8080/swagger-ui.html,进入swagger接口文档界面。
4. 首先访问findAll接口,此时并没有数据,所以返回结果为空。
然后调用save接口,分别插入以下三条数据。
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{ "id": 1, "name": "111", "email": "111@qq.com", "password": "111" } |
"id": 1,
"name": "111",
"email": "111@qq.com",
"password": "111"
}
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{ "id": 2, "name": "222", "email": "222@qq.com", "password": "222" } |
"id": 2,
"name": "222",
"email": "222@qq.com",
"password": "222"
}
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{ "id": 3, "name": "333", "email": "333@qq.com", "password": "333" } |
"id": 3,
"name": "333",
"email": "333@qq.com",
"password": "333"
}
接着回来继续调用findAll接口,可以看到我们已经成功的插入了三条数据。
接着测试分页查询接口findPage,输入{ "page": 0, "size": 2 },标识查询第一页,每页显示两条记录,下面返回正确的分页查询数据。
最后我们测试一下删除接口delete,删除掉id为1的数据,再次调用findAll接口,我们发现目标记录已经成功被删除。
参考资料
项目主页:https://spring.io/projects/spring-data-jpa
参考文档:https://docs.spring.io/spring-data/jpa/docs/current/reference/html/
网上资料:http://www.360doc.com/content/17/0801/09/16915_675758662.shtml
网上资料:https://www.ibm.com/developerworks/cn/opensource/os-cn-spring-jpa/index.html