Spring-data-jpa 笔记（一）

Spring Data JPA简介：

可以理解为 JPA 规范的再次封装抽象，底层还是使用了 Hibernate 的 JPA 技术实现，引用 JPQL（Java Persistence Query Language）查询语言，属于 Spring 的整个生态体系的一部分。

优势：

属于 Spring 的整个生态体系的一部分上手简单、开发效率高，ORM提供的能力他都提供，ORM框架没有提供的业务逻辑功能Spring-data-jpa也提供，全方位的解决用户的需求。使用Spring-data-jpa进行开发的过程中，常用的功能，我们几乎不需要写一条sql语句。

Spring Data操作主要特性：

提供模板操作，如 Spring Data Redis 和 Spring Data Riak；

强大的 Repository 和定制的数据储存对象的抽象映射；

对数据访问对象的支持（Auting 等）。

Spring Data JPA 的主要类及结构图:

七个大 Repository 接口：

Repository（org.springframework.data.repository）；

CrudRepository（org.springframework.data.repository）；

PagingAndSortingRepository（org.springframework.data.repository）；

JpaRepository（org.springframework.data.jpa.repository）；

QueryByExampleExecutor（org.springframework.data.repository.query）；

JpaSpecificationExecutor（org.springframework.data.jpa.repository）；

QueryDslPredicateExecutor（org.springframework.data.querydsl）。

两大 Repository 实现类：

SimpleJpaRepository（org.springframework.data.jpa.repository.support）；

QueryDslJpaRepository（org.springframework.data.jpa.repository.support）。

Quick start:

以spring-boot2.1.3 ,mysql5.5+ 为技术场景

开发环境：

SPRING STS，MAVEN3.0+,JDK1.8

1、创建sringboot工程

完整工程结构图如下：

pom.xml

 <?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>2.1.3.RELEASE</version>

         <relativePath /> <!-- lookup parent from repository -->

     </parent>

     <groupId>com.zhengjiang</groupId>

     <artifactId>springboot-demo</artifactId>

     <version>0.0.1-SNAPSHOT</version>

     <name>springboot-demo</name>

     <description>Demo project for Spring Boot</description>

     <properties>

         <java.version>1.8</java.version>

     </properties>

     <dependencies>

         <dependency>

             <groupId>org.springframework.boot</groupId>

             <artifactId>spring-boot-starter-web</artifactId>

         </dependency>

         <dependency>

             <groupId>org.springframework.boot</groupId>

             <artifactId>spring-boot-starter-test</artifactId>

             <scope>test</scope>

         </dependency>

         <dependency>

             <groupId>org.springframework.boot</groupId>

             <artifactId>spring-boot-devtools</artifactId>

             <optional>true</optional>

         </dependency>

         <dependency>

             <groupId>org.springframework.boot</groupId>

             <artifactId>spring-boot-starter-data-jpa</artifactId>

         </dependency>

         <dependency>

             <groupId>mysql</groupId>

             <artifactId>mysql-connector-java</artifactId>

             <version>6.0.6</version>

         </dependency>

         <dependency>

             <groupId>com.alibaba</groupId>

             <artifactId>druid-spring-boot-starter</artifactId>

             <version>1.1.6</version>

         </dependency>

         <!-- import lombok -->

         <dependency>

             <groupId>org.projectlombok</groupId>

             <artifactId>lombok</artifactId>

             <scope>provided</scope>

         </dependency>

     </dependencies>

     <build>

         <plugins>

             <plugin>

                 <groupId>org.springframework.boot</groupId>

                 <artifactId>spring-boot-maven-plugin</artifactId>

                 <configuration>

                     <fork>true</fork>

                 </configuration>

             </plugin>

         </plugins>

     </build>

 </project>

2、修改application.properties 为yml配置

 spring:

   profiles:

     active: product

   datasource:

     driver-class-name: com.mysql.jdbc.Driver

     url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone=UTC

     username: root

     password:

   jpa:

     hibernate:

       ddl-auto: update

     show-sql: true

   jackson:

     date-format: yyyy-MM-dd HH:mm:ss

     time-zone: UTC

创建实体类UserInfo：

 package com.zhengjiang.springboot.demo.entity;

 import java.util.Date;

 import javax.persistence.Entity;

 import javax.persistence.GeneratedValue;

 import javax.persistence.Id;

 import javax.persistence.Table;

 import org.springframework.stereotype.Component;

 import com.fasterxml.jackson.annotation.JsonIgnoreProperties;

 import lombok.Data;

 import lombok.ToString;

 @Data

 @ToString

 @Entity

 @Table(name = "t_sys_user")

 @Component

 @JsonIgnoreProperties(value = { "hibernateLazyInitializer", "handler" })

 public class UserInfo{

     public UserInfo() {}

     public UserInfo(String name) {this.name = name;}

     @Id

     @GeneratedValue

     private  Long id; //ID

     private  String name; //姓名

     private  String jobNumber; //工号

     private Date createTime; //创建时间

 }

创建一个 Repository

 package com.zhengjiang.springboot.demo.respository;

 import org.springframework.data.jpa.repository.JpaRepository;

 import org.springframework.data.jpa.repository.JpaSpecificationExecutor;

 import com.zhengjiang.springboot.demo.entity.UserInfo;

 public interface UserRepository extends JpaRepository<UserInfo, Long>,JpaSpecificationExecutor<UserInfo> {

     UserInfo findByName(String name);

 }

创建service 以及实现类

 package com.zhengjiang.springboot.demo.service;

 import java.util.List;

 import org.springframework.data.domain.Page;

 import com.zhengjiang.springboot.demo.entity.UserInfo;

 public interface UserService {

     UserInfo findById(Long id);

     List<UserInfo> getUserList();

     UserInfo getUserByName(String name);

     UserInfo addUserInfo(UserInfo userInfo);

     UserInfo updateUserInfoById(UserInfo userInfo);

     void deleteUserInfoById(Long Id);

     List<UserInfo>getCurrentUserList();

     Page<UserInfo> getPageUserList();

 }

 package com.zhengjiang.springboot.demo.service.impl;

 import java.util.List;

 import org.springframework.beans.factory.annotation.Autowired;

 import org.springframework.data.domain.Page;

 import org.springframework.data.domain.Sort;

 import org.springframework.stereotype.Service;

 import org.springframework.data.domain.PageRequest;

 import com.zhengjiang.springboot.demo.entity.UserInfo;

 import com.zhengjiang.springboot.demo.respository.UserRepository;

 import com.zhengjiang.springboot.demo.service.UserService;

 @Service

 public class UserServiceImpl implements UserService {

     @Autowired

     private UserRepository userRepository;

     @Override

     public UserInfo findById(Long id) {

         return userRepository.getOne(id);

     }

     @Override

     public List<UserInfo> getUserList() {

         return userRepository.findAll();

     }

     @Override

     public UserInfo getUserByName(String name) {

         UserInfo userInfo = userRepository.findByName(name);

         return userInfo;

     }

     @Override

     public UserInfo addUserInfo(UserInfo userInfo) {

         return userRepository.save(userInfo);

     }

     @Override

     public UserInfo updateUserInfoById(UserInfo userInfo) {

         return userRepository.save(userInfo);

     }

     @Override

     public void deleteUserInfoById(Long id) {

         userRepository.deleteById(id);

     }

     @Override

     public List<UserInfo> getCurrentUserList() {

         Sort sort=new Sort(Sort.Direction.DESC,"createTime");

         return userRepository.findAll(sort);

     }

     @Override

     public Page<UserInfo> getPageUserList() {

         Sort sort=new Sort(Sort.Direction.DESC,"createTime");

         PageRequest pageable=new PageRequest(0,5,sort);

         userRepository.findAll(pageable);

         return userRepository.findAll(pageable);

     }

 }

创建controller

 package com.zhengjiang.springboot.demo.controller;

 import java.text.SimpleDateFormat;

 import java.util.Date;

 import java.util.List;

 import java.util.TimeZone;

 import javax.servlet.http.HttpServletRequest;

 import org.springframework.beans.factory.annotation.Autowired;

 import org.springframework.beans.propertyeditors.CustomDateEditor;

 import org.springframework.data.domain.Page;

 import org.springframework.web.bind.ServletRequestDataBinder;

 import org.springframework.web.bind.annotation.GetMapping;

 import org.springframework.web.bind.annotation.InitBinder;

 import org.springframework.web.bind.annotation.PostMapping;

 import org.springframework.web.bind.annotation.PutMapping;

 import org.springframework.web.bind.annotation.RequestMapping;

 import org.springframework.web.bind.annotation.RequestParam;

 import org.springframework.web.bind.annotation.RestController;

 import com.zhengjiang.springboot.demo.entity.UserInfo;

 import com.zhengjiang.springboot.demo.service.UserService;

 @RestController

 @RequestMapping("/test")

 public class TestController {

         @Autowired

         private UserService userService;

         /**

          *

          * @param id

          * @return

          */

         @GetMapping(value = "/getOne")

         public UserInfo getOne(@RequestParam("id") Long id) {

             return userService.findById(id);

         }

         /**

          * 获取所有用户

          * @return

          */

         @GetMapping(value = "/getUserList")

         public List<UserInfo> getUserList() {

             return userService.getUserList();

         }

         /**

          * 根据用户名查找

          * @param name

          * @return

          */

         @GetMapping(value = "/getUserInfo")

         public UserInfo getUserInfoByName(@RequestParam("name") String name) {

             UserInfo u = userService.getUserByName(name);

             return u;

         }

         /**

          * 根据createTime倒序查询

          * @return

          */

         @GetMapping(value = "/getCurrentUserList")

         public List<UserInfo> getCurrentUserList(){

             return userService.getCurrentUserList();

         }

         /**

          * 分页查找

          * @return

          */

         @GetMapping(value="/getPageUserList")

         public Page<UserInfo> getPageUserList(){

             return userService.getPageUserList();

         }

         /**

          * 添加用户

          * @param userInfo

          * @return

          */

         @PostMapping(value = "/addUserInfo")

         public UserInfo addUserInfo(UserInfo userInfo) {

             return userService.addUserInfo(userInfo);

         }

         /**

          * 更新用户

          * @param userInfo

          * @return

          */

         @PostMapping(value ="/updateUserInfo")

         public UserInfo updateUserInfo(UserInfo userInfo){

             return userService.updateUserInfoById(userInfo);

         }

         /**

          * 删除用户

          * @param id

          */

         @PostMapping(value="/deleteUserInfo")

         public void deleteUserInfo(@RequestParam("id") Long id){

              userService.deleteUserInfoById(id);

         }

         @InitBinder

         protected void init(HttpServletRequest request, ServletRequestDataBinder binder) {

             SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

             dateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));/*TimeZone时区，解决差8小时的问题*/

             binder.registerCustomEditor(Date.class, new CustomDateEditor(dateFormat, false));

         }

 }

用postman 测试接口。

巴特西

Spring-data-jpa 笔记（一）

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