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。