【SpringBoot】SpringBoot 与JPA整合（十四）

　　本章介绍SpringBoot与JPA整合

整合流程

　　1、新建一个SpringBoot Web项目

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <project xmlns="http://maven.apache.org/POM/4.0.0"
 3          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 4          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 5     <modelVersion>4.0.0</modelVersion>
 6 
 7     <groupId>com.test</groupId>
 8     <artifactId>test-springboot-jpa</artifactId>
 9     <version>1.0-SNAPSHOT</version>
10 
11 
12     <parent>
13         <groupId>org.springframework.boot</groupId>
14         <artifactId>spring-boot-starter-parent</artifactId>
15         <version>2.1.8.RELEASE</version>
16     </parent>
17 
18     <properties>
19 
20         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
21         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
22         <java.version>1.8</java.version>
23     </properties>
24 
25     <dependencies>
26 
27         <dependency>
28             <groupId>org.springframework.boot</groupId>
29             <artifactId>spring-boot-starter-web</artifactId>
30         </dependency>
31 
32 
33         <dependency>
34             <groupId>org.springframework.boot</groupId>
35             <artifactId>spring-boot-starter-data-jpa</artifactId>
36         </dependency>
37 
38         <dependency>
39             <groupId>org.springframework.boot</groupId>
40             <artifactId>spring-boot-starter-jdbc</artifactId>
41         </dependency>
42 
43         <!-- mysql -->
44         <dependency>
45             <groupId>mysql</groupId>
46             <artifactId>mysql-connector-java</artifactId>
47             <version>8.0.12</version>
48         </dependency>
49 
50         <dependency>
51             <groupId>org.springframework.boot</groupId>
52             <artifactId>spring-boot-starter-test</artifactId>
53             <scope>test</scope>
54         </dependency>
55 
56     </dependencies>
57 
58 
59     <!-- SpringBoot打包插件，可以将代码打包成一个可执行的jar包 -->
60     <build>
61         <plugins>
62             <plugin>
63                 <groupId>org.springframework.boot</groupId>
64                 <artifactId>spring-boot-maven-plugin</artifactId>
65             </plugin>
66         </plugins>
67     </build>
68 </project>

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　　2、引入JPA依赖和JDBC依赖

1 <dependency>
2     <groupId>org.springframework.boot</groupId>
3     <artifactId>spring-boot-starter-data-jpa</artifactId>
4 </dependency>
5 
6 <dependency>
7     <groupId>org.springframework.boot</groupId>
8     <artifactId>spring-boot-starter-jdbc</artifactId>
9 </dependency>

　　3、添加配置信息

 1 spring:
 2   datasource:
 3     username: admin
 4     password: 123456
 5     url: jdbc:mysql://127.0.0.1:3306/test_jpa 6     driver-class-name: com.mysql.jdbc.Driver
 7   jpa:
 8     # 底层通过hibernate来实现的
 9     hibernate:
10       # 更新或者创建数据表结构
11       ddl-auto: update
12       # 控制台显示SQL
13     show-sql: true

　　4、编写一个User实体类

 1 package com.test.springboot.entity;
 2 
 3 import org.springframework.context.annotation.Configuration;
 4 
 5 import javax.persistence.*;
 6 
 7 // 使用JAP注解配置映射关系
 8 
 9 // 告诉JPA这是一个实体类（和数据表映射的类）
10 @Entity
11 // @Table来指定和那个数据表对应；如果省略默认表名就是user;
12 @Table(name="jpa_user")
13 public class User {
14 
15     // 这是一个主键
16     @Id
17     @GeneratedValue(strategy =  GenerationType.IDENTITY)
18     private Integer id;
19 
20     @Column(name = "last_name", length = 50)
21     private String lastName;
22 
23     // 省略默认列名就是属性名
24     @Column
25     private String email;
26 
27     public Integer getId() {
28         return id;
29     }
30 
31     public void setId(Integer id) {
32         this.id = id;
33     }
34 
35     public String getLastName() {
36         return lastName;
37     }
38 
39     public void setLastName(String lastName) {
40         this.lastName = lastName;
41     }
42 
43     public String getEmail() {
44         return email;
45     }
46 
47     public void setEmail(String email) {
48         this.email = email;
49     }
50 }

　　5、编写一个UserRepository类

package com.test.springboot.repository;

import com.test.springboot.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;

public interface UserRepository extends JpaRepository<User, Integer> {

}

　　6、编写一个UserController类

 1 package com.test.springboot.controller;
 2 
 3 import com.test.springboot.entity.User;
 4 import com.test.springboot.repository.UserRepository;
 5 import org.springframework.beans.factory.annotation.Autowired;
 6 import org.springframework.web.bind.annotation.GetMapping;
 7 import org.springframework.web.bind.annotation.PathVariable;
 8 import org.springframework.web.bind.annotation.RestController;
 9 
10 import java.util.Optional;
11 
12 @RestController
13 public class UserController {
14 
15     @Autowired
16     UserRepository userRepository;
17 
18     @GetMapping("/user/{id}")
19     public User getUser(@PathVariable("id") Integer id) {
20         Optional<User> optional = userRepository.findById(id);
21         if(optional.isPresent()) {
22             return optional.get();
23         }
24         return null;
25     }
26 
27 
28     @GetMapping("/user")
29     public User insertUser(User user){
30         User user1 = userRepository.save(user);
31         return user1;
32     }
33 }

　　7、启动SpringBoot Web项目进行测试，查看启动日志，可以看到它自动生成了表

　　　浏览器输入地址http://localhost:8080/user?lastName=%E6%9D%8E%E5%9B%9B&email=xx@163.com，新增用户

　　　查看用户，输入地址：http://localhost:8080/user/1