Java框架spring Boot学习笔记（五）：Spring Boot操作MySQL数据库增、删、改、查

在pom.xml添加一下代码，添加操作MySQL的依赖jar包。

 <dependency>

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

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

 </dependency>

 <dependency>

 　　<groupId>mysql</groupId>

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

 </dependency>

新建dbpeople的一个数据库,用户名root，密码123456

编写生成配置文件application-prod.yml

 server:

   port: 8082

   context-path: /

修改application.yml文件

 spring:

   profiles:

     active: prod

   datasource:

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

     url: jdbc:mysql://localhost:3306/dbpeople?useSSL=true

  username: root   password: 123456   jpa:   hibernate:   ddl-auto: create #update  show-sql: true

添加一个people类People.java

 package com.example.demo;

 import javax.persistence.Entity;

 import javax.persistence.GeneratedValue;

 import javax.persistence.Id;

 //@Entity对应数据库中的一个表

 @Entity

 public class People {

     //@Id配合@GeneratedValue，表示id自增长

     @Id

     @GeneratedValue

     private Integer id;

     private String name;

     private Integer age;

     //必须要有一个无参的构造函数，不然数据库会报错

     public People() {

     }

     public Integer getId() {

         return id;

     }

     public void setId(Integer id) {

         this.id = id;

     }

     public String getName() {

         return name;

     }

     public void setName(String name) {

         this.name = name;

     }

     public Integer getAge() {

         return age;

     }

     public void setAge(Integer age) {

         this.age = age;

     }

 }

添加一个注入类PeopleProperties.java

 package com.example.demo;

 import org.springframework.boot.context.properties.ConfigurationProperties;

 import org.springframework.stereotype.Component;

 //获取注入还需要加一个@Component注解，@ConfigurationProperties(prefix = "people")获取前缀是people的配置

 @Component

 @ConfigurationProperties(prefix = "people")

 public class PeopleProperties {

     private String name;

     private Integer age;

     public void setName(String name) {

         this.name = name;

     }

     public void setAge(Integer age) {

         this.age = age;

     }

     public String getName() { return name; }

     public Integer getAge() { return age; }

 }

编写一个数据库操作自定义接口，定制操作接口，这里只演示定制查询接口

PeopleRepository.java

 package com.example.demo;

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

 import java.util.List;

 public interface PeopleRepository extends JpaRepository<People,Integer> {

     //通过年龄来查询

     public List<People> findByAge(Integer age);

 }

编写数据库操作类，可以进行增、删、改、查等操作。

 package com.example.demo;

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

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

 import java.util.List;

 @RestController

 public class PeopleController {

     @Autowired

     private PeopleRepository peopleRepository;

     /**

      * 查询数据库中所有列表

      * @return

      */

     @GetMapping(value = "/people")

     public List<People> girlList(){

         return peopleRepository.findAll();

     }

     /**

      * 增加一个人的数据

      * @param name

      * @param age

      * @return

      */

     @PostMapping(value = "/people")

     public People peopleAdd(@RequestParam("name") String name,

                             @RequestParam("age") Integer age){

         People people = new People();

         people.setName(name);

         people.setAge(age);

         return peopleRepository.save(people);

     }

     /**

      * 查询一个人

      * @param id

      * @return

      */

     @GetMapping(value = "/people/{id}")

     public People peopleFindOne(@PathVariable("id") Integer id){

         return peopleRepository.findOne(id);

     }

     /**

      * 修改一个人的数据

      * @param id

      * @param name

      * @param age

      */

     @PutMapping(value = "/people/{id}")

     public People peopleUpdate(@PathVariable("id") Integer id,

                              @RequestParam("name") String name,

                              @RequestParam("age") Integer age){

         People people = new People();

         people.setId(id);

         people.setName(name);

         people.setAge(age);

         return peopleRepository.save(people);

     }

     /**

      * 删除一个人的数据

      * @param id

      */

     @DeleteMapping(value = "/people/{id}")

     public void peopleDelete(@PathVariable("id") Integer id){

         peopleRepository.delete(id);

     }

     /**

      * 通过年龄查询列表

      * @param age

      * @return

      */

     @GetMapping(value = "/people/age/{age}")

     public List<People> peopleListByAge(@PathVariable("age") Integer age){

         return peopleRepository.findByAge(age);

     }

 }