数据库的操作

1. 首先增加依赖，在pom.xml中增加以下依赖
   
   
   
   

   <!-- 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>
   

2. 配置数据库
   修改application.yml
   
   

   datasource:
       driver-class-name: com.mysql.jdbc.Driver
       url: jdbc:mysql://127.0.0.1:3306/dbgirl
       username: root
       password: 123456
   jpa:
       hibernate:
         ddl-auto: update
       show-sql: true
   
   

3. 编写实体类
   
   

   package com.example.demo2;
   
   import javax.persistence.Entity;
   import javax.persistence.GeneratedValue;
   import javax.persistence.Id;
   
   @Entity
   public class Girl {
       @Id
       @GeneratedValue
       private int id;
       private String userName;
       private String password;
       private Integer age;
   
       public int getId() {
           return id;
       }
   
       public void setId(int id) {
           this.id = id;
       }
   
       public String getUserName() {
           return userName;
       }
   
       public void setUserName(String userName) {
           this.userName = userName;
       }
   
       public String getPassword() {
           return password;
       }
   
       public void setPassword(String password) {
           this.password = password;
       }
   
       public Integer getAge() {
           return age;
       }
   
       public void setAge(Integer age) {
           this.age = age;
       }
   }
   
   

4. JpaRepository 引入
   
   

   package com.example.demo2;
   
   import org.springframework.data.jpa.repository.JpaRepository;
   
   import java.util.List;
   
   public interface GirlRepo extends JpaRepository<Girl,Integer> {
       public List<Girl> findByAge(Integer age);
   }
   
   

5. 编写CURD
   
   

   package com.example.demo2;
   
   import org.springframework.beans.factory.annotation.Autowired;
   import org.springframework.web.bind.annotation.*;
   
   import java.util.List;
   
   @RestController
   public class IndexController {
       @Autowired
       private GirlRepo girlRepo;
   
       /**
        * 查询所有数据
        * @return
        */
       @GetMapping(value = "/findAllGirl")
       public List<Girl> findAllGirl(){
           return girlRepo.findAll();
       }
   
       /**
        * 添加一个girl
        * @param userName
        * @param password
        * @param age
        * @return
        */
       @PostMapping(value = "/addGirl")
       public Girl addGirl(@RequestParam("userName") String userName,@RequestParam("password") String password,@RequestParam("age") Integer age){
           Girl girl = new Girl();
           girl.setAge(age);
           girl.setUserName(userName);
           girl.setPassword(password);
           return girlRepo.save(girl);
       }
   
       /**
        * 删除一个girl
        * @param id
        */
       @DeleteMapping("/delGirl")
       public void delGirl(@RequestParam("id") Integer id){
           girlRepo.delete(id);
       }
   
       /**
        * 查询一个girl
        * @param id
        * @return
        */
       @GetMapping("/getOneGirl")
       public Girl getOneGirl(@RequestParam("id") Integer id){
           return girlRepo.findOne(id);
       }
   
       /**
        * 更新girl
        * @param id
        * @param userName
        * @param password
        * @param age
        * @return
        */
       @PutMapping("/updateGirl")
       public Girl updateGirl(@RequestParam("id") Integer id,
               @RequestParam(value = "userName",required = false) String userName,
               @RequestParam(value = "password",required = false) String password,
               @RequestParam(value = "age",required = false) Integer age){
           Girl girl = new Girl();
           girl.setId(id);
           girl.setUserName(userName);
           girl.setPassword(password);
           girl.setAge(age);
           return girlRepo.save(girl);
       }
   
       /**
        * 通过年龄查找
        * @param age
        */
       @GetMapping("/findGirlByAge")
       public List<Girl> findGirlByAge(@RequestParam("age") Integer age){
           return girlRepo.findByAge(age);
       }
   }