一、Spring Boot原理
用戶從頁面前端，也就是我們所說的 view 層進(jìn)行查詢訪問，進(jìn)入到 controller 層找到對應(yīng)的接口，接 著 controller 進(jìn)行對 service 層進(jìn)行業(yè)務(wù)功能的調(diào)用，service 要進(jìn)入 dao 層查詢數(shù)據(jù)，dao 層調(diào)用 mapper.xml 文件生成 sql 語句到數(shù)據(jù)庫中進(jìn)行查詢
二、實現(xiàn)過程
2.1、準(zhǔn)備數(shù)據(jù)庫user表插入四條數(shù)據(jù)
2.2、model下創(chuàng)建一個User類
與數(shù)據(jù)庫的字段一一對應(yīng)
@Getter @Setter
public class User {
private int id;
private String username;
private String password;
private int age;
}
2.3、dao下創(chuàng)建一個UserDao接口
@Repository注解修飾哪個類，則表明這個類具有對對象進(jìn)行CRUD（增刪改查）的功能
@Repository
public interface UserDao {
public User getUserById(@Param("id") int id);
public List<User> getUserByAge(@Param("age") int age);
public List<User> getUserByName(@Param("username") String username);
public int insertUser(@RequestBody User user);
}
通過UserMapping.xml配置文件實現(xiàn)UserDao接口
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.demo.dao.UserDao">
<select id="getUserById" resultType="User">
select * from `user` where id=#{id}
</select>
<select id="getUserByAge" resultType="User">
select * from `user` where age=#{age}
</select>
<select id="getUserByName" resultType="User">
select * from `user` where username like concat("%",#{username},"%")
</select>
<insert id="insertUser" parameterType="User">
<selectKey keyProperty="id" order="AFTER" resultType="int">
SELECT LAST_INSERT_ID()
</selectKey>
insert into user (username, password, age)
values (#{username,jdbcType=VARCHAR}, #{password,jdbcType=VARCHAR}, #{age,jdbcType=INTEGER})
</insert>
</mapper>
2.4、Service下創(chuàng)建一個UserService接口
public interface UserService {
public User queryUserById(int id);
public List<User> queryUserByAge(int age);
public List<User> queryUserByName(String username);
public int insertUser(User user);
}
再創(chuàng)建一個UserServiceImpl實現(xiàn)UserService
@Service
public class UserSeviceImpl implements UserService {
@Autowired
private UserDao userDao;
@Override
public User queryUserById(int id) {
return userDao.getUserById(id);
}
@Override
public List<User> queryUserByAge(int age) {
return userDao.getUserByAge(age);
}
@Override
public List<User> queryUserByName(String username) {
return userDao.getUserByName(username);
}
@Override
public int insertUser(User user) {
return userDao.insertUser(user);
}
}
2.5、controller下創(chuàng)建一個UserController
@GetMapping是代表該查詢接口用的是get方式
@RequestMapping(value="/insert",method = RequestMethod.POST)代表該插入接口用post方式
@RestController
public class UserController {
@Autowired
private UserService userService;
@GetMapping("/userid")
public User getUserById(@RequestParam("id") int id){
return userService.queryUserById(id);
}
@GetMapping("/username")
public List<User> getUserByUsername(@RequestParam("username") String username){
return userService.queryUserByName(username);
}
@RequestMapping(value="/insert",method = RequestMethod.POST)
public User insertUser(@RequestBody User user){
int x = userService.insertUser(user);
return user;
}
}
2.6、application.yml文件連接數(shù)據(jù)庫
server:
port: 8080
spring:
datasource:
driver-class-name: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://localhost:3306/testingdev9?useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai
username: root
password: 123456
mybatis:
mapper-locations:
- classpath:mapper/*.xml
- classpath*:com/**/mapper/*.xml
type-aliases-package: com.example.demo.model
2.7、啟動DemoApplication文件
出現(xiàn)Started DemoApplication代表啟動成功了
2.8、使用postman調(diào)用接口
如下圖根據(jù)id查詢
如下圖插入數(shù)據(jù)
可以看到數(shù)據(jù)庫多了一條數(shù)據(jù)
到此這篇關(guān)于使用Spring Boot實現(xiàn)操作數(shù)據(jù)庫的接口的過程的文章就介紹到這了,更多相關(guān)Spring Boot操作數(shù)據(jù)庫接口內(nèi)容請搜索服務(wù)器之家以前的文章或繼續(xù)瀏覽下面的相關(guān)文章希望大家以后多多支持服務(wù)器之家！
原文鏈接：https://blog.csdn.net/qq_39537481/article/details/118884915
