准备数据库：
配置maven仓库 <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-jdbc</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>2.1.0</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <scope>runtime</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-tomcat</artifactId> <scope>provided</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <!-- Gson --> <dependency> <groupId>com.google.code.gson</groupId> <artifactId>gson</artifactId> <version>2.8.5</version> </dependency> application.properties中添加mybatis映射文件配置 这一步是配置xml文件的位置，如果不配置，找不到xml映射文件 #配置mybatis #指定sql映射文件位置 claspath:resources文件夹 mybatis.mapper-locations=classpath:mapper/*.xml 添加映射对象dao public class User { private int id; private String head_pic; private String user_name; private String account; private String pw; @Override public String toString() { JSONObject jsonObject = new JSONObject(); jsonObject.put("account",account); jsonObject.put("pw",pw); return jsonObject.toString(); } //getters... //setters... } 添加关联映射对象的java类 @Repository可以换成@Mapper @Repository//映射mapper文件，替代@mapper public interface UserMapper { User Sel(int id); } 添加数据service @Service//service标识 public class UserService { @Autowired//自动初始化对象 UserMapper userMapper; public User Sel(int id){ return userMapper.Sel(id); } } 添加控制器controller注意写法，get请求参数不需要配置，如果配置成/getUser/{id}这种形式，浏览器会报错
Whitelabel Error Page This application has no explicit mapping for /error, so you are seeing this as a fallback. Fri Nov 01 14:56:52 CST 2019 There was an unexpected error (type=Not Found, status=404). No message available
@RestController//controller标识 @RequestMapping("/abc")//请求路径 public class UserController{ @Autowired//自动初始化对象 UserService userService; @GetMapping("/getUser")//请求路径 public String getUser(int id){ System.out.print("id = "+id); return userService.Sel(id).toString(); } } 浏览器显示查询结果 输入网址：http://localhost:8888/abc/getUser?id=1 显示结果：