1.pom.xml引入依赖 2.数据库建表（id设为自动递增） 插入一条记录
3.数据库配置 4.建包和类 5.Hello.java
package com.example.demo.Controller; import com.example.demo.Service.UserService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; @RestController public class Hello{ @Autowired private UserService userService; @RequestMapping("/getUserInfo") public Object getUserById(Integer id){ return userService.getUserById(id).toString(); } @RequestMapping("/insertUserInfo") public Object insertUser(String username,String sex){ userService.insertUser(username,sex); return "success"; } }6.User.java
package com.example.demo.Entity; public class User { private int id; private String username; private String sex; public void setId(int id){ this.id = id; } public int getId() { return id; } public void setUsername(String username){ this.username = username; } public String getUsername(){ return username; } public void setSex(String sex) { this.sex = sex; } public String getSex(){ return sex; } @Override public String toString() { return "User{" + "id=" + id + ", username='" + username + '\'' + ", sex='" + sex + '\'' + '}'; } }7.UserMapper.java
package com.example.demo.Mapper; import com.example.demo.Entity.User; import org.apache.ibatis.annotations.*; @Mapper public interface UserMapper { @Select("select * from user where id = #{id}") User getUserById(@Param("id") Integer id); @Insert("insert into user values(NULL,#{username},#{sex})") void insertUser(@Param("username") String username, @Param("sex") String sex); }8.UserService.java
package com.example.demo.Service; import com.example.demo.Entity.User; public interface UserService { User getUserById(Integer id); void insertUser(String username, String sex); }9.UserServiceImpl.java
package com.example.demo.Service; import com.example.demo.Entity.User; import com.example.demo.Mapper.UserMapper; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; @Service public class UserServiceImpl implements UserService { @Autowired private UserMapper userMapper; @Override public User getUserById(Integer id){ return userMapper.getUserById(id); } @Override public void insertUser(String username, String sex) { userMapper.insertUser(username,sex); } }10.在浏览器中进行测试 （1）查询ID为1的用户信息 （2）插入用户Linda （3）查询ID为2的用户信息 11.SpringBoot ResultFul风格 JSON格式 加特定请求，如Get、Post Get用来查数据，Post用来插数据
Hello.java改为：
package com.example.demo.Controller; import com.example.demo.Service.UserService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PostMapping; import org.springframework.web.bind.annotation.RestController; @RestController public class Hello{ @Autowired private UserService userService; @GetMapping("/getUserInfo") public Object getUserById(Integer id){ return userService.getUserById(id).toString(); } @PostMapping("/insertUserInfo") public Object insertUser(String username,String sex){ userService.insertUser(username,sex); return "success"; } }注意：PostMapping需要测试工具（如PostMan）来测试，不能在浏览器地址栏中测试：
