1.1新建项目

选择Spring Initializr或者maven项目都可以

初始化好的项目

1.2 引pom

完全可以和java项目中引入依赖画等号

引入SQLServer的驱动包 还有我们要来操作数据库的Mybatis -plus

org.projectlombok

lombok

com.microsoft.sqlserver

sqljdbc4

4.0

com.baomidou

mybatis-plus-boot-starter

3.0.5

1.3 改yml

spring:

datasource:

driver-class-name: com.microsoft.sqlserver.jdbc.SQLServerDriver

url: jdbc:sqlserver://localhost:1433;databaseName=demo01

username: sa

password: 123456rw

1.4新建实体类绑定表

新建User表和数据库中表帮绑定

@Data

@TableName("user1")

public class User {

private Integer id;

private String name;

}

1.5 建Mapper接口

@Repository

public interface UserMapper extends BaseMapper {

}

1.6让启动时扫描dao层mapper接口

@SpringBootApplication

@MapperScan("com.rw.Mapper")

public class Main {

public static void main(String[] args) {

SpringApplication.run(Main.class, args);

}

}

1.7写接口去测试

@Controller

public class TestController {

@Autowired

private UserMapper userMapper;

@RequestMapping("getAllUser")

@ResponseBody//把返回值打印到页面(JSON)

public List getAlluser(){

//queryWrapper 查询条件 如果过传递 null 就是查询所有数据

//先创建一个条件对象

QueryWrapper queryWrapper=new QueryWrapper<>();

//添加条件

//eq 是等于 查询id==1 的数据

//queryWrapper.eq("id","2");

/**

* ne 是不等于

*/

//queryWrapper.ge("id","5");

//queryWrapper.between("id",2,5);

//queryWrapper.like("name","小");

queryWrapper.orderByDesc("id");

return userMapper.selectList(queryWrapper);

}

@ResponseBody

@RequestMapping("/add")

public String add(){

User user=new User();

user.setId(11);

user.setName("小王");

int insert = userMapper.insert(user);

if (insert>0){

return "添加成功！";

}else {

return "添加失败！";

}

}

@RequestMapping("/update")

@ResponseBody

public String update(){

//1.查询要修改的内容

User user = userMapper.selectById("3");

System.out.println(user);

//2.修改

user.setName("New Hello");

//userMapper.updateById() 根据你user的id进行修改

int i = userMapper.update(user,new QueryWrapper().eq("id","3"));

if (i>0){

System.out.println("修改成功！");

return "修改成功！";

}else {

System.out.println("修改失败！");

return "修改失败";

}

}

@RequestMapping("/delete")

@ResponseBody

public String delete(){

//创建一个条件对象

QueryWrapper wrapper=new QueryWrapper();

//添加条件

/**

* 删除的是 name=New Hello 这条数据

*/

wrapper.eq("name","New Hello");

int delete = userMapper.delete(wrapper);

if (delete>0){

return "删除成功！";

}else {

return "删除失败！";

}

}

}

标签：queryWrapper,return,userMapper,SQLServer,id,Maven,plus,user,public

来源： https://blog.csdn.net/weixin_45498245/article/details/110304807