位置：首页>> 软件编程>> java编程>> springboot 使用mybatis查询的示例代码

springboot 使用mybatis查询的示例代码

作者：子岚天羽卿怜水　　发布时间：2022-03-30 03:19:09　

标签：springboot,mybatis,查询

示例1

项目结构

代码controller中 UserController.java

package com.example.demo1110.controller;

import com.example.demo1110.entity.User;
import com.example.demo1110.service.UserService;
import org.apache.ibatis.annotations.Param;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

@RestController
@RequestMapping("/user")
@CrossOrigin //解决跨域名获取
public class UserController {
@Autowired
private UserService userService;

@GetMapping("/all")
public List<User> getListUser(){
return userService.listUser();
}

@GetMapping("/getId/id={id}")
private User getId(@PathVariable("id") Integer id){
return userService.queryById(id);
}

@PostMapping("/EditUser")
private Map<String,Object> editUser(@RequestBody User user){
System.out.println(user);
HashMap<String,Object> map = new HashMap<>();
try {
userService.editUser(user);
map.put("success",true);
map.put("msg","修改员工成功");
}catch (Exception e){
e.printStackTrace();
map.put("success",false);
map.put("msg","修改员工失败");
}
return map;
}

@GetMapping("/getName")
public List<User> getName(@Param("name") String name){
return userService.queryByName(name);
}

@PostMapping("/addUser")
public Map<String,Object> addUser(@RequestBody User user){
HashMap<String,Object> map = new HashMap<>();
try {
userService.addUser(user);
map.put("success",true);
map.put("msg","添加员工成功");
}catch (Exception e){
e.printStackTrace();
map.put("success",false);
map.put("msg","添加用户失败");
}
return map;
}

@GetMapping("/deletUser/{id}")
public Map<String,Object> deletUser(@PathVariable("id") Integer id){
System.out.println(id);
HashMap<String,Object> map = new HashMap<>();
try {
userService.deleteUserById(id);
map.put("success",true);
map.put("msg","删除员工成功");
}catch (Exception e){
e.printStackTrace();
map.put("success",false);
map.put("msg","删除用户失败");
}
return map;
}
}

entity中 User.java

package com.example.demo1110.entity;
import lombok.Data;
@Data
public class User {
private int id;
private String name;
private int age;
private String city;
}

mapper中 UserDao.java

package com.example.demo1110.mapper;
import com.example.demo1110.entity.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;
import java.util.List;
@Mapper
@Repository
public interface UserDao {
//查询所有记录
public List<User> listUser();
//按id查询
public User queryById(Integer id);
//按姓名模糊查询
public List<User> queryByName(String name);

//保存用户
public int addUser(User user);
//根据员工id删除
public int deleteUserById(Integer id);
//修改员工信息
public int editUser(User user);
}

service中 UserService.java

package com.example.demo1110.service;

import com.example.demo1110.entity.User;

import java.util.List;

public interface UserService {
//查询所有记录
public List<User> listUser();
//按id查询
public User queryById(Integer id);
//按姓名模糊查询
public List<User> queryByName(String name);

//保存用户
public boolean addUser(User user);

//根据员工id删除
public boolean deleteUserById(Integer id);

//修改员工信息
public boolean editUser(User user);
}

service impl中 UserServiceImpl.java

package com.example.demo1110.service.impl;

import com.example.demo1110.entity.User;
import com.example.demo1110.mapper.UserDao;
import com.example.demo1110.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserServiceImpl implements UserService {
@Autowired
private UserDao userDao;

@Override
public List<User> listUser() {
return userDao.listUser();
}

@Override
public User queryById(Integer id) {
return userDao.queryById(id);
}

@Override
public List<User> queryByName(String name) {
return userDao.queryByName(name);
}

@Override
public boolean addUser(User user) {
int i = userDao.addUser(user);
if(i > 0){
return true;
}else {
return false;
}
}

@Override
public boolean deleteUserById(Integer id) {
int i = userDao.deleteUserById(id);
if(i > 0){
return true;
}else {
return false;
}
}

@Override
public boolean editUser(User user) {
int i = userDao.editUser(user);
if(i > 0){
return true;
}else {
return false;
}
}

}

主java文件 Demo1110Application.java

package com.example.demo1110;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@MapperScan("com.example.demo1110.mapper")
@SpringBootApplication
public class Demo1110Application {

public static void main(String[] args) {
SpringApplication.run(Demo1110Application.class, args);
}

}

UserMapper.xml

<?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.demo1110.mapper.UserDao">
<select id="listUser" resultType="com.example.demo1110.entity.User">
select * from user
</select>

<select id="queryById" parameterType="int" resultType="com.example.demo1110.entity.User">
select * from user
where id = #{id}
</select>

<select id="queryByName" parameterType="String" resultType="com.example.demo1110.entity.User">
select * from user
where username = #{name}
</select>

<insert id="addUser" parameterType="com.example.demo1110.entity.User">
insert into user values (#{id},#{username},#{age},#{city})
</insert>

<delete id="deleteEmployeeById" parameterType="int">
delete from user where id = #{id}
</delete>

<update id="editEmployee" parameterType="com.example.demo1110.entity.User">
update user
set username = #{name},age = #{age},city = #{city}
where id = #{id}
</update>
</mapper>

application.yml

spring:
datasource:
url: jdbc:mysql://127.0.0.1:3306/mybatisdemo?characterEncoding=utf-8&useSSL=false
username: root
password: root
driver-class-name: com.mysql.cj.jdbc.Driver
mybatis:
mapper-locations: classpath*:mapper/*Mapper.xml
type-aliases-package: com.example.demo1110.entity

数据SQL

SET FOREIGN_KEY_CHECKS=0;

-- ----------------------------
-- Table structure for user
-- ----------------------------
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`name` varchar(255) NOT NULL,
`age` int(6) NOT NULL,
`city` varchar(255) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of user
-- ----------------------------
INSERT INTO `user` VALUES ('1', '小明', '18', '深圳');
INSERT INTO `user` VALUES ('2', '小明1', '18', '深圳');

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.5.6</version>
<relativePath/> 
</parent>
<groupId>com.example</groupId>
<artifactId>demo1110</artifactId>
<version>1.0.0</version>
<name>demo1110</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<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>2.2.0</version>
</dependency>

<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.0.9</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>
</dependencies>

<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>

</project>

示例2

项目结构

数据sql

SET FOREIGN_KEY_CHECKS=0;

-- ----------------------------
-- Table structure for user
-- ----------------------------
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`name` varchar(255) NOT NULL,
`age` int(6) NOT NULL,
`city` varchar(255) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of user
-- ----------------------------
INSERT INTO `user` VALUES ('1', '小明', '18', '深圳');
INSERT INTO `user` VALUES ('2', '小明1', '18', '深圳');

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.5.6</version>
<relativePath/> 
</parent>
<groupId>com.example</groupId>
<artifactId>demo1110</artifactId>
<version>1.0.0</version>
<name>demo1110</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<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>2.2.0</version>
</dependency>

<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.0.9</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>
</dependencies>

<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>

</project>

application.yml

spring:
datasource:
url: jdbc:mysql://127.0.0.1:3306/mybatisdemo?characterEncoding=utf-8&useSSL=false
username: root
password: root
driver-class-name: com.mysql.cj.jdbc.Driver
mybatis:
mapper-locations: classpath*:mapper/*Mapper.xml
type-aliases-package: com.example.demo1110.entity
#打印sql语句
##
#logging.level.com.example.demo1110.mapper=DEBUG
logging:
level:
com.example.demo1110.mapper: debug

Demo1110Application.java

package com.example.demo1110;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@MapperScan("com.example.demo1110.mapper")
@SpringBootApplication
public class Demo1110Application {

public static void main(String[] args) {
SpringApplication.run(Demo1110Application.class, args);
}

}

entity ->User.java

package com.example.demo1110.entity;

import lombok.Data;

@Data
public class User {
private int id;
private String name;
private int age;
private String city;

public User(Integer id, String name, Integer age) {
this.id = id;
this.name = name;
this.age = age;
}
public User(){

}

@Override
public String toString() {
return "User{" +
"id=" + id +
", name='" + name + '\'' +
", age=" + age +
", city=" + city +
'}';
}
}

mapper -> UserMapper.java

package com.example.demo1110.mapper;

import com.example.demo1110.entity.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;

import java.util.List;

@Mapper
@Repository
public interface UserMapper {
/*//查询所有记录
public List<User> listUser();
//按id查询
public User queryById(Integer id);
//按姓名模糊查询
public List<User> queryByName(String name);

//保存用户
public int addUser(User user);
//根据员工id删除
public int deleteUserById(Integer id);
//修改员工信息
public int editUser(User user);*/
/**
* 查询全部s
* @return
*/
List<User> findAllUser();

/**
* 根据id查询
* @param id
* @return
*/
User findUser(Integer id);

/**
* 新增
* @param user
*/
void insertUser(User user);

/**
* 根据id删除
* @param id
*/
void deleteUser(Integer id);

/**
* 更新
* @param user
*/
void updateUser(User user);
/**
* 批量删除
* @param ids
*/

void deleteUserByList(Integer[] ids);
}

service -> UserService.java

package com.example.demo1110.service;
import com.example.demo1110.entity.User;
import java.util.List;
public interface UserService {
/*//查询所有记录
public List<User> listUser();
//按id查询
public User queryById(Integer id);
//按姓名模糊查询
public List<User> queryByName(String name);
//保存用户
public boolean addUser(User user);
//根据员工id删除
public boolean deleteUserById(Integer id);
//修改员工信息
public boolean editUser(User user);*/
/**
* 查询全部
* @return
*/
List<User> findAll();
/**
* 根据id查询
* @param id
* @return
*/
User findUserById(Integer id);
/**
* 新增
* @param user
*/
void insertUser(User user);
/**
* 更新
* @param user
*/
void updateUser(User user);
/**
* 删除单个用户
* @param id
*/
void deleteUser(Integer id);
void deleteUserByList(Integer[] ids);
}

service impl ->UserServiceImpl.java

package com.example.demo1110.service.impl;
import com.example.demo1110.entity.User;
import com.example.demo1110.mapper.UserMapper;
import com.example.demo1110.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class UserServiceImpl implements UserService {
/*@Autowired
private UserMapper userDao;
@Override
public List<User> listUser() {
return userDao.listUser();
}
@Override
public User queryById(Integer id) {
return userDao.queryById(id);
}
@Override
public List<User> queryByName(String name) {
return userDao.queryByName(name);
}
@Override
public boolean addUser(User user) {
int i = userDao.addUser(user);
if(i > 0){
return true;
}else {
return false;
}
}
@Override
public boolean deleteUserById(Integer id) {
int i = userDao.deleteUserById(id);
if(i > 0){
return true;
}else {
return false;
}
}
@Override
public boolean editUser(User user) {
int i = userDao.editUser(user);
if(i > 0){
return true;
}else {
return false;
}
}*/
@Autowired
private UserMapper userMapper;
@Override
public User findUserById(Integer id) {
return userMapper.findUser(id);
}
@Override
public List<User> findAll() {
return userMapper.findAllUser();
}
@Override
public void insertUser(User user) {
userMapper.insertUser(user);
}
@Override
public void updateUser(User user) {
userMapper.updateUser(user);
}
@Override
public void deleteUser(Integer id) {
userMapper.deleteUser(id);
}
@Override
public void deleteUserByList(Integer[] ids) {
userMapper.deleteUserByList(ids);
}
}

controller ->UserController.java

package com.example.demo1110.controller;

import com.example.demo1110.entity.User;
import com.example.demo1110.service.UserService;
import org.apache.ibatis.annotations.Param;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

@RestController
@RequestMapping("/user")
@CrossOrigin //解决跨域名获取
public class UserController {
/*@Autowired
private UserService userService;

@GetMapping("/all")
public List<User> getListUser(){
return userService.listUser();
}

@GetMapping("/getId/id={id}")
private User getId(@PathVariable("id") Integer id){
return userService.queryById(id);
}

@PostMapping("/EditUser")
private Map<String,Object> editUser(@RequestBody User user){
System.out.println(user);
HashMap<String,Object> map = new HashMap<>();
try {
userService.editUser(user);
map.put("success",true);
map.put("msg","修改员工成功");
}catch (Exception e){
e.printStackTrace();
map.put("success",false);
map.put("msg","修改员工失败");
}
return map;
}

@GetMapping("/getName")
public List<User> getName(@Param("name") String name){
return userService.queryByName(name);
}

@PostMapping("/addUser")
public Map<String,Object> addUser(@RequestBody User user){
HashMap<String,Object> map = new HashMap<>();
try {
userService.addUser(user);
map.put("success",true);
map.put("msg","添加员工成功");
}catch (Exception e){
e.printStackTrace();
map.put("success",false);
map.put("msg","添加用户失败");
}
return map;
}

@GetMapping("/deletUser/{id}")
public Map<String,Object> deletUser(@PathVariable("id") Integer id){
System.out.println(id);
HashMap<String,Object> map = new HashMap<>();
try {
userService.deleteUserById(id);
map.put("success",true);
map.put("msg","删除员工成功");
}catch (Exception e){
e.printStackTrace();
map.put("success",false);
map.put("msg","删除用户失败");
}
return map;
}*/
@Autowired
private UserService userService;

@GetMapping("/{id}")
public User findUserByid(@PathVariable("id") Integer id){
return userService.findUserById(id);
}

@GetMapping("/findAll")
public List<User> findAll(){
return userService.findAll();
}

@PostMapping("/add")
// // post转实体对象只能用raw application/json格式传参 key-value跟实体对应 controller用@RequestBody
public void insertUser(@RequestBody User user){
userService.insertUser(user);
}

@PutMapping("/update")
public void updateUser(@RequestBody User user){
userService.updateUser(user);
}

@DeleteMapping("/delete/{id}")
public void deleteUser(@PathVariable("id") Integer id){
userService.deleteUser(id);
}

@DeleteMapping("/deleteBatch")
public void deleteBatch(@RequestBody Integer[] ids){
userService.deleteUserByList(ids);
}
}

controller ->IndexController.java

package com.example.demo1110.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController

public class IndexController {
@RequestMapping ("/")
String home () {
return "hello world!!";
}
}

resources mapper -> UserMapper.xml

<?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.demo1110.mapper.UserMapper">
<resultMap id="user" type="com.example.demo1110.entity.User">
<id column="id" property="id"/>
<result column="age" property="age"/>
<result column="name" property="name"/>
</resultMap>
<select id="findUser" parameterType="int" resultMap="user">
select * from user
<where>
<if test="_parameter!=null">
and id = #{id}
</if>
</where>
</select>

<select id="findAllUser" resultMap="user">
select * from user
</select>

<sql id="key">
<trim suffixOverrides=",">
<if test="id!=null">
id,</if>
<if test="name!=null">
name,
</if>

<if test="age!=null">
age,
</if>
</trim>
</sql>
<sql id="value">
<trim suffixOverrides=",">
<if test="id!=null">
#{id},
</if>
<if test="name!=null">
#{name},
</if>
<if test="age!=null">
#{age},
</if>
</trim>
</sql>

<insert id="insertUser" parameterType="user">
insert into user(<include refid="key"/>) values (<include refid="value"/>)
</insert>

<update id="updateUser" parameterType="user">
UPDATE user
<trim prefix="set" suffixOverrides=",">
<if test="age!=null">age=#{age},</if>
<if test="name!=null and name !=''">name=#{name},</if>
</trim>
WHERE id=#{id}

</update>
<delete id="deleteUser" parameterType="Integer">
delete from user where id = #{id}
</delete>

<delete id="deleteUserByList">
delete from user where id in
<foreach collection="array" open="(" close=")" separator="," item="id">
#{id}
</foreach>
</delete>

</mapper>