Springboot+mybatis整合，实现rest服务，http、json传输
项目结构如下：
Controller 控制层 entity 实体层 mapper数据操作层 service 业务逻辑层
application.yml application-dev.yml 配置文件
idea=>spring initializer=>next
配置application.yml及application-dev.yml文件
1、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 http://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>2.1.3.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>cn.mark</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>demo</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-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>2.0.0</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-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
2、application.yml
spring:
profiles:
active: dev
3、application-dev.yml
server:
port: 8080
spring:
datasource:
username: root
password: 123456
url: jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone=UTC
driver-class-name: com.mysql.jdbc.Driver
mybatis:
type-aliases-package: cn.mark.demo.entity
mapper-locations: classpath:mapping/*Mapper.xml
#showsql
logging:
level:
cn:
mark:
demo:
mapper: debug
4、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="cn.mark.demo.dao.UserMapper"><!namespace must be correct!>
<resultMap id="BaseResultMap" type="cn.mark.demo.entity.User">
<result column="id" jdbcType="INTEGER" property="id"/>
<result column="username" jdbcType="VARCHAR" property="userName"/>
<result column="password" jdbcType="VARCHAR" property="passWord"/>
<result column="realName" jdbcType="VARCHAR" property="realName"/>
</resultMap>
<sql id="Base_Column_List">
id, username, password, realName
</sql>
<select id="getUserById" resultType="cn.mark.demo.entity.User">
select * from user where id=#{id}
</select>
<select id="getAllUsers" resultMap="BaseResultMap">
select
<include refid="Base_Column_List"/>
from user
</select>
<select id="saveUser" parameterType="cn.mark.demo.entity.User">
insert into
user(id, username, password, realName)
values
(#{id},#{userName},#{passWord},#{realName})
</select>
<update id="updateUser" parameterType="cn.mark.demo.entity.User">
update
user
set
<if test="userName!=null">
username = #{userName},
</if>
<if test="passWord!=null">
password = #{passWord},
</if>
<if test="realName!=null">
realName = #{realName}
</if>
where
id=#{id}
</update>
<delete id="deleteUser" parameterType="java.lang.Integer">
delete from user
where id=#{id}
</delete>
</mapper>
5\ DemoApplication.java
package cn.mark.demo;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@MapperScan("cn.mark.demo.dao")//一定要添加这句
@SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}
6\ UserService.java
package cn.mark.demo.service;
import cn.mark.demo.entity.User;
import cn.mark.demo.dao.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class UserService {
@Autowired
private UserMapper userMapper;
public User getUserById(int id){
return userMapper.getUserById(id);
};
public List<User> getAllUsers(){
return userMapper.getAllUsers();
}
public void saveUser(User user){
userMapper.saveUser(user);
}
public void updateUser(User user){
userMapper.updateUser(user);
}
public void deleteUser(int id){
userMapper.deleteUser(id);
}
}
7\ User.java
package cn.mark.demo.entity;
public class User {
private Integer id;
private String userName;
private String passWord;
private String realName;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getPassWord() {
return passWord;
}
public void setPassWord(String passWord) {
this.passWord = passWord;
}
public String getRealName() {
return realName;
}
public void setRealName(String realName) {
this.realName = realName;
}
}
8\ UserMapper.java
package cn.mark.demo.dao;
import cn.mark.demo.entity.User;
import org.springframework.stereotype.Repository;
import org.apache.ibatis.annotations.Select;
import java.util.List;
@Repository
public interface UserMapper {
public User getUserById(int id);
public List<User> getAllUsers();
public void saveUser(User user);
public void updateUser(User user);
public void deleteUser(int id);
}
9\ UserController.java
package cn.mark.demo.controller;
import cn.mark.demo.entity.User;
import cn.mark.demo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.util.List;
@RestController
@RequestMapping("/testBoot")
public class UserController {
@Autowired
private UserService userService;
@RequestMapping("getUser/{id}")
public User getUserById(@PathVariable int id){
return userService.getUserById(id);
}
@RequestMapping("getUsers")
public List<User> getAllUsers(){
return userService.getAllUsers();
}
@RequestMapping(value = "saveUser",method = RequestMethod.POST)
public void saveUser(@RequestBody User user){
userService.saveUser(user);
}
@RequestMapping(value = "updateUser",method = RequestMethod.PUT)
public void updateUser(@RequestBody User user){
userService.updateUser(user);
}
@RequestMapping(value = "deleteUser/{id}",method = RequestMethod.DELETE)
public void deleteUser(@PathVariable int id){
userService.deleteUser(id);
}
}
1.检查xml文件所在package名称是否和Mapper interface所在的包名
<mapper namespace="me.tspace.pm.dao.UserDao">
mapper的namespace写的不对！！！注意系修改。
2.UserDao的方法在UserDao.xml中没有，然后执行UserDao的方法会报此
3. UserDao的方法返回值是List<User>,而select元素没有正确配置ResultMap,或者只配置ResultType!
4. 如果你确认没有以上问题,请任意修改下对应的xml文件,比如删除一个空行,保存.问题解决
5.看下mapper的XML配置路径是否正确