前言
最近在工作中需要使用到mybatis，需要实现某个功能。
但是发现需要编写一个sql，但是mybatis的映射文件入参是List集合和Map<String,Integer>,需要循环List，然后通过List循环出来的值为Key获取Map中的值作为sql的入参，遇到了一些问题。
但是经过不懈的努力，最后终于解决了这个问题。顺便分享一下自己的经验。
1.项目结构
2.pom文件配置
server:
port: 8379
spring:
datasource:
username: root
url: jdbc:mysql://localhost:3306/shop?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone=UTC
driver-class-name: com.mysql.jdbc.Driver
mybatis:
mapper-locations: classpath:mapping/*Mapper.xml
type-aliases-package: com.example.bean
#showSql
logging:
level:
com:
example:
dao : debug3.其他的业务代码
package com.example.bean;
import lombok.Data;
@Data
public class SysUser {
private Integer id;
private String username;
private String image;
}package com.example.controller;
import com.example.bean.SysUser;
import com.example.service.SysUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
@RestController
public class SysUserController {
@Autowired
private SysUserService sysUserService;
@GetMapping("/getSysUserById/{id}")
SysUser getSysUserById(@PathVariable("id") String id) {
List<String> ids = new ArrayList<>();
Map<String, Integer> infoMap = new HashMap<>();
infoMap.put("1", 1);
infoMap.put("8", 8);
infoMap.put("9", 9);
ids.add(id);
return sysUserService.getSysUserById(ids, infoMap);
}
}package com.example.dao;
import com.example.bean.SysUser;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;
import java.util.List;
import java.util.Map;
@Mapper
public interface SysUserMapper {
SysUser getSysUserById(@Param("ids") List<String> ids,@Param("infoMap") Map<String,Integer> infoMap);
}package com.example.service;
import com.example.bean.SysUser;
import com.example.dao.SysUserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
import java.util.Map;
@Service
public class SysUserService {
@Autowired
private SysUserMapper sysUserMapper;
public SysUser getSysUserById(List<String> ids, Map<String, Integer> infoMap) {
return sysUserMapper.getSysUserById(ids,infoMap);
}
}<?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.dao.SysUserMapper">
<select id="getSysUserById" resultType="com.example.bean.SysUser">
<foreach collection="ids" item="id">
<bind name="userId" value="infoMap[id]"/>
select * from sys_user where id = #{userId}
</foreach>
</select>
</mapper>
第一种采用#符的取值法
是可以防止sql注入的，可以通过循环List获取Map的值
<?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.dao.SysUserMapper">
<select id="getSysUserById" resultType="com.example.bean.SysUser">
<foreach collection="ids" item="id">
<!-- <bind name="userId" value="infoMap[id]"/>-->
select * from sys_user where id = '${infoMap[id]}'
</foreach>
</select>
</mapper>
第二种方式采用$符的取值法
也可以获取，虽然不能防止sql注入，但是可以做白名单的校验，防止sql注入
4.总结
本人小白一枚，以上仅为个人经验，希望能给大家一个参考，也希望大家多多支持Devmax。