SpringBoot + Mybatis实现关键字模糊查询

1. 先写一个REST端点——Controller

Class: controller/TestController.class

package controller;

@GetMapping("/search")
public List<UserInfo> search(String keyword) {
     return userInfoService.searchByKeyWord(keyword);
}

2. 写业务接口——sevice

Class：service/UserinfoService.class

package service;

@Service
public interface UserInfoService {
	//关键词模糊查询
    List<UserInfo> searchByKeyWord(String keyword);
}

3. 写业务接口的实现类——service/impl

Class: service/impl/UserInfoServiceImpl.class

package service.impl;

@Service
public class UserInfoServiceImpl implements UserInfoService {
	@Override
    public List<UserInfo> searchByKeyWord(String keyword) {
        return userInfoDao.searchByKeyWord(keyword);
    }
}

4. 写映射层接口——dao

Class: dao/UserInfoDao.class

package dao;

@Mapper
public interface UserInfoDao {
	//关键词模糊查询
    List<UserInfo> searchByKeyWord(String keyword);
}

5. 写sql映射文件——resource/mapper

UserInfo.xml

DOCTYPE mapper  PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="dao.UserInfoDao">
	<select id="searchByKeyWord" parameterType="String" resultType="UserInfo">
        SELECT * FROM userinfo
        WHERE 1 = 1
        <if test="keyword != null and keyword != ''">
            AND id||username||role LIKE '%'||#{keyword}||'%'
        if>
        ORDER BY id
    select>
mapper>

• Id, username, role 是要查询表中的字段
• ||用于拼接，与CONCAT关键字类似