MyBatis-Plus条件构造器之condition参数的使用

<?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>

 <groupid>org.kaven</groupid>
 <artifactid>mybatis-plus</artifactid>
 <version>1.0-snapshot</version>

 <parent>
  <groupid>org.springframework.boot</groupid>
  <artifactid>spring-boot-starter-parent</artifactid>
  <version>2.3.4.release</version>
  <relativepath/>
 </parent>

 <properties>
  <java.version>1.8</java.version>
 </properties>

 <dependencies>
  <dependency>
   <groupid>org.springframework.boot</groupid>
   <artifactid>spring-boot-starter</artifactid>
  </dependency>
  <dependency>
   <groupid>org.springframework.boot</groupid>
   <artifactid>spring-boot-starter-test</artifactid>
  </dependency>
  <dependency>
   <groupid>org.springframework.boot</groupid>
   <artifactid>spring-boot-starter-webflux</artifactid>
  </dependency>
  <dependency>
   <groupid>com.baomidou</groupid>
   <artifactid>mybatis-plus-boot-starter</artifactid>
   <version>3.4.0</version>
  </dependency>
  <dependency>
   <groupid>mysql</groupid>
   <artifactid>mysql-connector-java</artifactid>
   <version>5.1.49</version>
  </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>

spring:
 application:
 name: mybatis-plus
 datasource:
 driver-class-name: com.mysql.jdbc.driver
 username: root
 password: itkaven@123
 url: jdbc:mysql://127.0.0.1:3306/test?characterencoding=utf-8&usessl=false

server:
 port: 8085

logging:
 level:
 root: warn
 com.kaven.mybatisplus.dao: trace
 pattern:
 console: '%p%m%n'

mybatis-plus:
 mapper-locations: classpath:mappers/*.xml

package com.kaven.mybatisplus.entity;

import com.baomidou.mybatisplus.annotation.tablefield;
import com.baomidou.mybatisplus.annotation.tableid;
import com.baomidou.mybatisplus.annotation.tablename;
import lombok.data;

@tablename("user")
@data
public class user {

 @tableid
 private string id;

 @tablefield("username")
 private string username;

 @tablefield("password")
 private string password;

 @tablefield("age")
 private integer age;

 /**
  * 使用 @tablefield(exist = false) ，表示该字段在数据库中不存在 ，所以不会插入数据库中
  * 使用 transient 、 static 修饰属性也不会插入数据库中
  */
 @tablefield(exist = false)
 private string phone;
}

package com.kaven.mybatisplus.dao;

import com.baomidou.mybatisplus.core.mapper.basemapper;
import com.kaven.mybatisplus.entity.user;
import org.springframework.stereotype.component;


@component
public interface usermapper extends basemapper<user> {}

package com.kaven.mybatisplus;

import org.mybatis.spring.annotation.mapperscan;
import org.springframework.boot.springapplication;
import org.springframework.boot.autoconfigure.springbootapplication;

@springbootapplication
@mapperscan(basepackages = "com.kaven.mybatisplus.dao")
public class apprun {
 public static void main(string[] args) {
  springapplication.run(apprun.class , args);
 }
}

package com.kaven.mybatisplus.dao;

import com.baomidou.mybatisplus.core.conditions.query.querywrapper;
import com.kaven.mybatisplus.entity.user;
import org.junit.test;
import org.junit.runner.runwith;
import org.springframework.beans.factory.annotation.autowired;
import org.springframework.boot.test.context.springboottest;
import org.springframework.test.context.junit4.springrunner;
import org.springframework.util.collectionutils;
import org.springframework.util.stringutils;

import java.util.arrays;
import java.util.list;


@runwith(springrunner.class)
@springboottest
public class usermapperconditiontest {

 @autowired
 private usermapper usermapper;

 @test
 public void selectlist(){
  string username = "k";
  list<integer> agelist = arrays.aslist(22 , 40 , 30);
  list<user> userlist = usermapper.selectlist(condition(username , agelist));
  userlist.foreach(system.out::println);
 }

 public querywrapper<user> condition(string username , list<integer> agelist){
  querywrapper<user> userquerywrapper = new querywrapper<>();
  if(!stringutils.isempty(username)){
   userquerywrapper.like("username" , username);
  }
  if(!collectionutils.isempty(agelist)){
   userquerywrapper.in("age" , agelist);
  }
  return userquerywrapper;
 }
}

package com.kaven.mybatisplus.dao;

import com.baomidou.mybatisplus.core.conditions.query.querywrapper;
import com.kaven.mybatisplus.entity.user;
import org.junit.test;
import org.junit.runner.runwith;
import org.springframework.beans.factory.annotation.autowired;
import org.springframework.boot.test.context.springboottest;
import org.springframework.test.context.junit4.springrunner;
import org.springframework.util.collectionutils;
import org.springframework.util.stringutils;

import java.util.arrays;
import java.util.list;


@runwith(springrunner.class)
@springboottest
public class usermapperconditiontest {

 @autowired
 private usermapper usermapper;

 @test
 public void selectlist(){
  string username = "k";
  list<integer> agelist = arrays.aslist(22 , 40 , 30);
  list<user> userlist = usermapper.selectlist(condition(username , agelist));
  userlist.foreach(system.out::println);
 }

 public querywrapper<user> condition(string username , list<integer> agelist){
  querywrapper<user> userquerywrapper = new querywrapper<>();
//  if(!stringutils.isempty(username)){
//   userquerywrapper.like("username" , username);
//  }
//  if(!collectionutils.isempty(agelist)){
//   userquerywrapper.in("age" , agelist);
//  }
  userquerywrapper.like(!stringutils.isempty(username) , "username" , username)
      .in(!collectionutils.isempty(agelist) , "age" , agelist);
  return userquerywrapper;
 }
}