mybatisPlus条件构造器AbstractWrapper

配置，接口，实体类等就不再写了，可以参考上一篇

https://blog.csdn.net/qq_43560721/article/details/89487137

这里简单举几个例子：

package cn.xxs.test;

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

import org.apache.ibatis.session.RowBounds;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.junit.Before;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.baomidou.mybatisplus.mapper.EntityWrapper;
import cn.xxs.mapper.UserMapper;
import cn.xxs.pojo.Student;


public class Test {
	
	private SqlSessionFactory sqlSessionFactory;
	
	@Before
	public void init() {
		//通过输入流创建SqlSessionFactory
		sqlSessionFactory = (SqlSessionFactory) new ClassPathXmlApplicationContext("bean.xml").getBean("sqlSessionFactory");
	}
	/**
	 * allEq
	 * @throws IOException 
	 */
	@org.junit.Test
	public void allEq() throws IOException {		
		//创建SqlSession对象
		SqlSession ss = sqlSessionFactory.openSession();		
		//多态的运用,为掉方法做准备			
		UserMapper userMapper = ss.getMapper(UserMapper.class);					
		//map中的第一个参数指的是表中的列的名字，第二参数对应的传入的参数
		Map<String,Object> columnMap = new HashMap<String, Object>();
		columnMap.put("studentName", "s");
		EntityWrapper<Student> wrapper = new EntityWrapper<Student>();
		wrapper.allEq(columnMap);
		//使用
		List<Student> stuList = userMapper.selectList(wrapper);	
			//控制台输出
		for(Student student:stuList) {
			System.out.println(student);
		}
		//释放资源
		ss.close();	
	}	
	
	/**
	 * eq
	 * @throws IOException 
	 */
	@org.junit.Test
	public void eq() throws IOException {		
		//创建SqlSession对象
		SqlSession ss = sqlSessionFactory.openSession();		
		//多态的运用,为掉方法做准备			
		UserMapper userMapper = ss.getMapper(UserMapper.class);							
		
		EntityWrapper<Student> wrapper = new EntityWrapper<Student>();
		wrapper.eq("studentId",1);		
		//使用
		List<Student> stuList = userMapper.selectList(wrapper);	
			//控制台输出
		for(Student student:stuList) {
			System.out.println(student);
		}
		//释放资源
		ss.close();	
	}	
	/**
	 * like
	 * @throws IOException 
	 */
	@org.junit.Test
	public void like() throws IOException {		
		//创建SqlSession对象
		SqlSession ss = sqlSessionFactory.openSession();		
		//多态的运用,为掉方法做准备			
		UserMapper userMapper = ss.getMapper(UserMapper.class);							
		
		EntityWrapper<Student> wrapper = new EntityWrapper<Student>();		
		wrapper.like("studentName","s");
		//使用
		List<Student> stuList = userMapper.selectList(wrapper);	
			//控制台输出
		for(Student student:stuList) {
			System.out.println(student);
		}
		//释放资源
		ss.close();	
	}	
	/**
	 * gt查询结果不带第1条
	 * @throws IOException 
	 */
	@org.junit.Test
	public void gt() throws IOException {		
		//创建SqlSession对象
		SqlSession ss = sqlSessionFactory.openSession();		
		//多态的运用,为掉方法做准备			
		UserMapper userMapper = ss.getMapper(UserMapper.class);							
		
		EntityWrapper<Student> wrapper = new EntityWrapper<Student>();		
		wrapper.gt("studentId",1);
		//使用
		List<Student> stuList = userMapper.selectList(wrapper);	
			//控制台输出
		for(Student student:stuList) {
			System.out.println(student);
		}
		//释放资源
		ss.close();	
	}	
	/**
	 * ge 查询结果带第1条
	 * @throws IOException 
	 */
	@org.junit.Test
	public void ge() throws IOException {		
		//创建SqlSession对象
		SqlSession ss = sqlSessionFactory.openSession();		
		//多态的运用,为掉方法做准备			
		UserMapper userMapper = ss.getMapper(UserMapper.class);							
		
		EntityWrapper<Student> wrapper = new EntityWrapper<Student>();		
		wrapper.ge("studentId",1);
		//使用
		List<Student> stuList = userMapper.selectList(wrapper);	
			//控制台输出
		for(Student student:stuList) {
			System.out.println(student);
		}
		//释放资源
		ss.close();	
	}	
	/**
	 * between 查询结果带第1条和第五条
	 * @throws IOException 
	 */
	@org.junit.Test
	public void between() throws IOException {		
		//创建SqlSession对象
		SqlSession ss = sqlSessionFactory.openSession();		
		//多态的运用,为掉方法做准备			
		UserMapper userMapper = ss.getMapper(UserMapper.class);							
		
		EntityWrapper<Student> wrapper = new EntityWrapper<Student>();		
		wrapper.between("studentId",1,5);
		//使用
		List<Student> stuList = userMapper.selectList(wrapper);	
			//控制台输出
		for(Student student:stuList) {
			System.out.println(student);
		}
		//释放资源
		ss.close();	
	}	
	
	/**
	 *  分页查询
	 * @throws IOException 
	 */
	@org.junit.Test
	public void pageFind() throws IOException {		
		//创建SqlSession对象
		SqlSession ss = sqlSessionFactory.openSession();		
		//多态的运用,为掉方法做准备			
		UserMapper userMapper = ss.getMapper(UserMapper.class);							
		
		EntityWrapper<Student> wrapper = new EntityWrapper<Student>();		
		//第一个参数：起始位置，第二个参数：查询条数
		RowBounds rowBounds = new RowBounds(0,1);
		//使用
		List<Student> stuList = userMapper.selectPage(rowBounds, wrapper);	
			//控制台输出
		for(Student student:stuList) {
			System.out.println(student);
		}
		//释放资源
		ss.close();	
	}
}
           

更多条件构造器见

https://mp.baomidou.com/guide/wrapper.html#abstractwrapper