动态sql和模糊查询

<?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.hous.day6.userMapper">
	<!-- 
		根据id查询到一个对象
		模糊查询：name like #{name} 或者  name like '%${name}%'
		查询条件and处理：使用<where>标签
	 -->
	<select id="getUser" parameterType="com.hous.day6.ConditionUser" 
		resultType="com.hous.day6.User">
		select * from users 
		<where>
			<if test="name != '%null%'">
				and name like #{name} 
			</if>
			<if test="minAge != 0 and maxAge != 0">
				and age between #{minAge} and #{maxAge}
			</if>
		</where> 
	</select>
</mapper>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
	
	<environments default="development">
		<environment id="development">
			<transactionManager type="JDBC"/>
			<dataSource type="POOLED">
				<property name="driver" value="com.mysql.jdbc.Driver"/>
				<property name="url" value="jdbc:mysql://localhost:3306/mybatis"/>
				<property name="username" value="root" />
				<property name="password" value="root" />
			</dataSource>
		</environment>
	</environments>
	
	<mappers>
		<mapper resource="com/hous/day6/userMapper.xml" />
	</mappers>
</configuration>

package com.hous.day6;

import static org.junit.Assert.*;

import java.io.InputStream;
import java.util.List;

import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Before;
import org.junit.Test;

public class MyTest {
	
	private SqlSessionFactory factory = null;
	
	@Before
	public void setUp() throws Exception {
		String resource = "day6/config.xml";
		InputStream config = MyTest.class.getClassLoader().getResourceAsStream(resource);
		factory = new SqlSessionFactoryBuilder().build(config);
	}

	@Test
	public void testGetUsers() {
		SqlSession session = factory.openSession();
		String statement = "com.hous.day6.userMapper.getUser";
		String name = null;
		ConditionUser conditionUser = new ConditionUser("%"+name+"%", 1, 100);
		List<User> users = session.selectList(statement, conditionUser);
		session.commit();
		session.close();
		System.out.println("查询结果：" + users);
	}

}

package com.hous.day6;

public class ConditionUser {
	private String name;
	private int minAge;
	private int maxAge;

	public ConditionUser(String name, int minAge, int maxAge) {
		super();
		this.name = name;
		this.minAge = minAge;
		this.maxAge = maxAge;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public int getMinAge() {
		return minAge;
	}

	public void setMinAge(int minAge) {
		this.minAge = minAge;
	}

	public int getMaxAge() {
		return maxAge;
	}

	public void setMaxAge(int maxAge) {
		this.maxAge = maxAge;
	}

}

package com.hous.day6;

public class User {
	private int id;
	private String name;
	private int age;

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}

	@Override
	public String toString() {
		return "User [id=" + id + ", name=" + name + ", age=" + age + "]";
	}

}