mybatis 之动态SQL查询

首先创建数据库：

mybatis 之动态SQL查询

然后创建实体类：

package com.wfl.mybatis.bean6;

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 + "]";
}

}

------------------

package com.wfl.mybatis.bean6;

public class ConditionUser {

private String name;
private int minAge;
private int 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;
}
@Override
public String toString() {
  return "ConditionUser [name=" + name + ", minAge=" + minAge + ", maxAge=" + maxAge + "]";
}
public ConditionUser(String name, int minAge, int maxAge) {
  super();
  this.name = name;
  this.minAge = minAge;
  this.maxAge = maxAge;
}

}

------------

重要的是配置文件：

<?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.wfl.mybatis.service6.classMapper">
     
     <select id="getUser" parameterType="com.wfl.mybatis.bean6.ConditionUser"
              resultType="com.wfl.mybatis.bean6.User">
              
              select * from d_user where age>=#{minAge} and age<=#{maxAge}
          
          <if test='name!="%null%"'>and name like#{name}</if>
      </select>
</mapper>
----------------------------

去conf.xml文件注册，然后是测试类：

package com.wfl.mybatis.service6;

import java.io.IOException;
import java.io.Reader;
import java.util.List;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import com.wfl.mybatis.bean6.ConditionUser;
import com.wfl.mybatis.bean6.User;

public class UserTest {

public static void main(String[] args) throws IOException{
  //获取字符流
  Reader reader=Resources.getResourceAsReader("conf.xml");
  //获取绘画对象工厂类
  SqlSessionFactory sessionFactory=new SqlSessionFactoryBuilder().build(reader);
  //获取绘画对象操作数据语句
  SqlSession sqlSession=sessionFactory.openSession();
  //配置文件中的sql语句
  String statement="com.wfl.mybatis.service6.classMapper.getUser";
  //执行sql语句，得到返回结果
  List<User> list=sqlSession.selectList(statement, new ConditionUser("%a%",1,17));
  System.out.println(list);
}
}

mybatis 之 动态SQL查询

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mybatis 之动态SQL查询