动态SQL与模糊查询

一：

1.需求

　　实现多条件查询用户（姓名模糊查询，年龄在指定的最小值与最大值之间）

2.结构目录

　　

3.准备数据与建表

 CREATE TABLE d_user(
     id int PRIMARY KEY AUTO_INCREMENT,
     name VARCHAR(20),
     age INT(3)
 );
 INSERT INTO d_user(name,age) VALUES('Tom',12);
 INSERT INTO d_user(name,age) VALUES('Bob',14);
 INSERT INTO d_user(name,age) VALUES('Jack',18);

4.新建实体类User.java

 package com.cao.bean;

 public class User {
     private int id;
     private String name;
     private int age;
     public User() {}

     public User(int id, String name, int age) {
         super();
         this.id = id;
         this.name = name;
         this.age = 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 + "]";
     }

 }

5.新建实体类ConditionUser

 package com.cao.bean;

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

 }

6.映射文件

 <?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="getUserLike">
     <select id="getUser" parameterType="com.cao.bean.ConditionUser" resultType="com.cao.bean.User">
         select * from d_user where
         <if test='name != "%null%"'>
             name like #{name} and
         </if>
         age between #{minAge} and #{maxAge}
     </select>
 </mapper>

7.配置文件Configuration.xml

 <?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">
         <property name="" value=""/>
       </transactionManager>
       <dataSource type="UNPOOLED">
         <property name="driver" value="com.mysql.jdbc.Driver"/>
         <property name="url" value="jdbc:mysql://127.0.0.1:3308/mybatis"/>
         <property name="username" value="root"/>
         <property name="password" value="123456"/>
       </dataSource>
     </environment>
   </environments>

    <mappers>
       <mapper resource="com/cao/sql/config/users.xml"/>
    </mappers>

 </configuration>

8.测试类

 package com.cao.test;

 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 org.junit.Test;

 import com.cao.bean.ConditionUser;
 import com.cao.bean.User;

 public class MainTest {
     @Test
     public void test1() throws Exception {
         Reader reader=Resources.getResourceAsReader("com/cao/config/Configuration.xml");
         SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(reader);
         SqlSession sqlSession=sqlSessionFactory.openSession(true);                //true后是自动提交
         //
         String statement="getUserLike.getUser";
         String name="o";
         ConditionUser conditionUser=new ConditionUser("%"+name+"%",13,18);
         //
         List<User> selectList = sqlSession.selectList(statement, conditionUser);
         System.out.println(selectList);
         sqlSession.close();
     }
 }

9.效果