MyBatis模糊查询(注解方式+映射文件方式)

本博客以一个demo的形式说明模糊查询实现的两种方法：

项目结构如图：



ConditionUser.java:

package com.mybatis.entity;

public class ConditionUser {

private String name;

private int minAge;

private int maxAge;

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;
}

}

User.java:

package com.mybatis.entity;

public class User {

/*
* ID
*/
private int id;

/*
* 用户姓名
*/
private String name;

/*
* age
*/
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 + "]";
}

}

我们先以注解方式实现：

<?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>

<!-- 数据库配置文件  -->
<properties resource="db.properties" />

<!-- 实体类,简称 -设置别名 -->
<typeAliases>
<typeAlias alias="User" type="com.mybatis.entity.User" />
</typeAliases>

<!-- 读取db.properties里的数据，进行数据库配置 -->
<environments default="development">
<environment id="development">
<transactionManager type="JDBC" />
<dataSource type="POOLED">
<property name="driver" value="${driver}"/>
<property name="url" value="${url}" />
<property name="username" value="${username}"/>
<property name="password" value="${password}"/>
</dataSource>
</environment>
</environments>

<!--
注册userMapper.xml文件
<mappers>
<mapper resource="com/mybatis/mapper/userMapper.xml"/>
</mappers>
-->

<mappers>
<mapper class="com.mybatis.mapper.UserMapper"/>
</mappers>

</configuration>

db.properties:

driver=com.mysql.jdbc.Driver
url=jdbc\:mysql\://localhost\:3306/db_mysql?useUnicode\=true&characterEncoding\=utf-8
username=root
password=111

UserMapper.java:

package com.mybatis.mapper;

import java.util.List;

import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;

import com.mybatis.entity.ConditionUser;
import com.mybatis.entity.User;

public interface UserMapper {
@Insert("insert into users(name,age) values(#{name},#{age})")
public void save(User user);
@Update("update users set name=#{name},age=#{age} where id=#{id}")
public boolean update(User user);
@Delete("delete from users where id=#{id}")
public boolean delete(int id);
@Select("select * from users where id=#{id}")
public User findById(int id);
@Select("select * from users where name like #{name} and age >= #{minAge}")
public List<User> findAll(ConditionUser u);
}

测试：

String resource = "mybatis-config.xml";
try{
//加载Mybatis的配置文件
Reader reader = Resources.getResourceAsReader(resource);
//构建sqlSession的工厂
SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);
//创建可以执行sql的SqlSession
SqlSession session = sessionFactory.openSession();
//			List<User> list  = session.selectList("com.mybatis.mapper.userMapper.findById",new ConditionUser("%a%",0, 1));
//	        System.out.println(list);
UserMapper mapper = session.getMapper(UserMapper.class);
List<User> list = mapper.findAll(new ConditionUser("%a%", 0, 1));
System.out.println(list);

Classes c = session.selectOne("com.mybatis.mapper.classesMapper.findById4",1);
System.out.println(c);

}catch (Exception e) {
e.printStackTrace();
}
}

然后以映射文件的方式实现：

注意注解方式和映射文件方式是会冲突的，所以要先删了注解的接口类

然后，在新建userMapper.xml:

<?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">
<!--
为这个mapper指定一个唯一的namespace，namespace的值习惯上设置成包名+sql映射文件名，这样就能够保证namespace的值是唯一的
-->
<mapper namespace="com.mybatis.mapper.userMapper">

<!--
在select标签中编写查询的SQL语句， 设置select标签的id属性为findById，id属性值必须是唯一的，不能够重复
parameterType可以在MyBatis的配置文件里设置，也可以直接用包名+类名
-->

<insert id="save" parameterType="User">
insert into users(id,name,age) value(#{name},#{age})
</insert>
<update id="update" parameterType="User">
update users set name=#{name},age=#{age} where id=#{id}
</update>
<delete id="delete" parameterType="int">
delete from users where id=#{id}
</delete>
<select id="findById" parameterType="com.mybatis.entity.ConditionUser" resultType="User">
select * from users where age>=#{minAge}
<if test='name!="%null%"'>and name like #{name}</if>
</select>
<select id="findAll" resultType="User">
select * from users
</select>
</mapper>

修改mybatis配置文件：

<?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>

<!-- 数据库配置文件  -->
<properties resource="db.properties" />

<!-- 实体类,简称 -设置别名 -->
<typeAliases>
<typeAlias alias="User" type="com.mybatis.entity.User" />

</typeAliases>

<!-- 读取db.properties里的数据，进行数据库配置 -->
<environments default="development">
<environment id="development">
<transactionManager type="JDBC" />
<dataSource type="POOLED">
<property name="driver" value="${driver}"/>
<property name="url" value="${url}" />
<property name="username" value="${username}"/>
<property name="password" value="${password}"/>
</dataSource>
</environment>
</environments>

<!--
注册userMapper.xml文件
<mappers>
<mapper resource="com/mybatis/mapper/userMapper.xml"/>
</mappers>
-->

<mappers>
<mapper resource="com/mybatis/mapper/userMapper.xml"/>
</mappers>

</configuration>

测试：

String resource = "mybatis-config.xml";
try{
//加载Mybatis的配置文件
Reader reader = Resources.getResourceAsReader(resource);
//构建sqlSession的工厂
SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);
//创建可以执行sql的SqlSession
SqlSession session = sessionFactory.openSession();
List<User> list  = session.selectList("com.mybatis.mapper.userMapper.findById",new ConditionUser("%a%",0, 1));
System.out.println(list);
//	        UserMapper mapper = session.getMapper(UserMapper.class);
//	        List<User> list = mapper.findAll(new ConditionUser("%a%", 0, 1));
//	        System.out.println(list);

Classes c = session.selectOne("com.mybatis.mapper.classesMapper.findById4",1);
System.out.println(c);

}catch (Exception e) {
e.printStackTrace();
}