MyBatis三个查询方法_selectList_selectOne_selectMap

mybatis-cfg.xml的配置：

<?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>
  <!-- properties加载配置文件
   -->
  <properties resource="db.properties"></properties>
  <settings>
  	<setting name="logImpl" value="LOG4J"/>
  </settings>
  	<environments default="dev">
 		<environment id="dev">
 			<transactionManager type="JDBC"/>
 			<dataSource type="POOLED">
 				<property name="driver" value="${jdbc.driver}"/>
 				<property name="url" value="${jdbc.url}"/>
 				<property name="username" value="${jdbc.username}"/>
 				<property name="password" value="${jdbc.password}"/>

 			</dataSource>
 		</environment>
  	</environments>
  	<mappers >
  		<mapper resource="com/bjsxt/mapper/UserMapper.xml"/>
  	</mappers>
  </configuration>

db.properties:

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://192.168.5.129:3306/bjsxt
jdbc.username=root
jdbc.password=root

log4j.properties:

# Set root category priority to INFO and its only appender to CONSOLE.
log4j.rootCategory=info, CONSOLE
# log4j.rootCategory=DEBUG, CONSOLE, LOGFILE

# 单独设置SQL语句的输出级别为DEBUG级别
# 方法级别
# log4j.logger.com.bjsxt.mapper.UserMapper.selAll=DEBUG
# 类级别
# log4j.logger.com.bjsxt.mapper.UserMapper=DEBUG
# 包级别
log4j.logger.com.bjsxt.mapper=DEBUG

# CONSOLE is set to be a ConsoleAppender using a PatternLayout.
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=- %m%l%n

# LOGFILE is set to be a File appender using a PatternLayout.
log4j.appender.LOGFILE=org.apache.log4j.FileAppender
log4j.appender.LOGFILE.File=d:/test.log
log4j.appender.LOGFILE.Append=true
log4j.appender.LOGFILE.layout=org.apache.log4j.PatternLayout
log4j.appender.LOGFILE.layout.ConversionPattern=- %m %l%n

User实体类

package com.bjsxt.pojo;

import java.io.Serializable;

public class User implements Serializable{
	private int id;
	private String username;
	private String password;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
	@Override
	public String toString() {
		return "User [id=" + id + ", username=" + username + ", password=" + password + "]";
	}
	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + id;
		result = prime * result + ((password == null) ? 0 : password.hashCode());
		result = prime * result + ((username == null) ? 0 : username.hashCode());
		return result;
	}
	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		User other = (User) obj;
		if (id != other.id)
			return false;
		if (password == null) {
			if (other.password != null)
				return false;
		} else if (!password.equals(other.password))
			return false;
		if (username == null) {
			if (other.username != null)
				return false;
		} else if (!username.equals(other.username))
			return false;
		return true;
	}
	public User() {
		super();
	}

}

selectList_selectOne_selectMap:

<?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.bjsxt.mapper.UserMapper">
  	<select id="sellAll" resultType="com.bjsxt.pojo.User">
  		select * from t_user
  	</select>

  	<select id="sellOne" resultType="com.bjsxt.pojo.User">
  		select * from t_user where id=2
  	</select>

  </mapper>

package com.bjsxt.TestSelect;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import java.util.Map;
import java.util.Set;

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.bjsxt.pojo.User;

public class TestSelect {

	@Test
	public void testSelectList() throws IOException {
		InputStream is = Resources.getResourceAsStream("mybatis-cfg.xml");
		SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);
		SqlSession session = factory.openSession();

		List<User> list = session.selectList("com.bjsxt.mapper.UserMapper.sellAll");

		for (User user : list) {
			System.out.println(user);
		}
		session.close();
	}

	@Test
	public void testSelectOne() throws IOException {
		InputStream is = Resources.getResourceAsStream("mybatis-cfg.xml");
		SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);
		SqlSession session = factory.openSession();

		User u = session.selectOne("com.bjsxt.mapper.UserMapper.sellOne");
		System.out.println(u);
		session.close();
	}

	@Test
	public void testSelectMap() throws IOException {
		InputStream is = Resources.getResourceAsStream("mybatis-cfg.xml");
		SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);
		SqlSession session = factory.openSession();

		Map<Integer, User> map = session.selectMap("com.bjsxt.mapper.UserMapper.sellAll", "id");
		Set<Integer> ks = map.keySet();
		for (Integer k : ks) {
			System.out.println(map.get(k));
		}
		session.close();
	}

}