MyBatis接口式实现查询功能

根目录：

数据库表：

接口类：

package com.qst.dao;

import com.qst.mybatis.Employee;

public interface EmployeeMapper {
	public Employee getEmpById(Integer id);
}

JAVABEAN:

package com.qst.mybatis;

public class Employee {
	private Integer id;
	private String name;
	private String email;
	private String gender;
	@Override
	public String toString() {
		return "Employee [id=" + id + ", name=" + name + ", email=" + email + ", gender=" + gender + "]";
	}
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getEmail() {
		return email;
	}
	public void setEmail(String email) {
		this.email = email;
	}
	public String getGender() {
		return gender;
	}
	public void setGender(String gender) {
		this.gender = gender;
	}

}

测试类：

package com.qst.test;

import java.io.IOException;
import java.io.InputStream;

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.jupiter.api.Test;

import com.qst.dao.EmployeeMapper;
import com.qst.mybatis.Employee;

class myBatisTest {

	public  SqlSessionFactory getSqlsessionFactory() throws IOException {
		String resource = "mybatis-config.xml";
		InputStream inputStream = Resources.getResourceAsStream(resource);
		return new SqlSessionFactoryBuilder().build(inputStream);
		
	
	}
 /*
   public void test01() throws IOException {
 
	 SqlSessionFactory sqlSessionFactory = getSqlsessionFactory();
		SqlSession openSession = sqlSessionFactory.openSession();
		try {
	Employee employee = openSession.selectOne("com.qst.BlogMapper.selectEmp", 1);
	System.out.println(employee);	
		}finally {
			openSession.close();
		}

 }
  */
 	@Test
	public void test02() throws IOException {
		SqlSessionFactory sqlSessionFactory = getSqlsessionFactory();
		SqlSession openSession = sqlSessionFactory.openSession();
		try{
		EmployeeMapper mapper = openSession.getMapper(EmployeeMapper.class);
		Employee empById = mapper.getEmpById(1);
		System.out.println(empById);
		}finally {
			openSession.close();
		}
		

	}
}

XML文件

EmployeeMapper.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">
<mapper namespace="com.qst.dao.EmployeeMapper">

	<select id="getEmpById" resultType="employee">
		select * from employee where id = #{id}
	</select>
</mapper>

mybatis-config.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>
<properties resource="db.properties"></properties>
<settings >
<setting name="mapUnderscoreToCamelCase" value="true"/>
</settings>

<!-- 别名    (建议使用全类名)-->
<typeAliases>
<!-- 默认别名employee 不分大小写 -->
<typeAlias type="com.qst.mybatis.Employee" alias="employee"/>
<!-- 批量别名   使用@Alias注解起新的别名 
<package name="com.qst.mybatis"/>
 -->
</typeAliases>

	<environments default="development">
		<environment id="development">
			<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="EmployeeMapper.xml" />
	</mappers>
	
</configuration>

log4j.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE log4j:configuration PUBLIC "-//log4j/log4j Configuration//EN" "log4j.dtd">
<log4j:configuration>
    <!--输出到控制台-->
    <appender name="consoleAppender" class="org.apache.log4j.ConsoleAppender">
        <param name="Threshold" value="DEBUG"/>
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="[%d{HH:mm:ss:SSS}] [%p] - %l - %m%n"/>
        </layout>
    </appender>

    <!--输出到文件（info）-->
    <!--将生成“info.log.2014-06-11”这样的日志文件-->
    <appender name="fileAppenderInfo" class="org.apache.log4j.DailyRollingFileAppender">
        <param name="File" value="${user.home}/logs/website/info.log" />
        <param name="DatePattern" value=".yyyy-MM-dd" />
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="[%d{HH:mm:ss:SSS}] [%p] - %l - %m%n"/>
        </layout>
        <filter class="org.apache.log4j.varia.LevelRangeFilter">
            <param name="LevelMin" value="INFO" />
            <param name="LevelMax" value="INFO" />
        </filter>
    </appender>

    <!--输出到文件（warn）-->
    <appender name="fileAppenderWarn" class="org.apache.log4j.DailyRollingFileAppender">
        <param name="File" value="${user.home}/logs/website/warn.log" />
        <param name="DatePattern" value=".yyyy-MM-dd" />
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="[%d{HH:mm:ss:SSS}] [%p] - %l - %m%n"/>
        </layout>

        <filter class="org.apache.log4j.varia.LevelRangeFilter">
            <param name="LevelMin" value="WARN" />
            <param name="LevelMax" value="WARN" />
        </filter>
    </appender>

    <!--输出到文件（error）-->
    <appender name="fileAppenderError" class="org.apache.log4j.DailyRollingFileAppender">
        <param name="File" value="${user.home}/logs/website/error.log" />
        <param name="DatePattern" value=".yyyy-MM-dd" />
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="[%d{HH:mm:ss:SSS}] [%p] - %l - %m%n"/>
        </layout>
        <filter class="org.apache.log4j.varia.LevelRangeFilter">
            <param name="LevelMin" value="ERROR" />
            <param name="LevelMax" value="ERROR" />
        </filter>
    </appender>

    <!--屏蔽所有org.springframework.*输出的Debug（及以下）信息-->
    <logger name="org.springframework">
        <level value="INFO"></level>
    </logger>

    <root>
        <level value="ALL"/>
        <appender-ref ref="consoleAppender" />
        <appender-ref ref="fileAppenderInfo" />
        <appender-ref ref="fileAppenderWarn" />
        <appender-ref ref="fileAppenderError" />
    </root>
</log4j:configuration>

properties配置文件

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mybatis
jdbc.username=root
jdbc.password=root