mybatis配置文件的一些操作_opsession.selectone-优快云博客

本文介绍了MyBatis的基本配置方法，包括mybatis-config.xml文件的设置与使用、EmployeeMapper.xml文件中的SQL语句配置、JavaBean类的设计、接口定义及其实现方式。通过具体的例子展示了如何利用MyBatis进行数据库操作。

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一.mybatis-config.xml 主要负责连接数据库,和一些配置

<?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">
<!-- 使用propertys 引入外部文件 source引入类文件 URL 网络或磁盘 <setings >标签 -->

<configuration>
	<properties resource="conf.properties"></properties>
	<settings>
		<!-- 开启驼峰命名 A_Name映射为aName -->
		<setting name="mapUnderscoreToCamelCase" value="true" />
	</settings>
	<!-- 别名处理器 -->
	<typeAliases>
		<!-- 默认命名为类名小写 employee -->
		<typeAlias type="com.cws.mybatis.bean.Employee" />
	</typeAliases>
	<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>
	<!-- 注册配置文件 -->
	<mappers>
		<mapper resource="EmployeeMapper.xml" />
	</mappers>
</configuration>

二.EmployeeMapper.xml

配置文件 负责处理sql语句和编写

<?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">
<!--接口具体位置 -->
<mapper namespace="com.cws.mybatis.dao.EmployMapper">
	<!-- namespace 名称空间 id 唯一标示 re...Type 返回值类型 #{id}从参数取出id 使用接口 id为方法 开启驼峰命名后 -->
	<!-- <select id="getEmpbyId" resultType="com.cws.mybatis.bean.Employee"> 
		select id,last_name lastName,gender,email from tbl_emp where id = #{id} </select> -->
	<!-- <select id="getEmpbyId" resultType="com.cws.mybatis.bean.Employee"> 
		不适用别名 -->
		
		<!-- 使用type处理器 -->
	<select id="getEmpbyId" resultType="employee">
		select * from tbl_emp where id = #{id}
	</select>
</mapper>

三.Employee.java bean类

package com.cws.mybatis.bean;

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

四.接口,负责代理处理SQL方法

package com.cws.mybatis.dao;

import com.cws.mybatis.bean.Employee;

public interface EmployMapper {

	
	public Employee getEmpbyId(Integer id);
}

五.关联配置文件,实现接口类

//关联配置文件
	public SqlSessionFactory getSqlSessionFactory()throws IOException {
		String resource = "mybatis-config.xml";
		InputStream inputStream = Resources.getResourceAsStream(resource);
		SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().
				build(inputStream);
	return sqlSessionFactory;
		
	}
	

/*	@Test
	public void test() throws IOException {
		SqlSession opsession=getSqlSessionFactory().openSession();
		try {
			
			Employee employee= opsession.selectOne("selectEmp", 1);
			System.out.println(employee);
		} finally {
		
			opsession.close();// TODO: handle exception
		}
		
		 
		
	}
	*/
	@Test
	public void text01() throws IOException{
		SqlSessionFactory sqlSessionFactory=getSqlSessionFactory();
		SqlSession openSession=sqlSessionFactory.openSession();
		try {
			//实现接口类
			EmployMapper mapper=openSession.getMapper(EmployMapper.class);
			//实现接口方法
			Employee employee=mapper.getEmpbyId(1);
			 
			System.out.println(employee);
			
			
		} finally {
			//关闭 
			openSession.close();
		}
		
	}