MyBatis 框架第2章

落日映苍穹つ 2022-12-16 11:58 174阅读 0赞

# MyBatis 框架 #

### MyBatis 框架 ###

*  MyBatis 框架
 *   *  第2章 MyBatis HelloWorld
     *   *  2.1 开发环境的准备
         *  2.2 创建测试表
         *  2.3 创建javaBean
         *  2.3 创建MyBatis的全局配置文件
         *  2.4 创建Mybatis的sql映射文件
         *  2.5 测试
         *  2.6 Mapper接口开发MyBatis HelloWorld

## 第2章 MyBatis HelloWorld ##

### 2.1 开发环境的准备 ###

1)导入MyBatis框架的jar包、Mysql驱动包、log4j的jar包  
下面展示一些 `导包`。

myBatis-3.4.1.jar
    mysql-connector-java-5.1.37-bin.jar
    log4j.jar

2)导入log4j 的配置文件  
下面展示一些 `导入配置文件`。

<?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
     
    <log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
     
     <appender name="STDOUT" class="org.apache.log4j.ConsoleAppender">
       <param name="Encoding" value="UTF-8" />
       <layout class="org.apache.log4j.PatternLayout">
        <param name="ConversionPattern" value="%-5p %d{MM-dd HH:mm:ss,SSS} %m  (%F:%L) \n" />
       </layout>
     </appender>
     <logger name="java.sql">
       <level value="debug" />	
     </logger>
     <logger name="org.apache.ibatis">
       <level value="info" />
     </logger>
     <root>
       <level value="debug" />
       <appender-ref ref="STDOUT" />
     </root>
    </log4j:configuration>

**//可根据自行修改**

### 2.2 创建测试表 ###

下面展示一些 `创建`。

-- 创建库
    CREATE DATABASE test_mybatis;
    -- 使用库
    USE test_mybatis;
    -- 创建表
    CREATE TABLE tbl_employee(
       id INT(11) PRIMARY KEY AUTO_INCREMENT,
       last_name VARCHAR(50),
       email VARCHAR(50),
       gender CHAR(1)
    );

### 2.3 创建javaBean ###

下面展示一些 `javaBean`。

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

### 2.3 创建MyBatis的全局配置文件 ###

下面展示一些 `1)参考MyBatis的官网手册`。

<?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" />
    			
    			<dataSource type="POOLED">
    				<property name="driver" value="com.mysql.jdbc.Driver" />
    				<property name="url" value="jdbc:mysql://localhost:3306/mybatis_1129" />
    				<property name="username" value="root" />
    				<property name="password" value="1234" />
    			</dataSource>
    		</environment>
    	</environments>
    	
    	<mappers>
    		<mapper resource="EmployeeMapper.xml" />
    	</mappers>
    </configuration>

### 2.4 创建Mybatis的sql映射文件 ###

下面展示一些 `1)参考MyBatis的官方手册`。

<?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="suibian">
    	<select id="selectEmployee" resultType="com.atguigu.myabtis.helloWorld.Employee">
    		select id ,last_name lastName ,email ,gender from tbl_employee where id = #{
        id}
    		
    	</select>
    </mapper>

### 2.5 测试 ###

下面展示一些 `1)参考MyBatis的官方手册`。

@Test
    	public void test() throws Exception {
        
    		String resource = "mybatis-config.xml";
    		
    		try {
        
    			Employee employee = 
    					session.selectOne("suibian.selectEmployee", 1001);
    			System.out.println(employee);
    		} finally {
        
    			session.close();
    		}
    	}

### 2.6 Mapper接口开发MyBatis HelloWorld ###

***1）下面展示一些 `编写Mapper接口`。***

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

***2)完成两个绑定***  
①Mapper接口与Mapper映射文件的绑定  
在Mppper映射文件中的标签中的namespace中必须指定Mapper接口  
的全类名  
②Mapper映射文件中的增删改查标签的id必须指定成Mapper接口中的方法名.

***3）下面展示一些 `获取Mapper接口的代理实现类对象`。***

@Test
    	public void test()  throws Exception{
        
    		String resource = "mybatis-config.xml";
    		InputStream inputStream =
                     Resources.getResourceAsStream(resource);
    		SqlSessionFactory sqlSessionFactory = 
    				new SqlSessionFactoryBuilder()
                  .build(inputStream);		
    		SqlSession session = 
                             sqlSessionFactory.openSession();
    		
    		try {
        
    			//Mapper接口:获取Mapper接口的 代理实现类对象
    			EmployeeMapper mapper =
                     session.getMapper(EmployeeMapper.class);		
    			Employee employee = 
                      mapper.getEmployeeById(1006);
    			System.out.println(employee);
    		} finally {
        
    			session.close();
    		}
    	}