MyBatisPlus系列二：基本使用

迷南。 2022-04-25 04:36 259阅读 0赞

1、创建表和数据  
![在这里插入图片描述][2019050112503279.png]

CREATE TABLE tbl_employee(    
    	id INT(11) PRIMARY KEY AUTO_INCREMENT,    
    	last_name VARCHAR(50),    
    	email VARCHAR(50),    
    	gender CHAR(1),    
    	age int 
    ); 
    INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Tom','tom@atguigu.com',1,22); 
    INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Jerry','jerry@atguigu.com',0,25); 
    INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Black','black@atguigu.com',1,30); 
    INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('White','white@atguigu.com',0,35);

2、引入依赖

<dependencies>
      		
    		<dependency>
    		    <groupId>com.baomidou</groupId>
    		    <artifactId>mybatis-plus</artifactId>
    		    <version>2.3</version>
    		</dependency>		
    		
    		<dependency>
    			<groupId>junit</groupId>
    			<artifactId>junit</artifactId>
    			<version>4.9</version>
    		</dependency>
    		
    		<dependency>
    			<groupId>log4j</groupId>
    			<artifactId>log4j</artifactId>
    			<version>1.2.17</version>
    		</dependency>
    		
    		<dependency>
    			<groupId>com.mchange</groupId>
    			<artifactId>c3p0</artifactId>
    			<version>0.9.5.2</version>
    		</dependency>
    		
    		<dependency>
    			<groupId>mysql</groupId>
    			<artifactId>mysql-connector-java</artifactId>
    			<version>5.1.37</version>
    		</dependency>
    		
    		<dependency>
    			<groupId>org.springframework</groupId>
    			<artifactId>spring-context</artifactId>
    			<version>4.3.10.RELEASE</version>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework</groupId>
    			<artifactId>spring-orm</artifactId>
    			<version>4.3.10.RELEASE</version>
    		</dependency>
      </dependencies>

3、创建实体类Employee

/**
     * 	 因为每个基本类型都有一个默认值:  
     * 	   int ==> 0
     * 	   boolean ==> false
     *	无法表示null。所以使用包装类型
     */
    public class Employee {
    	
    	private Integer id ;
    	private String  lastName; 
    	private String  email ;
    	private Integer gender; 
    	private Integer age ;
    		
    	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 Integer getGender() {
    		return gender;
    	}
    	public void setGender(Integer gender) {
    		this.gender = gender;
    	}
    	public Integer getAge() {
    		return age;
    	}
    	public void setAge(Integer age) {
    		this.age = age;
    	}
    	@Override
    	public String toString() {
    		return "Employee [id=" + id + ", lastName=" + lastName + ", email=" + email + ", gender=" + gender + ", age="
    				+ age + "]";
    	}
    }

4、创建mybatis全局配置文件

<?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>
    	
    </configuration>

5、创建log4j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>

6、创建db.porperties

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

7、创建spring配置文件

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
    	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    	xmlns:context="http://www.springframework.org/schema/context"
    	xmlns:tx="http://www.springframework.org/schema/tx"
    	xmlns:mybatis-spring="http://mybatis.org/schema/mybatis-spring"
    	xsi:schemaLocation="http://mybatis.org/schema/mybatis-spring http://mybatis.org/schema/mybatis-spring-1.2.xsd
    		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
    		http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">
    	
    	
    	<context:property-placeholder location="classpath:db.properties"/>
    	<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
    		<property name="driverClass" value="${jdbc.driver}"></property>
    		<property name="jdbcUrl" value="${jdbc.url}"></property>
    		<property name="user" value="${jdbc.username}"></property>
    		<property name="password" value="${jdbc.password}"></property>
    	</bean>
    	
    	
    	<bean id="dataSourceTransactionManager" 
    		class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
    		<property name="dataSource" ref="dataSource"></property>
    	</bean>
    	
    	<tx:annotation-driven transaction-manager="dataSourceTransactionManager"/>
    	
    	
    	<bean id="sqlSessionFactoryBean" class="com.baomidou.mybatisplus.spring.MybatisSqlSessionFactoryBean">
    		
    		<property name="dataSource" ref="dataSource"></property>
    		<property name="configLocation" value="classpath:mybatis-config.xml"></property>
    		
    		<property name="typeAliasesPackage" value="com.atguigu.mp.beans"></property>
    	</bean>
    
    	
    	<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
    		<property name="basePackage" value="com.atguigu.mp.mapper"></property>
    	</bean>
    </beans>

测试：

public class TestMP {
    	private ApplicationContext ioc = 
    				new ClassPathXmlApplicationContext("applicationContext.xml");
    
    	@Test
    	public void testDataSource() throws Exception {
    		DataSource ds  = ioc.getBean("dataSource",DataSource.class);
    		System.out.println(ds);
    		Connection conn = ds.getConnection();
    		System.out.println(conn);
    	}
    }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpemhpcWlhbmcxMjE3_size_16_color_FFFFFF_t_70]

[2019050112503279.png]: /images/20220210/55dc976f979745949433a48e15dfad04.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpemhpcWlhbmcxMjE3_size_16_color_FFFFFF_t_70]: /images/20220210/c45d5ae3b8ba45cfbd25a644b72d4a6e.png