Spring Boot和Maven 整合Mybatis项目

程序员文章站 2022-03-02 15:29:12

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Mybatis 原理和流程

运行原理：

1. 创建会话工厂SqlSessionFactory，跟进配置文件创建。

2. SqlSessionFactory创建SqlSession。

3. SqlSession操作数据库（发出sql增、删、改、查）

4. Mybatis在内部整合Sql语句（拼接等），输入参数、输出类型，

5. 最后关闭SqlSession。

Spring与Mybatis整合后，上面的SqlSessionFactory和SqlSession都直接在Spring的bean中配置。

1. 添加依赖，spring boot统一进行了版本管理，并整合了日志的依赖等。

在添加dbcp时，需要最新版本，否则会报错，亲测。spring boot没有整合dbcp, springboot用的自己的配置文件application.properties

错误为：java.lang.IllegalAccessError: org.apache.commons.dbcp.DelegatingPreparedStatement.isClosed()Z

能查询到结果，但不能返回数据。只需更新dbcp版本就可以。

打开pom.xml，在Dependencies标签查看的依赖：

Spring Boot和Maven 整合Mybatis项目

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>

	<groupId>com.plin</groupId>
	<artifactId>springMvcMybatis</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>springMvcMybatis</name>
	<description>Demo project for Spring Boot</description>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.0.1.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
		<java.version>1.8</java.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<dependency>
			<groupId>org.mybatis.spring.boot</groupId>
			<artifactId>mybatis-spring-boot-starter</artifactId>
			<version>1.3.2</version>
		</dependency>

		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<scope>runtime</scope>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
		
		<dependency>  
            <groupId>junit</groupId>  
            <artifactId>junit</artifactId>  
            <version>4.11</version>  
            <!-- 表示开发的时候引入，发布的时候不会加载此包 -->  
            <scope>test</scope>  
        </dependency>  
		
		 <!-- 导入Mysql数据库链接jar包 -->  
        <dependency>  
            <groupId>mysql</groupId>  
            <artifactId>mysql-connector-java</artifactId>  
        </dependency> 
        
		<dependency>  
         	<groupId>commons-dbcp</groupId>
    		<artifactId>commons-dbcp</artifactId>
    		<version>1.4</version>
        </dependency>  
        
		<!-- https://mvnrepository.com/artifact/org.apache.commons/commons-pool2 -->
		<dependency>
		    <groupId>org.apache.commons</groupId>
		    <artifactId>commons-pool2</artifactId>
		    <version>2.4.2</version>
		</dependency>
       
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>
</project>

2. 项目结构

Spring Boot和Maven 整合Mybatis项目

3. 配置文件,

spring配置mybatis就是两个，加载sqlSession 和Mapper映射的。

mybatis的配置的也是两个：SqlMapConfig.xml和XXXmapper.xml，mapper.xml会有很多，会根据业务来添加，主要配置sql语句和操作数据库接口（类似Dao）。

db.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mybatis
jdbc.username=root
jdbc.password=123456

log4j.properties

# Global logging configuration

log4j.rootLogger=DEBUG, stdout
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n

SqlMapConfig.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>
	<!-- 别名定义 -->
	<typeAliases>
	<!-- 批量别名定义 
		指定包名，mybatis自动扫描包中的po类，自动定义别名，别名就是类名（首字母大写或小写都可以）
		-->
		<package name="com.plin.ssm.po"/>		
	</typeAliases>		
	<!-- 加载 映射文件
	和spring整合后，使用mapper扫描器，这里不需要配置了
	遵循一些规范：需要将mapper接口类名和mapper.xml映射文件名称保持一致，且在一个目录 中
	 -->
	<mappers>
	    <package name="com.plin.ssm.mapper"/>
	</mappers>
</configuration>

applicationContext.xml

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
	xsi:schemaLocation="http://www.springframework.org/schema/beans 
		http://www.springframework.org/schema/beans/spring-beans-3.2.xsd 
		http://www.springframework.org/schema/mvc 
		http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd 
		http://www.springframework.org/schema/context 
		http://www.springframework.org/schema/context/spring-context-3.2.xsd 
		http://www.springframework.org/schema/aop 
		http://www.springframework.org/schema/aop/spring-aop-3.2.xsd 
		http://www.springframework.org/schema/tx 
		http://www.springframework.org/schema/tx/spring-tx-3.2.xsd ">
	
    <!-- 加载配置文件 -->
	<context:property-placeholder location="classpath:db.properties" />
	
	<!-- 数据源，使用dbcp -->
	<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
		destroy-method="close">
		<property name="driverClassName" value="${jdbc.driver}" />
		<property name="url" value="${jdbc.url}" />
		<property name="username" value="${jdbc.username}" />
		<property name="password" value="${jdbc.password}" />
		<property name="maxActive" value="10" />
		<property name="maxIdle" value="5" />
	</bean>
	
	<!-- sqlSessinFactory -->
	<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
		<!-- 加载mybatis的配置文件 -->
		<property name="configLocation" value="mybatis/SqlMapConfig.xml" />
		<!-- 数据源 -->
		<property name="dataSource" ref="dataSource" />
	</bean>
	
	<!-- mapper配置 
	MapperFactoryBean：根据mapper接口生成代理对象
	-->
	<!-- 	mapperInterface指定mapper接口 -->      
        <!-- <bean id="itemsMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
		<property name="mapperInterface" value="com.plin.ssm.mapper.ItemsMapper"/>
		<property name="sqlSessionFactory" ref="sqlSessionFactory"/>
	</bean> -->
		<!-- 指定扫描的包名 
		如果扫描多个包，每个包中间使用半角逗号分隔
		-->
	<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">    
		<property name="basePackage" value="com.plin.ssm.mapper"/>
		<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>		
	</bean>    
</beans>

4. java代码

Items.java

package com.plin.ssm.po;

import java.util.Date;

public class Items {
    private Integer items_id;

    private String items_name;

    private Float items_price;

    private String items_pic;

    private Date items_createtime;

    private String items_detail;

	public Integer getItems_id() {
		return items_id;
	}

	public void setItems_id(Integer items_id) {
		this.items_id = items_id;
	}

	public String getItems_name() {
		return items_name;
	}

	public void setItems_name(String items_name) {
		this.items_name = items_name;
	}

	public Float getItems_price() {
		return items_price;
	}

	public void setItems_price(Float items_price) {
		this.items_price = items_price;
	}

	public String getItems_pic() {
		return items_pic;
	}

	public void setItems_pic(String items_pic) {
		this.items_pic = items_pic;
	}

	public Date getItems_createtime() {
		return items_createtime;
	}

	public void setItems_createtime(Date items_createtime) {
		this.items_createtime = items_createtime;
	}

	public String getItems_detail() {
		return items_detail;
	}

	public void setItems_detail(String items_detail) {
		this.items_detail = items_detail;
	}

	@Override
	public String toString() {
		return "Items [items_id=" + items_id + ", items_name=" + items_name
				+ ", items_price=" + items_price + ", items_pic=" + items_pic
				+ ", items_createtime=" + items_createtime + ", items_detail="
				+ items_detail + "]";
	}
      
}

ItemsMapper.java

package com.plin.ssm.mapper;

import java.util.List;

import org.apache.ibatis.annotations.Param;

import com.plin.ssm.po.Items;

public interface ItemsMapper {

    int deleteByPrimaryKey(Integer items_id);

    int insert(Items record);

    int insertSelective(Items record);

    Items selectByPrimaryKey(int items_id);

    int updateByPrimaryKeySelective(Items record);

    int updateByPrimaryKeyWithBLOBs(Items record);

    int updateByPrimaryKey(Items record);
}

ItemsMapper.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">

<!-- namespace命名空间，作用就是对sql进行分类化管理，理解sql隔离 
注意：使用mapper代理方法开发，namespace有特殊重要的作用，namespace等于mapper接口地址
-->
<mapper namespace="com.plin.ssm.mapper.ItemsMapper">
	<select id="selectByPrimaryKey" parameterType="int" resultType="items">
		SELECT * FROM items WHERE items_id=#{value}
	</select>
		
	<insert id="insert" parameterType="Items">
		<!-- selectKey将主键返回，需要再返回 -->
		<selectKey keyProperty="items_id" order="AFTER" resultType="java.lang.Integer">
			select LAST_INSERT_ID()
		</selectKey>
		INSERT INTO `mybatis`.`items` (`items_name`, `items_price`, `items_detail`, `items_createtime`) 
		VALUES (#{items_name}, #{items_price}, #{items_detail}, #{items_createtime});
	</insert>	
</mapper>

5. 测试

测试代码

package com.plin.ssm.mapper;

import java.util.Date;

import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.plin.ssm.po.Items;

public class ItemsMapperTest {
	private ApplicationContext applicationContext;
	
	
	@Before
	public void setUp() throws Exception {
		
	}


	@Test
	public void testSelectByPrimaryKey() {
		applicationContext = new ClassPathXmlApplicationContext("classpath:spring/applicationContext.xml");
		ItemsMapper itemsMapper = (ItemsMapper) applicationContext.getBean("itemsMapper");
		Items items = itemsMapper.selectByPrimaryKey(1);
		System.out.println(items);
	}
	
	
	@Test
	public void testInsert() {
		applicationContext = new ClassPathXmlApplicationContext("classpath:spring/applicationContext.xml");
		ItemsMapper itemsMapper = (ItemsMapper) applicationContext.getBean("itemsMapper");
		Items items = new Items();
		items.setItems_name("苹果");
		items.setItems_price(34F);
		items.setItems_detail("真甜");
		items.setItems_createtime(new Date());
		int lastInsertedId= itemsMapper.insert(items);
		System.out.println(lastInsertedId);
	}	
}

6. 测试结果

testSelectByPrimaryKey测试结果：

Spring Boot和Maven 整合Mybatis项目

testInsert测试结果：

Spring Boot和Maven 整合Mybatis项目

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