第三章 Maven核心技术

第一节 Maven仓库概念

• 解压maven文件夹下lib目录中的maven-model-builder-3.3.9.jar,打开pom.xml

<project>
  <modelVersion>4.0.0</modelVersion>

  <repositories>
    <repository>
      <id>central</id>
      <name>Central Repository</name>
     <!-- 配置远程仓库地址 -->
      <url>https://repo.maven.apache.org/maven2</url>
      <layout>default</layout>
      <snapshots>
        <enabled>false</enabled>
      </snapshots>
    </repository>
  </repositories>
           

Maven的依赖特性

• 依赖传递
  • 1.创建user-dao

    

    问题：maven第三方jar显示灰色

  • 原因:maven 跟已有版本jar冲突，灰色无效jar，需要删除。但由于maven默认了灰色。依赖已有jar的时候不会报错
  • 解决方法：

<dependency>
    <groupId>org.junit.jupiter</groupId>
    <artifactId>junit-jupiter-api</artifactId>
    <version>5.3.1</version>
    <scope>test</scope><!--将改行删除掉掉-->
</dependency>
           

问题2：测试模块显示灰色
           

• 原因：这是由于在pom.xml中junit的版本为3.8.1，而3.x版本为编程方式，4.x是注解方式。本次测试使用的是注解方式，故应该修改junit版本，修改后代码如下所示：

<!-- https://mvnrepository.com/artifact/junit/junit -->
<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.12</version>
</dependency>

           

• 2.pom.xml中添加依赖，如下

<dependency>
			<groupId>org.mybatis</groupId>
			<artifactId>mybatis</artifactId>
			<version>3.4.6</version>
		</dependency>
		<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>5.1.6</version>
		</dependency>
		<!-- https://mvnrepository.com/artifact/log4j/log4j -->
		<dependency>
			<groupId>log4j</groupId>
			<artifactId>log4j</artifactId>
			<version>1.2.17</version>
		</dependency>
           

• 3.配置资源文件
  • log日志配置

log4j.rootLogger=DEBUG, Console  
  
#Console  
log4j.appender.Console=org.apache.log4j.ConsoleAppender  
log4j.appender.Console.layout=org.apache.log4j.PatternLayout  
log4j.appender.Console.layout.ConversionPattern=%d [%t] %-5p [%c] - %m%n  
  
log4j.logger.java.sql.ResultSet=INFO  
log4j.logger.org.apache=INFO  
log4j.logger.java.sql.Connection=DEBUG  
log4j.logger.java.sql.Statement=DEBUG  
log4j.logger.java.sql.PreparedStatement=DEBUG  
           

• mybatis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>
	<!-- 别名 -->
	<typeAliases>
		<package name="com.java1234.user.entity"/>
	</typeAliases>
</configuration>

           

• 4.新建maven项目：user-service
  • 4.1配置spring

<dependency>
  		<groupId>org.springframework</groupId>
  		<artifactId>spring-core</artifactId>
  		<version>4.1.7.RELEASE</version>
  	</dependency>
  	<dependency>
  		<groupId>org.springframework</groupId>
  		<artifactId>spring-beans</artifactId>
  		<version>4.1.7.RELEASE</version>
  	</dependency>
  	<dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-tx</artifactId>
         <version>4.1.7.RELEASE</version>
        </dependency>
  	<dependency>
  		<groupId>org.springframework</groupId>
  		<artifactId>spring-context</artifactId>
  		<version>4.1.7.RELEASE</version>
  	</dependency>
  	<dependency>
  		<groupId>org.springframework</groupId>
  		<artifactId>spring-context-support</artifactId>
  		<version>4.1.7.RELEASE</version>
  	</dependency>
  	<dependency>
		<groupId>org.springframework</groupId>
		<artifactId>spring-web</artifactId>
		<version>4.1.7.RELEASE</version>
	</dependency>
  	
  	<dependency>
		<groupId>org.springframework</groupId>
		<artifactId>spring-webmvc</artifactId>
		<version>4.1.7.RELEASE</version>
	</dependency>
	
	<dependency>
		<groupId>org.springframework</groupId>
		<artifactId>spring-aop</artifactId>
		<version>4.1.7.RELEASE</version>
	</dependency>
	
	
	<dependency>
		<groupId>org.springframework</groupId>
		<artifactId>spring-aspects</artifactId>
		<version>4.1.7.RELEASE</version>
	</dependency>

	
	<dependency>
		<groupId>org.springframework</groupId>
		<artifactId>spring-jdbc</artifactId>
		<version>4.1.7.RELEASE</version>
	</dependency>
  
	  <dependency>
		<groupId>org.mybatis</groupId>
		<artifactId>mybatis-spring</artifactId>
		<version>1.2.3</version>
	</dependency>
           

• 4.2 加载依赖

<dependency>
    	<groupId>com.fuju.user</groupId>
    	<artifactId>user-dao</artifactId>
    	<version>0.0.1-SNAPSHOT</version>
    </dependency>
           

依赖的特性：user-service->spring-core->commons-logging

依赖的选择：最短路径和最新申明