1、Hello项目的pom.xml文件

<?xml version="1.0" ?>
<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.victor.maven</groupId>
    <artifactId>Hello</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>Hello</name>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.0</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

2、Hello项目源码

import org.junit.Test;
import static junit.framework.Assert.*;

public class Hello {
    public String sayHello(String name){
        return "Hello "+name+"!";
    }
}


public class HelloTest {
    @Test
    public void testHello(){
        Hello hello = new Hello();
        String results = hello.sayHello("litingwei");
        assertEquals("Hello litingwei!",results);   
    }
}

3、HelloFriend项目的pom.xml文件

<?xml version="1.0" ?>
<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.victor.maven</groupId>
      <artifactId>HelloFriend</artifactId>
      <version>0.0.1-SNAPSHOT</version>
      <name>HelloFriend</name>
      
    <dependencies>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.0</version>
            <scope>test</scope>
        </dependency>       
            
        <dependency>
            <groupId>com.victor.maven</groupId>
            <artifactId>Hello</artifactId>
            <version>0.0.1-SNAPSHOT</version>
            <scope>compile</scope>
        </dependency>
            
    </dependencies>
</project>

4、HelloFriend项目主程序

import com.victor.maven.Hello;
public class HelloFriend {

    public String sayHelloToFriend(String name){
        Hello hello = new Hello();
        String str = hello.sayHello(name)+" I am "+this.getMyName();
        System.out.println(str);
        return str;
    }

    public String getMyName(){
        return "John";
    }

}

5、HelloFriend项目测试程序

import static junit.framework.Assert.assertEquals;
import org.junit.Test;
import com.victor.maven.Hello;
public class HelloFriendTest {

    @Test
    public void testHelloFriend(){
        HelloFriend helloFriend = new HelloFriend();
        String results = helloFriend.sayHelloToFriend("litingwei");
        assertEquals("Hello litingwei! I am John",results);
    }

}

6、Maven Jar包依赖总结

关键是对Hello的依赖
这里Hello就是我们的第一个Maven工程，现在HelloFriend对它有依赖。那么这个依赖能否成功呢？更进一步的问题是：HelloFriend工程会到哪里去找Hello呢？
答案是：本地仓库。任何一个Maven工程会根据坐标到本地仓库中去查找它所依赖的jar包。如果能够找到则可以正常工作，否则就不行。