本文主要向大家介绍了JAVA语言之第3章：Maven使用入门/3.2 编写源代码，通过具体的内容向大家展示，希望对大家学习JAVA语言有所帮助。

• 编写源代码

1. 安装Maven约定，源代码要存放在src/java/main，所以依次创建三个目录




2. 按照POM中的<groupId>com.wys.myapp</groupId>和<artifactId>HelloWord</artifactId>创建目录：com\wys\myapp\helloWorld，这个目录是约定存在本项目的Java源代码的，所以最后的目录是：




3. 创建HelloWorld.java源代码文件：
   

   
   package com.wys.myapp.mypackage

public class HelloWorld{
public String SayHello(){
return "hello world";
}

public static void main(String[] args) {
    System.out.println(new HelloWorld().SayHello());
}

}

4. 切换到项目的根目录，也就是POM.xml文件所在目录
[c:\~]$ cd D:\MavenTest\HelloWord

    5. 执行情况和编译目录
[D:\MavenTest\HelloWord]$ mvn clean compile
[INFO] Scanning for projects...
[INFO]                                                                        
[INFO] ------------------------------------------------------------------------
[INFO] Building My first Maven project 0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ HelloWord ---
[INFO] Deleting D:\MavenTest\HelloWord\target
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ HelloWord ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\MavenTest\HelloWord\src\main\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ HelloWord ---
[INFO] Changes detected - recompiling the module!
[WARNING] File encoding has not been set, using platform encoding GBK, i.e. build is platform dependent!
[INFO] Compiling 1 source file to D:\MavenTest\HelloWord\target\classes
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.277 s
[INFO] Finished at: 2018-08-02T13:35:47+08:00
[INFO] Final Memory: 13M/108M
[INFO] ------------------------------------------------------------------------

    6. 完成后Maven自动新建target目录存在class文件![](//i2.51cto.com/images/blog/201812/16/f042f37a911d32a6a15b434d2c12de35.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)
    7. 在POM.xml下新增加依赖：junit（单元测试jar包）和新的控件

        1. 新的依赖
<dependencies>
         <dependency>
                   <groupId>junit</groupId>
                   <artifactId>junit</artifactId>
                   <version>4.11</version>
                   <scope>test</scope>
         </dependency>
  </dependencies>

        2. 新的插件
<build>
         <plugins>
                   <plugin>
                            <groupId>org.apache.maven.plugins</groupId>
                            <artifactId>maven-compiler-plugin</artifactId>
                            <configuration>
                            <source>1.5</source>
                            <targer>1.5</targer>
                            </configuration>
                   </plugin>
         </plugins>
  </build>

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