几条总结：

一。在ant的构建文件中，根元素始终是：<project>

二。ant的概念模型：项目包含目标，目标包含任务，也就是把所有的目标放在目标中，即：所有的target，在project根标签下，且不要有其他东西在project根标签下。所有的执行过程，在targert标签中

三。在ant中，任何一个任务失败，会导致整个构建过程的终止

四。javac命令中依赖关系检查仅仅局限于在比对源文件与目标文件的日期上

我的代码：

HelloWorld.java//主类

package com.laolang.hello;import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;import com.laolang.stu.Student;public class HelloWorld {public static void main(String[] args) {BufferedReader br = new BufferedReader(new InputStreamReader(System.in));Student stu = null;int id = 0;String name = null;int age = 0;String sex = null;try {System.out.print("输入学号：");id = Integer.parseInt(br.readLine());System.out.print("输入姓名：");name = br.readLine();System.out.print("输入年龄：");age = Integer.parseInt(br.readLine());System.out.print("输入性别：");sex = br.readLine();} catch (NumberFormatException | IOException e) {e.printStackTrace();}stu = new Student(id, name, age, sex);System.out.println("student:");System.out.println(stu);System.out.println("Hello World!");System.out.println("小代码！");}}

Student.java//学生类

package com.laolang.stu;public class Student {public Student() {super();}public Student(int stuId, String stuName, int stuAge, String stuSex) {super();this.stuId = stuId;this.stuName = stuName;this.stuAge = stuAge;this.stuSex = stuSex;}@Overridepublic String toString() {return "Student [stuId=" + stuId + ", stuName=" + stuName+ ", stuAge=" + stuAge + ", stuSex=" + stuSex+ "]";}public int getStuId() {return stuId;}public void setStuId(int stuId) {this.stuId = stuId;}public String getStuName() {return stuName;}public void setStuName(String stuName) {this.stuName = stuName;}public int getStuAge() {return stuAge;}public void setStuAge(int stuAge) {this.stuAge = stuAge;}public String getStuSex() {return stuSex;}public void setStuSex(String stuSex) {this.stuSex = stuSex;}private int stuId;private String stuName;private int stuAge;private String stuSex;}

build.xml

<?xml version="1.0" encoding="utf-8"?>
<project name="hello" default="archive"><description>这是使用ant进行JAVA开发的第一个完整的例子</description><!-- 初始化  --><target name="init" description="初始化"><mkdir dir="build/classes" /><mkdir dir="dist" /></target><!-- 编译  --><target name="compile" depends="init" description="编译"><javac srcdir="src" destdir="build/classes" /></target><!-- 打包  --><target name="archive" depends="compile" description="打包"><jar destfile="dist/project.jar" basedir="build/classes" /></target><!-- 清除  --><target name="clean" depends="init" description="清除中间文件"><delete dir="build" /><delete dir="dist" /></target><!-- 运行  --><target name="execute" depends="compile" description="运行"><echo level="warning" message="running" /><javaclassname="com.laolang.hello.HelloWorld"classpath="build/classes"><arg file="." /></java></target>
</project>

运行效果：

laolang@laolang:~/code/ant/book/two/first_build_35$ l
总用量 8.0K
4.0K -rw-rw-r-- 1 laolang laolang 1011 11月 21 21:54 build.xml
4.0K drwxrwxr-x 3 laolang laolang 4.0K 11月 21 21:12 src/
laolang@laolang:~/code/ant/book/two/first_build_35$ tree
.
├── build.xml
└── src└── com└── laolang├── hello│   └── HelloWorld.java└── stu└── Student.java5 directories, 3 files
laolang@laolang:~/code/ant/book/two/first_build_35$ ant -projecthelp
Buildfile: /home/laolang/code/ant/book/two/first_build_35/build.xml
这是使用ant进行JAVA开发的第一个完整的例子
Main targets:archive  打包clean    清除中间文件compile  编译execute  运行init     初始化
Default target: archive
laolang@laolang:~/code/ant/book/two/first_build_35$ ant compile
Buildfile: /home/laolang/code/ant/book/two/first_build_35/build.xmlinit:[mkdir] Created dir: /home/laolang/code/ant/book/two/first_build_35/build/classes[mkdir] Created dir: /home/laolang/code/ant/book/two/first_build_35/distcompile:[javac] /home/laolang/code/ant/book/two/first_build_35/build.xml:14: warning: 'includeantruntime' was not set, defaulting to build.sysclasspath=last; set to false for repeatable builds[javac] Compiling 2 source files to /home/laolang/code/ant/book/two/first_build_35/build/classesBUILD SUCCESSFUL
Total time: 1 second
laolang@laolang:~/code/ant/book/two/first_build_35$ ant execute
Buildfile: /home/laolang/code/ant/book/two/first_build_35/build.xmlinit:compile:[javac] /home/laolang/code/ant/book/two/first_build_35/build.xml:14: warning: 'includeantruntime' was not set, defaulting to build.sysclasspath=last; set to false for repeatable buildsexecute:[echo] running
1001
tianya
34
nan[java] 输入学号：输入姓名：输入年龄：输入性别：student:[java] Student [stuId=1001, stuName=tianya, stuAge=34, stuSex=nan][java] Hello World![java] 小代码！BUILD SUCCESSFUL
Total time: 7 seconds
laolang@laolang:~/code/ant/book/two/first_build_35$ ant archive
Buildfile: /home/laolang/code/ant/book/two/first_build_35/build.xmlinit:compile:[javac] /home/laolang/code/ant/book/two/first_build_35/build.xml:14: warning: 'includeantruntime' was not set, defaulting to build.sysclasspath=last; set to false for repeatable buildsarchive:[jar] Building jar: /home/laolang/code/ant/book/two/first_build_35/dist/project.jarBUILD SUCCESSFUL
Total time: 0 seconds
laolang@laolang:~/code/ant/book/two/first_build_35$ tree
.
├── build
│   └── classes
│       └── com
│           └── laolang
│               ├── hello
│               │   └── HelloWorld.class
│               └── stu
│                   └── Student.class
├── build.xml
├── dist
│   └── project.jar
└── src└── com└── laolang├── hello│   └── HelloWorld.java└── stu└── Student.java12 directories, 6 files
laolang@laolang:~/code/ant/book/two/first_build_35$ ant clean
Buildfile: /home/laolang/code/ant/book/two/first_build_35/build.xmlinit:clean:[delete] Deleting directory /home/laolang/code/ant/book/two/first_build_35/build[delete] Deleting directory /home/laolang/code/ant/book/two/first_build_35/distBUILD SUCCESSFUL
Total time: 0 seconds
laolang@laolang:~/code/ant/book/two/first_build_35$ tree
.
├── build.xml
└── src└── com└── laolang├── hello│   └── HelloWorld.java└── stu└── Student.java5 directories, 3 files
laolang@laolang:~/code/ant/book/two/first_build_35$ l
总用量 8.0K
4.0K -rw-rw-r-- 1 laolang laolang 1011 11月 21 21:54 build.xml
4.0K drwxrwxr-x 3 laolang laolang 4.0K 11月 21 21:12 src/
laolang@laolang:~/code/ant/book/two/first_build_35$