在Java中使用ANT提取文件

Question

我正在尝试使用 Ant 的功能将压缩文件的内容提取到临时文件夹。显然，我在这里做错了一件事或多件事，但它们碰巧是我无法理解的，因为网络上此类代码的示例似乎很少且过时：

//...

public static void extract(File src, File dest){
    String path = src.getPath();
    String ext = path.substring(path.lastIndexOf('.') + 1).toLowerCase();

    Expander expander = null;

    if(ext.equals("tar")) {
        expander = new Expander("untar","untar");
    } else if(ext.equals("jar")) {
        expander = new Expander("unzip","unzip");
    } else if(ext.equals("zip")) {
        expander = new Expander("unzip","unzip");
    } else {
        // ...
    }

    expander.setSrc(src);
    expander.setDest(dest);
    expander.execute();
}
//...

以上基于： http://www.jajakarta.org/ant/ant-1.6.1/docs/en/manual/antexternal.html

Expander 类：

import org.apache.tools.ant.Project;
import org.apache.tools.ant.Target;
import org.apache.tools.ant.taskdefs.Expand;

class Expander extends Expand{
    public Expander(String taskType, String taskName){
        this.setProject(new Project());
        this.getProject().init();
        this.setOwningTarget(new Target());
        this.setTaskType(taskType);
        this.setTaskName(taskName);
    }
}

在 Expander 构造函数内，我得到以下内容运行时：

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/tools/ant/launch/AntMain
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClassCond(Unknown Source)
    at java.lang.ClassLoader.defineClass(Unknown Source)
    at java.security.SecureClassLoader.defineClass(Unknown Source)
    at java.net.URLClassLoader.defineClass(Unknown Source)
    at java.net.URLClassLoader.access$000(Unknown Source)
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at org.apache.tools.ant.Project.initProperties(Project.java:313)
    at org.apache.tools.ant.Project.init(Project.java:300)
    at Expander.<init>(Expander.java:8)
    at Main.extract(Main.java:151)
    at Main.getDeliverableFiles(Main.java:130)
    at Main.main(Main.java:36)
caused by: java.lang.ClassNotFoundException: org.apache.tools.ant.launch.AntMain
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    ... 18 more

Answer 1

ant-launcher jar您的 java 程序的类路径中缺少。

我使用 Maven 的搜索网站来查找包含缺失类的 jar：

http://search.maven.org/#advancedsearch|gav

替代解决方案

为什么不使用 Groovy 来代替 Java 中的逻辑呢？ ANT 支持已融入语言中：

def ant = new AntBuilder()

ant.unzip(src:"example.zip", dest:"exampleDir")

Answer 2

测试了这将是新的 Ant 版本：

static public void unzip(String zipFilepath, String destinationDir) {

    final class Expander extends Expand {
        public Expander() {
            Project antp = new Project();
            this.setProject(antp);
            this.getProject().init();
        }
    }
    File source = new File(zipFilepath);
    String folder = source.getName().substring(0,source.getName().indexOf('.'));
    File destFolderFinal = new File(destinationDir+"/"+folder);
    destFolderFinal.mkdirs();

    Expander expander = new Expander();
    expander.setSrc(source);
    expander.setDest(destFolderFinal);
    expander.setOverwrite(false);
    expander.execute();
}