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[Java代码] 分享代码片段：将指定位置的war包加入classpath的classloader实现

2016-03-18 16:06 701 查看

一般来说，可以被加入到java classpath中的东西，除了文件夹，就只有jar包了；

但有的时候，我们可能希望将一个已经存在的war包里面的所有class文件加入classpath，这包括/WEB-INF/classes下的所有class文件和/WEB-INF/lib下的所有jar包；

直接将该war包加入classpath中是不能达到上述目的的，那么就可以使用下面这个工具达到此目的：

package kilim.tools;
http://www.nvzi91.cn/gongjingai/29953.html
import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.net.MalformedURLException;

import java.net.URL;

import java.net.URLClassLoader;

import java.util.Enumeration;

import java.util.jar.JarEntry;

import java.util.jar.JarFile;
http://www.nvzi91.cn/penqiangyan/29954.html
/**

* classloader which allows user to set a war archive path to be included in the

* classpath dynamically.

*

* @author <a href="mailto:miles.wy.1@gmail.com">pf_miles</a>

*http://www.nvzi91.cn/jingqiqianzonghezheng/29955.html

*/

public class WarPathClassLoader extends URLClassLoader {

private boolean warPathSet;

private String explodedWarPath;

public WarPathClassLoader(ClassLoader parent) {

super(new URL[0], parent);

}

public void setWarPath(String path) {

if (this.warPathSet)

throw new RuntimeException("War archive path already set. Kilim-fiber tools cannot weave multiple war archives at the same time.");

File w = new File(path);

if (w.exists()) {

final File dir;

try {http://www.nvzi91.cn/tongjing/29956.html

warPathSet = true;

// 0.create a temp dir

dir = createTempDirectory(w.getName());

// 1.extract the war to the temp dir

extractTo(w, dir);

// 2.add /WEB-INF/classes to cp

File clses = locateFile(dir, "WEB-INF", "classes");

super.addURL(clses.toURI().toURL());

// 3.add all jars under /WEB-INF/lib/ to cp

File lib = locateFile(dir, "WEB-INF", "lib");

File[] jars = lib.listFiles();

for (File j : jars)

super.addURL(j.toURI().toURL());

} catch (MalformedURLException e) {

throw new RuntimeException(e);

}http://www.nvzi91.cn/penqiangyan/29957.html

// delete temp dir when exit

Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {

public void run() {

if (dir != null) {

delRecur(dir);

}

}

}));

this.explodedWarPath = dir.getAbsolutePath();

} else {

throw new RuntimeException("File not exists: " + path);

}

}

private static void delRecur(File file) {

if (!file.exists())

return;

if (file.isDirectory()) {

// 1.del sub files first

for (File s : file.listFiles())

delRecur(s);

// 2.del the dir

file.delete();

} else {

file.delete();

}

}http://www.kmrlyy.com/waiyinyan/33470.html

private static File locateFile(File dir, String... paths) {

File cur = dir;

outter: for (String p : paths) {

File[] all = cur.listFiles();

for (File f : all) {

if (p.equals(f.getName())) {

cur = f;

continue outter;

}

}

throw new RuntimeException("No path named '" + p + "' found in file: " + cur.getAbsolutePath());

}

return cur;

}

// extract content of 'w' to dir

private static void extractTo(File w, File dir) {

String dirPath = dir.getAbsolutePath();

if (!dirPath.endsWith("/"))

dirPath += "/";

try {

JarFile jar = new JarFile(w);

Enumeration<JarEntry> e = jar.entries();

byte[] buf = new byte[4096];
http://www.kmrlyy.com/baidaiyichang/33471.html
while (e.hasMoreElements()) {

JarEntry file = (JarEntry) e.nextElement();

File f = new File(dirPath + file.getName());

if (file.isDirectory()) { // if its a directory, create it

f.mkdirs();

continue;

}

InputStream is = jar.getInputStream(file);

FileOutputStream fos = ensureOpen(f);

// write contents of 'is' to 'fos'

for (int avai = is.read(buf); avai != -1; avai = is.read(buf)) {

fos.write(buf, 0, avai);

}http://www.kmrlyy.com/nvxingbuyun/33472.html

fos.close();

is.close();

}

} catch (IOException e) {

throw new RuntimeException(e);

}

}

// if does not exist, create one, and ensure all parent dirs exist

private static FileOutputStream ensureOpen(File f) throws IOException {

if (!f.exists()) {

File p = f.getParentFile();

if (p != null && !p.exists())

p.mkdirs();

f.createNewFile();

}http://www.kmrlyy.com/gongjingmilan/33473.html

return new FileOutputStream(f);

}

private static File createTempDirectory(String dirName) {

final File temp;

try {

temp = File.createTempFile(dirName, Long.toString(System.currentTimeMillis()));

temp.deleteOnExit();

} catch (IOException e) {

throw new RuntimeException(e);

}
http://m.nvzi91.cn/penqiangyan/29362.html
if (!(temp.delete())) {

throw new RuntimeException("Could not delete temp file: " + temp.getAbsolutePath());

}http://www.kmrlyy.com/fkjbcs/33474.html

if (!(temp.mkdir())) {

throw new RuntimeException("Could not create temp directory: " + temp.getAbsolutePath());

}http://m.nvzi91.cn/qiaokelinanzhong/29363.html

return (temp);

}http://m.nvzi91.cn/renliuzhunbei/031829361.html

www.kmrlyy.com

/**

* get the temporary directory path which contains the exploded war files

*/www.nvzi91.cn

public String getExplodedWarPath() {

if (this.explodedWarPath == null)

throw new RuntimeException("'explodedWarPath' is null, maybe the war path is not set.");

return this.explodedWarPath;

}www.nvzi91.cn

m.nvzi91.cn

}

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