---JarCleaner工具

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Java Tomcat Web 应用服务器脚本

java的jar是一个很不错的技术。可是现在开源的发展，使得一个项目中会用到很多很多的jar文件（我们的一个项目中，刚开始lib目录下有超过100兆的jar文件），一直怀疑有些文件是用不到的，但是又不太确定哪些是有用的，哪些是没用的。

想了想，决定还是做个小工具，一劳永逸地解决这个问题吧。

此小工具能完成如下功能：

1、将原来lib路径的所有jar备份到lib\bak目录下；

2、删除不用的jar

那怎么判断哪些是没用的呢？

这里用到了java -verbose:class，这个命令会将所有加载class的过程打印出来，如果是jar中的class, 还会指明是从哪个jar中加载的。

因此，通过在tomcat或者其他应用服务器的启动脚本中，添加-verbose:class，然后运行，即可获得加载信息。将其复制到一个log文件中，作为参数传递给JarCleaner即可。

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashSet;
import java.util.Set;
/**
*
* JarCleaner is an utility class to remove all un-referenced jar under the webapp\lib path.<br/>
* Before run this class, you need have two informations prepared. <br/>
* 1. The webapp lib path, such as: c:\tomcat\webapps\demo\WEB-INF\lib <br/>
* 2. The log file, which is generated by console, when adding "-verbose:class" argument <br/>
* in the end of the java command which is used to start the server.
*
*
* @author Leo Liu
* <a href="http://www.smilingleo.cn">Homepage</a>
*
*/
public class JarCleaner {
public Set<String> getNecessaryJarSet(String appLibPath , String logFile){
String pattern = "\\[Loaded.*[\\/].*\\.jar\\]";
Set<String> jarSet = new HashSet<String>();
BufferedReader br = null;
try {
br = new BufferedReader(new FileReader(new File(logFile)));
} catch (FileNotFoundException ee) {
System.out.println("Can't find the log file." + ee.getMessage());
}
String aLine = "";
while(true){
try {
aLine = br.readLine();
} catch (IOException e) {
System.out.println("End of log file.");
}
if (aLine == null) break;
if (aLine.matches(pattern)){
String[] strs = aLine.split("from");
if (strs.length <= 0) continue;
String jarName = strs[strs.length - 1].trim();
if (jarName.startsWith("file")){
jarName = jarName.substring(6);
}
jarName = jarName.substring(0, jarName.length() - 1);
if (jarName.indexOf("/") > 0){
jarName = jarName.replaceAll("[/]", "\\\\");
}
// Only filter the jars in the web app path.
if (jarName.startsWith(appLibPath)){
if (!jarSet.contains(jarName))
jarSet.add(jarName);
}
}
}
return jarSet;
}
public Set<String> backupOriginalJars(String appLibPath){
File libPath = new File(appLibPath);
File[] jars = libPath.listFiles();
Set<String> jarSet = new HashSet<String>();
File bakPath = new File(appLibPath + "\\bak");
if (!bakPath.exists())
bakPath.mkdir();
for (File jar : jars){
String jarName = jar.getAbsolutePath();
jarName.replaceAll("[/]", "\\\\");
jarSet.add(jarName);
// Backup the file to bak path
File newJar = new File(appLibPath + "\\bak\\" + jar.getName());
copyFile(newJar, jar);
}
return jarSet;
}
public void cleanJars(Set<String> allJars, Set<String> jarSet){
allJars.removeAll(jarSet);
for (String jarName : allJars){
File oldJar = new File(jarName);
oldJar.delete();
}
}
private void copyFile(File targetFile, File file) {
if (targetFile.exists()) {
System.out.println("File:" + targetFile.getAbsolutePath()
+ " already existed, skip that file!");
return;
} else {
createFile(targetFile, true);
}
System.out.println("copied " + file.getAbsolutePath() + " to "
+ targetFile.getAbsolutePath());
try {
InputStream is = new FileInputStream(file);
FileOutputStream fos = new FileOutputStream(targetFile);
byte[] buffer = new byte[1024];
while (is.read(buffer) != -1) {
fos.write(buffer);
}
is.close();
fos.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
private void createFile(File file, boolean isFile) {
if (!file.exists()) {
if (!file.getParentFile().exists()) {
createFile(file.getParentFile(), false);
} else {
if (isFile) {
try {
file.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
} else {
file.mkdir();
}
}
}
}
/**
* @param args
*/
public static void main(String[] args) throws Exception{
if (args.length != 2){
System.out.println("Usage : java JarCleaner <webapp lib path> <class verbose log file>\n" +
"This command will backup all jar files in your specified webapp lib path,\n" +
"and remain the necessary jars only.\n" +
" <webapp lib path> : the full path of your web application located.\n" +
" <class verbose file> : the full path of your log file. \n" +
" use:java -verbose:class to get the log content.\n\n" +
"Note: You must shut down the server before run this command.");
System.exit(-1);
}
String appLibPath = args[0].trim();
String logFile = args[1].trim();
JarCleaner cleaner = new JarCleaner();
// Get the referenced jars.
Set<String> jarSet = cleaner.getNecessaryJarSet(appLibPath, logFile);
// Get all jars in web app lib path.
Set<String> allJars = cleaner.backupOriginalJars(appLibPath);
// Remove all non-referenced jar files.
cleaner.cleanJars(allJars, jarSet);
}
}