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);
- }
- }