Java JAR文件是普通的ZIP文件。因此，您可以使用处理ZIP的代码来打开和修改它。
这是一个有效的代码片段（由David提供）：
import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.util.ArrayList;import java.util.zip.ZipEntry;import java.util.zip.ZipInputStream;import java.util.zip.ZipOutputStream;public class JarUpdater { public static void main(String[] args) { File[] contents = {new File("F:\ResourceTest.txt"), new File("F:\ResourceTest2.bmp")}; File jarFile = new File("F:\RepackMe.jar"); try { updateZipFile(jarFile, contents); } catch (IOException e) { e.printStackTrace(); } } public static void updateZipFile(File zipFile, File[] files) throws IOException { // get a temp file File tempFile = File.createTempFile(zipFile.getName(), null); // delete it, otherwise you cannot rename your existing zip to it. tempFile.delete(); boolean renameOk=zipFile.renameTo(tempFile); if (!renameOk) { throw new RuntimeException("could not rename the file "+zipFile.getAbsolutePath()+" to "+tempFile.getAbsolutePath()); } byte[] buf = new byte[1024]; ZipInputStream zin = new ZipInputStream(new FileInputStream(tempFile)); ZipOutputStream out = new ZipOutputStream(new FileOutputStream(zipFile)); ZipEntry entry = zin.getNextEntry(); while (entry != null) { String name = entry.getName(); boolean notInFiles = true; for (File f : files) { if (f.getName().equals(name)) { notInFiles = false; break; } } if (notInFiles) { // Add ZIP entry to output stream. out.putNextEntry(new ZipEntry(name)); // Transfer bytes from the ZIP file to the output file int len; while ((len = zin.read(buf)) > 0) { out.write(buf, 0, len); } } entry = zin.getNextEntry(); } // Close the streams zin.close(); // Compress the files for (int i = 0; i < files.length; i++) { InputStream in = new FileInputStream(files[i]); // Add ZIP entry to output stream. out.putNextEntry(new ZipEntry(files[i].getName())); // Transfer bytes from the file to the ZIP file int len; while ((len = in.read(buf)) > 0) { out.write(buf, 0, len); } // Complete the entry out.closeEntry(); in.close(); } // Complete the ZIP file out.close(); tempFile.delete(); }}
