无效的条目压缩大小

Question

我正在使用一个称为ASM的字节码库来改变类文件,然后我想将每个类文件写回一个jar文件而不是一个充满类文件的文件夹.我这样做是通过运行此代码:

当ZipException因为不是预期的大小而抛出时,我的问题就出现了

java.util.zip.ZipException: invalid entry compressed size (expected 695 but got 693 bytes)
    at java.util.zip.ZipOutputStream.closeEntry(Unknown Source)
    at org.steinburg.client.accessor.Accessor.accessJar(Accessor.java:64)
    at org.steinburg.client.accessor.Accessor.<init>(Accessor.java:41)
    at Loader.main(Loader.java:5)


package org.steinburg.client.accessor;

import java.io.DataInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.jar.JarOutputStream;

import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassWriter;

public class Accessor {

private String input;
private File inFile;
private JarEntry jarEntry;
private JarFile jarFile;
private Enumeration<JarEntry> entries;
private InputStream is;

private String out;
private File outFile;
private FileOutputStream fos;
private JarOutputStream jos;

private byte[] bytes;

public Accessor(){
    try{
        input = new String("Input Jar.jar");
        inFile = new File(input);
        jarFile = new JarFile(inFile);
        entries = jarFile.entries();
        out = new String("Output Jar.jar");
        outFile = new File(out);
        fos = new FileOutputStream(outFile);
        jos = new JarOutputStream(fos);
        accessJar();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

protected final void accessJar(){
    try {
        while (entries.hasMoreElements()){
            jarEntry = entries.nextElement();
            is = jarFile.getInputStream(jarEntry);
            if (jarEntry.getName().endsWith(".class")){
                ClassReader cr = new ClassReader(is);
                ClassWriter cw = new ClassWriter(cr, 0);
                FieldAdapter fa = new FieldAdapter(cw);
                cr.accept(fa, 0);
                bytes = cw.toByteArray();
            } else {
                bytes = readBytes(is);
            }
            JarEntry je = new JarEntry(jarEntry);
            jos.putNextEntry(je);
            jos.write(bytes);
            jos.closeEntry();
        }
        jos.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

protected byte[] readBytes(InputStream inputStream){
    try{
        DataInputStream reader = new DataInputStream(inputStream);
        byte[] toReturn = new byte[reader.available()];
        reader.readFully(toReturn);
        reader.close();
        return toReturn;
    } catch (Exception e){
        e.printStackTrace();
        return null;
    }
}

}

ClassReader,ClassWriter(库的每个部分)和FieldAdapter(由我自己制作)只是为了代码,并且为了获得整个类的字节,我使用了cw.toByteArray().字节码操作本身没有问题,它只是通过JarOutputStream写入新的jar文件.有谁知道如何解决这个问题？

Answer 1

有问题的一行是这样的:

JarEntry je = new JarEntry(jarEntry);

因为它也会复制压缩的大小.

除非您关心保留除名称之外的其他字段,否则应使用此构造函数并仅提供文件名,如下所示:

JarEntry je = new JarEntry(jarEntry.getName ());

然后将自动计算压缩的大小.

Answer 2

通过这种方式,它不会复制Jar属性和其他元信息.在最初打包后修改jar/zip文件时会导致此问题.

你可以这样做:

JarEntry je = new JarEntry(jarEntry);
je.setCompressedSize(-1);

这将导致重新计算条目的大小,并且您将复制原始jarEntry中的所有其他属性