从流中读取JarEntry

Question

I have jar as input stream. I want to read JarEntry directly from stream. I do not have jar file, and I don't want to create temporar jar file.

I tried code like this:

    JarInputStream jis = new JarInputStream(in);
    JarEntry je = null;

    while ((je = jis.getNextJarEntry()) != null)
    {
        byte[] classbytes = new byte[(int) je.getSize()];
        System.out.println("size of array: " + classbytes.length);
        jis.read(classbytes, 0, classbytes.length);
    }

The problem with this code: je.getSize() returns -1 (it means jarEntry size unknown).

1) Maybe you have idea how to work around this?

2) Maybe you know why jarEntry size is unknown? (I used Eclipse File>Export>Jar File to create it)

Answer 1

You can loop around the read method and read into a fixed sized array, appending the just read bytes into the final storage.

Alternatively you can use a different type inputStream as passed into your JarInputStream.