JarResources.java Source code

Introduction

Here is the source code for JarResources.java

Source

import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
import java.util.zip.ZipInputStream;

public final class JarResources {
    Hashtable htSizes = new Hashtable();
    Hashtable htJarContents = new Hashtable();
    private String jarFileName;

    public JarResources(String jarFileName) throws Exception {
        this.jarFileName = jarFileName;
        ZipFile zf = new ZipFile(jarFileName);
        Enumeration e = zf.entries();
        while (e.hasMoreElements()) {
            ZipEntry ze = (ZipEntry) e.nextElement();

            htSizes.put(ze.getName(), new Integer((int) ze.getSize()));
        }
        zf.close();

        // extract resources and put them into the hashtable.
        FileInputStream fis = new FileInputStream(jarFileName);
        BufferedInputStream bis = new BufferedInputStream(fis);
        ZipInputStream zis = new ZipInputStream(bis);
        ZipEntry ze = null;
        while ((ze = zis.getNextEntry()) != null) {
            if (ze.isDirectory()) {
                continue;
            }

            int size = (int) ze.getSize();
            // -1 means unknown size.
            if (size == -1) {
                size = ((Integer) htSizes.get(ze.getName())).intValue();
            }

            byte[] b = new byte[(int) size];
            int rb = 0;
            int chunk = 0;
            while (((int) size - rb) > 0) {
                chunk = zis.read(b, rb, (int) size - rb);
                if (chunk == -1) {
                    break;
                }
                rb += chunk;
            }

            htJarContents.put(ze.getName(), b);
        }
    }

    public byte[] getResource(String name) {
        return (byte[]) htJarContents.get(name);
    }

    private String dumpZipEntry(ZipEntry ze) {
        StringBuffer sb = new StringBuffer();
        if (ze.isDirectory()) {
            sb.append("d ");
        } else {
            sb.append("f ");
        }

        if (ze.getMethod() == ZipEntry.STORED) {
            sb.append("stored   ");
        } else {
            sb.append("defalted ");
        }

        sb.append(ze.getName());
        sb.append("\t");
        sb.append("" + ze.getSize());
        if (ze.getMethod() == ZipEntry.DEFLATED) {
            sb.append("/" + ze.getCompressedSize());
        }

        return (sb.toString());
    }

    public static void main(String[] args) throws Exception {
        JarResources jr = new JarResources("a.jar");
        byte[] buff = jr.getResource("b.gif");
    }
}