signatureinputstream.java

一个java开发的非常全面的关于证书发放

package net.sourceforge.jcetaglib.tools;

import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.security.Signature;
import java.security.SignatureException;

/**
 * SignatureInputStream. As data is read it updates a MAC
 */


public class SignatureInputStream extends FilterInputStream {
    private Signature sig = null;

    public SignatureInputStream(InputStream st,
                                Signature sig) {
        super(st);
        this.sig = sig;
    }

    public int read()
            throws IOException {
        int n = in.read();
        if (n > -1) {
            try {
                sig.update((byte) n);
            } catch (SignatureException s_ex) {
                throw(new IOException(s_ex.getMessage()));
            }
        }

        return (n);
    }

    public int read(byte[] b)
            throws IOException {
        int n = in.read(b);
        if (n > -1) {
            try {
                sig.update(b, 0, n);
            } catch (SignatureException s_ex) {
                throw new IOException(s_ex.getMessage());
            }
        }

        return (n);
    }

    public int read(byte[] b,
                    int o,
                    int l)
            throws IOException {
        int n = in.read(b, o, l);
        if (n > -1) {
            try {
                sig.update(b, o, n);
            } catch (SignatureException s_ex) {
                throw(new IOException(s_ex.getMessage()));
            }
        }

        return (n);
    }
}