digest.java

一个java开发的非常全面的关于证书发放

/*
  Name:         Digest.java
  Licensing:    LGPL

  API:          Sun (http://java.sun.com) JCE 1.2.2 API (cleanroom implementation by Bouncy Castle)
  Provider:     Bouncy Castle (http://www.bouncycastle.org)

  Disclaimer:

  COVERED CODE IS PROVIDED UNDER THIS LICENSE ON AN "AS IS" BASIS, WITHOUT WARRANTY OF ANY KIND,
  EITHER EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES THAT THE COVERED CODE
  IS FREE OF DEFECTS, MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE OR NON-INFRINGING. THE ENTIRE
  RISK AS TO THE QUALITY AND PERFORMANCE OF THE COVERED CODE IS WITH YOU. SHOULD ANY COVERED CODE
  PROVE DEFECTIVE IN ANY RESPECT, YOU (NOT THE INITIAL DEVELOPER OR ANY OTHER CONTRIBUTOR)
  ASSUME THE COST OF ANY NECESSARY SERVICING, REPAIR OR CORRECTION. THIS DISCLAIMER OF WARRANTY
  CONSTITUTES AN ESSENTIAL PART OF THIS LICENSE. NO USE OF ANY COVERED CODE IS AUTHORIZED
  HEREUNDER EXCEPT UNDER THIS DISCLAIMER.
*/

package net.sourceforge.jcetaglib.taglib.crypto;

import net.sourceforge.jcetaglib.lib.Clean;
import net.sourceforge.jcetaglib.lib.Digesters;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.BodyTagSupport;
import java.io.IOException;

/**
 * JSP tag used for creating message digests (hashing) of strings and files
 *
 * @jsp.tag
 * name="digest"
 * display-name="Digest"
 * body-content="JSP"
 * example="
 * 		<%-- Create a message digest from the body of the tag using the MD5 algorithm --%>

 *		<jce:digest algorithm=\"MD5\">

 *		This was a normal text

 *		</jce:digest>"
 *
 * description="JSP tag used for creating message digests (hashing) of strings and files"
 *
 * @author Gert Van Ham
 * @author [e-mail]
 * @author http://jcetaglib.sourceforge.net
 * @version $Id: Digest.java,v 1.5 2004/04/15 07:28:35 hamgert Exp $
 */
public class Digest extends BodyTagSupport {

    private static final String PAGE = "page";
    private static final String REQUEST = "request";
    private static final String SESSION = "session";
    private static final String APPLICATION = "application";

    private StringBuffer value; // tag attribute
    private String var;     // tag attribute
    private int scope = PageContext.PAGE_SCOPE;       // tag attribute

    private String algorithm = "Tiger"; // tag attribute
    private String file;                // tag attribute

    private StringBuffer input;    // what we'll store in scope:var
    private StringBuffer output;   // return text

    public static int getScope(String scope) {
        int ret = PageContext.PAGE_SCOPE; // default

        if (REQUEST.equalsIgnoreCase(scope))
            ret = PageContext.REQUEST_SCOPE;
        else if (SESSION.equalsIgnoreCase(scope))
            ret = PageContext.SESSION_SCOPE;
        else if (APPLICATION.equalsIgnoreCase(scope))
            ret = PageContext.APPLICATION_SCOPE;
        else if (PAGE.equalsIgnoreCase(scope))
            ret = PageContext.PAGE_SCOPE;

        return ret;
    } //getScope()

    public int doEndTag() throws JspException {
        // determine the value by...
        if (value != null) {
            // ... reading our attribute
            input = value;
        } else {
            // ... retrieving and trimming our body
            if (bodyContent == null || bodyContent.getString() == null) {
                input = new StringBuffer("");
            } else {
                input = new StringBuffer(bodyContent.getString().trim());
            }
        }

        try {
            if (file != null) {
                output = Digesters.hashFile(file, algorithm);
            } else {
                output = Digesters.hash(input, algorithm);
            }

        } catch (Exception e) {
            throw new JspException("JCE Exception: " + e.getMessage(), e);
        }

        // decide what to do with the result
        if (var != null) {
            if (output != null) {
                pageContext.setAttribute(var, output, scope);
            }
        } else {
            if (bodyContent != null) {
                bodyContent.clearBody();
            }

            try {
                JspWriter w = pageContext.getOut();
                w.print(output);
            } catch (IOException ex) {
                throw new JspException(ex.getMessage(), ex);
            }
        }

        return EVAL_PAGE;
    } // doEndTag()

    public void release() {
        // Cleanup all sensitive information
        Clean.blank(value);
        Clean.blank(input);
        Clean.blank(output);

        super.release();
    } //release()

    /**
     * @jsp.attribute
     *     description="Optional attribute, the string to hash. The body of the tag will be taken if omitted"
     *     type="java.lang.StringBuffer"
     *     required="false"
     *     rtexprvalue="true"
     */
    public void setValue(StringBuffer value) {
        this.value = value;
    }

    public StringBuffer getValue() {
        return value;
    }

    /**
     * @jsp.attribute
     *     description="Optional attribute, variable to store the message digest. The hashed string will be printed if omitted"
     *     type="java.lang.String"
     *     required="false"
     *     rtexprvalue="false"
     */
    public void setVar(String var) {
        this.var = var;
    }

    public String getVar() {
        return var;
    }

    /**
     * @jsp.attribute
     *     description="Scope of the 'var' attribute. Can be 'page', 'session', 'request' or 'application'. Default is 'page'"
     *     type="java.lang.String"
     *     required="false"
     *     rtexprvalue="false"
     */
    public void setScope(String scope) {
        this.scope = getScope(scope);
    }

    /**
     * @jsp.attribute
     *     description="The hash algorithm. Default is 'Tiger'"
     *     type="java.lang.String"
     *     required="false"
     *     rtexprvalue="true"
     */
    public void setAlgorithm(String algorithm) {
        this.algorithm = algorithm;
    }

    /**
     * @jsp.attribute
     *     description="Create a message digest from a file instead of a string"
     *     type="java.lang.String"
     *     required="false"
     *     rtexprvalue="true"
     */
    public void setFile(String file) {
        this.file = file;
    }
}