jspservlet.java

低版本的tomcat 对于有些老版本的应用还真的需要老版的中间件

    protected ServletContext context = null;
    protected Hashtable jsps = new Hashtable();
    //    protected Hashtable loadedJSPs = new Hashtable();
    protected ServletConfig config;
    protected JasperLoader loader;
    protected Options options;
    protected ClassLoader parentClassLoader;
    protected ServletEngine engine;
    protected String serverInfo;

    /** Set to true to provide Too Much Information on errors */
    private final boolean insecure_TMI = false;

    static boolean firstTime = true;
    static boolean jdk12=false;
    static {
        try {
            Class.forName( "java.security.PrivilegedAction" );
            jdk12=true;
        } catch(Throwable ex ) {
        }
    }

    public void init(ServletConfig config)
    throws ServletException
    {
        super.init(config);
        this.config = config;
        this.context = config.getServletContext();
        this.serverInfo = context.getServerInfo();

        options = new EmbededServletOptions(config, context);

        parentClassLoader = (ClassLoader) context.getAttribute(Constants.SERVLET_CLASS_LOADER);
        if(parentClassLoader == null)
            parentClassLoader = this.getClass().getClassLoader();

        // getClass().getClassLoader() returns null in JDK 1.1.6/1.1.8
        if(parentClassLoader != null) {
            Constants.message("jsp.message.parent_class_loader_is", 
                              new Object[] {
                                  parentClassLoader.toString()
                              }, Logger.DEBUG);
        } else {
            Constants.message("jsp.message.parent_class_loader_is", 
                              new Object[] {
                                  "<none>"
                              }, Logger.DEBUG);
        }
        if( loader==null ) {
            if( jdk12 ) {
                try {
                    Class ld=Class.forName("org.apache.jasper.servlet.JasperLoader12");
                    loader=(JasperLoader)ld.newInstance();
                } catch(Throwable t ) {
                    t.printStackTrace();
                }
            }
            if( loader==null )
                loader = new org.apache.jasper.servlet.JasperLoader();

            loader.setParentClassLoader(parentClassLoader);
            loader.setOptions(options);
            Object pd=context.getAttribute("org.apache.tomcat.protection_domain");
            loader.setProtectionDomain( pd );
        }
        if(firstTime) {
            firstTime = false;
            Constants.message("jsp.message.scratch.dir.is", 
                              new Object[] { 
                                  options.getScratchDir().toString() 
                              }, Logger.INFORMATION );
            Constants.message("jsp.message.dont.modify.servlets", Logger.INFORMATION);
            JspFactory.setDefaultFactory(new JspFactoryImpl());
        }
    }

    private void serviceJspFile(HttpServletRequest request, 
                                HttpServletResponse response, String jspUri, 
                                Throwable exception, boolean precompile) 
    throws ServletException, IOException
    {
        boolean isErrorPage = exception != null;
        JspServletWrapper wrapper = null;

        /*
         * Several threads may be handling requests for the same jspUri.
         * Only one of them is allowed to create the JspServletWrapper.
         */
        synchronized(jsps){
            wrapper = (JspServletWrapper) jsps.get(jspUri);
            if(wrapper == null) {
                wrapper = new JspServletWrapper(jspUri, isErrorPage);
                jsps.put(jspUri, wrapper);
            }
        }

        wrapper.service(request, response, precompile);
    }


    boolean preCompile(HttpServletRequest request) 
    throws ServletException 
    {
        boolean precompile = false;
        String precom = request.getParameter(Constants.PRECOMPILE);
        String qString = request.getQueryString();

        if(precom != null) {
            if(precom.equals("true"))
                precompile = true;
            else if(precom.equals("false"))
                precompile = false;
            else {
                // This is illegal.
                throw new ServletException("Can't have request parameter " +
                                           " jsp_precomile set to " + precom);
            }
        } else if(qString != null && (qString.startsWith(Constants.PRECOMPILE) ||
                                      qString.indexOf("&" + Constants.PRECOMPILE)
                                      != -1))
            precompile = true;

        return precompile;
    }



    public void service (HttpServletRequest request, 
                         HttpServletResponse response)
    throws ServletException, IOException
    {
        try {
            String includeUri 
            = (String) request.getAttribute(Constants.INC_SERVLET_PATH);

            String jspUri;

            if(includeUri == null)
                jspUri = request.getServletPath();
            else
                jspUri = includeUri;

//	    System.out.println("JspServletWrapper: " + includeUri + " " +
//                            jspUri + 
// 			       (String) request.getAttribute(
//                                  Constants.INC_REQUEST_URI));

            boolean precompile = preCompile(request);

            Logger jasperLog = Constants.jasperLog;

            if(jasperLog != null &&
               jasperLog.matchVerbosityLevel(Logger.INFORMATION)) {
                jasperLog.log("JspEngine --> "+jspUri);
                jasperLog.log("\t     ServletPath: "+request.getServletPath());
                jasperLog.log("\t        PathInfo: "+request.getPathInfo());
                jasperLog.log("\t        RealPath: "
                              +getServletConfig().getServletContext().getRealPath(jspUri));
                jasperLog.log("\t      RequestURI: "+request.getRequestURI());
                jasperLog.log("\t     QueryString: "+request.getQueryString());
                jasperLog.log("\t  Request Params: ");
                Enumeration e = request.getParameterNames();
                while(e.hasMoreElements()) {
                    String name = (String) e.nextElement();
                    jasperLog.log("\t\t "+name+" = "+request.getParameter(name));
                }
            }
            serviceJspFile(request, response, jspUri, null, precompile);
        } catch(RuntimeException e) {
            throw e;
        } catch(ServletException e) {
            throw e;
        } catch(IOException e) {
            throw e;
        } catch(Throwable e) {
            throw new ServletException(e);
        }

        // It's better to throw the exception - we don't
        // know if we can deal with sendError ( buffer may be
        // commited )
        // catch (Throwable t) {
        // 	    unknownException(response, t);
        // 	}
    }

    public void destroy() {
        if(Constants.jasperLog != null)
            Constants.jasperLog.log("JspServlet.destroy()", Logger.INFORMATION);

        Enumeration servlets = jsps.elements();
        while(servlets.hasMoreElements())
            ((JspServletWrapper) servlets.nextElement()).destroy();
    }


    /*  Check if we need to reload a JSP page.
     *
     *  Side-effect: re-compile the JSP page.
     *
     *  @param classpath explicitly set the JSP compilation path.
     *  @return true if JSP files is newer
     */
    boolean loadJSP(String jspUri, String classpath, 
                    boolean isErrorPage, HttpServletRequest req, HttpServletResponse res) 
    throws JasperException, FileNotFoundException 
    {
        // Loader knows how to set the right priviledges, and call
        // doLoadeJsp
        return loader.loadJSP( this,jspUri, classpath, isErrorPage, req, res );
    }

    /*  Check if we need to reload a JSP page.
     *
     *  Side-effect: re-compile the JSP page.
     *
     *  @param classpath explicitly set the JSP compilation path.
     *  @return true if JSP files is newer
     */

    /*
     * A word about the thread synchronization below.  The call to 
     * compiler.isOutDated() is outside the synchronization block on purpose.  
     * The expectation is that for the vast majority of cases the JSP source file 
     * will not have changed and there will be no need to recompile the 
     * implementation class.  For those cases when a compile is required, we 
     * enter a block that is synchronized on the JspServletWrapper object for 
     * this JSP page.  Because the initial out dated check is unsynchronized, it 
     * is possible for more than one request to attempt to enter the synchronized 
     * compile block.  The compile() method contains performs an outdated check 
     * of its own.  The first thread into the block will cause a compile, the 
     * subsequent threads will essentially skip the compilation and instantiation 
     * steps.  
     * 
     * One other thing to note is that there is a window of time between the 
     * compiler.compile() call and the end of the synchronized block where a new 
     * thread entering doLoadJSP() will be told that that implementation class is 
     * up to date even though the code in the synchronized block has not 
     * completed loading and instantiating the class.  In this case doLoadJSP() 
     * will return false without attempting to compile the class.  This is OK 
     * because the JspServletWrapper.getServlet() method used by the 
     * JspServletWrapper.service() method is synchronized.  Thus, the service 
     * method will not receive the servlet class until it has been completely loaded and 
     * instantiated.  
     * 
     * The bottom line is that we avoid synchronizing a fairly expensive 
     * operation (isOutDated) but pay a small price of some unnecessary 
     * compilation attempts in the atypical case of a modified JSP file.  
     */
    protected boolean doLoadJSP(String jspUri, String classpath, 
                                boolean isErrorPage, HttpServletRequest req, HttpServletResponse res) 
    throws JasperException, FileNotFoundException 
    {
        JspServletWrapper jsw=(JspServletWrapper) jsps.get(jspUri);
        if( jsw==null ) {
            throw new JasperException("Can't happen - JspServletWrapper=null");
        }
        JspCompilationContext ctxt = new JspEngineContext(loader, classpath,
                                                          context, jspUri, 
                                                          isErrorPage, options,
                                                          req, res);
        boolean outDated = false; 

        Compiler compiler = null;
        synchronized(jsw){
            /*
             * Creating a compiler opens the associated .class file (if it exists)
             * and reads the actual class name.  If we allow a compiler to be
             * created while a compile is going on then bad things can happen.
             */
            compiler = ctxt.createCompiler();
        }

        try {


            outDated = compiler.isOutDated();
            if(!jsw.isInstantiated() || outDated ) {
                synchronized(jsw){
                    outDated = compiler.compile();
                    if(!jsw.isInstantiated() || outDated) {
                        if( null ==ctxt.getServletClassName() ) {
                            compiler.computeServletClassName();
                        }
                        jsw.instantiateServlet(loader.loadClass(ctxt.getFullClassName()));
                    }
                }
            }
        } catch(FileNotFoundException ex) {
            compiler.removeGeneratedFiles();
            throw ex;
        } catch(JasperException ex) {
            throw ex;
        } catch(ClassNotFoundException cex) {
                throw new JasperException(Constants.getString("jsp.error.unable.load"), 
                                          cex);
        } catch(Exception ex) {
            throw new JasperException(Constants.getString("jsp.error.unable.compile"),
                                      ex);
        }

        return outDated;
    }

    /**
 * Determines whether the current JSP class is older than the JSP file
 * from whence it came
 */
    public boolean isOutDated(File jsp, JspCompilationContext ctxt,
                              Mangler mangler ) {
        File jspReal = null;
        boolean outDated;

        jspReal = new File(ctxt.getRealPath(jsp.getPath()));

        File classFile = new File(mangler.getClassFileName());
        if(classFile.exists()) {
            outDated = classFile.lastModified() < jspReal.lastModified();
        } else {
            outDated = true;
        }

        return outDated;
    }

}