java.net.URLConnection#setDefaultUseCaches ( )源码实例Demo

public static void main(String[] args) throws Exception {
    URLConnection conn = B7050028.class.getResource("B7050028.class").openConnection();
    int len = conn.getContentLength();
    byte[] data = new byte[len];
    InputStream is = conn.getInputStream();
    is.read(data);
    is.close();
    conn.setDefaultUseCaches(false);
    File jar = File.createTempFile("B7050028", ".jar");
    jar.deleteOnExit();
    OutputStream os = new FileOutputStream(jar);
    ZipOutputStream zos = new ZipOutputStream(os);
    ZipEntry ze = new ZipEntry("B7050028.class");
    ze.setMethod(ZipEntry.STORED);
    ze.setSize(len);
    CRC32 crc = new CRC32();
    crc.update(data);
    ze.setCrc(crc.getValue());
    zos.putNextEntry(ze);
    zos.write(data, 0, len);
    zos.closeEntry();
    zos.finish();
    zos.close();
    os.close();
    System.out.println(new URLClassLoader(new URL[] {new URL("jar:" + jar.toURI() + "!/")}, ClassLoader.getSystemClassLoader().getParent()).loadClass(B7050028.class.getName()));
}
 

public static void main(String[] args) throws Exception {
    URLConnection conn = B7050028.class.getResource("B7050028.class").openConnection();
    int len = conn.getContentLength();
    byte[] data = new byte[len];
    InputStream is = conn.getInputStream();
    is.read(data);
    is.close();
    conn.setDefaultUseCaches(false);
    File jar = File.createTempFile("B7050028", ".jar");
    jar.deleteOnExit();
    OutputStream os = new FileOutputStream(jar);
    ZipOutputStream zos = new ZipOutputStream(os);
    ZipEntry ze = new ZipEntry("B7050028.class");
    ze.setMethod(ZipEntry.STORED);
    ze.setSize(len);
    CRC32 crc = new CRC32();
    crc.update(data);
    ze.setCrc(crc.getValue());
    zos.putNextEntry(ze);
    zos.write(data, 0, len);
    zos.closeEntry();
    zos.finish();
    zos.close();
    os.close();
    System.out.println(new URLClassLoader(new URL[] {new URL("jar:" + jar.toURI() + "!/")}, ClassLoader.getSystemClassLoader().getParent()).loadClass(B7050028.class.getName()));
}
 

public static void main(String[] args) throws Exception {
    URLConnection conn = B7050028.class.getResource("B7050028.class").openConnection();
    int len = conn.getContentLength();
    byte[] data = new byte[len];
    InputStream is = conn.getInputStream();
    is.read(data);
    is.close();
    conn.setDefaultUseCaches(false);
    File jar = File.createTempFile("B7050028", ".jar");
    jar.deleteOnExit();
    OutputStream os = new FileOutputStream(jar);
    ZipOutputStream zos = new ZipOutputStream(os);
    ZipEntry ze = new ZipEntry("B7050028.class");
    ze.setMethod(ZipEntry.STORED);
    ze.setSize(len);
    CRC32 crc = new CRC32();
    crc.update(data);
    ze.setCrc(crc.getValue());
    zos.putNextEntry(ze);
    zos.write(data, 0, len);
    zos.closeEntry();
    zos.finish();
    zos.close();
    os.close();
    System.out.println(new URLClassLoader(new URL[] {new URL("jar:" + jar.toURI() + "!/")}, ClassLoader.getSystemClassLoader().getParent()).loadClass(B7050028.class.getName()));
}
 

public static void main(String[] args) throws Exception {
    URLConnection conn = B7050028.class.getResource("B7050028.class").openConnection();
    int len = conn.getContentLength();
    byte[] data = new byte[len];
    InputStream is = conn.getInputStream();
    is.read(data);
    is.close();
    conn.setDefaultUseCaches(false);
    File jar = File.createTempFile("B7050028", ".jar");
    jar.deleteOnExit();
    OutputStream os = new FileOutputStream(jar);
    ZipOutputStream zos = new ZipOutputStream(os);
    ZipEntry ze = new ZipEntry("B7050028.class");
    ze.setMethod(ZipEntry.STORED);
    ze.setSize(len);
    CRC32 crc = new CRC32();
    crc.update(data);
    ze.setCrc(crc.getValue());
    zos.putNextEntry(ze);
    zos.write(data, 0, len);
    zos.closeEntry();
    zos.finish();
    zos.close();
    os.close();
    System.out.println(new URLClassLoader(new URL[] {new URL("jar:" + jar.toURI() + "!/")}, ClassLoader.getSystemClassLoader().getParent()).loadClass(B7050028.class.getName()));
}
 

public static void main(String[] args) throws Exception {
    URLConnection conn = B7050028.class.getResource("B7050028.class").openConnection();
    int len = conn.getContentLength();
    byte[] data = new byte[len];
    InputStream is = conn.getInputStream();
    is.read(data);
    is.close();
    conn.setDefaultUseCaches(false);
    File jar = File.createTempFile("B7050028", ".jar");
    jar.deleteOnExit();
    OutputStream os = new FileOutputStream(jar);
    ZipOutputStream zos = new ZipOutputStream(os);
    ZipEntry ze = new ZipEntry("B7050028.class");
    ze.setMethod(ZipEntry.STORED);
    ze.setSize(len);
    CRC32 crc = new CRC32();
    crc.update(data);
    ze.setCrc(crc.getValue());
    zos.putNextEntry(ze);
    zos.write(data, 0, len);
    zos.closeEntry();
    zos.finish();
    zos.close();
    os.close();
    System.out.println(new URLClassLoader(new URL[] {new URL("jar:" + jar.toURI() + "!/")}, ClassLoader.getSystemClassLoader().getParent()).loadClass(B7050028.class.getName()));
}
 

void checkJAR(boolean defaultValue) throws IOException {
    URLConnection.setDefaultUseCaches("JAR", defaultValue);
    assertEquals(URLConnection.getDefaultUseCaches("JAr"), defaultValue);

    URLConnection jarFileURLConn = jarFileURL.openConnection();
    URLConnection jarHttpURLConn = jarHttpURL.openConnection();
    assertEquals(jarFileURLConn.getUseCaches(), defaultValue);
    assertEquals(jarHttpURLConn.getUseCaches(), defaultValue);
    jarFileURLConn.setUseCaches(!defaultValue);
    jarHttpURLConn.setUseCaches(!defaultValue);
    assertEquals(jarFileURLConn.getUseCaches(), !defaultValue);
    assertEquals(jarHttpURLConn.getUseCaches(), !defaultValue);

    URLConnection.setDefaultUseCaches("JaR", !defaultValue); // case-insensitive
    assertEquals(URLConnection.getDefaultUseCaches("jAR"), !defaultValue);

    jarFileURLConn = jarFileURL.openConnection();
    jarHttpURLConn = jarHttpURL.openConnection();
    assertEquals(jarFileURLConn.getUseCaches(), !defaultValue);
    assertEquals(jarHttpURLConn.getUseCaches(), !defaultValue);
    jarFileURLConn.setUseCaches(defaultValue);
    jarHttpURLConn.setUseCaches(defaultValue);
    assertEquals(jarFileURLConn.getUseCaches(), defaultValue);
    assertEquals(jarHttpURLConn.getUseCaches(), defaultValue);
}
 

public static void main(String[] args) throws Exception {
    URLConnection conn = B7050028.class.getResource("B7050028.class").openConnection();
    int len = conn.getContentLength();
    byte[] data = new byte[len];
    InputStream is = conn.getInputStream();
    is.read(data);
    is.close();
    conn.setDefaultUseCaches(false);
    File jar = File.createTempFile("B7050028", ".jar");
    jar.deleteOnExit();
    OutputStream os = new FileOutputStream(jar);
    ZipOutputStream zos = new ZipOutputStream(os);
    ZipEntry ze = new ZipEntry("B7050028.class");
    ze.setMethod(ZipEntry.STORED);
    ze.setSize(len);
    CRC32 crc = new CRC32();
    crc.update(data);
    ze.setCrc(crc.getValue());
    zos.putNextEntry(ze);
    zos.write(data, 0, len);
    zos.closeEntry();
    zos.finish();
    zos.close();
    os.close();
    System.out.println(new URLClassLoader(new URL[] {new URL("jar:" + jar.toURI() + "!/")}, ClassLoader.getSystemClassLoader().getParent()).loadClass(B7050028.class.getName()));
}
 

public static void main(String[] args) throws Exception {
    URLConnection conn = B7050028.class.getResource("B7050028.class").openConnection();
    int len = conn.getContentLength();
    byte[] data = new byte[len];
    InputStream is = conn.getInputStream();
    is.read(data);
    is.close();
    conn.setDefaultUseCaches(false);
    File jar = File.createTempFile("B7050028", ".jar");
    jar.deleteOnExit();
    OutputStream os = new FileOutputStream(jar);
    ZipOutputStream zos = new ZipOutputStream(os);
    ZipEntry ze = new ZipEntry("B7050028.class");
    ze.setMethod(ZipEntry.STORED);
    ze.setSize(len);
    CRC32 crc = new CRC32();
    crc.update(data);
    ze.setCrc(crc.getValue());
    zos.putNextEntry(ze);
    zos.write(data, 0, len);
    zos.closeEntry();
    zos.finish();
    zos.close();
    os.close();
    System.out.println(new URLClassLoader(new URL[] {new URL("jar:" + jar.toURI() + "!/")}, ClassLoader.getSystemClassLoader().getParent()).loadClass(B7050028.class.getName()));
}
 

public static void main(String[] args) throws Exception {
    URLConnection conn = B7050028.class.getResource("B7050028.class").openConnection();
    int len = conn.getContentLength();
    byte[] data = new byte[len];
    InputStream is = conn.getInputStream();
    is.read(data);
    is.close();
    conn.setDefaultUseCaches(false);
    File jar = File.createTempFile("B7050028", ".jar");
    jar.deleteOnExit();
    OutputStream os = new FileOutputStream(jar);
    ZipOutputStream zos = new ZipOutputStream(os);
    ZipEntry ze = new ZipEntry("B7050028.class");
    ze.setMethod(ZipEntry.STORED);
    ze.setSize(len);
    CRC32 crc = new CRC32();
    crc.update(data);
    ze.setCrc(crc.getValue());
    zos.putNextEntry(ze);
    zos.write(data, 0, len);
    zos.closeEntry();
    zos.finish();
    zos.close();
    os.close();
    System.out.println(new URLClassLoader(new URL[] {new URL("jar:" + jar.toURI() + "!/")}, ClassLoader.getSystemClassLoader().getParent()).loadClass(B7050028.class.getName()));
}
 

protected Optional<InputStream> newStream(final URL url) {
  try {
    final URLConnection connection = urlConnectionFactory.apply(url);

    // Turn off URL connection caching to avoid open file leaks. When caching is on, the
    // InputStream
    // returned is left open, even after you call 'InputStream.close()'
    connection.setDefaultUseCaches(
        false); // TODO: verify - setDefaultUseCaches(false) may not be necessary
    connection.setUseCaches(false);
    return Optional.of(connection.getInputStream());
  } catch (final IOException e) {
    log.log(Level.SEVERE, "Unable to open: " + url, e);
    return Optional.empty();
  }
}
 

/**
 * Disables caching for JAR URL connections. For Java 8 and earlier, this also disables
 * caching for ALL URL connections.
 *
 * @throws IOException If a dummy JAR URLConnection can not be created
 */
public void disableCachingForJarUrlConnections() throws IOException {
    // Doesn't matter that this JAR doesn't exist - just as
    // long as the URL is well-formed
    URL url = new URL("jar:file://dummy.jar!/");
    URLConnection uConn = url.openConnection();
    uConn.setDefaultUseCaches(false);
}
 

/**
 * Enables or disables caching for URLConnection.
 *
 * @return the value of useCaching before this call
 */
public static boolean setUseCaching(boolean useCache) {
    try {
        URLConnection URLConnection = new URL("http://localhost/").openConnection();
        boolean oldValue = URLConnection.getDefaultUseCaches();
        URLConnection.setDefaultUseCaches(useCache);
        return oldValue;
    } catch(Exception ex) {
        return true;
    }
}
 

void checkFile() throws IOException {
    URLConnection fileURLConn = fileURL.openConnection();
    assertTrue(fileURLConn.getDefaultUseCaches());

    // set default default to false and check other values the same
    fileURLConn.setDefaultUseCaches(false);
    fileURLConn.setDefaultUseCaches("fiLe", true);
    assertFalse(fileURLConn.getDefaultUseCaches());
    assertTrue(URLConnection.getDefaultUseCaches("fiLE"));
}
 

/**
 * Called when the applet is initialized.
 */
@Override
public void init() {
  try {
    // get applet parameter - URL from which to get the CAS
    String casURL = getParameter("CasUrl");

    // open URL connection to get the serialized CAS
    URLConnection con = new URL(casURL).openConnection();

    con.setDoInput(true);
    con.setDoOutput(true);
    con.setUseCaches(false);
    con.setDefaultUseCaches(false);
    con.setRequestProperty("Content-Type", "application/octet-stream");
    // con.connect();

    InputStream in = con.getInputStream();
    ByteArrayOutputStream byteStream = new ByteArrayOutputStream();
    byte[] buf = new byte[2048];
    int bytesRead = in.read(buf);
    while (bytesRead > 0) {
      byteStream.write(buf, 0, bytesRead);
      bytesRead = in.read(buf);
    }
    byte[] bytes = byteStream.toByteArray();
    in.close();
    byteStream.close();
    System.out.println("Got " + bytes.length + " bytes.");

    // deserialize CAS
    CASMgr casMgr = CASFactory.createCAS();
    CASCompleteSerializer serializer = (CASCompleteSerializer) SerializationUtils
            .deserialize(bytes);
    Serialization.deserializeCASComplete(serializer, casMgr);

    // get 2nd applet parameter - right-to-left text orientation
    boolean rightToLeft = false;
    String rightToLeftParam = getParameter("RightToLeftTextOrientation");
    if (rightToLeftParam != null && rightToLeftParam.equalsIgnoreCase("true")) {
      rightToLeft = true;
    }

    // create viewer component and add to this applet
    mViewer = new CasAnnotationViewer();
    // NOTE: it seems to be important to add the viewer to the frame
    // before calling setCAS. If we do it the other way around
    // we seem to frequently cause the browser to hang.
    getContentPane().add(mViewer);

    mViewer.setCAS(casMgr.getCAS().getView(CAS.NAME_DEFAULT_SOFA));
    mViewer.setRightToLeftTextOrientation(rightToLeft);

    // add a listener that detects resize events
    addComponentListener(new MyComponentListener());

    // set initial size of tree viewer panel
    resizeTreeViewer();

  } catch (Exception e) {
    e.printStackTrace();
  }

}
 

@Override
protected
void
doProcess()
{
  try
  {
    ProxyWrapper proxyWrapper = ApplicationProperties.getProxy();
    URL url = new URL(getURL());
    URLConnection connection = url.openConnection(proxyWrapper.createProxy());
    String latestVersion = null;

    connection.setConnectTimeout(TIMEOUT);
    connection.setDefaultUseCaches(false);
    connection.setReadTimeout(TIMEOUT);

    latestVersion = readVersion(connection);

    signalProcessIsDone();

    if(CURRENT_VERSION.equals(latestVersion) == true)
    {
      inform(getProperty("no_update.title"),
          getProperty("no_update.description"));
    }
    else
    {
      if(decide(getProperty("update.title"),
          getProperty("update.description")) == true)
      {
        ResourceHelper.openURL(getSharedProperty("url"));
      }
    }
  }
  catch(Exception exception)
  {
    // Ignore errors if the dialog was canceled.
    if(canProcess() == true)
    {
      signalProcessIsDone();

      if(exception instanceof SocketTimeoutException)
      {
        error(getProperty("error.title"),
            getProperty("network_error.description"));
      }
      else
      {
        error(getProperty("error.title"),
            getProperty("no_service_error.description"));
      }
    }
  }
}
 

private InputStream openConnectionForUrl(URL url) throws IOException {
    URLConnection urlConnection = url.openConnection();
    urlConnection.setDefaultUseCaches(false);
    return urlConnection.getInputStream();
}
 

/**
 * Override to set up your specific external resource.
 * @throws Throwable if setup fails (which will disable {@code after}
 */
public void before() throws Throwable {
    for (Handler h : Logger.getLogger("").getHandlers()) {
        if (h instanceof ConsoleHandler) {
            ((ConsoleHandler) h).setFormatter(new DeltaSupportLogFormatter());
        }
    }

    if (Thread.interrupted()) { // JENKINS-30395
        LOGGER.warning("was interrupted before start");
    }

    if(Functions.isWindows()) {
        // JENKINS-4409.
        // URLConnection caches handles to jar files by default,
        // and it prevents delete temporary directories on Windows.
        // Disables caching here.
        // Though defaultUseCache is a static field,
        // its setter and getter are provided as instance methods.
        URLConnection aConnection = new File(".").toURI().toURL().openConnection();
        origDefaultUseCache = aConnection.getDefaultUseCaches();
        aConnection.setDefaultUseCaches(false);
    }
    
    // Not ideal (https://github.com/junit-team/junit/issues/116) but basically works.
    if (Boolean.getBoolean("ignore.random.failures")) {
        RandomlyFails rf = testDescription.getAnnotation(RandomlyFails.class);
        if (rf != null) {
            throw new AssumptionViolatedException("Known to randomly fail: " + rf.value());
        }
    }

    env = new TestEnvironment(testDescription);
    env.pin();
    recipe();
    AbstractProject.WORKSPACE.toString();
    User.clear();

    try {
        Field theInstance = Jenkins.class.getDeclaredField("theInstance");
        theInstance.setAccessible(true);
        if (theInstance.get(null) != null) {
            LOGGER.warning("Jenkins.theInstance was not cleared by a previous test, doing that now");
            theInstance.set(null, null);
        }
    } catch (Exception x) {
        LOGGER.log(Level.WARNING, null, x);
    }

    try {
        jenkins = hudson = newHudson();
        // If the initialization graph is corrupted, we cannot expect that Jenkins is in the good shape.
        // Likely it is an issue in @Initializer() definitions (see JENKINS-37759).
        // So we just fail the test.
        if (jenkins.getInitLevel() != InitMilestone.COMPLETED) {
            throw new Exception("Jenkins initialization has not reached the COMPLETED initialization stage. Current state is " + jenkins.getInitLevel() +
                    ". Likely there is an issue with the Initialization task graph (e.g. usage of @Initializer(after = InitMilestone.COMPLETED)). See JENKINS-37759 for more info");
        }
    } catch (Exception e) {
        // if Hudson instance fails to initialize, it leaves the instance field non-empty and break all the rest of the tests, so clean that up.
        Field f = Jenkins.class.getDeclaredField("theInstance");
        f.setAccessible(true);
        f.set(null,null);
        throw e;
    }

    jenkins.setCrumbIssuer(new TestCrumbIssuer());  // TODO: Move to _configureJenkinsForTest after JENKINS-55240
    _configureJenkinsForTest(jenkins);
    configureUpdateCenter();

    // expose the test instance as a part of URL tree.
    // this allows tests to use a part of the URL space for itself.
    jenkins.getActions().add(this);

    JenkinsLocationConfiguration.get().setUrl(getURL().toString());
}
 

/**
 * Override to tear down your specific external resource.
 */
public void after() throws Exception {
    try {
        if (jenkins!=null) {
            for (EndOfTestListener tl : jenkins.getExtensionList(EndOfTestListener.class))
                tl.onTearDown();
        }

        // cancel pending asynchronous operations, although this doesn't really seem to be working
        for (WebClient client : clients) {
            // unload the page to cancel asynchronous operations
            try {
                client.getPage("about:blank");
            } catch (IOException e) {
                // ignore
            }
            client.close();
        }
        clients.clear();

    } finally {
        _stopJenkins(server, tearDowns, jenkins);

        try {
            env.dispose();
        } finally {
            // Hudson creates ClassLoaders for plugins that hold on to file descriptors of its jar files,
            // but because there's no explicit dispose method on ClassLoader, they won't get GC-ed until
            // at some later point, leading to possible file descriptor overflow. So encourage GC now.
            // see http://bugs.sun.com/view_bug.do?bug_id=4950148
            // TODO use URLClassLoader.close() in Java 7
            System.gc();

            // restore defaultUseCache
            if(Functions.isWindows()) {
                URLConnection aConnection = new File(".").toURI().toURL().openConnection();
                aConnection.setDefaultUseCaches(origDefaultUseCache);
            }
        }
    }
}
 

@Override
protected void  setUp() throws Exception {
    if (Thread.interrupted()) { // JENKINS-30395
        LOGGER.warning("was interrupted before start");
    }

    if(Functions.isWindows()) {
        // JENKINS-4409.
        // URLConnection caches handles to jar files by default,
        // and it prevents delete temporary directories on Windows.
        // Disables caching here.
        // Though defaultUseCache is a static field,
        // its setter and getter are provided as instance methods.
        URLConnection aConnection = new File(".").toURI().toURL().openConnection();
        origDefaultUseCache = aConnection.getDefaultUseCaches();
        aConnection.setDefaultUseCaches(false);
    }
    
    env.pin();
    recipe();
    for (Runner r : recipes) {
        if (r instanceof WithoutJenkins.RunnerImpl)
            return; // no setup
    }
    AbstractProject.WORKSPACE.toString();
    User.clear();

    // just in case tearDown failed in the middle, make sure to really clean them up so that there's no left-over from earlier tests
    ExtensionList.clearLegacyInstances();
    DescriptorExtensionList.clearLegacyInstances();

    try {
        jenkins = hudson = newHudson();
    } catch (Exception e) {
        // if Jenkins instance fails to initialize, it leaves the instance field non-empty and break all the rest of the tests, so clean that up.
        Field f = Jenkins.class.getDeclaredField("theInstance");
        f.setAccessible(true);
        f.set(null,null);
        throw e;
    }
    jenkins.setNoUsageStatistics(true); // collecting usage stats from tests are pointless.
    
    jenkins.setCrumbIssuer(new TestCrumbIssuer());

    jenkins.servletContext.setAttribute("app", jenkins);
    jenkins.servletContext.setAttribute("version","?");
    WebAppMain.installExpressionFactory(new ServletContextEvent(jenkins.servletContext));
    JenkinsLocationConfiguration.get().setUrl(getURL().toString());

    // set a default JDK to be the one that the harness is using.
    jenkins.getJDKs().add(new JDK("default",System.getProperty("java.home")));

    configureUpdateCenter();

    // expose the test instance as a part of URL tree.
    // this allows tests to use a part of the URL space for itself.
    jenkins.getActions().add(this);

    // cause all the descriptors to reload.
    // ideally we'd like to reset them to properly emulate the behavior, but that's not possible.
    for( Descriptor d : jenkins.getExtensionList(Descriptor.class) )
        d.load();

    // allow the test class to inject Jenkins components
    jenkins.lookup(Injector.class).injectMembers(this);

    setUpTimeout();
}
 

@Override
protected void tearDown() throws Exception {
    try {
        if (jenkins!=null) {
            for (EndOfTestListener tl : jenkins.getExtensionList(EndOfTestListener.class))
                tl.onTearDown();
        }

        if (timeoutTimer!=null) {
            timeoutTimer.cancel();
            timeoutTimer = null;
        }

        // cancel pending asynchronous operations, although this doesn't really seem to be working
        for (WebClient client : clients) {
            // unload the page to cancel asynchronous operations
            client.getPage("about:blank");
            client.close();
        }
        clients.clear();
    } finally {
        if (server!=null)
            server.stop();
        for (LenientRunnable r : tearDowns)
            r.run();

        if (jenkins!=null)
            jenkins.cleanUp();
        ExtensionList.clearLegacyInstances();
        DescriptorExtensionList.clearLegacyInstances();

        try {
            env.dispose();
        } catch (Exception x) {
            x.printStackTrace();
        }

        // Jenkins creates ClassLoaders for plugins that hold on to file descriptors of its jar files,
        // but because there's no explicit dispose method on ClassLoader, they won't get GC-ed until
        // at some later point, leading to possible file descriptor overflow. So encourage GC now.
        // see http://bugs.sun.com/view_bug.do?bug_id=4950148
        System.gc();
        
        // restore defaultUseCache
        if(Functions.isWindows()) {
            URLConnection aConnection = new File(".").toURI().toURL().openConnection();
            aConnection.setDefaultUseCaches(origDefaultUseCache);
        }
    }
}