Java FileDescriptor.out方法代码示例

import java.io.FileDescriptor; //导入方法依赖的package包/类
/**
 * Initialize the system class.  Called after thread initialization.
 */
private static void initPhase1() {

    // VM might invoke JNU_NewStringPlatform() to set those encoding
    // sensitive properties (user.home, user.name, boot.class.path, etc.)
    // during "props" initialization, in which it may need access, via
    // System.getProperty(), to the related system encoding property that
    // have been initialized (put into "props") at early stage of the
    // initialization. So make sure the "props" is available at the
    // very beginning of the initialization and all system properties to
    // be put into it directly.
    props = new Properties();
    initProperties(props);  // initialized by the VM

    // There are certain system configurations that may be controlled by
    // VM options such as the maximum amount of direct memory and
    // Integer cache size used to support the object identity semantics
    // of autoboxing.  Typically, the library will obtain these values
    // from the properties set by the VM.  If the properties are for
    // internal implementation use only, these properties should be
    // removed from the system properties.
    //
    // See java.lang.Integer.IntegerCache and the
    // VM.saveAndRemoveProperties method for example.
    //
    // Save a private copy of the system properties object that
    // can only be accessed by the internal implementation.  Remove
    // certain system properties that are not intended for public access.
    VM.saveAndRemoveProperties(props);

    lineSeparator = props.getProperty("line.separator");
    VersionProps.init();

    FileInputStream fdIn = new FileInputStream(FileDescriptor.in);
    FileOutputStream fdOut = new FileOutputStream(FileDescriptor.out);
    FileOutputStream fdErr = new FileOutputStream(FileDescriptor.err);
    setIn0(new BufferedInputStream(fdIn));
    setOut0(newPrintStream(fdOut, props.getProperty("sun.stdout.encoding")));
    setErr0(newPrintStream(fdErr, props.getProperty("sun.stderr.encoding")));

    // Setup Java signal handlers for HUP, TERM, and INT (where available).
    Terminator.setup();

    // Initialize any miscellaneous operating system settings that need to be
    // set for the class libraries. Currently this is no-op everywhere except
    // for Windows where the process-wide error mode is set before the java.io
    // classes are used.
    VM.initializeOSEnvironment();

    // The main thread is not added to its thread group in the same
    // way as other threads; we must do it ourselves here.
    Thread current = Thread.currentThread();
    current.getThreadGroup().add(current);

    // register shared secrets
    setJavaLangAccess();

    // Subsystems that are invoked during initialization can invoke
    // VM.isBooted() in order to avoid doing things that should
    // wait until the VM is fully initialized. The initialization level
    // is incremented from 0 to 1 here to indicate the first phase of
    // initialization has completed.
    // IMPORTANT: Ensure that this remains the last initialization action!
    VM.initLevel(1);
}
 

import java.io.FileDescriptor; //导入方法依赖的package包/类
/**
 * Determine if output goes to the screen.
 * 
 * @return <code>true</code> if output is directed to STOUT or STDERR.
 */
public boolean isScreen() {
	return fd == FileDescriptor.out || fd == FileDescriptor.err;
}