java中"System.out.println()"的确切含义是什么？

Question

任何人都可以解释下面的含义::

System.out.println()

我知道 :

系统:是一个班级

我不知道"出去"

println :静态方法.

Answer 1

out是一个静态字段,用于保存PrintStream对象的引用.

println 不是一个静态的方法.

这是out变量的声明System.java

/**
 * The "standard" output stream. This stream is already
 * open and ready to accept output data. Typically this stream
 * corresponds to display output or another output destination
 * specified by the host environment or user.
 * <p>
 * For simple stand-alone Java applications, a typical way to write
 * a line of output data is:
 * <blockquote><pre>
 *     System.out.println(data)
 * </pre></blockquote>
 * <p>
 * See the <code>println</code> methods in class <code>PrintStream</code>.
 *
 * @see     java.io.PrintStream#println()
 * @see     java.io.PrintStream#println(boolean)
 * @see     java.io.PrintStream#println(char)
 * @see     java.io.PrintStream#println(char[])
 * @see     java.io.PrintStream#println(double)
 * @see     java.io.PrintStream#println(float)
 * @see     java.io.PrintStream#println(int)
 * @see     java.io.PrintStream#println(long)
 * @see     java.io.PrintStream#println(java.lang.Object)
 * @see     java.io.PrintStream#println(java.lang.String)
 */
public final static PrintStream out = nullPrintStream();

这就是println方法的样子:

/**
 * Terminates the current line by writing the line separator string.  The
 * line separator string is defined by the system property
 * <code>line.separator</code>, and is not necessarily a single newline
 * character (<code>'\n'</code>).
 */
public void println() {
newLine();
}