system.setout

系统类setOut()方法 (System class setOut() method)

• setOut() method is available in java.lang package.

  setOut()方法在java.lang包中可用。

• setOut() method is used to assign again the standard output stream or in other words, this method is used to reassign the standard output stream.

  setOut()方法用于再次分配标准输出流，或者换句话说，该方法用于重新分配标准输出流。

• The setOut() method is redirected because it does not write the output on the editor.

  setOut()方法被重定向，因为它没有在编辑器上写入输出。

• The setOut() method does not write the output to the proper JTextArea like setErr() method and it returns null.

  setOut()方法不会像setErr()方法那样将输出写入适当的JTextArea，并且它返回null。

• This is a static method, so this method is accessible with the class name too.

  这是一个静态方法，因此也可以使用类名访问此方法。

• setOut() method may throw an exception while writing the output to the standard output stream and the description is given below

  setOut()方法在将输出写入标准输出流时可能会引发异常，下面给出了描述

  SecurityException: In this exception, the checkPermission() method does not allow reassigning of the latest standard output stream when the security manager exists.

  SecurityException：在这种例外情况下，当安全管理器存在时， checkPermission()方法不允许重新分配最新的标准输出流。

Syntax:

句法：

    public static void setOut(PrintStream set_out);

Parameter(s):

参数：

• set_out – represents the latest standard output stream.

  set_out –代表最新的标准输出流。

Return value:

返回值：

The return type of this method is void, it returns nothing

此方法的返回类型为void ，不返回任何内容

Example:

例：

// Java program to demonstrate the example of
// setOut() method of System Class.
import java.lang.*;
import java.io.*;
public class SetOutMethod {public static void main(String[] args) throws Exception {// Creating an instance of File
File file = new File("E://Programs//getProperties().doc");
// By using exists() method returns true if file exists
System.out.println("file existing is  = " + file.exists());
// Creating an instance of FileOutputStream fos
FileOutputStream fos = new FileOutputStream(file);
System.setOut(new PrintStream(fos));
System.out.println("File Writing Done!!");
}
}

Output

输出量

E:\Programs>javac SetOutMethod.java
E:\Programs>java SetOutMethod
file existing is  = true

Output – if file does not exist

输出–如果文件不存在

E:\Programs>javac SetOutMethod.java
E:\Programs>java SetOutMethod
Exception in thread "main" java.io.FileNotFoundException:
E:/Programs/getProperties().doc (No such file or directory)
at java.base/java.io.FileOutputStream.open0(Native Method)
at java.base/java.io.FileOutputStream.open(FileOutputStream.java:299)
at java.base/java.io.FileOutputStream.<init>(FileOutputStream.java:238)
at java.base/java.io.FileOutputStream.<init>(FileOutputStream.java:188)
at SetOutMethod.main(SetOutMethod.java:16)

翻译自: https://www.includehelp.com/java/system-class-setout-method-with-example.aspx

system.setout