Java 中的 PrintStream setError()方法,示例

原文:https://www . geesforgeks . org/print stream-set error-method-in-Java-with-examples/

Java 中 【打印流】 类的 setError() 方法用来设置这个打印流实例的错误状态。此方法用作指示符,指示流中发生了错误。它是受保护的,因此需要通过派生 PrintStream 类来使用它来实现。

语法:

protected void setError()

参数:该方法不接受任何参数。

返回值:这个方法不返回任何东西。

下面的方法说明了 setError()方法的工作原理:

程序 1:

// Java program to demonstrate
// PrintStream setError() method

import java.io.*;

// extending the PrintStream Class
class GFG extends PrintStream {

    // Defining the protected constructor
    public GFG(OutputStream out)
    {
        super(System.out);
    }

    // Driver Code
    public static void main(String[] args)
    {

        // The string to be written in the Stream
        String str = "GeeksForGeeks";

        try {

            // Create a GFG instance
            GFG stream
                = new GFG(System.out);

            // Write the above string to this stream
            // This will put the string in the stream
            // till it is printed on the console
            stream.print(str);

            stream.flush();

            // Use the protected setError() method
            stream.setError();
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

Output:

GeeksForGeeks

程序 2:

// Java program to demonstrate
// PrintStream setError() method

import java.io.*;

// extending the PrintStream Class
class GFG extends PrintStream {

    // Defining the protected constructor
    public GFG(OutputStream out)
    {
        super(System.out);
    }

    // Driver Code
    public static void main(String[] args)
    {

        try {

            // Create a GFG instance
            GFG stream
                = new GFG(System.out);

            // Write the char to this stream
            // This will put the char in the stream
            // till it is printed on the console
            stream.write(65);

            stream.flush();

            // Use the protected setError() method
            stream.setError();
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

Output:

A