Java Java类设置 2

Java Java类设置 1
更多方法：

PrintWriter printf(Locale l, String format, Object... args) ：一种使用指定格式字符串和参数将格式化字符串写入此编写器的便捷方法。

Syntax :public PrintWriter printf(Locale l,
        String format,
        Object... args)
Parameters:
l - The locale to apply during formatting. If l is null then no localization is applied.
format - A format string as described in Format string syntax
args - Arguments referenced by the format specifiers in the format string.
Returns: This writer
Throws:
IllegalFormatException
NullPointerException

import java.io.*;
import java.util.Locale;
//Java program to demonstrate printf method
public class PrintWriterDemo {
    public static void main(String[] args) {
        String s = "for";
  
        // create PrintWriter object
        PrintWriter pr= new PrintWriter(System.out);
  
        // printf this string
        pr.printf(Locale.CANADA, "Geeks%sGeeks", s);
  
        // flush the stream
        pr.flush();
  
    }
}

Output:
GeeksforGeeks

PrintWriter printf(String format, Object... args) ：使用指定的格式字符串和参数将格式化字符串写入此编写器的便捷方法。

Syntax :public PrintWriter printf(String format,
        Object... args)
Parameters:
format - A format string as described in Format string syntax
args - Arguments referenced by the format specifiers in the format string.
Returns: This writer
Throws:
IllegalFormatException
NullPointerException

import java.io.*;
//Java program to demonstrate printf(String format, Object... args) method
public class PrintWriterDemo {
    public static void main(String[] args) {
        String s = "for";
  
        // create PrintWriter object
        PrintWriter pr= new PrintWriter(System.out);
  
        // printf this string
        pr.printf("Geeks%sGeeks", s);
  
        // flush the stream
        pr.flush();
  
    }
}

Output:
GeeksforGeeks

void println()：通过写入行分隔符字符串来终止当前行。

Syntax :public void println()

import java.io.*;
//Java program to demonstrate println() method
public class PrintWriterDemo {
    public static void main(String[] args) {
        String s = "GeeksforGeeks";
  
        // create PrintWriter object
        PrintWriter pr= new PrintWriter(System.out);
  
        // printf this string
        pr.printf("%s", s);
  
        // flush the stream
        pr.flush();
  
    }
}

Output:
GeeksforGeeks

void println(boolean x)：打印一个布尔值，然后终止该行。

Syntax :public void println(boolean x)

import java.io.*;
//Java program to demonstrate println(boolean) method
public class PrintWriterDemo {
    public static void main(String[] args) {
  
        // create PrintWriter object
        PrintWriter pr= new PrintWriter(System.out);
  
        // print a boolean and change line
        pr.println(true);
        pr.print("New Line");
  
        // flush the stream
        pr.flush();
  
    }
}

Output:
true
New Line

void println(char x)：打印一个字符，然后终止该行。

Syntax :public void println(char x)

import java.io.*;
//Java program to demonstrate println(char x) method
public class PrintWriterDemo {
  
    public static void main(String[] args) {
        char c = 'a';
  
        // create PrintWriter object
        PrintWriter pr= new PrintWriter(System.out);
  
        // print a char and change line
        pr.println(c);
        pr.println('b');
  
        // flush the stream
        pr.flush();
  
    }
}

Output:
a
b

void println(char[] x)：打印一个字符数组，然后终止该行。

Syntax :public void println(char[] x)

import java.io.*;
//Java program to demonstrate println(char[] x) method
public class PrintWriterDemo {
    public static void main(String[] args) {
        char[] c = {'a', 'b', 'c'};
  
        // create PrintWriter object
        PrintWriter pr= new PrintWriter(System.out);
  
        // print an array and change line
        pr.println(c);
  
        // flush the stream
        pr.flush();
  
  
    }
}

Output:
abc

void println(double x)：打印一个双精度然后终止该行。

Syntax :public void println(double x)

import java.io.*;
//Java program to demonstrate println(double x) method
public class PrintWriterDemo {
    public static void main(String[] args) {
        double c = 176.348;
  
        // create PrintWriter object
        PrintWriter pr= new PrintWriter(System.out);
  
        // print a double and change line
        pr.println(c);
  
        // flush the stream
        pr.flush();
  
    }
}

输出：

176.348

void println(float x)：打印一个浮点数，然后终止该行。

Syntax :public void println(float x)

//Java program to demonstrate println(float x) method
 import java.io.*;
public class PrintWriterDemo {
  
    public static void main(String[] args) {
        float c = 5.76348f;
  
        // create PrintWriter object
        PrintWriter pr= new PrintWriter(System.out);
  
        // print a float and change line
        pr.println(c);
  
        // flush the stream
        pr.flush();
  
  
    }
}

输出：

5.76348

void println(int x)：打印一个整数，然后终止该行。

Syntax :public void println(boolean x)

import java.io.*;
//Java program to demonstrate println(int x) method
public class PrintWriterDemo {
  
    public static void main(String[] args) {
        int c = 15;
  
        // create PrintWriter object
        PrintWriter pr= new PrintWriter(System.out);
  
        // print an integer and change line
        pr.println(c);
  
        // flush the stream
        pr.flush();
  
  
    }
}

输出：

void println(long x)：打印一个长整数，然后终止该行。

Syntax :public void println(long x)

import java.io.*;
//Java program to demonstrate println(long x) method
public class PrintWriterDemo {
  
    public static void main(String[] args) {
        long c = 1252344125l;
        try {
            // create PrintWriter object
            PrintWriter pr= new PrintWriter(System.out);
  
            // print a long and change line
            pr.println(c);
  
            // flush the stream
            pr.flush();
  
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}

输出：

1252344125

void println(Object x) ：打印一个对象，然后终止该行。

Syntax :public void println(Object x)

import java.io.*;
//Java program to demonstrate println(Object x) method
public class PrintWriterDemo {
  
    public static void main(String[] args) {
        Object c = 10;
  
        // create PrintWriter object
        PrintWriter pr= new PrintWriter(System.out);
  
        // print an object and change line
        pr.println(c);
  
        // flush the stream
        pr.flush();
  
    }
}

输出：

void println(String x) ：打印一个字符串，然后终止该行。

Syntax :public void println(boolean x)

import java.io.*;
//Java program to demonstrate println(String x) method
public class PrintWriterDemo {
  
    public static void main(String[] args) {
        String c = "GeeksforGeeks";
  
        // create PrintWriter object
        PrintWriter pr= new PrintWriter(System.out);
  
        // print a string and change line
        pr.println(c);
  
        // flush the stream
        pr.flush();
  
    }
}

输出：

GeeksforGeeks

protected void setError() ：将流的错误状态设置为 true。

Syntax :public void println(String x)

import java.io.*;
//Java program to demonstrate setError() method
public class PrintWriterDemo extends PrintWriter {
  
    public PrintWriterDemo(OutputStream out) {
        super(out);
    }
  
    public static void main(String[] args) {
        char c[] = {70, 71, 72, 73, 74, 75, 76};
  
        // create PrintWriter object
        PrintWriterDemo pr= new PrintWriterDemo(System.out);
  
        // write char 1-3
        pr.write(c, 1, 3);
  
        // flush the stream
        pr.flush();
  
        // set an internal error
        pr.setError();
    }
}

输出：

GHI

void write(char [] buf, int off, int len) ：从偏移量 off 开始的指定 char 数组写入 len char 到此流。

Syntax :public void write(char [] buf,
        int off,
        int len)
Overrides:
write in class FilterOutputStream
Parameters:
buf - A char array
off - Offset from which to start taking char 
len - Number of char to write

import java.io.*;
//Java program to demonstrate write() method
public class PrintWriterDemo {
  
    public static void main(String[] args) {
        char c[] = {70, 71, 72, 73, 74, 75, 76};
        // create PrintWriter object
        PrintWriter pr= new PrintWriter(System.out);
  
        // write char 1-3
        pr.write(c, 1, 3);
  
        // flush the stream
        pr.flush();
  
    }
}

输出：

GHI

void write(int b) ：将指定的字符写入此流。

Syntax :public void write(int b)
Overrides:
write in class Writer
Parameters:
 b - The char to be written

import java.io.*;
//Java program to demonstrate write(int b) method
public class PrintWriterDemo {
  
    public static void main(String[] args) {
        int c = 70;
  
        // create PrintWriter object
        PrintWriter pr= new PrintWriter(System.out);
  
        // write char c which is character F in ASCII
        pr.write(c);
  
        // flush the stream
        pr.flush();
  
    }
}

输出：

void write(String s) ：写入一个字符串。

Syntax :public void write(String s)
Parameters:
s - String to be written

import java.io.*;
public class PrintWriterDemo {
  
   public static void main(String[] args) {
      String s = "Hello";
      try {
  
         // create a new writer
         PrintWriter pw = new PrintWriter(System.out);
  
         // write strings
         pw.write(s);
         pw.write(" World");
  
         // flush the writer
         pw.flush();
  
      } catch (Exception ex) {
         ex.printStackTrace();
      }
   }
}

Hello World

void write(String s, int off, int len) ：写入字符串的一部分。

Syntax :public void write(String s,
         int off,
         int len)
Parameters:
s - A String
off - Offset from which to start writing characters
len - Number of characters to write

import java.io.*;
  
public class PrintWriterDemo {
  
   public static void main(String[] args) {
      String s = "Hello World";
      try {
  
         // create a new writer
         PrintWriter pw = new PrintWriter(System.out);
  
         // write substrings
         pw.write(s, 0, 5);
         pw.write(s, 6, 5);
  
         // flush the writer
         pw.flush();
  
      } catch (Exception ex) {
         ex.printStackTrace();
      }
   }
}

HelloWorld