package com.tomhu.format;public class FormatTest1 {public static void main(String[] args) {int x = 5;double y = 3.141592;// 一般方式System.out.println("x = " + x + ", y = " + y);// printf()方式System.out.printf("x = %d, y = %f\n", x, y);// format()方式System.out.format("x = %d, y = %f\n", x, y);}
}

x = 5, y = 3.141592
x = 5, y = 3.141592
x = 5, y = 3.141592

public PrintStream printf(String format, Object ... args) {return format(format, args);
}

public PrintStream format(String format, Object ... args) {try {synchronized (this) {ensureOpen();if ((formatter == null)|| (formatter.locale() != Locale.getDefault()))formatter = new Formatter((Appendable) this);formatter.format(Locale.getDefault(), format, args);}} catch (InterruptedIOException x) {Thread.currentThread().interrupt();} catch (IOException x) {trouble = true;}return this;
}

package com.tomhu.format;import java.util.Formatter;public class FormatTest2 {public static void main(String[] args) {String name = "huhx";int age = 22;Formatter formatter = new Formatter(System.out);formatter.format("My name is %s, and my age is %d ", name, age);formatter.close();}
}

My name is huhx, and my age is 22 

%[argument_index$][flags][width][.precision]conversionThe optional argument_index is a decimal integer indicating the position of the argument in the argument list. The first argument is referenced by "1$", the second by "2$", etc.The optional flags is a set of characters that modify the output format. The set of valid flags depends on the conversion.The optional width is a non-negative decimal integer indicating the minimum number of characters to be written to the output.The optional precision is a non-negative decimal integer usually used to restrict the number of characters. The specific behavior depends on the conversion.The required conversion is a character indicating how the argument should be formatted. The set of valid conversions for a given argument depends on the argument's data type.

package com.tomhu.format;import java.util.Formatter;public class FormatTest3 {static Formatter formatter = new Formatter(System.out);public static void printTitle() {formatter.format("%-15s %-5s %-10s\n", "huhx", "linux", "liuli");formatter.format("%-15s %-5s %-10s\n", "zhangkun", "yanzi", "zhangcong");formatter.format("%-15s %-5s %-10s\n", "zhangkun", "yanzhou", "zhangcong");}public static void print() {formatter.format("%-15s %5d %10.2f\n", "My name is huhx", 5, 4.2);formatter.format("%-15.4s %5d %10.2f\n", "My name is huhx", 5, 4.1);}public static void main(String[] args) {printTitle();System.out.println("----------------------------");print();formatter.close();}
}

huhx            linux liuli
zhangkun        yanzi zhangcong
zhangkun        yanzhou zhangcong
----------------------------
My name is huhx     5       4.20
My n                5       4.10

package com.tomhu.format;public class FormatTest4 {public static void main(String[] args) {int age = 22;String name = "huhx";String info = String.format("My name is %s and my age is %d", name, age);System.out.println(info);}
}

My name is huhx and my age is 22

public static String format(String format, Object... args) {return new Formatter().format(format, args).toString();
}

package com.tomhu.format;public class FormatTest5 {public static String format(byte[] data) {StringBuilder builder = new StringBuilder();int n = 0;for(byte b: data) {if (n %16 == 0) {builder.append(String.format("%05x: ", n));}builder.append(String.format("%02x ", b));n ++;if (n % 16 == 0) {builder.append("\n");}}builder.append("\n");return builder.toString();}public static void main(String[] args) {String string = "my name is huhx, welcome to my blog";System.out.println(format(string.getBytes()));}
}

00000: 6d 79 20 6e 61 6d 65 20 69 73 20 68 75 68 78 2c
00010: 20 77 65 6c 63 6f 6d 65 20 74 6f 20 6d 79 20 62
00020: 6c 6f 67 

作者： huhx 出处： www.cnblogs.com/huhx