java string.format 字符串格式

public class String_Format_Test {


 @Test
 public void String_format(){
     
     //-----------------------------------------------
     //$    被格式化的参数索引
     //%s     字符串类型
     //控制台输出：1024.00MB
     //-----------------------------------------------
     String FORMAT_F_UNIT = "%1$-1.2f%2$s";
     System.out.println(String.format(FORMAT_F_UNIT, 1024f,"MB"));

     
     //-----------------------------------------------
     //控制台输出：1024.00
     //-----------------------------------------------
     FORMAT_F_UNIT="%1$-1.2f";
     System.out.println(String.format(FORMAT_F_UNIT, 1024f));
     
     //-----------------------------------------------
     //控制台输出：1024.000000
     //-----------------------------------------------     
     FORMAT_F_UNIT="%1$f";
     System.out.println(String.format(FORMAT_F_UNIT, 1024f));
     
     
     //-----------------------------------------------
     //控制台输出：1024.000000
     //-----------------------------------------------     
     FORMAT_F_UNIT="%f";
     System.out.println(String.format(FORMAT_F_UNIT, 1024f));
     
     //-----------------------------------------------
     //控制台输出：1024.000
     //-----------------------------------------------
     FORMAT_F_UNIT="%1.3f";
     System.out.println(String.format(FORMAT_F_UNIT, 1024f));     
     
     //-----------------------------------------------
     //控制台输出：102.479
     //-----------------------------------------------
     FORMAT_F_UNIT="%1.3f";
     System.out.println(String.format(FORMAT_F_UNIT, 102.4789f));         
          
     long l=Long.MAX_VALUE;
     
     double d=l/1024;
     System.out.println(d); //9.007199254740991E15
     System.out.println(String.format(FORMAT_F_UNIT, d));//9007199254740991.000    
     
     float f=l/1024;
     System.out.println(f); //9.0071993E15 
     System.out.println(String.format(FORMAT_F_UNIT, f));//9007199254740992.000
     
     FORMAT_F_UNIT="%1.2f";
     System.out.println(String.format(FORMAT_F_UNIT, d));//9007199254740991.00
     System.out.println(String.format(FORMAT_F_UNIT, f));//9007199254740992.00
 
 }

 
 @Test
 public void decimal_Format(){
     DecimalFormat a = new DecimalFormat("#.00%");  
     String s = a.format(0.56845);
     String h = a.format(0.56855);
     System.out.println(s);//56.84%  
     System.out.println(h);//56.86%  
     
     System.out.println(a.format(0.5680));//56.80%  
     
     NumberFormat df = new DecimalFormat("#.00");  
     System.out.println(df.format(8.8445));//8.84  
     System.out.println(df.format(8.8455));//8.85  
 }


}