java取小数点前两位,并四舍五入

ava 取小数点前两位的4种办法  
//取小数点的几种办法  
class TestDot2   
{  
//方法1  
public void test1(double c)  
{  
   java.text.DecimalFormat df = new java.text.DecimalFormat("#.##");  
   System.out.println(df.format(c));  
}  
//方法2  
public void test2(double c)  
{  
     
   java.math.BigDecimal bd   =   new   java.math.BigDecimal(String.valueOf(c));     
   bd   =   bd.setScale(2,java.math.BigDecimal.ROUND_HALF_UP);     
   System.out.println(bd);  
}  
//方法3  
public void test3(double c)  
{  
   long   l1   =   Math.round(c*100);   //四舍五入     
        double   ret   =   l1/100.0;               //注意：使用   100.0   而不是   100       
  
   System.out.println(ret);  
}  
//方法4  
public void test4(double c)  
{   
   c=((int)(c*100))/100.0;   
   System.out.println(c);  
}  
public static void main(String[] args)   
{  
   double c = 3.056;  
   TestDot2 td2 = new TestDot2();  
   //td2.test1(c);  
   //td2.test2(c);  
   //td2.test3(c);  
   td2.test4(c);  
}  
}