字符串转换的类,如230991.291==>230,991.291

public class FloattoString{

//if given 230991.291, should return the String "230,991.291"
//if given 200.0, should return the string "200"
//if given 87238.001, should return the string "87,238.001"
//if give -23870.0, should return the string "-23,870"

public String doubleToString(double value){
String strValue=value+"";
String strInt="";//取其整形部分
String strDec="";//取其小数部分
String result="";
//检查是否有小数点
int pos=strValue.lastIndexOf(".");
//if(pos>0){
//把字符按小数点拆分

strInt=strValue.substring(0, pos);
strDec=strValue.substring(pos);

int intValue=Integer.parseInt(strInt);
//加上小数部分
if(intValue!=value){
result+=strDec;
}

//如果是正数则直接输出，负数则加上负号
String resultTemp="";
if(intValue>=0){
resultTemp=getResult(intValue);
result=resultTemp+result;
}else{
intValue=intValue*-1;
resultTemp=getResult(intValue);
result="-"+resultTemp+result;
}
//如果小数点后为0则不按整数输出
//}
return result;

}
//把传过来的整弄值变成123456789--->123,456,789
private String getResult(int value){
int intValue=value;
String result="";
while(true){
int t1=intValue/1000;
int t2=intValue%1000;
if(t1!=0){
result=","+t2+result;
}
//最后一次前面不加","
if(t1==0){
result=t2+result;
break;
}
intValue=t1;
}
return result;
}
public static void main(String[] args){
//if given 230991.291, should return the String "230,991.291"
//if given 200.0, should return the string "200"
//if given 87238.001, should return the string "87,238.001"
//if give -23870.0, should return the string "-23,870"
double a=(double)230991.291;
double b=(double)200.0;
double c=(double)87238.001;
double d=(double)-23870.0;
double e=(double)1234567;
FloattoString fs=new FloattoString();
String rs=fs.doubleToString(a);
System.out.println(rs);
System.out.println(fs.doubleToString(b));
System.out.println(fs.doubleToString(c));
System.out.println(fs.doubleToString(d));
System.out.println(fs.doubleToString(e));
//System.out.println(123.0==123);
}

}