可配置保留小数位数的四舍五入方法

无聊写了个可配置保留小数位数的四舍五入方法,大家有兴趣的就看看,顺便试试有没有没考虑到的问题. (前提传入的参数一定是数字,因为我外面已经处理了)

代码如下:
_____________________________________________
/**
* @param str 处理参数
* @param num 保留小数位数
* @return 返回值
*/
public static String RoundOf(String str, int num){
if(str.indexOf(".") > -1){
String str1 = str.substring(str.indexOf(".") + 1,str.indexOf(".") + 1 + str.length() - (str.indexOf(".") + 1));
int i = 0; if(num < 0) num = 0; //如果指定要保留的小数位小于零,则初始化为零
if(str1.length() > num){
if(Integer.valueOf(str1.substring(num,num + 1)) > 4){
int val = 0;
val = Integer.valueOf(str1.substring(0,num + 1)) + (10 - Integer.valueOf(str1.substring(num,num + 1)));
if(String.valueOf(val).length() > (num + 1)){
i = 1;
str1 = String.valueOf(val).substring(1,num + 1);
}else{
str1 = String.valueOf(val).substring(0,num);
}
}else{
str1 = str1.substring(0,num);
}
if(str.indexOf(".") > 0){
String str2 = str.substring(0,str.indexOf("."));
if(num > 0){
str = String.valueOf(Integer.valueOf(str2) + i) + "." + str1;
}else{
str = String.valueOf(Integer.valueOf(str2) + i);
}
}else{
if(num > 0){
str = String.valueOf(i) + "." + str1;
}else{
str = String.valueOf(i);
}
}
}else if(str1.length() < num){
for(int n = 0;n < (num - str1.length());n++){
str = str + "0";
}
}
}return str;
}
__________________________________________
结束.
 <script type="text/javascript"><!--google_ad_client = "pub-8894273660285713";google_ad_width = 468;google_ad_height = 60;google_ad_format = "468x60_as";google_ad_type = "text_image";//2007-09-14: CSDN区google_ad_channel = "2561687419";//--></script> <script type="text/javascript" src="http://pagead2.googlesyndication.com/pagead/show_ads.js"></script>