java中有类似sql中rpad这个方法的吗？
如题，JAVA中有类似这种字符串右补齐的方法吗？
PS：
rpad(var_name,5, 'a ');
当var_name = 'bb '的时候，返回值为 'bbaaa ';
当var_name = 'bbb '的时候，返回值为 'bbbaa ';
请朋友们指点下，谢谢。
[解决办法]
自己写吧！
public String rpad(String str,int num,String pad){
String n_str=str;
if(str==null)
n_str= " ";
for(int i=str.length();i <num;i++){
n_str+=pad;
}
return n_str;
}
[解决办法]
StringBuffer的insert方法和这个差不多吧
[解决办法]
没有：
用这个吧
package com.capitalnd.util;
import java.text.*;
/**
* StringPadderはひもに左のパッドおよび右のパッドの機能性を提供する
* @author penglee
* <br> 2007-07-03
*/
public class StringPadder {
private static StringBuffer strb;
private static StringCharacterIterator sci;
/** method to left pad a string with a given string to a given size. This
* method will repeat the padder string as many times as is necessary until
* the exact specified size is reached. If the specified size is less than the size of
* the original string then the original string is returned unchanged.
* Example1 - original string "cat ", padder string "white ", size 8 gives "whitecat ".
* Example2 - original string "cat ", padder string "white ", size 15 gives "whitewhitewhcat ".
* Example3 - original string "cat ", padder string "white ", size 2 gives "cat ".
* @return String the newly padded string
* @param stringToPad The original string
* @param padder The string to pad onto the original string
* @param size The required size of the new string
*/
public static String leftPad (String stringToPad, String padder, int size)
{
if (padder.length() == 0)
{
return stringToPad;
}
strb = new StringBuffer(size);
sci = new StringCharacterIterator(padder);
while (strb.length() < (size - stringToPad.length()))
{
for (char ch = sci.first(); ch != CharacterIterator.DONE ; ch = sci.next())
{
if (strb.length() < size - stringToPad.length())
{
strb.insert( strb.length(),String.valueOf(ch));
}
}
}
return strb.append(stringToPad).toString();
}
/** method to right pad a string with a given string to a given size. This
* method will repeat the padder string as many times as is necessary until
* the exact specified size is reached. If the specified size is less than the size of
* the original string then the original string is returned unchanged.
* Example1 - original string "cat ", padder string "white ", size 8 gives "catwhite ".
* Example2 - original string "cat ", padder string "white ", size 15 gives "catwhitewhitewh ".
* Example3 - original string "cat ", padder string "white ", size 2 gives "cat ".
* @return String the newly padded string
* @param stringToPad The original string
* @param padder The string to pad onto the original string
* @param size The required size of the new string
*/
public static String rightPad (String stringToPad, String padder, int size)
{
if (padder.length() == 0)
{
return stringToPad;
}
strb = new StringBuffer(stringToPad);
sci = new StringCharacterIterator(padder);
while (strb.length() < size)
{
for (char ch = sci.first(); ch != CharacterIterator.DONE ; ch = sci.next())
{
if (strb.length() < size)
{
strb.append(String.valueOf(ch));
}
}
}
return strb.toString();
}
}
[解决办法]
Apache Jakarta Commons Long 中有 StringUtils 类，有 rightPad 和 leftPad 两个静态方法，用的方法和 rpad 一模一样。
在你的 classpath 下的其他外部 jar 中可能就有这个包，Jakarta Commons Lang 的官方下载地址：
http://commons.apache.org/downloads/download_lang.cgi
