下面是另一种向右填充的方法:

// put the number of spaces, or any character you like, in your paddedString

String paddedString = "--------------------";

String myStringToBePadded = "I like donuts";

myStringToBePadded = myStringToBePadded + paddedString.substring(myStringToBePadded.length());

//result:
myStringToBePadded = "I like donuts-------";

下面是另一种向右填充的方法:

// put the number of spaces, or any character you like, in your paddedString

String paddedString = "--------------------";

String myStringToBePadded = "I like donuts";

myStringToBePadded = myStringToBePadded + paddedString.substring(myStringToBePadded.length());

//result:
myStringToBePadded = "I like donuts-------";

s =字符串填充 n =期望长度 c = Char到pad

private String padStart( String s, int n, char c ){
    if( n <= 0 ) return s;
    else return String.format("%" + n + "s", s).replace(' ', c);
}

从Java 1.5开始，string. format()可以用于左/右填充给定的字符串。

public static String padRight(String s, int n) {
     return String.format("%-" + n + "s", s);  
}

public static String padLeft(String s, int n) {
    return String.format("%" + n + "s", s);  
}

...

public static void main(String args[]) throws Exception {
 System.out.println(padRight("Howto", 20) + "*");
 System.out.println(padLeft("Howto", 20) + "*");
}

输出为:

Howto               *
               Howto*

public static String LPad(String str, Integer length, char car) {
  return (str + String.format("%" + length + "s", "").replace(" ", String.valueOf(car))).substring(0, length);
}

public static String RPad(String str, Integer length, char car) {
  return (String.format("%" + length + "s", "").replace(" ", String.valueOf(car)) + str).substring(str.length(), length + str.length());
}

LPad("Hi", 10, 'R') //gives "RRRRRRRRHi"
RPad("Hi", 10, 'R') //gives "HiRRRRRRRR"
RPad("Hi", 10, ' ') //gives "Hi        "
RPad("Hi", 1, ' ')  //gives "H"
//etc...

你可以通过保留填充数据来减少每次调用的开销，而不是每次都重新构建:

public class RightPadder {

    private int length;
    private String padding;

    public RightPadder(int length, String pad) {
        this.length = length;
        StringBuilder sb = new StringBuilder(pad);
        while (sb.length() < length) {
            sb.append(sb);
        }
        padding = sb.toString();
   }

    public String pad(String s) {
        return (s.length() < length ? s + padding : s).substring(0, length);
    }

}

作为一种替代方法，您可以将结果长度作为pad(…)方法的参数。在这种情况下，在该方法中而不是在构造函数中调整隐藏填充。

(提示:为了获得额外的学分，让它是线程安全的!: -)