本篇文章主要介绍了Java中实现String.padLeft和String.padRight,小编觉得挺不错的,现在分享给大家,也给大家做个参考。一起跟随小编过来看看吧
因为习惯了C#中的padLeft和padRight,接触Java后突然失去这两个功能,觉得别扭,就试着实现了这两个方法。
Java中String.format()中带有字符串对齐功能如下:
System.out.println(String.format("*%1$-10s*", "moon")); System.out.println(String.format("*%1$10s*", "moon"));
输出:
以上方法经过简单的变换可以得到:
public static String padWhitespaceLeft(String s, int len) { return String.format("%1$" + len + "s", s); } public static String padWhitespaceRight(String s, int len) { return String.format("%1$-" + len + "s", s); }
调用下面方法:
System.out.println("*" + padWhitespaceLeft("moon", 12) + "*"); System.out.println("*" + padWhitespaceRight("moon", 12) + "*");
可以得到结果:
以上只是介绍左右对齐时,补空白符的方法,但是在实际开发过程中,单纯的补空白符也许满足不了开发要求,为此我还要做一次强化改进:
/** * @作者 尧 * @功能 String左对齐 */ public static String padLeft(String src, int len, char ch) { int diff = len - src.length(); if (diff <= 0) { return src; } char[] charr = new char[len]; System.arraycopy(src.toCharArray(), 0, charr, 0, src.length()); for (int i = src.length(); i < len; i++) { charr[i] = ch; } return new String(charr); } /** * @作者 尧 * @功能 String右对齐 */ public static String padRight(String src, int len, char ch) { int diff = len - src.length(); if (diff <= 0) { return src; } char[] charr = new char[len]; System.arraycopy(src.toCharArray(), 0, charr, diff, src.length()); for (int i = 0; i < diff; i++) { charr[i] = ch; } return new String(charr); }
调用方法如下:
System.out.println("*" + padLeft("moon", 12, '-') + "*"); System.out.println("*" + padRight("moon", 12, '-') + "*");
输出结果:
这样在Java中处理字符串对齐就可以像C#那样简单了。
效率也是有保障的。
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