将十六进制转换为具有3位数的char

时间:2012-07-05 14:26:55

标签: java unicode utf-8 hex

当十六进制有3位数

时,将十六进制转换为字符时出现问题

我有两种方法可以在十进制值127

上转义和转换字符 转义test\\b8时生成

test¸

unescape执行以下操作:

for (int i=0, n=node.length; i<n; i++) {
    if(c == "\\"){
          char c2 = node[i + 1];
          char c3 = node[i + 2];
          int i= Integer.parseInt(str,16);
          char c = (char)i;
          System.out.println("Char is:=" + c);
    }
}

输出 - test¸

正如您所看到的,我将斜杠后的前两个字符转换为char。一切正常。但是,有时候字符有3个十六进制数字(例如test\\2d8。这应该是test˘)。当这进入我的unescape方法时,不会使用全部3个字符。只有前2个,因此产生了错误的结果。

有没有办法确定何时转换2或3个字符

1 个答案:

答案 0 :(得分:0)

这就是我要做的事情:

String raw = new String(node); // might be a better way to get a string from the chars
int slashPos = raw.indexOf('\\');
if(slashPos >= 0) {
    String hex = raw.substring(slashPos + 1);
    int value = Integer.parseInt(hex,16);
}

通过这种方式,我们并不特别为2,3,4或100位数设置任何东西(尽管我确定100位数会引发异常:-))。相反,我们将协议用作字符串中的“里程碑”,然后只接受斜杠之后的所有内容都是十六进制字符串。

class HexParse {

    private static class HexResult {
        final boolean exists;
        final int value;
        HexResult(boolean e, int v) { exists = e; value = v; }
    }

    private final String raw;
    private final HexResult result;

    public HexParse(String raw) {
        this.raw = raw;
        int slashPos = raw.indexOf('\\');
        boolean noSlash = slashPos < 0;
        boolean noTextAfterSlash = slashPos > raw.length() - 2;
        if(noSlash || noTextAfterSlash) {
            result  = new HexResult(false,0);
        } else {
            // throws exception if second part of string contains non-hex chars
            result = new HexResult(true,Integer.parseInt(raw.substring(slashPos + 1),16));
        }
    }

    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append(raw).append(" ");
        if(result.exists) {
            sb.append("has hex of decimal value ").append(result.value);
        } else {
            sb.append("has no hex");
        }
        return sb.toString();
    }

    public static void main(String...args) {
        System.out.println(new HexParse("test`hello")); // none
        System.out.println(new HexParse("haha\\abcdef")); // hex
        System.out.println(new HexParse("good\\f00d")); // hex
        System.out.println(new HexParse("\\84b")); // hex
        System.out.println(new HexParse("\\")); // none
        System.out.println(new HexParse("abcd\\efgh")); //exception
    }

}

c:\files\j>javac HexParse.java

c:\files\j>java HexParse
test`hello has no hex
haha\abcdef has hex of decimal value 11259375
good\f00d has hex of decimal value 61453
\84b has hex of decimal value 2123
\ has no hex
Exception in thread "main" java.lang.NumberFormatException: For input string: "e
fgh"
        at java.lang.NumberFormatException.forInputString(NumberFormatException.
java:48)
        at java.lang.Integer.parseInt(Integer.java:458)
        at HexParse.<init>(HexParse.java:21)
        at HexParse.main(HexParse.java: