每日学习笔记(23)

1,从前端传过来的参数是"\u9676\u9676\u6D4B\u8BD5\u8D26\u53F701"这样的unicode编码，需要将其转换为中文字符串，发现java.util.Properties类中有一个loadConvert函数可以完成这件事，直接copy过来使用。

public static String loadConvert(char[] in, int off, int len, char[] convtBuf) {  
        if (convtBuf.length < len) {  
            int newLen = len * 2;  
            if (newLen < 0) {  
                newLen = Integer.MAX_VALUE;  
            }  
            convtBuf = new char[newLen];  
        }  
        char aChar;  
        char[] out = convtBuf;  
        int outLen = 0;  
        int end = off + len;  
  
        while (off < end) {  
            aChar = in[off++];  
            if (aChar == '\\') {  
                aChar = in[off++];  
                if (aChar == 'u') {  
                    // Read the xxxx  
                    int value = 0;  
                    for (int i = 0; i < 4; i++) {  
                        aChar = in[off++];  
                        switch (aChar) {  
                        case '0':  
                        case '1':  
                        case '2':  
                        case '3':  
                        case '4':  
                        case '5':  
                        case '6':  
                        case '7':  
                        case '8':  
                        case '9':  
                            value = (value << 4) + aChar - '0';  
                            break;  
                        case 'a':  
                        case 'b':  
                        case 'c':  
                        case 'd':  
                        case 'e':  
                        case 'f':  
                            value = (value << 4) + 10 + aChar - 'a';  
                            break;  
                        case 'A':  
                        case 'B':  
                        case 'C':  
                        case 'D':  
                        case 'E':  
                        case 'F':  
                            value = (value << 4) + 10 + aChar - 'A';  
                            break;  
                        default:  
                            throw new IllegalArgumentException(  
                                    "Malformed \\uxxxx encoding.");  
                        }  
                    }  
                    out[outLen++] = (char) value;  
                } else {  
                    if (aChar == 't')  
                        aChar = '\t';  
                    else if (aChar == 'r')  
                        aChar = '\r';  
                    else if (aChar == 'n')  
                        aChar = '\n';  
                    else if (aChar == 'f')  
                        aChar = '\f';  
                    out[outLen++] = aChar;  
                }  
            } else {  
                out[outLen++] = (char) aChar;  
            }  
        }  
        return new String(out, 0, outLen);  
    }