okhttp、okio添加参数(addParams)出现的java.lang.IllegalArgumentException：Unexpected code point

这是我们项目，收集到的，用户出现过不少次的一个问题。根据堆栈发现是出现在用户修改自己的个人资料时出现的。

项目的网络框架用的是okhttp，在bugly上的样子如下图

查看堆栈信息，找到抛出这个异常的地方，在okhttp的okio这个jar包的Buffer类中，的writeUtf8CodePoint（）这个方法中

Buffer类的源码如下

@Override public Buffer writeUtf8CodePoint(int codePoint) {    if (codePoint < 0x80) {      // Emit a 7-bit code point with 1 byte.      writeByte(codePoint);    } else if (codePoint < 0x800) {      // Emit a 11-bit code point with 2 bytes.      writeByte(codePoint >>  6        | 0xc0); // 110xxxxx      writeByte(codePoint       & 0x3f | 0x80); // 10xxxxxx    } else if (codePoint < 0x10000) {      if (codePoint >= 0xd800 && codePoint <= 0xdfff) {        throw new IllegalArgumentException(            "Unexpected code point: " + Integer.toHexString(codePoint));//可能抛出异常的地方 A      }      // Emit a 16-bit code point with 3 bytes.      writeByte(codePoint >> 12        | 0xe0); // 1110xxxx      writeByte(codePoint >>  6 & 0x3f | 0x80); // 10xxxxxx      writeByte(codePoint       & 0x3f | 0x80); // 10xxxxxx    } else if (codePoint <= 0x10ffff) {      // Emit a 21-bit code point with 4 bytes.      writeByte(codePoint >> 18        | 0xf0); // 11110xxx      writeByte(codePoint >> 12 & 0x3f | 0x80); // 10xxxxxx      writeByte(codePoint >>  6 & 0x3f | 0x80); // 10xxxxxx      writeByte(codePoint       & 0x3f | 0x80); // 10xxxxxx    } else {      throw new IllegalArgumentException(          "Unexpected code point: " + Integer.toHexString(codePoint));//可能抛出异常的地方 B    }    return this;  }

从源码，可以看到，有两个地方可能出现这种情况，而这个方法的代码，是进行Utf-8编码时，根据规则

大于0xd800 并且小于0xdfff的范围，是做其他用的（详情可参看Unicode编码以及Utf-8等相关知识），而大于0x10ffff是超出了Unicode的编码范围的。

现在我们需要知道这个方法在哪里被调用的，以及codePoint是什么东西，怎么来的？

最终我们找到了okhttp3这个jar包中的HttpUrl这个类中的canonicalize这个方法中，该方法源码如下

 static void canonicalize(Buffer out, String input, int pos, int limit, String encodeSet,      boolean alreadyEncoded, boolean strict, boolean plusIsSpace, boolean asciiOnly) {    Buffer utf8Buffer = null; // Lazily allocated.    int codePoint;    for (int i = pos; i < limit; i += Character.charCount(codePoint)) {      codePoint = input.codePointAt(i);      if (alreadyEncoded          && (codePoint == '\t' || codePoint == '\n' || codePoint == '\f' || codePoint == '\r')) {        // Skip this character.      } else if (codePoint == '+' && plusIsSpace) {        // Encode '+' as '%2B' since we permit ' ' to be encoded as either '+' or '%20'.        out.writeUtf8(alreadyEncoded ? "+" : "%2B");      } else if (codePoint < 0x20          || codePoint == 0x7f          || codePoint >= 0x80 && asciiOnly          || encodeSet.indexOf(codePoint) != -1          || codePoint == '%' && (!alreadyEncoded || strict && !percentEncoded(input, i, limit))) {        // Percent encode this character.        if (utf8Buffer == null) {          utf8Buffer = new Buffer();        }        utf8Buffer.writeUtf8CodePoint(codePoint);        while (!utf8Buffer.exhausted()) {          int b = utf8Buffer.readByte() & 0xff;          out.writeByte('%');          out.writeByte(HEX_DIGITS[(b >> 4) & 0xf]);          out.writeByte(HEX_DIGITS[b & 0xf]);        }      } else {        // This character doesn't need encoding. Just copy it over.        out.writeUtf8CodePoint(codePoint);      }    }  }

通过该方法 的源码，我们就可以知道codePoint是如何来的了，如此我们就找到了出现这种问题的原因，可能是用户输入某些还不能被识别的字符，那么我们为了避免用户应用出现崩溃的情况，我们可以进行提前规避。做法如下

在出现问题的地方，对每个参数进行如下代码的检查

private boolean checkIsUnLawful(String[] input){        if (input != null && input.length> 0){            for (int i = 0; i < input.length; i++) {                String length = input[i];                int codePoint;                if (!TextUtils.isEmpty(length)){                    for (int j = 0; j < length.length(); j += Character.charCount(codePoint)) {                        codePoint = length.codePointAt(j);                        if ((codePoint >= 0xd800 && codePoint <= 0xdfff) || codePoint > 0x10ffff) {                            return false;                        }                    }                }            }        }        return true;    }

问题就可以解决了