Java 实现 URL Decode
背景：
ElasticSearch 自定义脚本 Painless 当中可以支持 Java 的部分 API，但 6.x 版本没有对 URLDecode 的支持（发现 7.0 已经支持），而分析用户搜索当中需要对 URL 进行 Decode
因而需要自己实现
public class MyURLDecode {
public static void main(String[] args) {
String str = "/controller/action?&s=%e8%ad%ac%e5%a6%82%e6%9c%9d%e9%9c%b2%e5%8e%bb%e6%97%a5%e8%8b%a6%e5%a4%9a&page=1&page_size=30";
String decodedStr = myURLDecode(str);
System.out.println(decodedStr); // /controller/action?&s=譬如朝露去日苦多&page=1&page_size=30
}
public static String URLDecode(String s) {
boolean needToChange = false;
int numChars = s.length();
StringBuilder sb = new StringBuilder();
int i = 0;
char c;
byte[] bytes = null;
String vv = "+%";
byte vNum1 = (byte)vv.charAt(0);
byte vNum2 = (byte)vv.charAt(1);
while (i < numChars) {
c = s.charAt(i);
byte cNum = (byte)c;
if (cNum == vNum1) {
sb.append(' ');
i++;
needToChange = true;
} else if (cNum == vNum2) {
if (bytes == null) {
bytes = new byte[(numChars - i) / 3];
}
int pos = 0;
String hexString = "";
int countHex = 0;
while (((i + 2) < numChars) && ((byte)c == vNum2)) {
int v = Integer.parseInt(s.substring(i + 1, i + 3), 16);
hexString += s.substring(i + 1, i + 3);
countHex += 1;
if (3 == countHex) {
int num = Integer.parseInt(hexString, 16);
String bitString = Integer.toString(num, 2);
String unicodeString = "";
if ((num & 0xf0000000L) > 0) {
unicodeString = bitString.substring(5, 8) + bitString.substring(10, 16) + bitString.substring(18, 24) + bitString.substring(26, bitString.length());
} else if ((num & 0xe00000) > 0) {
unicodeString = bitString.substring(4, 8) + bitString.substring(10, 16) + bitString.substring(18, bitString.length());
} else if ((num & 0xc000) > 0) {
unicodeString = bitString.substring(3, 8) + bitString.substring(10, bitString.length());
} else {
unicodeString = bitString.substring(1, bitString.length());
}
char result = (char)Integer.parseInt(unicodeString, 2);
sb.append(result);
hexString = "";
countHex = 0;
}
bytes[pos++] = (byte)v;
i += 3;
if (i < numChars) {
c = s.charAt(i);
}
}
needToChange = true;
} else {
sb.append(c);
i++;
}
}
String ret = needToChange ? sb.toString() : s;
return ret;
}
}
Lucene Query
{
"size": 0,
"query": {
"bool": {
// 筛选条件
}
},
"aggs": {
"result": {
"terms": {
"script": {
"lang": "painless",
"size": 2,
"source": "def m = /^\\/controller\\/action.+?s=(.+?)&.*?$/.matcher(doc['nginx.access.url'].value);\nif (m.matches()) {\n String s = m.group(1);\n boolean needToChange = false;\n int numChars = s.length();\n StringBuilder sb = new StringBuilder();\n int i = 0;\n\n char c;\n byte[] bytes = null;\n\n String vv = \"+%\";\n byte vNum1 = (byte)vv.charAt(0);\n byte vNum2 = (byte)vv.charAt(1);\n while (i < numChars) {\n c = s.charAt(i);\n byte cNum = (byte)c;\n if (cNum == vNum1) {\n sb.append(' ');\n i++;\n needToChange = true;\n } else if (cNum == vNum2) {\n if (bytes == null) {\n bytes = new byte[(numChars - i) / 3];\n }\n int pos = 0;\n\n String hexString = \"\";\n int countHex = 0;\n while (((i + 2) < numChars) && ((byte)c == vNum2)) {\n int v = Integer.parseInt(s.substring(i + 1, i + 3), 16);\n hexString += s.substring(i + 1, i + 3);\n countHex += 1;\n if (3 == countHex) {\n int num = Integer.parseInt(hexString, 16);\n String bitString = Integer.toString(num, 2);\n String unicodeString = \"\";\n if ((num & 0xf0000000L) > 0) {\n unicodeString = bitString.substring(5, 8) + bitString.substring(10, 16) + bitString.substring(18, 24) + bitString.substring(26, bitString.length());\n } else if ((num & 0xe00000) > 0) {\n unicodeString = bitString.substring(4, 8) + bitString.substring(10, 16) + bitString.substring(18, bitString.length());\n } else if ((num & 0xc000) > 0) {\n unicodeString = bitString.substring(3, 8) + bitString.substring(10, bitString.length());\n } else {\n unicodeString = bitString.substring(1, bitString.length());\n }\n char result = (char)Integer.parseInt(unicodeString, 2);\n sb.append(result);\n\n hexString = \"\";\n countHex = 0;\n }\n bytes[pos++] = (byte)v;\n i += 3;\n if (i < numChars) {\n c = s.charAt(i);\n }\n }\n\n needToChange = true;\n } else {\n sb.append(c);\n i++;\n }\n }\n\n String ret = needToChange ? sb.toString() : s;\n return ret.toUpperCase();\n} else {\n return \"N/A\";\n}"
}
}
}
}
}
输出
{
“took”: 2600,
“timed_out”: false,
“_shards”: {
“total”: 278,
“successful”: 278,
“skipped”: 276,
“failed”: 0
},
“hits”: {
“total”: 476944,
“max_score”: 0,
“hits”: []
},
“aggregations”: {
“results”: {
“doc_count_error_upper_bound”: 1419,
“sum_other_doc_count”: 359784,
“buckets”: [
{
“key”: “秋以为期”,
“doc_count”: 6514
},
{
“key”: “原野苍茫”,
“doc_count”: 4704
}
]
}
}
}
参考
java.net.URLDecoder.decode()方法（原有方法中new String()构造函数 ElasticSearch 只支持无参的形式，因此需要手工进行从字节数组转为 Unicode 字符）- https://blog.csdn.net/hezh1994/article/details/78899683
- https://www.elastic.co/guide/en/elasticsearch/painless/6.7/painless-api-reference.html
