我的Java独立应用程序从用户那里获得一个URL(指向一个文件)，我需要点击它并下载它。我面临的问题是，我不能正确编码HTTP URL地址…
例子:
URL: http://search.barnesandnoble.com/booksearch/first book.pdf
java.net.URLEncoder.encode(url.toString(), "ISO-8859-1");
回报我。
http%3A%2F%2Fsearch.barnesandnoble.com%2Fbooksearch%2Ffirst+book.pdf
但是，我想要的是
http://search.barnesandnoble.com/booksearch/first%20book.pdf
(空格替换为%20)
我猜URLEncoder不是为编码HTTP url设计的…JavaDoc说“HTML表单编码的实用程序类”…还有别的办法吗?
当前回答
你可以使用这样的函数。根据您的需要完成并修改:
/**
* Encode URL (except :, /, ?, &, =, ... characters)
* @param url to encode
* @param encodingCharset url encoding charset
* @return encoded URL
* @throws UnsupportedEncodingException
*/
public static String encodeUrl (String url, String encodingCharset) throws UnsupportedEncodingException{
return new URLCodec().encode(url, encodingCharset).replace("%3A", ":").replace("%2F", "/").replace("%3F", "?").replace("%3D", "=").replace("%26", "&");
}
使用示例:
String urlToEncode = ""http://www.growup.com/folder/intérieur-à_vendre?o=4";
Utils.encodeUrl (urlToEncode , "UTF-8")
结果是:http://www.growup.com/folder/int%C3%A9rieur-%C3%A0_vendre?o=4
其他回答
你可以使用这样的函数。根据您的需要完成并修改:
/**
* Encode URL (except :, /, ?, &, =, ... characters)
* @param url to encode
* @param encodingCharset url encoding charset
* @return encoded URL
* @throws UnsupportedEncodingException
*/
public static String encodeUrl (String url, String encodingCharset) throws UnsupportedEncodingException{
return new URLCodec().encode(url, encodingCharset).replace("%3A", ":").replace("%2F", "/").replace("%3F", "?").replace("%3D", "=").replace("%26", "&");
}
使用示例:
String urlToEncode = ""http://www.growup.com/folder/intérieur-à_vendre?o=4";
Utils.encodeUrl (urlToEncode , "UTF-8")
结果是:http://www.growup.com/folder/int%C3%A9rieur-%C3%A0_vendre?o=4
我开发了一个比其他解决方案更稳定的解决方案:
public class URLParamEncoder {
public static String encode(String input) {
StringBuilder resultStr = new StringBuilder();
for (char ch : input.toCharArray()) {
if (isUnsafe(ch)) {
resultStr.append('%');
resultStr.append(toHex(ch / 16));
resultStr.append(toHex(ch % 16));
} else {
resultStr.append(ch);
}
}
return resultStr.toString();
}
private static char toHex(int ch) {
return (char) (ch < 10 ? '0' + ch : 'A' + ch - 10);
}
private static boolean isUnsafe(char ch) {
if (ch > 128 || ch < 0)
return true;
return " %$&+,/:;=?@<>#%".indexOf(ch) >= 0;
}
}
如果任何人不想向他们的项目添加依赖项，这些函数可能会有帮助。
我们将URL的path部分传递到这里。您可能不想将完整的URL作为参数传递进来(查询字符串需要不同的转义，等等)。
/**
* Percent-encodes a string so it's suitable for use in a URL Path (not a query string / form encode, which uses + for spaces, etc)
*/
public static String percentEncode(String encodeMe) {
if (encodeMe == null) {
return "";
}
String encoded = encodeMe.replace("%", "%25");
encoded = encoded.replace(" ", "%20");
encoded = encoded.replace("!", "%21");
encoded = encoded.replace("#", "%23");
encoded = encoded.replace("$", "%24");
encoded = encoded.replace("&", "%26");
encoded = encoded.replace("'", "%27");
encoded = encoded.replace("(", "%28");
encoded = encoded.replace(")", "%29");
encoded = encoded.replace("*", "%2A");
encoded = encoded.replace("+", "%2B");
encoded = encoded.replace(",", "%2C");
encoded = encoded.replace("/", "%2F");
encoded = encoded.replace(":", "%3A");
encoded = encoded.replace(";", "%3B");
encoded = encoded.replace("=", "%3D");
encoded = encoded.replace("?", "%3F");
encoded = encoded.replace("@", "%40");
encoded = encoded.replace("[", "%5B");
encoded = encoded.replace("]", "%5D");
return encoded;
}
/**
* Percent-decodes a string, such as used in a URL Path (not a query string / form encode, which uses + for spaces, etc)
*/
public static String percentDecode(String encodeMe) {
if (encodeMe == null) {
return "";
}
String decoded = encodeMe.replace("%21", "!");
decoded = decoded.replace("%20", " ");
decoded = decoded.replace("%23", "#");
decoded = decoded.replace("%24", "$");
decoded = decoded.replace("%26", "&");
decoded = decoded.replace("%27", "'");
decoded = decoded.replace("%28", "(");
decoded = decoded.replace("%29", ")");
decoded = decoded.replace("%2A", "*");
decoded = decoded.replace("%2B", "+");
decoded = decoded.replace("%2C", ",");
decoded = decoded.replace("%2F", "/");
decoded = decoded.replace("%3A", ":");
decoded = decoded.replace("%3B", ";");
decoded = decoded.replace("%3D", "=");
decoded = decoded.replace("%3F", "?");
decoded = decoded.replace("%40", "@");
decoded = decoded.replace("%5B", "[");
decoded = decoded.replace("%5D", "]");
decoded = decoded.replace("%25", "%");
return decoded;
}
和测试:
@Test
public void testPercentEncode_Decode() {
assertEquals("", percentDecode(percentEncode(null)));
assertEquals("", percentDecode(percentEncode("")));
assertEquals("!", percentDecode(percentEncode("!")));
assertEquals("#", percentDecode(percentEncode("#")));
assertEquals("$", percentDecode(percentEncode("$")));
assertEquals("@", percentDecode(percentEncode("@")));
assertEquals("&", percentDecode(percentEncode("&")));
assertEquals("'", percentDecode(percentEncode("'")));
assertEquals("(", percentDecode(percentEncode("(")));
assertEquals(")", percentDecode(percentEncode(")")));
assertEquals("*", percentDecode(percentEncode("*")));
assertEquals("+", percentDecode(percentEncode("+")));
assertEquals(",", percentDecode(percentEncode(",")));
assertEquals("/", percentDecode(percentEncode("/")));
assertEquals(":", percentDecode(percentEncode(":")));
assertEquals(";", percentDecode(percentEncode(";")));
assertEquals("=", percentDecode(percentEncode("=")));
assertEquals("?", percentDecode(percentEncode("?")));
assertEquals("@", percentDecode(percentEncode("@")));
assertEquals("[", percentDecode(percentEncode("[")));
assertEquals("]", percentDecode(percentEncode("]")));
assertEquals(" ", percentDecode(percentEncode(" ")));
// Get a little complex
assertEquals("[]]", percentDecode(percentEncode("[]]")));
assertEquals("a=d%*", percentDecode(percentEncode("a=d%*")));
assertEquals(") (", percentDecode(percentEncode(") (")));
assertEquals("%21%20%2A%20%27%20%28%20%25%20%29%20%3B%20%3A%20%40%20%26%20%3D%20%2B%20%24%20%2C%20%2F%20%3F%20%23%20%5B%20%5D%20%25",
percentEncode("! * ' ( % ) ; : @ & = + $ , / ? # [ ] %"));
assertEquals("! * ' ( % ) ; : @ & = + $ , / ? # [ ] %", percentDecode(
"%21%20%2A%20%27%20%28%20%25%20%29%20%3B%20%3A%20%40%20%26%20%3D%20%2B%20%24%20%2C%20%2F%20%3F%20%23%20%5B%20%5D%20%25"));
assertEquals("%23456", percentDecode(percentEncode("%23456")));
}
如果你用的是弹簧，你可以试试 org.springframework.web.util.UriUtils # encodePath
URLEncoding可以很好地编码HTTP url，正如您不幸发现的那样。您传入的字符串“http://search.barnesandnoble.com/booksearch/first book.pdf”被正确且完整地编码为url编码的表单。你可以把你得到的整个冗长的字符串作为URL的参数传递回去，它可以被解码成你传递进去的字符串。
听起来，您想要做一些与将整个URL作为参数传递不同的事情。据我所知，你试图创建一个看起来像“http://search.barnesandnoble.com/booksearch/whateverTheUserPassesIn”的搜索URL。你唯一需要编码的是“whateverTheUserPassesIn”位，所以也许你所需要做的就是这样:
String url = "http://search.barnesandnoble.com/booksearch/" +
URLEncoder.encode(userInput,"UTF-8");
这应该会产生一些对你更有效的东西。
