How to encode URL to avoid special characters in Java

Question

i need java code to encode URL to avoid special characters such as spaces and   and  amp     etc

User · Answer

If you don t want to do it manually use Apache Commons - Codec library  The class you are looking at is  org apache commons codec net URLCodec  String final url    http   www google com       String final urlSafe   org apache commons codec net URLCodec encode url

User · Answer

Here is my solution which is pretty easy:

Instead of encoding the url itself i encoded the parameters that I was passing because the parameter was user input and the user could input any unexpected string of special characters so this worked for me fine :)

String review="User input"; /*USER INPUT AS STRING THAT WILL BE PASSED AS PARAMTER TO URL*/
try {
    review = URLEncoder.encode(review,"utf-8");
    review = review.replace(" " , "+");
} catch (UnsupportedEncodingException e) {
    e.printStackTrace();
}
String URL = "www.test.com/test.php"+"?user_review="+review;

User · Answer

URL construction is tricky because different parts of the URL have different rules for what characters are allowed   for example  the plus sign is reserved in the query component of a URL because it represents a space  but in the path component of the URL  a plus sign has no special meaning and spaces are encoded as   20    RFC 2396 explains  in section 2 4 2  that a complete URL is always in its encoded form   you take the strings for the individual components  scheme  authority  path  etc    encode each according to its own rules  and then combine them into the complete URL string   Trying to build a complete unencoded URL string and then encode it separately leads to subtle bugs  like spaces in the path being incorrectly changed to plus signs  which an RFC-compliant server will interpret as real plus signs  not encoded spaces    In Java  the correct way to build a URL is with the URI class   Use one of the multi-argument constructors that takes the URL components as separate strings  and it ll escape each component correctly according to that component s rules   The toASCIIString   method gives you a properly-escaped and encoded string that you can send to a server   To decode a URL  construct a URI object using the single-string constructor and then use the accessor methods  such as getPath    to retrieve the decoded components   Don t use the URLEncoder class   Despite the name  that class actually does HTML form encoding  not URL encoding   It s not correct to concatenate unencoded strings to make an  unencoded  URL and then pass it through a URLEncoder   Doing so will result in problems  particularly the aforementioned one regarding spaces and plus signs in the path

User · Answer

I also spent quite some time with this issue  so that s my solution   String urlString2Decode    http   www test com        path with blanks    String decodedURL   URLDecoder decode urlString2Decode   UTF-8    URL url   new URL decodedURL   URI uri   new URI url getProtocol    url getUserInfo    url getHost    url getPort    url getPath    url getQuery    url getRef     String decodedURLAsString   uri toASCIIString

User · Answer

I would echo what Wyzard wrote but add that:

for query parameters, HTML encoding is often exactly what the server is expecting; outside these, it is correct that URLEncoder should not be used
the most recent URI spec is RFC 3986, so you should refer to that as a primary source

I wrote a blog post a while back about this subject: Java: safe character handling and URL building

[java] How to encode URL to avoid special characters in Java?

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