I am expecting
System.out.println(java.net.URLEncoder.encode("Hello World", "UTF-8"));
to output:
Hello%20World
(20 is ASCII Hex code for space)
However, what I get is:
Hello+World
Am I using the wrong method? What is the correct method I should be using?
This behaves as expected. The URLEncoder implements the HTML Specifications for how to encode URLs in HTML forms.
From the javadocs:
This class contains static methods for converting a String to the application/x-www-form-urlencoded MIME format.
and from the HTML Specification:
application/x-www-form-urlencoded
Forms submitted with this content type must be encoded as follows:
- Control names and values are escaped. Space characters are replaced by `+'
You will have to replace it, e.g.:
System.out.println(java.net.URLEncoder.encode("Hello World", "UTF-8").replace("+", "%20"));
A space is encoded to %20 in URLs, and to + in forms submitted data (content type application/x-www-form-urlencoded). You need the former.
Using Guava:
dependencies {
compile 'com.google.guava:guava:23.0'
// or, for Android:
compile 'com.google.guava:guava:23.0-android'
}
You can use UrlEscapers:
String encodedString = UrlEscapers.urlFragmentEscaper().escape(inputString);
Don't use String.replace, this would only encode the space. Use a library instead.
This class perform application/x-www-form-urlencoded-type encoding rather than percent encoding, therefore replacing with + is a correct behaviour.
From javadoc:
When encoding a String, the following rules apply:
- The alphanumeric characters "a" through "z", "A" through "Z" and "0" through "9" remain the same.
- The special characters ".", "-", "*", and "_" remain the same.
- The space character " " is converted into a plus sign "+".
- All other characters are unsafe and are first converted into one or more bytes using some encoding scheme. Then each byte is represented by the 3-character string "%xy", where xy is the two-digit hexadecimal representation of the byte. The recommended encoding scheme to use is UTF-8. However, for compatibility reasons, if an encoding is not specified, then the default encoding of the platform is used.
Encode Query params
org.apache.commons.httpclient.util.URIUtil
URIUtil.encodeQuery(input);
OR if you want to escape chars within URI
public static String escapeURIPathParam(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;
}
Hello+World is how a browser will encode form data (application/x-www-form-urlencoded) for a GET request and this is the generally accepted form for the query part of a URI.
http://host/path/?message=Hello+World
If you sent this request to a Java servlet, the servlet would correctly decode the parameter value. Usually the only time there are issues here is if the encoding doesn't match.
Strictly speaking, there is no requirement in the HTTP or URI specs that the query part to be encoded using application/x-www-form-urlencoded key-value pairs; the query part just needs to be in the form the web server accepts. In practice, this is unlikely to be an issue.
It would generally be incorrect to use this encoding for other parts of the URI (the path for example). In that case, you should use the encoding scheme as described in RFC 3986.
http://host/Hello%20World
More here.
If you want to encode URI path components, you can also use standard JDK functions, e.g.
public static String encodeURLPathComponent(String path) {
try {
return new URI(null, null, path, null).toASCIIString();
} catch (URISyntaxException e) {
// do some error handling
}
return "";
}
The URI class can also be used to encode different parts of or whole URIs.
Update: I just realized that this does not work if there is a colon before a slash in the path or when the part before the colon is not valid URI scheme.
Just been struggling with this too on Android, managed to stumble upon Uri.encode(String, String) while specific to android (android.net.Uri) might be useful to some.
static String encode(String s, String allow)
The other answers either present a manual string replacement, URLEncoder which actually encodes for HTML format, Apache's abandoned URIUtil, or using Guava's UrlEscapers. The last one is fine, except it doesn't provide a decoder.
Apache Commons Lang provides the URLCodec, which encodes and decodes according to URL format rfc3986.
String encoded = new URLCodec().encode(str);
String decoded = new URLCodec().decode(str);
If you are already using Spring, you can also opt to use its UriUtils class as well.
Although quite old, nevertheless a quick response:
Spring provides UriUtils - with this you can specify how to encoded and which part is it related from an URI, e.g.
encodePathSegment
encodePort
encodeFragment
encodeUriVariables
....
I use them cause we already using Spring, i.e. no additonal library is required!
If you are using jetty then org.eclipse.jetty.util.URIUtil will solve the issue.
String encoded_string = URIUtil.encodePath(not_encoded_string).toString();
It's not one-liner, but you can use:
URL url = new URL("https://some-host.net/dav/files/selling_Rosetta Stone Case Study.png.aes");
URI uri = new URI(url.getProtocol(), url.getUserInfo(), url.getHost(), url.getPort(), url.getPath(), url.getQuery(), url.getRef());
System.out.println(uri.toString());
This will give you an output:
https://some-host.net/dav/files/selling_Rosetta%20Stone%20Case%20Study.png.aes
This worked for me
org.apache.catalina.util.URLEncoder ul = new org.apache.catalina.util.URLEncoder().encode("MY URL");
I was already using Feign so UriUtils was available to me but Spring UrlUtils was not.
<!-- https://mvnrepository.com/artifact/io.github.openfeign/feign-core -->
<dependency>
<groupId>io.github.openfeign</groupId>
<artifactId>feign-core</artifactId>
<version>11.8</version>
</dependency>
My Feign test code:
import feign.template.UriUtils;
System.out.println(UriUtils.encode("Hello World"));
Outputs:
Hello%20World
As the class suggests, it encodes URIs and not URLs but the OP asked about URIs and not URLs.
System.out.println(UriUtils.encode("https://some-host.net/dav/files/selling_Rosetta Stone Case Study.png.aes"));
Outputs:
https%3A%2F%2Fsome-host.net%2Fdav%2Ffiles%2Fselling_Rosetta%20Stone%20Case%20Study.png.aes
"+" is correct. If you really need %20, then replace the Plusses yourself afterwards.
Warning: This answer is heavily disputed (+8 vs. -6), so take this with a grain of salt.
Try below approach:
Add a new dependency
<!-- https://mvnrepository.com/artifact/org.apache.tomcat/tomcat-catalina -->
<dependency>
<groupId>org.apache.tomcat</groupId>
<artifactId>tomcat-catalina</artifactId>
<version>10.0.13</version>
</dependency>
Now do as follows:
String str = "Hello+World"; // For "Hello World", decoder is not required
// import java.net.URLDecoder;
String newURL = URLDecoder.decode(str, StandardCharsets.UTF_8);
// import org.apache.catalina.util.URLEncoder;
System.out.println(URLEncoder.DEFAULT.encode(newURL, StandardCharsets.UTF_8));
You'll get the output as:
Hello%20World
USE MyUrlEncode.URLencoding(String url , String enc) to handle the problem
public class MyUrlEncode {
static BitSet dontNeedEncoding = null;
static final int caseDiff = ('a' - 'A');
static {
dontNeedEncoding = new BitSet(256);
int i;
for (i = 'a'; i <= 'z'; i++) {
dontNeedEncoding.set(i);
}
for (i = 'A'; i <= 'Z'; i++) {
dontNeedEncoding.set(i);
}
for (i = '0'; i <= '9'; i++) {
dontNeedEncoding.set(i);
}
dontNeedEncoding.set('-');
dontNeedEncoding.set('_');
dontNeedEncoding.set('.');
dontNeedEncoding.set('*');
dontNeedEncoding.set('&');
dontNeedEncoding.set('=');
}
public static String char2Unicode(char c) {
if(dontNeedEncoding.get(c)) {
return String.valueOf(c);
}
StringBuffer resultBuffer = new StringBuffer();
resultBuffer.append("%");
char ch = Character.forDigit((c >> 4) & 0xF, 16);
if (Character.isLetter(ch)) {
ch -= caseDiff;
}
resultBuffer.append(ch);
ch = Character.forDigit(c & 0xF, 16);
if (Character.isLetter(ch)) {
ch -= caseDiff;
}
resultBuffer.append(ch);
return resultBuffer.toString();
}
private static String URLEncoding(String url,String enc) throws UnsupportedEncodingException {
StringBuffer stringBuffer = new StringBuffer();
if(!dontNeedEncoding.get('/')) {
dontNeedEncoding.set('/');
}
if(!dontNeedEncoding.get(':')) {
dontNeedEncoding.set(':');
}
byte [] buff = url.getBytes(enc);
for (int i = 0; i < buff.length; i++) {
stringBuffer.append(char2Unicode((char)buff[i]));
}
return stringBuffer.toString();
}
private static String URIEncoding(String uri , String enc) throws UnsupportedEncodingException { //对请求参数进行编码
StringBuffer stringBuffer = new StringBuffer();
if(dontNeedEncoding.get('/')) {
dontNeedEncoding.clear('/');
}
if(dontNeedEncoding.get(':')) {
dontNeedEncoding.clear(':');
}
byte [] buff = uri.getBytes(enc);
for (int i = 0; i < buff.length; i++) {
stringBuffer.append(char2Unicode((char)buff[i]));
}
return stringBuffer.toString();
}
public static String URLencoding(String url , String enc) throws UnsupportedEncodingException {
int index = url.indexOf('?');
StringBuffer result = new StringBuffer();
if(index == -1) {
result.append(URLEncoding(url, enc));
}else {
result.append(URLEncoding(url.substring(0 , index),enc));
result.append("?");
result.append(URIEncoding(url.substring(index+1),enc));
}
return result.toString();
}
}
Am I using the wrong method? What is the correct method I should be using?
Yes, this method java.net.URLEncoder.encode wasn't made for converting " " to "20%" according to spec (source).
The space character " " is converted into a plus sign "+".
Even this is not the correct method, you can modify this to: System.out.println(java.net.URLEncoder.encode("Hello World", "UTF-8").replaceAll("\\+", "%20"));have a nice day =).
