How to convert Strings to and from UTF8 byte array

Question

In Java, I have a String and I want to encode it as a byte array (in UTF8, or some other encoding). Alternately, I have a byte array (in some known encoding) and I want to convert it into a Java String. How do I do these conversions?

Answer 1

Here's a solution that avoids performing the Charset lookup for every conversion:

import java.nio.charset.Charset;

private final Charset UTF8_CHARSET = Charset.forName("UTF-8");

String decodeUTF8(byte[] bytes) {
    return new String(bytes, UTF8_CHARSET);
}

byte[] encodeUTF8(String string) {
    return string.getBytes(UTF8_CHARSET);
}

Answer 2

//query is your json   

 DefaultHttpClient httpClient = new DefaultHttpClient();
 HttpPost postRequest = new HttpPost("http://my.site/test/v1/product/search?qy=");

 StringEntity input = new StringEntity(query, "UTF-8");
 input.setContentType("application/json");
 postRequest.setEntity(input);   
 HttpResponse response=response = httpClient.execute(postRequest);

Answer 3

terribly late but i just encountered this issue and this is my fix:

private static String removeNonUtf8CompliantCharacters( final String inString ) {
    if (null == inString ) return null;
    byte[] byteArr = inString.getBytes();
    for ( int i=0; i < byteArr.length; i++ ) {
        byte ch= byteArr[i]; 
        // remove any characters outside the valid UTF-8 range as well as all control characters
        // except tabs and new lines
        if ( !( (ch > 31 && ch < 253 ) || ch == '\t' || ch == '\n' || ch == '\r') ) {
            byteArr[i]=' ';
        }
    }
    return new String( byteArr );
}

Answer 4

Reader reader = new BufferedReader(
    new InputStreamReader(
        new ByteArrayInputStream(
            string.getBytes(StandardCharsets.UTF_8)), StandardCharsets.UTF_8));

Answer 5

As an alternative, StringUtils from Apache Commons can be used.

 byte[] bytes = {(byte) 1};
 String convertedString = StringUtils.newStringUtf8(bytes);

or

 String myString = "example";
 byte[] convertedBytes = StringUtils.getBytesUtf8(myString);

If you have non-standard charset, you can use getBytesUnchecked() or newString() accordingly.

Answer 6

String original = "hello world";
byte[] utf8Bytes = original.getBytes("UTF-8");