Http Header Helper : HttpURLConnection « Network Protocol « Java

Http Header Helper


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import java.nio.charset.Charset;
import java.nio.charset.IllegalCharsetNameException;
import java.nio.charset.UnsupportedCharsetException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

public final class HttpHeaderHelper {
    public static final String ACCEPT_ENCODING = "Accept-Encoding";
    public static final String CONTENT_TYPE = "Content-Type";
    public static final String CONTENT_ID = "Content-ID";
    public static final String CONTENT_ENCODING = "Content-Encoding";
    public static final String CONTENT_TRANSFER_ENCODING = "Content-Transfer-Encoding";
    public static final String COOKIE = "Cookie";
    public static final String TRANSFER_ENCODING = "Transfer-Encoding";
    public static final String CHUNKED = "chunked";
    public static final String CONNECTION = "Connection";
    public static final String CLOSE = "close";
    public static final String AUTHORIZATION = "Authorization";
    private static final Charset UTF8 = Charset.forName("utf-8"); 

    private static Map<String, String> internalHeaders = new HashMap<String, String>();
    private static Map<String, String> encodings = new ConcurrentHashMap<String, String>();
    static {
        internalHeaders.put("Accept-Encoding", "accept-encoding");
        internalHeaders.put("Content-Encoding", "content-encoding");
        internalHeaders.put("Content-Type", "content-type");
        internalHeaders.put("Content-ID", "content-id");
        internalHeaders.put("Content-Transfer-Encoding", "content-transfer-encoding"); 
        internalHeaders.put("Transfer-Encoding", "transfer-encoding");
        internalHeaders.put("Connection", "connection");
        internalHeaders.put("authorization", "Authorization");
        internalHeaders.put("soapaction", "SOAPAction");
        internalHeaders.put("accept", "Accept");
    private HttpHeaderHelper() {
    public static List getHeader(Map<String, List<String>> headerMap, String key) {
        return headerMap.get(getHeaderKey(key));
    public static String getHeaderKey(String key) {
        if (internalHeaders.containsKey(key)) {
            return internalHeaders.get(key);
        } else {
            return key;
    //helper to map the charsets that various things send in the http Content-Type header 
    //into something that is actually supported by Java and the Stax parsers and such.
    public static String mapCharset(String enc) {
        if (enc == null) {
        //older versions of tomcat don't properly parse ContentType headers with stuff
        //after charset="UTF-8"
        int idx = enc.indexOf(";");
        if (idx != -1) {
            enc = enc.substring(0, idx);
        // Charsets can be quoted. But it's quite certain that they can't have escaped quoted or
        // anything like that.
        enc = enc.replace("\"", "").trim();
        enc = enc.replace("'", "");
        if ("".equals(enc)) {
        String newenc = encodings.get(enc);
        if (newenc == null) {
            try {
                newenc = Charset.forName(enc).name();
            } catch (IllegalCharsetNameException icne) {
                return null;
            } catch (UnsupportedCharsetException uce) {
                return null;
            encodings.put(enc, newenc);
        return newenc;


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