Java tutorial
/* * Copyright 2011 gitblit.com. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.gitblit.utils; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.lang.reflect.Type; import java.net.HttpURLConnection; import java.net.URLConnection; import java.text.DateFormat; import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Collection; import java.util.Date; import java.util.Locale; import java.util.Map; import java.util.TimeZone; import com.gitblit.Constants.AccessPermission; import com.gitblit.GitBlitException.ForbiddenException; import com.gitblit.GitBlitException.NotAllowedException; import com.gitblit.GitBlitException.UnauthorizedException; import com.gitblit.GitBlitException.UnknownRequestException; import com.gitblit.models.RepositoryModel; import com.gitblit.models.UserModel; import com.google.gson.ExclusionStrategy; import com.google.gson.FieldAttributes; import com.google.gson.Gson; import com.google.gson.GsonBuilder; import com.google.gson.JsonDeserializationContext; import com.google.gson.JsonDeserializer; import com.google.gson.JsonElement; import com.google.gson.JsonParseException; import com.google.gson.JsonPrimitive; import com.google.gson.JsonSerializationContext; import com.google.gson.JsonSerializer; import com.google.gson.JsonSyntaxException; import com.google.gson.reflect.TypeToken; /** * Utility methods for json calls to a Gitblit server. * * @author James Moger * */ public class JsonUtils { public static final Type REPOSITORIES_TYPE = new TypeToken<Map<String, RepositoryModel>>() { }.getType(); public static final Type USERS_TYPE = new TypeToken<Collection<UserModel>>() { }.getType(); /** * Creates JSON from the specified object. * * @param o * @return json */ public static String toJsonString(Object o) { String json = gson().toJson(o); return json; } /** * Convert a json string to an object of the specified type. * * @param json * @param clazz * @return the deserialized object * @throws JsonParseException * @throws JsonSyntaxException */ public static <X> X fromJsonString(String json, Class<X> clazz) throws JsonParseException, JsonSyntaxException { return gson().fromJson(json, clazz); } /** * Convert a json string to an object of the specified type. * * @param json * @param type * @return the deserialized object * @throws JsonParseException * @throws JsonSyntaxException */ public static <X> X fromJsonString(String json, Type type) throws JsonParseException, JsonSyntaxException { return gson().fromJson(json, type); } /** * Reads a gson object from the specified url. * * @param url * @param type * @return the deserialized object * @throws {@link IOException} */ public static <X> X retrieveJson(String url, Type type) throws IOException, UnauthorizedException { return retrieveJson(url, type, null, null); } /** * Reads a gson object from the specified url. * * @param url * @param type * @return the deserialized object * @throws {@link IOException} */ public static <X> X retrieveJson(String url, Class<? extends X> clazz) throws IOException, UnauthorizedException { return retrieveJson(url, clazz, null, null); } /** * Reads a gson object from the specified url. * * @param url * @param type * @param username * @param password * @return the deserialized object * @throws {@link IOException} */ public static <X> X retrieveJson(String url, Type type, String username, char[] password) throws IOException { String json = retrieveJsonString(url, username, password); if (StringUtils.isEmpty(json)) { return null; } return gson().fromJson(json, type); } /** * Reads a gson object from the specified url. * * @param url * @param clazz * @param username * @param password * @return the deserialized object * @throws {@link IOException} */ public static <X> X retrieveJson(String url, Class<X> clazz, String username, char[] password) throws IOException { String json = retrieveJsonString(url, username, password); if (StringUtils.isEmpty(json)) { return null; } return gson().fromJson(json, clazz); } /** * Retrieves a JSON message. * * @param url * @return the JSON message as a string * @throws {@link IOException} */ public static String retrieveJsonString(String url, String username, char[] password) throws IOException { try { URLConnection conn = ConnectionUtils.openReadConnection(url, username, password); InputStream is = conn.getInputStream(); BufferedReader reader = new BufferedReader(new InputStreamReader(is, ConnectionUtils.CHARSET)); StringBuilder json = new StringBuilder(); char[] buffer = new char[4096]; int len = 0; while ((len = reader.read(buffer)) > -1) { json.append(buffer, 0, len); } is.close(); return json.toString(); } catch (IOException e) { if (e.getMessage().indexOf("401") > -1) { // unauthorized throw new UnauthorizedException(url); } else if (e.getMessage().indexOf("403") > -1) { // requested url is forbidden by the requesting user throw new ForbiddenException(url); } else if (e.getMessage().indexOf("405") > -1) { // requested url is not allowed by the server throw new NotAllowedException(url); } else if (e.getMessage().indexOf("501") > -1) { // requested url is not recognized by the server throw new UnknownRequestException(url); } throw e; } } /** * Sends a JSON message. * * @param url * the url to write to * @param json * the json message to send * @return the http request result code * @throws {@link IOException} */ public static int sendJsonString(String url, String json) throws IOException { return sendJsonString(url, json, null, null); } /** * Sends a JSON message. * * @param url * the url to write to * @param json * the json message to send * @param username * @param password * @return the http request result code * @throws {@link IOException} */ public static int sendJsonString(String url, String json, String username, char[] password) throws IOException { try { byte[] jsonBytes = json.getBytes(ConnectionUtils.CHARSET); URLConnection conn = ConnectionUtils.openConnection(url, username, password); conn.setRequestProperty("Content-Type", "text/plain;charset=" + ConnectionUtils.CHARSET); conn.setRequestProperty("Content-Length", "" + jsonBytes.length); // write json body OutputStream os = conn.getOutputStream(); os.write(jsonBytes); os.close(); int status = ((HttpURLConnection) conn).getResponseCode(); return status; } catch (IOException e) { if (e.getMessage().indexOf("401") > -1) { // unauthorized throw new UnauthorizedException(url); } else if (e.getMessage().indexOf("403") > -1) { // requested url is forbidden by the requesting user throw new ForbiddenException(url); } else if (e.getMessage().indexOf("405") > -1) { // requested url is not allowed by the server throw new NotAllowedException(url); } else if (e.getMessage().indexOf("501") > -1) { // requested url is not recognized by the server throw new UnknownRequestException(url); } throw e; } } // build custom gson instance with GMT date serializer/deserializer // http://code.google.com/p/google-gson/issues/detail?id=281 public static Gson gson(ExclusionStrategy... strategies) { GsonBuilder builder = new GsonBuilder(); builder.registerTypeAdapter(Date.class, new GmtDateTypeAdapter()); builder.registerTypeAdapter(AccessPermission.class, new AccessPermissionTypeAdapter()); if (!ArrayUtils.isEmpty(strategies)) { builder.setExclusionStrategies(strategies); } return builder.create(); } public static class GmtDateTypeAdapter implements JsonSerializer<Date>, JsonDeserializer<Date> { private final DateFormat dateFormat; public GmtDateTypeAdapter() { dateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'", Locale.US); dateFormat.setTimeZone(TimeZone.getTimeZone("UTC")); } @Override public synchronized JsonElement serialize(Date date, Type type, JsonSerializationContext jsonSerializationContext) { synchronized (dateFormat) { String dateFormatAsString = dateFormat.format(date); return new JsonPrimitive(dateFormatAsString); } } @Override public synchronized Date deserialize(JsonElement jsonElement, Type type, JsonDeserializationContext jsonDeserializationContext) { try { synchronized (dateFormat) { Date date = dateFormat.parse(jsonElement.getAsString()); return new Date((date.getTime() / 1000) * 1000); } } catch (ParseException e) { throw new JsonSyntaxException(jsonElement.getAsString(), e); } } } private static class AccessPermissionTypeAdapter implements JsonSerializer<AccessPermission>, JsonDeserializer<AccessPermission> { private AccessPermissionTypeAdapter() { } @Override public synchronized JsonElement serialize(AccessPermission permission, Type type, JsonSerializationContext jsonSerializationContext) { return new JsonPrimitive(permission.code); } @Override public synchronized AccessPermission deserialize(JsonElement jsonElement, Type type, JsonDeserializationContext jsonDeserializationContext) { return AccessPermission.fromCode(jsonElement.getAsString()); } } public static class ExcludeField implements ExclusionStrategy { private Class<?> c; private String fieldName; public ExcludeField(String fqfn) throws SecurityException, NoSuchFieldException, ClassNotFoundException { this.c = Class.forName(fqfn.substring(0, fqfn.lastIndexOf("."))); this.fieldName = fqfn.substring(fqfn.lastIndexOf(".") + 1); } @Override public boolean shouldSkipClass(Class<?> arg0) { return false; } @Override public boolean shouldSkipField(FieldAttributes f) { return (f.getDeclaringClass() == c && f.getName().equals(fieldName)); } } }