Java tutorial
/* * Copyright 2017 Huawei Technologies Co., Ltd * * 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 io.servicecomb.foundation.common.utils; import java.io.File; import java.io.IOException; import java.net.URISyntaxException; import java.util.Arrays; import java.util.Comparator; import java.util.List; import java.util.Map.Entry; import java.util.Properties; import java.util.stream.Collectors; import org.apache.commons.io.FileUtils; import org.apache.log4j.PropertyConfigurator; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.core.io.Resource; import io.servicecomb.foundation.common.config.impl.PropertiesLoader; public final class Log4jUtils { private static final String MERGED_FILE = "merged.log4j.properties"; // spring boot??init?? private static boolean inited = false; private static final Object LOCK = new Object(); private Log4jUtils() { } public static void init() throws Exception { init(Arrays.asList("classpath*:config/base/log4j.properties", "classpath*:config/log4j.properties")); } public static void init(String locationPattern) throws Exception { init(Arrays.asList(locationPattern)); } public static void init(List<String> locationPatterns) throws Exception { if (inited) { return; } synchronized (LOCK) { if (inited) { return; } PropertiesLoader loader = new PropertiesLoader(locationPatterns); Properties properties = loader.load(); if (properties.isEmpty()) { throw new Exception("can not find resource " + locationPatterns); } PropertyConfigurator.configure(properties); inited = true; // ???merge? outputFile(loader.getFoundResList(), properties); } } private static void outputFile(List<Resource> resList, Properties properties) throws IOException, URISyntaxException { //??class???outputFile??log??? //must create org.slf4j.impl.Log4jLoggerAdapter by LoggerExtFactory //in order to redefine Log4jLoggerAdapter before other class load Log4jLoggerAdapter Logger log = LoggerFactory.getLogger(Log4jUtils.class); String content = genFileContext(resList, properties); //????,?? //log.info("Merged log4j:\n{}", content); Resource res = resList.get(resList.size() - 1); // ?res.getFilejar??getFile File file = new File(res.getURL().getPath()); if (!file.getParentFile().canWrite()) { log.error("Can not output {},because can not write to directory of file {}", MERGED_FILE, res.getURL().getPath()); return; } File mergedfile = new File(res.getFile().getParentFile(), MERGED_FILE); FileUtils.writeStringToFile(mergedfile, content); log.info("Write merged log4j config file to {}", mergedfile.getAbsolutePath()); } private static String genFileContext(List<Resource> resList, Properties properties) throws IOException { List<Entry<Object, Object>> entryList = properties.entrySet().stream() .sorted(new Comparator<Entry<Object, Object>>() { @Override public int compare(Entry<Object, Object> o1, Entry<Object, Object> o2) { return o1.getKey().toString().compareTo(o2.getKey().toString()); } }).collect(Collectors.toList()); StringBuilder sb = new StringBuilder(); for (Resource res : resList) { sb.append("#").append(res.getURL().getPath()).append("\n"); } for (Entry<Object, Object> entry : entryList) { sb.append(entry.getKey()).append("=").append(entry.getValue()).append("\n"); } return sb.toString(); } }