java异步写日志到文件中实现代码

 package com.tydic.ESUtil; import java.io.File; import java.io.FileWriter; import java.io.IOException; import java.io.InputStream; import java.io.PrintWriter; import java.util.Properties; public class LogWriter { // 日志的配置文件 public static final String LOG_CONFIGFILE_NAME = "log.properties"; // 日志文件名在配置文件中的标签 public static final String LOGFILE_TAG_NAME = "logfile"; // 默认的日志文件的路径和文件名称 private final String DEFAULT_LOG_FILE_NAME = "./logtext.log"; // 该类的唯一的实例 private static LogWriter logWriter; // 文件输出流 private PrintWriter writer; // 日志文件名 private String logFileName; /** * 默认构造函数 */ private LogWriter() throws LogException{ this.init(); } private LogWriter(String fileName) throws LogException{ this.logFileName = fileName; this.init(); } /** * 获取LogWriter的唯一实例。 * @return * @throws LogException */ public synchronized static LogWriter getLogWriter()throws LogException{ if (logWriter == null){ logWriter = new LogWriter(); } return logWriter; } public synchronized static LogWriter getLogWriter(String logFileName)throws LogException{ if (logWriter == null){ logWriter = new LogWriter(logFileName); } return logWriter; } /** * 往日志文件中写一条日志信息 * 为了防止多线程同时操作(写)日志文件，造成文件”死锁”。使用synchronized关键字 * @param logMsg  日志消息 */ public synchronized void log(String logMsg) { this.writer.println(new java.util.Date() + ": " + logMsg); } /** * 往日志文件中写一条异常信息 * 使用synchronized关键字。 * @param ex  待写入的异常 */ public synchronized void log(Exception ex) { writer.println(new java.util.Date() + ": "); ex.printStackTrace(writer); } /** * 初始化LogWriter * @throws LogException */ private void init() throws LogException{ //如果用户没有在参数中指定日志文件名，则从配置文件中获取。 if (this.logFileName == null){ this.logFileName = this.getLogFileNameFromConfigFile(); //如果配置文件不存在或者也没有指定日志文件名，则用默认的日志文件名。 if (this.logFileName == null){ this.logFileName = DEFAULT_LOG_FILE_NAME; } } File logFile = new File(this.logFileName); try { // 其中的FileWriter()中的第二个参数的含义是:是否在文件中追加内容 // PrintWriter()中的第二个参数的含义是：自动将数据flush到文件中 writer = new PrintWriter(new FileWriter(logFile, true), true); System.out.println("日志文件的位置：" + logFile.getAbsolutePath()); } catch (IOException ex) { String errmsg = "无法打开日志文件:" + logFile.getAbsolutePath(); // System.out.println(errmsg); throw new LogException(errmsg, ex); } } /** * 从配置文件中取日志文件名 * @return */ private String getLogFileNameFromConfigFile() { try { Properties pro = new Properties(); //在类的当前位置,查找属性配置文件log.properties InputStream fin = getClass().getResourceAsStream(LOG_CONFIGFILE_NAME); if (fin != null){ pro.load(fin);//载入配置文件 fin.close(); return pro.getProperty(LOGFILE_TAG_NAME); } else { System.err.println("无法打开属性配置文件: log.properties" ); } }catch (IOException ex) { System.err.println("无法打开属性配置文件: log.properties" ); } return null; } //关闭LogWriter public void close() { logWriter = null; if (writer != null){ writer.close(); } } public static void main(String[] args) { LogWriter logger = null; try { String fileName = "d:/temp/logger.log"; logger = LogWriter.getLogWriter(fileName); //     logger.log("First log!"); //     logger.log("第二个日志信息"); //     logger.log("Third log"); //     logger.log("第四个日志信息"); String content="tableaA|device_number|13701010"; StringBuffer sb=new StringBuffer(); for(int i=0;i<1000000;i++){ sb.append(content).append(i).append(";\n"); } content=sb.toString(); long startTime=System.currentTimeMillis(); logger.log(content); long endTime=System.currentTimeMillis(); System.out.println("总消耗时间："+(endTime-startTime)); logger.close(); //     ReadFromFile.readFileByLines(fileName); } catch (LogException e) { e.printStackTrace(); } } } 

 package com.tydic.ESUtil; public class AychWriter extends Thread { private String content; public AychWriter(String content){ this.content=content; } @Override public void run(){ System.out.println("开始执行run()"); LogWriter logger = null; String fileName = "d:/temp/logger.log"; long startTime=System.currentTimeMillis(); try { logger = LogWriter.getLogWriter(fileName); logger.log(this.content); } catch (LogException e1) { // TODO Auto-generated catch block e1.printStackTrace(); } long endTime=System.currentTimeMillis(); System.out.println("总消耗时间："+(endTime-startTime)); } } 

 package com.tydic.ESUtil; import java.io.FileWriter; import java.io.IOException; import org.junit.Test; public class test_test { /** * 同步向指定文件尾部写入字符串 */ public void testAppendMethodB(String fileName,String content) throws IOException{ try { //打开一个写文件器，构造函数中的第二个参数true表示以追加形式写文件 FileWriter writer = new FileWriter(fileName, true); writer.write(content); writer.close(); } catch (IOException e) { e.printStackTrace(); } } /** *调用上面同步写方法 */ @Test public void testWriteTOFile() throws IOException{ String fileName = "d:\\test.txt"; String content="tableaA|device_number|13701010"; StringBuffer sb=new StringBuffer(); for(int i=0;i<100000;i++){ sb.append(content).append(i).append(";\n"); } content=sb.toString(); long startTime=System.currentTimeMillis(); testAppendMethodB(fileName,content); long endTime=System.currentTimeMillis(); System.out.println("总消耗时间："+(endTime-startTime)); } /** * 异步调用写方法 * @throws IOException * @throws InterruptedException */ @Test public void testAsyncWriteTOFile() throws IOException, InterruptedException{ String fileName = "d:\\test.txt"; String content="tableaA|device_number|13701010"; StringBuffer sb=new StringBuffer(); for(int i=0;i<100000;i++){ sb.append(content).append(i).append(";\n"); } content=sb.toString(); System.out.println("start write..."); new AychWriter(content).start(); System.out.println("write over..."); Thread.sleep(30000); //重要，如果主线程挂了，调用线程也停止了 System.out.println("main Thread over"); } }