我要评论java异步写日志到文件中详解
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));
}
}
测试类：
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");
}
}
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