Java中Logger的使用

創建Logger
Logger級別
C:\Program Files\Java\jdk1.8.0_91\jre\lib\logging.properties
配置文件>Logger setLevel> hanlder setLevel
Handler
Formatter
Java logger的效率不如log4j（處理大量讀寫），但是它裏面的一些概念和設計理念跟log4j一致
 

package com.my.logger;

import java.util.logging.Level;
import java.util.logging.Logger;

public class TestLoggerBase {

	public static void main(String[] args) {
		Logger log = Logger.getLogger("MyLog");
		Logger log1 = Logger.getLogger("MyLog");
		System.out.println("判斷log:");
		System.out.println(log == log1);
		
		log.setLevel(Level.INFO);
//        log.setLevel(Level.CONFIG);
//        log.setLevel(Level.SEVERE);
//        log.setLevel(Level.ALL);
//        log.setLevel(Level.OFF);
		log.severe("S");
		log.warning("W");
        log.info("inf0");
        log.info("inf02");
        log.info("inf03");
        log.config("Config");
        log.fine("fine");
	}
}

運行結果：

package com.my.logger;

import java.util.logging.Level;
import java.util.logging.Logger;

public class MySimpleLogger {
	
	static Logger log = Logger.getLogger("MyLog");
			
	public static void main(String[] args) {
		
		test1(0);
	}

	public static void test1(int p_i) {
		log.setLevel(Level.WARNING);
		if(p_i == 0) {
			log.fine("這是一個調試信息1");
			log.info("執行api test1");
		}else {
			log.info("這是一個調試信息2");
			log.warning("執行api錯誤");
		}
		
	}

}

 運行結果：

package com.my.logger;

import java.io.IOException;
import java.util.logging.FileHandler;
import java.util.logging.Level;
import java.util.logging.Logger;

public class FileHandlerDemo {
	
	public static void main(String[] args) {
		
		Logger log2 = Logger.getLogger("MyLog4");
		try {
			
			FileHandler fileHandler = new FileHandler("D:\\testlogml0.log");
			fileHandler.setLevel(Level.WARNING);
			log2.addHandler(fileHandler);
			log2.info("bbb");
			log2.info("aaa");
			log2.warning("warning");
			log2.severe("severe");
			log2.config("config");
			log2.fine("fine");
			fileHandler.close();
			
		} catch (SecurityException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		
	}

}

package com.my.logger;

import java.util.logging.Formatter;
import java.util.logging.Handler;
import java.util.logging.LogRecord;

public class MyFormatter extends Formatter{

	@Override
	public String format(LogRecord record) {
		
		return "**** "+record.getLevel() + ":" + record.getMessage()+"\r\n";
	}
	
	public String getHead(Handler h) {
		return "this is header\r\n";
		
	}
	
	public String getTail(Handler h) {
		return "this is footer\r\n";
	}

}

package com.my.logger;

import java.util.logging.Formatter;
import java.util.logging.LogRecord;

public class MyOldFormatter extends Formatter{

	@Override
	public String format(LogRecord record) {

		return record.getLoggerName()+"_"+record.getLevel()+":"+record.getMessage()+"\n";
		
	}

}

package com.my.logger;

import java.io.IOException;
import java.util.logging.FileHandler;
import java.util.logging.Level;
import java.util.logging.Logger;

public class TestLoggerFormatter {

	public static void main(String[] args) {
		Logger log = Logger.getLogger("MyLog");
		log.setLevel(Level.INFO);
		try {
			
			FileHandler fileHandler = new FileHandler("D:/test999.log");
			fileHandler.setFormatter(new MyFormatter());
//			fileHandler.setFormatter(new MyOldFormatter());
			log.addHandler(fileHandler);
			log.info("aaa");
			log.info("bbb");
			fileHandler.close();
			
		} catch (SecurityException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}

運行結果：