簡單讀取TOMCAT的內存使用情況
創建文件memory.jsp,將該文件放到任意WEB項目里面,能訪問即可,代碼如下:
<%@page contentType="text/html" pageEncoding="UTF-8"%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>JVM memory</title> </head> <body> <% double total = (Runtime.getRuntime().totalMemory()) / (1024.0 1024); double max = (Runtime.getRuntime().maxMemory()) / (1024.0 1024); double free = (Runtime.getRuntime().freeMemory()) / (1024.0 * 1024); out.println("Java 虛擬機試圖使用的最大內存量(當前JVM的最大可用內存) maxMemory(): " + max + "MB<br/>"); out.println("Java 虛擬機中的內存總量(當前JVM占用的內存總數) totalMemory(): " + total + "MB<br/>"); out.println("Java 虛擬機中的空閑內存量(當前JVM空閑內存) freeMemory(): " + free + "MB<br/>"); out.println("因為JVM只有在需要內存時才占用物理內存使用,所以freeMemory()的值一般情況下都很小,<br/>" + "而JVM實際可用內存并不等于freeMemory(),而應該等于 maxMemory() - totalMemory() + freeMemory()。<br/>"); out.println("JVM實際可用內存: " + (max - total + free) + "MB<br/>"); %> </body> </html></pre>