JSP展示内存消耗

DecimalFormat df = new DecimalFormat("#.#");

// 当前JVM占用的内存总数(M)
double total = (Runtime.getRuntime().totalMemory()) / (1024.0 * 1024);

// JVM最大可用内存总数(M)
double max = (Runtime.getRuntime().maxMemory()) / (1024.0 * 1024);

// JVM空闲内存(M)
double free = (Runtime.getRuntime().freeMemory()) / (1024.0 * 1024);

// 可用内存内存(M)
double mayuse = Double.parseDouble(df.format(max - total + free));

// 已经使用内存(M)
double used = Double.parseDouble(df.format(total - free));

out.println("OS Name:	" + System.getProperty("os.name") + "<br/>");
out.println("OS Version:	" + System.getProperty("os.version") + "<br/>");
out.println("Architecture:	" + System.getProperty("os.arch") + "<br/>");
out.println("Java Home:	" + System.getProperty("java.home") + "<br/>");
out.println("JVM Version:	" + System.getProperty("java.vm.version") + "<br/>");
out.println("JVM Vendor:	" + System.getProperty("java.vm.vendor") + "<br/>");
out.println("JVM Max Memory: " + max + "MB<br/>");
out.println("JVM Total Memory: " + total + "MB<br/>");
out.println("JVM Usable Memory: " + mayuse + "MB<br/>");
out.println("JVM Used Memory: " + used + "MB<br/>");