Java后利用

Dump 内存

JSP方式

使用如下代码：

<%@ page import="com.sun.management.HotSpotDiagnosticMXBean" %>
<%@ page import="java.lang.management.ManagementFactory" %>
<%@ page import="javax.management.MBeanServer" %>
 
<%
    // Name of the HotSpotDiagnostic MBean
    final String HOTSPOT_BEAN_NAME = "com.sun.management:type=HotSpotDiagnostic";
    HotSpotDiagnosticMXBean hotspotMBean = null;
 
    // Initialize the HotSpotDiagnosticMXBean
    try {
        MBeanServer server = ManagementFactory.getPlatformMBeanServer();
        hotspotMBean = ManagementFactory.newPlatformMXBeanProxy(server, HOTSPOT_BEAN_NAME, HotSpotDiagnosticMXBean.class);
    } catch (Exception e) {
        out.println("Error initializing HotSpotDiagnosticMXBean: " + e.getMessage());
        e.printStackTrace();
    }
 
    // Dump heap to /tmp/.heapdump.hprof
    String heapDumpFile = "/tmp/.heapdump.hprof";
    boolean live = true;
 
    try {
        if (hotspotMBean != null) {
            hotspotMBean.dumpHeap(heapDumpFile, live);
            out.println("Heap dump created at: " + heapDumpFile);
        } else {
            out.println("Failed to initialize HotSpotDiagnosticMXBean.");
        }
    } catch (Exception e) {
        out.println("Error creating heap dump: " + e.getMessage());
        e.printStackTrace();
    }
%>

类方式

使用如下代码：

import com.sun.management.HotSpotDiagnosticMXBean;
 
import javax.management.MBeanServer;
import java.lang.management.ManagementFactory;
 
public class HeapDumpUtil {
 
    // Name of the HotSpotDiagnostic MBean
    private static final String HOTSPOT_BEAN_NAME = "com.sun.management:type=HotSpotDiagnostic";
    private static volatile HotSpotDiagnosticMXBean hotspotMBean;
    private static final String HeapDumpFile = "/tmp/.heapdump.hprof";
    private static boolean isDump = false;
    private static String message = "";
    
 
    public static void dumpHeap(String fileName, boolean live) {
	    if (isDump) return ;
	    isDump = true;
        initHotspotMBean();
        try {
            hotspotMBean.dumpHeap(fileName, live);
            message = "Heap dump created at: " + fileName;
        } catch (Exception e) {
	        message = "Error: " + e;
        }
    }
 
    private static void initHotspotMBean() {
        if (hotspotMBean == null) {
            synchronized (HeapDumpUtil.class) {
                if (hotspotMBean == null) {
                    try {
                        MBeanServer server = ManagementFactory.getPlatformMBeanServer();
                        hotspotMBean = ManagementFactory.newPlatformMXBeanProxy(server,
                                HOTSPOT_BEAN_NAME, HotSpotDiagnosticMXBean.class);
                    } catch (Exception e) {
	                    message = "Error: " + e;
                    }
                }
            }
        }
    }
 
	public HeapDumpUtil() {
	    dumpHeap(HeapDumpFile, true);
	}
 
	public String toString() {
        return message;
	}
 
    static {
        dumpHeap(HeapDumpFile, true);
    }
}

命令执行方式

jmap -dump:live,format=b,file=/tmp/dumpHeap.hprof [PID]

Jar内容获取

查询Jar结构

unzip -v xxx.jar

或者使用

jar tvf xxx.jar

只解压特定文件

unzip xxx.jar "*.properties" -d "/tmp/folder/"

或者使用

jar xf xxx.jar "/BOOT-INF/xxx"