编写java程序，自动监控程度，dump内存文件

步骤 1：编写 Java 程序

首先，编写一个 Java 程序，当内存使用达到 11GB 时生成 heap dump 文件，并以日期命名。将以下代码保存为 MemoryMonitor.java 文件：

import com.sun.management.HotSpotDiagnosticMXBean;
import javax.management.MBeanServer;
import java.lang.management.ManagementFactory;
import java.lang.management.MemoryMXBean;
import java.lang.management.MemoryUsage;
import java.text.SimpleDateFormat;
import java.util.Date;

public class MemoryMonitor {
    private static final long HEAP_DUMP_THRESHOLD = 11L * 1024L * 1024L * 1024L; // 11 GB
    private static final String DUMP_FILE_PATH = "/home/dumpfile/";
    private static final MemoryMXBean memoryMXBean = ManagementFactory.getMemoryMXBean();
    private static final HotSpotDiagnosticMXBean hotSpotDiagnosticMXBean;

    static {
        MBeanServer server = ManagementFactory.getPlatformMBeanServer();
        try {
            hotSpotDiagnosticMXBean = ManagementFactory.newPlatformMXBeanProxy(
                    server,
                    "com.sun.management:type=HotSpotDiagnostic",
                    HotSpotDiagnosticMXBean.class);
        } catch (Exception e) {
            throw new RuntimeException("Failed to initialize HotSpotDiagnosticMXBean", e);
        }
    }

    public static void main(String[] args) {
        new Thread(MemoryMonitor::monitorMemory).start();
    }

    private static void monitorMemory() {
        while (true) {
            MemoryUsage heapMemoryUsage = memoryMXBean.getHeapMemoryUsage();
            long usedMemory = heapMemoryUsage.getUsed();
            System.out.println("Used memory: " + usedMemory);
            if (usedMemory >= HEAP_DUMP_THRESHOLD) {
                try {
                    String timestamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
                    String dumpFilePath = DUMP_FILE_PATH + "heapdump_" + timestamp + ".hprof";
                    hotSpotDiagnosticMXBean.dumpHeap(dumpFilePath, true);
                    System.out.println("Heap dump generated at " + dumpFilePath);
                } catch (Exception e) {
                    e.printStackTrace();
                }
                break;
            }
            try {
                Thread.sleep(10000); // Check every 10 seconds
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
                break;
            }
        }
    }
}

步骤 2：编译 Java 程序

打开终端并运行以下命令来编译 Java 程序：

javac MemoryMonitor.java

步骤 3：创建启动脚本

创建一个启动脚本，以便在后台运行该程序并配置 JVM 参数。将以下内容保存为 start_memory_monitor.sh 文件：

#!/bin/bash

JAVA_OPTS="-XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/home/dumpfile -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintGCTimeStamps -XX:+PrintGCApplicationStoppedTime -Xloggc:/home/dumpfile/gc.log -XX:OnOutOfMemoryError='kill -3 %p'"

nohup java $JAVA_OPTS -cp . MemoryMonitor > /home/dumpfile/memory_monitor.log 2>&1 &
echo "MemoryMonitor started in background."

步骤 4：赋予脚本执行权限

运行以下命令，赋予脚本执行权限：

chmod +x start_memory_monitor.sh

步骤 5：运行脚本

运行启动脚本，使 Java 程序在后台运行：

./start_memory_monitor.sh

总结

1. 编写并保存 MemoryMonitor.java 文件。
2. 在终端中运行 javac MemoryMonitor.java 编译 Java 程序。
3. 创建并保存 start_memory_monitor.sh 启动脚本。
4. 运行 chmod +x start_memory_monitor.sh 赋予启动脚本执行权限。
5. 运行 ./start_memory_monitor.sh 启动 Java 程序并使其在后台运行。