在JAVA服务项目上线之后经常会出现宕机的情况

常见原因

内存溢出

1.查到服务进程号

[root@wms ~]# ps -ef|grep java

root 6399 6069 0 08:57 pts/2 00:00:00 grep --color=auto java

root 25374 1 0 Oct17 ? 00:21:19 /usr/local/jdk/jre/bin/java -Djava.util.logging.config.file=/home/Tomcat-wmsweb/conf/logging.properties -Djava.util.logging.manager=org.Apache.juli.ClassLoaderLogManager -Xms3072m -Xmx3072m -Xss512K -XX:PermSize=256m -XX:MaxPermSize=512m -Djdk.tls.ephemeralDHKeySize=2048 -Djava.endorsed.dirs=/home/tomcat-wmsweb/endorsed -classpath /home/tomcat-wmsweb/bin/bootstrap.jar:/home/tomcat-wmsweb/bin/tomcat-juli.jar -Dcatalina.base=/home/tomcat-wmsweb -Dcatalina.home=/home/tomcat-wmsweb -Djava.io.tmpdir=/home/tomcat-wmsweb/temp org.apache.catalina.startup.Bootstrap start

root 25401 1 2 Oct17 ? 03:14:13 /usr/local/jdk/jre/bin/java -Djava.util.logging.config.file=/home/tomcat-wms/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Xms3000m -Xmx3000m -Xss512K -XX:PermSize=256m -XX:MaxPermSize=512m -XX:-UseGCOverheadLimit -Djdk.tls.ephemeralDHKeySize=2048 -Djava.endorsed.dirs=/home/tomcat-wms/endorsed -classpath /home/tomcat-wms/bin/bootstrap.jar:/home/tomcat-wms/bin/tomcat-juli.jar -Dcatalina.base=/home/tomcat-wms -Dcatalina.home=/home/tomcat-wms -Djava.io.tmpdir=/home/tomcat-wms/temp org.apache.catalina.startup.Bootstrap start

[root@wms ~]#

2.查看内存使用情况

[root@wms ~]# jmap -heap 25401

Attaching to process ID 25401, please wait...

Debugger attached successfully.

Server compiler detected.

JVM version is 25.211-b12

using thread-local object allocation.

Parallel GC with 4 thread(s)

Heap Configuration:

MinHeapFreeRatio = 0

MaxHeapFreeRatio = 100

MaxHeapSize = 3145728000 (3000.0MB)

NewSize = 1048576000 (1000.0MB)

MaxNewSize = 1048576000 (1000.0MB)

OldSize = 2097152000 (2000.0MB)

NewRatio = 2

SurvivorRatio = 8

MetaspaceSize = 21807104 (20.796875MB)

CompressedClassSpaceSize = 1073741824 (1024.0MB)

MaxMetaspaceSize = 17592186044415 MB

G1HeapRegionSize = 0 (0.0MB)

Heap Usage:

PS Young Generation

Eden Space:

capacity = 607649792 (579.5MB)

used = 607649792 (579.5MB)

free = 0 (0.0MB)

100.0% used

From Space:

capacity = 213385216 (203.5MB)

used = 0 (0.0MB)

free = 213385216 (203.5MB)

0.0% used

To Space:

capacity = 201326592 (192.0MB)

used = 0 (0.0MB)

free = 201326592 (192.0MB)

0.0% used

PS Old Generation

capacity = 2097152000 (2000.0MB)

used = 2097149664 (1999.9977722167969MB)

free = 2336 (0.002227783203125MB)

99.99988861083985% used

121339 interned Strings occupying 10592008 bytes.

发现 Eden Space 100.0% used

PS Old Generation 100.0% used

确认为内存溢出

jmm内存模型

接下来我们需要查看到底是那个大对象造成的这个问题

由于堆内对象信息太多，因此需要输出到问题中查看

[root@wms ~]# jmap -histo:live 25401 >aaa.log

查看大对象信息

[root@wms ~]# vim aaa.log

num #instances #bytes class name

----------------------------------------------

1: 23798913 925276392 [C

2: 23791642 570999408 java.lang.String

3: 879806 201469128 [Ljava.lang.Object;

4: 717239 189351096 com.demo.inventory.query.GetTaskCountQueryItem

5: 5247003 125928072 java.lang.Double

6: 932106 82025328 java.lang.reflect.Method

7: 2144995 68639840 java.util.HashMap$Node

8: 1457567 46642144 java.sql.Timestamp

9: 725212 40611872 org.hibernate.engine.EntityEntry

10: 725213 34810224 org.hibernate.engine.EntityKey

11: 180443 26468992 [Ljava.util.HashMap$Node;

12: 549431 26372688 org.aspectj.weaver.reflect.ShadowMatchImpl

13: 655720 26228800 java.util.LinkedHashMap$Entry

14: 239773 25712128 java.lang.Class

15: 780484 24975488 org.apache.commons.collections.SequencedHashMap$Entry

16: 1535589 24569424 java.lang.Integer

17: 656230 20999360 java.util.concurrent.ConcurrentHashMap$Node

18: 869529 20868696 java.util.ArrayList

19: 822486 20851440 [Ljava.lang.String;

20: 66016 19964336 [B

21: 549431 17581792 org.aspectj.weaver.patterns.ExposedState

22: 705540 15311776 [Z

23: 549431 11702568 [Lorg.aspectj.weaver.ast.Var;

24: 725212 11603392 org.hibernate.util.IdentityMap$IdentityKey

25: 158941 8900696 java.util.LinkedHashMap

26: 324828 7247936 [I

27: 162778 6511120 java.lang.ref.SoftReference

28: 476 6288080 [Ljava.util.concurrent.ConcurrentHashMap$Node;

29: 110595 5308560 java.util.HashMap

30: 155487 4975584 java.lang.ref.WeakReference

31: 16090 3732880 com.demo.inventory.query.WmInvLotLocTraceIdQueryItem

32: 163337 3313312 [Ljava.lang.Class;

33: 41098 3287840 java.lang.reflect.Constructor

34: 51249 3279936 org.hibernate.mApping.Column

35: 81913 3276520 java.util.WeakHashMap$Entry

36: 35571 3047840 [[Ljava.lang.String;

37: 51247 2869832 org.hibernate.mapping.Property

38: 51249 2459952 org.hibernate.mapping.SimpleValue

39: 49720 1988800 org.hibernate.annotations.common.reflection.java.JavaXProperty

40: 48352 1934080 org.hibernate.tuple.StandardProperty

41: 78677 1888248 java.beans.MethodRef

42: 33011 1848616 java.beans.MethodDescriptor

43: 28059 1795776 java.net.URL

44: 49694 1590208 org.hibernate.annotations.common.reflection.java.JavaXSimpleType

最后确认为

com.demo.inventory.query.GetTaskCountQueryItem 对象导致了系统宕机，需要在程序中优化

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版权声明：本文为CSDN博主「可爱帅」的原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接及本声明。

原文链接：https://blog.csdn.net/weixin_43159039/article/details/102676161