// process all array elements
Class clazz = obj.getClass();
if (clazz.isArray()) {
if (clazz.getName().length() != 2) {// skip primitive type array
int length = Array.getLength(obj);
for (int i = 0; i < length; i++) {
stack.add(Array.get(obj, i));
}
}
return result;
}
// process all fields of the object
while (clazz != null) {
Field[] fields = clazz.getDeclaredFields();
for (int i = 0; i < fields.length; i++) {
if (!Modifier.isStatic(fields[i].getModifiers())) {
if (fields[i].getType().isPrimitive()) {
continue; // skip primitive fields
} else {
fields[i].setAccessible(true);
try {
// objects to be estimated are put to stack
Object objectToAdd = fields[i].get(obj);
if (objectToAdd != null) {
stack.add(objectToAdd);
}
} catch (IllegalAccessException ex) {
assert false;
}
}
}
}
clazz = clazz.getSuperclass();
}
return result;
}
}
然后我们可以做一个测试：
public class Test {
static class Person{
private int id;
private String name;
private String address;
public Person(int id, String name, String address) {
this.id = id;
this.name = name;
this.address = address;
}
}
public static void main(String[] args) throws Exception {
Person p = new Person(12, "xujsh","bj");
long size = SizeOfAgent.fullSizeOf(p);
System.out.println(size);
}
}
切换到命令行：
D:\workspace\objsize\src>java -version
java version "1.6.0_22"
Java(TM) SE Runtime Environment (build 1.6.0_22-b04)
Java HotSpot(TM) Client VM (build 17.1-b03, mixed mode, sharing)
D:\workspace\objsize\src>javac com/bj58/test/*.java
D:\workspace\objsize\src>jar -cvfm size.jar MANIFEST.MF com/bj58/test/*
标明清单(manifest)
增加：com/bj58/test/SizeOfAgent.class(读入= 3119) (写出= 1698)(压缩了 45%)
增加：com/bj58/test/SizeOfAgent.java(读入= 3147) (写出= 1204)(压缩了 61%)
增加：com/bj58/test/Test$Person.class(读入= 442) (写出= 305)(压缩了 30%)
增加：com/bj58/test/Test.class(读入= 692) (写出= 441)(压缩了 36%)
增加：com/bj58/test/Test.java(读入= 509) (写出= 290)(压缩了 43%)
D:\workspace\objsize\src>java -javaagent:size.jar com.bj58.test.Test
24
MANIFEST.MF：
Manifest-Version: 1.0
Main-Class: com.bj58.test.Test
Premain-Class: com.bj58.test.SizeOfAgent
Boot-Class-Path:
Can-Redefine-Classes: false
【注意】MANIFEST.MF文件的格式要求比较严格，每一行要满足：key:空格value回车
如何在web应用程序里面使用呢？
以我的tomcat为例，
(1)把size.jar上传tomcat的lib目录下面
(2)修改catalina.sh:
添加一行：
JAVA_OPTS="$JAVA_OPTS -javaagent:$CATALINA_HOME/lib/size.jar" //这一行是新添加的
if [ -z "$LOGGING_MANAGER" ]; then
JAVA_OPTS="$JAVA_OPTS -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager"
else
JAVA_OPTS="$JAVA_OPTS $LOGGING_MANAGER"
fi
(3)在应用里面添加一个controler：
@Path(value = "/api/size")
@GET
public ActionResult size() {
Map
long size = SizeOfAgent