Project
mini-jn
├─── pom.xml
├─── src
│ └─── main
│ └─── java
│ ├─── boot
│ │ └─── filter
│ │ ├─── BigIntegerFilter.java
│ │ ├─── HttpClientFilter.java
│ │ ├─── InetAddressFilter.java
│ │ ├─── LinkedTreeMapFilter.java
│ │ └─── VMManagementImplFilter.java
│ ├─── jn
│ │ ├─── agent
│ │ │ └─── LoadTimeAgent.java
│ │ ├─── asm
│ │ │ ├─── MyClassNode.java
│ │ │ └─── tree
│ │ │ ├─── BigIntegerNode.java
│ │ │ ├─── HttpClientNode.java
│ │ │ ├─── InetAddressNode.java
│ │ │ ├─── LinkedTreeMapNode.java
│ │ │ └─── VMManagementImplNode.java
│ │ ├─── cst
│ │ │ └─── Const.java
│ │ ├─── Main.java
│ │ └─── utils
│ │ ├─── ClassUtils.java
│ │ ├─── FileUtils.java
│ │ └─── TransformerUtils.java
│ ├─── run
│ │ └─── instrument
│ │ └─── StaticInstrumentation.java
│ └─── sample
│ └─── Program.java
└─── target
├─── boot-support.jar
└─── mini-jn.jar
$ mvn clean package
$ cd ./target/classes/
$ jar -cvf boot-support.jar boot/
$ mv boot-support.jar ../
测试
VMManagementImpl
package sample;
import sun.management.VMManagement;
import java.lang.management.ManagementFactory;
import java.lang.management.RuntimeMXBean;
import java.lang.reflect.Field;
import java.util.List;
public class Program {
public static void main(String[] args) throws Exception {
RuntimeMXBean runtime = ManagementFactory.getRuntimeMXBean();
Field jvm = runtime.getClass().getDeclaredField("jvm");
jvm.setAccessible(true);
VMManagement mgmt = (sun.management.VMManagement) jvm.get(runtime);
System.out.println(mgmt.getClass());
List<String> vmArguments = mgmt.getVmArguments();
for (String item : vmArguments) {
System.out.println(item);
}
}
}
第一次运行：
$ java -cp ./target/classes/ -Duser.language=en -Duser.country=US -Djanf.debug=true sample.Program
class sun.management.VMManagementImpl
-Duser.language=en
-Duser.country=US
-Djanf.debug=true
第二次运行：
$ java -cp ./target/classes/ -Duser.language=en -Duser.country=US -Djanf.debug=true -javaagent:./target/mini-jn.jar sample.Program
Premain-Class: jn.agent.LoadTimeAgent
Can-Redefine-Classes: true
Can-Retransform-Classes: true
Can-Set-Native-Method-Prefix: true
========= ========= =========
class sun.management.VMManagementImpl
-Duser.language=en
-Duser.country=US
InetAddress
package sample;
import java.net.InetAddress;
public class Program {
public static void main(String[] args) throws Exception {
getAllByName();
isReachable();
}
private static void getAllByName() {
try {
String host = "jetbrains.com";
InetAddress[] addresses = InetAddress.getAllByName(host);
System.out.println("host: " + host);
for (InetAddress item : addresses) {
System.out.println(" " + item);
}
} catch (Exception ignored) {
}
}
private static void isReachable() {
try {
String host = "jetbrains.com";
String ip = "13.33.141.66";
String[] array = ip.split("\\.");
byte[] ip_bytes = new byte[4];
for (int i = 0; i < 4; i++) {
ip_bytes[i] = (byte) (Integer.parseInt(array[i]) & 0xff);
}
InetAddress address = InetAddress.getByAddress(host, ip_bytes);
boolean reachable = address.isReachable(2000);
System.out.println(reachable);
} catch (Exception ignored) {
}
}
}
第一次运行：
$ java -cp ./target/classes/ sample.Program
host: jetbrains.com
jetbrains.com/13.33.141.66
jetbrains.com/13.33.141.72
jetbrains.com/13.33.141.29
jetbrains.com/13.33.141.64
true
第二次运行：
$ java -cp ./target/classes/ -javaagent:./target/mini-jn.jar sample.Program
Premain-Class: jn.agent.LoadTimeAgent
Can-Redefine-Classes: true
Can-Retransform-Classes: true
Can-Set-Native-Method-Prefix: true
========= ========= =========
Reject dns query: jetbrains.com
Reject dns reachable test: jetbrains.com
false
HttpClient
package sample;
import java.net.URL;
import java.net.URLConnection;
public class Program {
public static void main(String[] args) throws Exception {
URL url = new URL("https://account.jetbrains.com/lservice/rpc/validateKey.action");
URLConnection urlConnection = url.openConnection();
urlConnection.connect();
}
}
第一次运行：
$ java -cp ./target/classes/ sample.Program
第二次运行：
$ java -cp ./target/classes/ -javaagent:./target/mini-jn.jar sample.Program
Premain-Class: jn.agent.LoadTimeAgent
Can-Redefine-Classes: true
Can-Retransform-Classes: true
Can-Set-Native-Method-Prefix: true
========= ========= =========
Exception in thread "main" java.net.SocketTimeoutException: connect timed out
at boot.filter.HttpClientFilter.testURL(HttpClientFilter.java:15)
at sun.net.www.http.HttpClient.openServer(Unknown Source)
LinkedTreeMap
package sample;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import jn.cst.Const;
public class Program {
public static void main(String[] args) throws Exception {
Gson gson = new GsonBuilder().setPrettyPrinting().create();
Object obj = gson.fromJson(Const.LICENSE_JSON, Object.class);
System.out.println(gson.toJson(obj));
}
}
第一次运行：
$ java -cp ./target/classes/\;./target/lib/gson-2.8.9.jar sample.Program
{
"licenseId": "HELLOWORLD",
"licenseeName": "Jerry",
"products": [
{
"code": "II",
"fallbackDate": "2020-01-10",
"paidUpTo": "2021-01-09"
}
],
"gracePeriodDays": 7.0,
"autoProlongated": false,
"isAutoProlongated": false
}
第二次运行：
$ java -cp ./target/classes/ -javaagent:./target/mini-jn.jar sample.Program
Premain-Class: jn.agent.LoadTimeAgent
Can-Redefine-Classes: true
Can-Retransform-Classes: true
Can-Set-Native-Method-Prefix: true
========= ========= =========
{
"licenseId": "HELLOWORLD",
"licenseeName": "Tom",
"products": [
{
"code": "II",
"fallbackDate": "2020-01-10",
"paidUpTo": "2022-12-31"
}
],
"gracePeriodDays": "30",
"autoProlongated": false,
"isAutoProlongated": false
}
BigInteger
package sample;
import java.math.BigInteger;
public class Program {
public static void main(String[] args) {
// a^b mod c
BigInteger a = new BigInteger("5");
BigInteger b = new BigInteger("3");
BigInteger c = new BigInteger("101");
BigInteger actualValue = a.modPow(b, c);
System.out.println(actualValue);
BigInteger expectedValue = new BigInteger("21");
System.out.println(expectedValue);
}
}
第一次运行：
$ java -cp ./target/classes/ sample.Program
24
21
第二次运行：
$ java -cp ./target/classes/ -javaagent:./target/mini-jn.jar sample.Program
Premain-Class: jn.agent.LoadTimeAgent
Can-Redefine-Classes: true
Can-Retransform-Classes: true
Can-Set-Native-Method-Prefix: true
========= ========= =========
21
21