I have come across a problem that bothers me a lot in this beautiful world of programming, and that is about java dynamically switching proxy ip. This is like looking for a straw in the sea as difficult. But after unremitting efforts, I finally found some methods, and now I will share it with you.

java dynamic proxy

Before I start explaining java dynamic switching proxy ip, let's first understand java dynamic proxy. java dynamic proxy is a very flexible design pattern, it can dynamically create an interface implementation class at runtime, so that you can add additional processing logic to the interface's methods without modifying the source code. Simply put, it's like decorating a house that can be flexibly remodeled to suit your needs.

"`java
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.
import java.lang.reflect.Proxy;

public interface Subject {
void request().
}

public class RealSubject implements Subject {
public void request() {
System.out.println("Real Subject executing request");
}
}

public class DynamicProxy implements InvocationHandler {
private Object target.

public Object bind(Object target) {
this.target = target;
return Proxy.newProxyInstance(target.getClass().getClassLoader(), target.getClass().getInterfaces(), this);
}

public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
System.out.println("Dynamic Proxy executing request");
return method.invoke(target, args);
}
}

public class Client {
public static void main(String[] args) {
RealSubject realSubject = new RealSubject();
DynamicProxy dynamicProxy = new DynamicProxy();
Subject subjectProxy = (Subject) dynamicProxy.bind(realSubject);
subjectProxy.request();
}
}
“`

The above code is a simple example of dynamic proxying. With dynamic proxying, we can add additional logic before and after the execution of the request method, so that the method can be enhanced without changing the original code.

Parameter description

Next we will talk about java dynamic switching proxy ip problem. In the actual project, sometimes we will encounter the need to dynamically switch the proxy ip situation, such as web crawlers and so on. This time you need to use the characteristics of the java dynamic proxy to achieve.

First, we can use third party proxy ip service, such as ipipgo proxy ip service, they will provide a pool of ip, we can dynamically get the proxy ip from the pool. then, when accessing the network, we can switch the proxy ip before initiating the request through the dynamic proxy, in order to achieve the effect of anti-crawler.

"`java
public interface HttpRequest {
void sendRequest().
}

public class RealHttpRequest implements HttpRequest {
public void sendRequest() {
System.out.println("Real HttpRequest sending request");
}
}

public class DynamicIPProxy implements InvocationHandler {
private Object target.

public Object bind(Object target) {
this.target = target;
return Proxy.newProxyInstance(target.getClass().getClassLoader(), target.getClass().getInterfaces(), this);
}

public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
switchIP().
return method.invoke(target, args);
}

private void switchIP() {
// Get a new ip from the proxy ip pool
System.out.println("Switching to a new proxy ip");
}
}

public class HttpClient {
public static void main(String[] args) {
RealHttpRequest realHttpRequest = new RealHttpRequest();
DynamicIPProxy dynamicIPProxy = new DynamicIPProxy();
HttpRequest requestProxy = (HttpRequest) dynamicIPProxy.bind(realHttpRequest);
requestProxy.sendRequest();
}
}
“`

The above code is a simple example of dynamically switching proxy ip. With dynamic proxies, we can switch the proxy ip before sending a request to achieve the purpose of anti-crawler.

Through these simple examples, I believe we have a certain understanding of the principles and implementation of java dynamic proxy and dynamic switching proxy ip. I hope these contents can help you. Finally, I hope that when you use proxy ip to comply with relevant laws and regulations, do not use for illegal purposes. Thank you for reading!