用Java代码实现长连接变成短链接，短链接跳转成长连接，起服务在浏览器运营起来

实现长连接变成短链接，短链接跳转成长连接需要使用URL Shortener服务。下面是一个简单的Java代码示例，使用Google的URL Shortener API将长链接转换为短链接：

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;

public class URLShortener {
    public static void main(String[] args) {
        String longUrl = "http://example.com/very-long-url";
        String apiKey = "YOUR_API_KEY";

        try {
            URL url = new URL("https://www.googleapis.com/urlshortener/v1/url?key=" + apiKey);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("POST");
            connection.setRequestProperty("Content-Type", "application/json");

            String postData = "{\"longUrl\": \"" + longUrl + "\"}";
            connection.setDoOutput(true);
            connection.getOutputStream().write(postData.getBytes("UTF-8"));

            BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            String response = reader.readLine();

            // Parse the JSON response to get the short URL
            String shortUrl = response.substring(response.indexOf("\"id\": \"") + 7, response.indexOf("\","));
            System.out.println("Short URL: " + shortUrl);

            reader.close();
            connection.disconnect();
        } catch (Exception e) {
            System.err.println("Error: " + e.getMessage());
        }
    }
}

要将短链接跳转到长链接，可以使用Java的HttpURLConnection类。下面是一个简单的示例：

import java.net.HttpURLConnection;
import java.net.URL;

public class URLRedirector {
    public static void main(String[] args) {
        String shortUrl = "http://short.com/abc123";

        try {
            URL url = new URL(shortUrl);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setInstanceFollowRedirects(false);
            connection.connect();

            String longUrl = connection.getHeaderField("Location");
            System.out.println("Long URL: " + longUrl);

            connection.disconnect();
        } catch (Exception e) {
            System.err.println("Error: " + e.getMessage());
        }
    }
}

要在浏览器中运行服务，可以使用Java的HttpServer类。下面是一个简单的示例：

import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import com.sun.net.httpserver.HttpServer;

import java.io.IOException;
import java.io.OutputStream;
import java.net.InetSocketAddress;

public class SimpleHttpServer {
    public static void main(String[] args) throws Exception {
        HttpServer server = HttpServer.create(new InetSocketAddress(8000), 0);
        server.createContext("/hello", new HelloHandler());
        server.setExecutor(null);
        server.start();
        System.out.println("Server started on port 8000");
    }

    static class HelloHandler implements HttpHandler {
        @Override
        public void handle(HttpExchange t) throws IOException {
            String response = "Hello, world!";
            t.sendResponseHeaders(200, response.length());
            OutputStream os = t.getResponseBody();
            os.write(response.getBytes());
            os.close();
        }
    }
}

在浏览器中访问http://localhost:8000/hello即可看到"Hello, world!"的输出。