com.sun.net.httpserver 創(chuàng)建 web 服務(wù)

VishKozus 發(fā)布于2019-08-15 17:46 / 735人閱讀

摘要：今天我瞎翻的源代碼，發(fā)現(xiàn)可以用包下提供的很快速的創(chuàng)建服務(wù)，它的創(chuàng)建方式和極其的類似。創(chuàng)建服務(wù)創(chuàng)建服務(wù)并注冊(cè)前面創(chuàng)建的，使用來處理請(qǐng)求。使用默認(rèn)的只要運(yùn)行這個(gè)方法，一個(gè)服務(wù)就啟動(dòng)了，監(jiān)聽端口是，下面是我寫了兩個(gè)完整的例子。

我最開始學(xué)習(xí) Java web 編程是要去寫一個(gè) servlet，重寫里面的 service 方法，然后去配置 web.xml 文件，最后就是部署到 tomcat 或者 jetty 容器中并啟動(dòng)。后來就是使用一些框架，struts2 SpringMvc。今天我瞎翻 JDK 的源代碼，發(fā)現(xiàn)可以用 com.sun.net.httpserver 包下提供的 API 很快速的創(chuàng)建 web 服務(wù)，它的創(chuàng)建方式和 golang 極其的類似。

HttpHandler

首先要實(shí)現(xiàn) HttpHandler，重寫 handle 方法。

public class MyHandler implements HttpHandler {
    @Override
    public void handle(HttpExchange httpExchange) throws IOException {
    
    }
}

創(chuàng)建 web 服務(wù)

創(chuàng)建 web 服務(wù)并注冊(cè)前面創(chuàng)建的 handler，使用 handler 來處理請(qǐng)求。

public class Main {

    public static void main(String[] args) {
        try {
            HttpServer server = HttpServer.create(new InetSocketAddress(8000), 0);
            server.createContext("/web", new MyHandler());
            // 使用默認(rèn)的 excutor
            server.setExecutor(null);
            server.start();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

只要運(yùn)行這個(gè) main 方法，一個(gè) web 服務(wù)就啟動(dòng)了，監(jiān)聽端口是 8000，下面是我寫了兩個(gè)完整的例子。

GetHandler

package me.deweixu.handler;

import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import netscape.javascript.JSObject;

import java.io.IOException;
import java.io.OutputStream;
import java.util.Map;

/**
 * Created by simeone
 *
 * @author: simeone
 * @Date: 2018/5/19
 */
public class GetHandler implements HttpHandler {
    @Override
    public void handle(HttpExchange httpExchange) throws IOException {
        System.out.println("Method: " + httpExchange.getRequestMethod());
        String param = httpExchange.getRequestURI().getQuery();
        System.out.println("Param:" + param);
        httpExchange.sendResponseHeaders(200, 0);

        OutputStream os = httpExchange.getResponseBody();
        os.write(param.getBytes());
        os.close();
    }

}

PostHandler

package me.deweixu.handler;

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

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.Reader;
import java.io.UnsupportedEncodingException;

/**
 * Created by simeone
 *
 * @author: simeone
 * @Date: 2018/5/19
 */
public class PostHandler implements HttpHandler {
    @Override
    public void handle(HttpExchange httpExchange) throws IOException {
        System.out.println("Method: " + httpExchange.getRequestMethod());

        InputStream is = httpExchange.getRequestBody();
        String response = is2string(is);
        System.out.println("response: " + response);
        is.close();
        httpExchange.sendResponseHeaders(200, response.length());

        Headers headers = httpExchange.getResponseHeaders();
        headers.set("Content-Type", "application/json; charset=utf8");

        OutputStream os = httpExchange.getResponseBody();
        os.write(response.getBytes());
        os.close();
    }

    private String is2string(InputStream is) throws IOException {
        final int bufferSize = 1024;
        final char[] buffer = new char[bufferSize];
        final StringBuilder out = new StringBuilder();
        Reader in = new InputStreamReader(is, "UTF-8");
        for (; ; ) {
            int rsz = in.read(buffer, 0, buffer.length);
            if (rsz < 0)
                break;
            out.append(buffer, 0, rsz);
        }
        return out.toString();
    }
}

Main

package me.deweixu;

import com.sun.net.httpserver.HttpServer;
import me.deweixu.handler.GetHandler;
import me.deweixu.handler.PostHandler;

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

public class Main {

    public static void main(String[] args) {
        try {
            HttpServer server = HttpServer.create(new InetSocketAddress(8000), 0);
            server.createContext("/post", new PostHandler());
            server.createContext("/get", new GetHandler());
            server.setExecutor(null);
            server.start();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

測試

# get
$ curl http://127.0.0.1:8000/get?name=simeone&address=beijing
name=simeone&address=beijing

# post
$ curl -H "Content-Type: application/json" -d "{"username":"simeone", "address":"beijing"}" http://127.0.0.1:8000/post
{"username":"simeone", "address":"beijing"}