JAVA代码java.net.URLConnection发送HTTP请求的方法

最新推荐文章于 2021-02-25 03:40:41 发布

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本文展示了如何使用Java实现HTTP GET和POST请求，包括URL连接、参数设置、发送请求、接收响应等关键步骤，并提供了实际示例代码。

HTTP请求粗分为两种，一种是GET请求，一种是POST请求。使用Java发送这两种请求的Source Code大同小异，只是一些参数设置的不同。步骤如下：

1、通过统一资源定位器（java.net.URL）获取连接器（java.net.URLConnection）
2、设置请求的参数
3、发送请求
4、以输入流的形式获取返回内容
5、关闭输入流

Get请求示例：

package com.nicchagil.httprequestdemo;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;

public class HttpGetRequest {

    /**
     * Main
     * @param args
     * @throws Exception 
     */
    public static void main(String[] args) throws Exception {
        System.out.println(doGet());
    }

    /**
     * Get Request
     * @return
     * @throws Exception
     */
    public static String doGet() throws Exception {
        URL localURL = new URL("http://localhost:8080/OneHttpServer/");
        URLConnection connection = localURL.openConnection();
        HttpURLConnection httpURLConnection = (HttpURLConnection)connection;

        httpURLConnection.setRequestProperty("Accept-Charset", "utf-8");
        httpURLConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");

        InputStream inputStream = null;
        InputStreamReader inputStreamReader = null;
        BufferedReader reader = null;
        StringBuffer resultBuffer = new StringBuffer();
        String tempLine = null;

        if (httpURLConnection.getResponseCode() >= 300) {
            throw new Exception("HTTP Request is not success, Response code is " + httpURLConnection.getResponseCode());
        }

        try {
            inputStream = httpURLConnection.getInputStream();
            inputStreamReader = new InputStreamReader(inputStream);
            reader = new BufferedReader(inputStreamReader);

            while ((tempLine = reader.readLine()) != null) {
                resultBuffer.append(tempLine);
            }

        } finally {

            if (reader != null) {
                reader.close();
            }

            if (inputStreamReader != null) {
                inputStreamReader.close();
            }

            if (inputStream != null) {
                inputStream.close();
            }

        }

        return resultBuffer.toString();
    }

}

HttpGetRequest

POST请求实例：

package com.nicchagil.httprequestdemo;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;

public class HttpPostRequest {

    /**
     * Main
     * @param args
     * @throws Exception 
     */
    public static void main(String[] args) throws Exception {
        System.out.println(doPost());
    }

    /**
     * Post Request
     * @return
     * @throws Exception
     */
    public static String doPost() throws Exception {
        String parameterData = "username=nickhuang&blog=http://www.cnblogs.com/nick-huang/";

        URL localURL = new URL("http://localhost:8080/OneHttpServer/");
        URLConnection connection = localURL.openConnection();
        HttpURLConnection httpURLConnection = (HttpURLConnection)connection;

        httpURLConnection.setDoOutput(true);
        httpURLConnection.setRequestMethod("POST");
        httpURLConnection.setRequestProperty("Accept-Charset", "utf-8");
        httpURLConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
        httpURLConnection.setRequestProperty("Content-Length", String.valueOf(parameterData.length()));

        OutputStream outputStream = null;
        OutputStreamWriter outputStreamWriter = null;
        InputStream inputStream = null;
        InputStreamReader inputStreamReader = null;
        BufferedReader reader = null;
        StringBuffer resultBuffer = new StringBuffer();
        String tempLine = null;

        try {
            outputStream = httpURLConnection.getOutputStream();
            outputStreamWriter = new OutputStreamWriter(outputStream);

            outputStreamWriter.write(parameterData.toString());
            outputStreamWriter.flush();

            if (httpURLConnection.getResponseCode() >= 300) {
                throw new Exception("HTTP Request is not success, Response code is " + httpURLConnection.getResponseCode());
            }

            inputStream = httpURLConnection.getInputStream();
            inputStreamReader = new InputStreamReader(inputStream);
            reader = new BufferedReader(inputStreamReader);

            while ((tempLine = reader.readLine()) != null) {
                resultBuffer.append(tempLine);
            }

        } finally {

            if (outputStreamWriter != null) {
                outputStreamWriter.close();
            }

            if (outputStream != null) {
                outputStream.close();
            }

            if (reader != null) {
                reader.close();
            }

            if (inputStreamReader != null) {
                inputStreamReader.close();
            }

            if (inputStream != null) {
                inputStream.close();
            }

        }

        return resultBuffer.toString();
    }

}

HttpPostRequest