Java网络编程实现HTTP请求方式

Java网络编程实现HTTP请求方式

在现今繁忙的互联网时代，向服务器发送HTTP请求是很常见的一种操作。HTTP请求中GET和POST两种方式是最常见的使用方式，而Java语言模拟实现就是有一定技巧的。下面将介绍如何使用Java网络编程实现HTTP GET POST请求方式。

代码示例

// 发送GET请求
public static String sendGet(String url, String param) throws IOException {
    String result = "";
    String urlNameString = url + "?" + param;
    URL realURL = new URL(urlNameString);
    // 打开和URL之间的连接
    URLConnection connection = realURL.openConnection();
    // 设置通用的请求属性
    connection.setRequestProperty("accept", "*/*");
    connection.setRequestProperty("connection", "Keep-Alive");
    connection.setRequestProperty("user-agent",
            "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)");
    // 建立实际的连接
    connection.connect();
    // 获取所有响应头字段
    Map"">> map = connection.getHeaderFields();
    // 遍历所有的响应头字段
    for (String key : map.keySet()) {
        System.out.println(key + "--->" + map.get(key));
    }
    // 定义 BufferedReader输入流来读取URL的响应
    BufferedReader in = new BufferedReader(new InputStreamReader(
            connection.getInputStream()));
    String line;
    while ((line = in.readLine()) != null) {
        result += line;
    }
    if (in != null) {
        in.close();
    }
    return result;
}

// 发送POST请求
public static String sendPost(String url, String param) throws IOException {
    String result = "";
    URL realURL = new URL(url);
    // 打开和URL之间的连接
    URLConnection connection = realURL.openConnection();
    // 设置通用的请求属性
    connection.setRequestProperty("accept", "*/*");
    connection.setRequestProperty("connection", "Keep-Alive");
    connection.setRequestProperty("user-agent",
            "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)");
    // 发送POST请求必须设置如下两行
    connection.setDoOutput(true);
    connection.setDoInput(true);
    // 获取URLConnection对象对应的输出流
    PrintWriter out = new PrintWriter(connection.getOutputStream());
    // 发送请求参数
    out.print(param);
    // flush输出流的缓冲
    out.flush();
    // 定义BufferedReader输入流来读取URL的响应
    BufferedReader in = new BufferedReader(new InputStreamReader(
            connection.getInputStream()));
    String line;
    while ((line = in.readLine()) != null) {
        result += line;
    }
    if (out != null) {
        out.close();
    }
    if (in != null) {
        in.close();
    }
    return result;
}    
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