Java 纯HTTP请求 禁止302自动重定向

Java 纯HTTP Get请求获取响应内容，如果发生302重定向，继而模拟请求域获取重定向后的响应内容。

关键点：设置conn.setInstanceFollowRedirects为false即可

示例代码

public static void main(String[] args) {
    try {  
        StringBuffer buffer = new StringBuffer();
        
        String url = "http://localhost:8080/istock/login?u=name&p=pass";  
        System.out.println("访问地址:" + url); 
        
        //发送get请求
        URL serverUrl = new URL(url);  
        HttpURLConnection conn = (HttpURLConnection) serverUrl.openConnection();  
        conn.setRequestMethod("GET");  
        //必须设置false，否则会自动redirect到重定向后的地址  
        conn.setInstanceFollowRedirects(false);
        conn.addRequestProperty("Accept-Charset", "UTF-8;");  
        conn.addRequestProperty("User-Agent", "Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.9.2.8) Firefox/3.6.8");  
        conn.addRequestProperty("Referer", "http://matols.com/");  
        conn.connect();  
        
        //判定是否会进行302重定向
        if (conn.getResponseCode() == 302) { 
            //如果会重定向，保存302重定向地址，以及Cookies,然后重新发送请求(模拟请求)
            String location = conn.getHeaderField("Location");  
            String cookies = conn.getHeaderField("Set-Cookie");  
            
            serverUrl = new URL(location);  
            conn = (HttpURLConnection) serverUrl.openConnection();  
            conn.setRequestMethod("GET");
            conn.setRequestProperty("Cookie", cookies);
            conn.addRequestProperty("Accept-Charset", "UTF-8;");  
            conn.addRequestProperty("User-Agent","Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.9.2.8) Firefox/3.6.8");  
            conn.addRequestProperty("Referer", "http://matols.com/");  
            conn.connect();  
            System.out.println("跳转地址:" + location); 
        }
        
        //将返回的输入流转换成字符串  
        InputStream inputStream = conn.getInputStream();  
        InputStreamReader inputStreamReader = new InputStreamReader(inputStream,"utf-8");  
        BufferedReader bufferedReader = new BufferedReader(inputStreamReader); 
        String str = null;  
        while ((str = bufferedReader.readLine()) != null) {  
            buffer.append(str);  
        }  
        bufferedReader.close();  
        inputStreamReader.close();  
        // 释放资源  
        inputStream.close();  
        inputStream = null;  
        System.out.println(buffer.toString());
    } catch (Exception e) {  
        e.printStackTrace();  
    }  
}

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