Java中HTTP请求返回乱码 - GZIP压缩问题

原因

用Java调用雪球的API,结果返回的是乱码,一番研究后发现是因为返回的数据使用了GZIP压缩,需要先解压才能得到正确数据。

思路

使用了GZIP压缩的数据在响应头里会有一项名为content-encoding的参数,值为gzip
Java中可以使用.getHeaderField()读取响应头的参数。
如果没有这项参数,会返回null

解决方法

.getHeaderField("content-encoding")读取content-encoding参数的值。
如果值不为空,通过值判断是否用了gzip压缩。
使用了gzip就解压,没用就不处理。

代码

关键部分

// 获取响应头content-encoding数据,如果是gzip就解压(以后可能要改成部分对比.contains()而不是全部对比)
String contentEncoding = conn.getHeaderField("content-encoding");
if((contentEncoding != null)&&(contentEncoding.equals("gzip"))){
    is = new GZIPInputStream(conn.getInputStream());
}else{
    is = conn.getInputStream();
}

完整代码

  • 部分地方需要按需修改
import java.io.*;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.zip.GZIPInputStream;

public class HttpURLConnectionTools {
    public String doPost(String URL, String jsonStr) {
        OutputStreamWriter out = null;
        BufferedReader in = null;
        InputStream is = null;
        StringBuilder result = new StringBuilder();
        HttpURLConnection conn = null;
        try {
            java.net.URL url = new URL(URL);
            conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("POST");
            // 发送POST请求必须设置为true
            conn.setDoOutput(true);
            conn.setDoInput(true);
            // 设置连接超时时间和读取超时时间
            conn.setConnectTimeout(30000);
            conn.setReadTimeout(10000);
            conn.setRequestProperty("Content-Type", "application/json");
            conn.setRequestProperty("Accept", "application/json");
            // 获取输出流
            out = new OutputStreamWriter(conn.getOutputStream());
            out.write(jsonStr);
            out.flush();
            out.close();
            // 取得输入流,并使用Reader读取
            if (200 == conn.getResponseCode()) {
                // 获取响应头content-encoding数据,如果是gzip就解压(以后可能要改成部分对比.contains()而不是全部对比)
                String contentEncoding = conn.getHeaderField("content-encoding");
                if((contentEncoding != null)&&(contentEncoding.equals("gzip"))){
                    is = new GZIPInputStream(conn.getInputStream());
                }else{
                    is = conn.getInputStream();
                }
                in = new BufferedReader(new InputStreamReader(is, "UTF-8"));
                String line;
                while ((line = in.readLine()) != null) {
                    result.append(line);
                    System.out.println(line);
                }
            } else {
                System.out.println("ResponseCode is an error code:" + conn.getResponseCode());
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (out != null) {
                    out.close();
                }
                if (in != null) {
                    in.close();
                }
            } catch (IOException ioe) {
                ioe.printStackTrace();
            }
        }
        return result.toString();
    }

    public String doGet(String URL) {
        HttpURLConnection conn = null;
        InputStream is = null;
        BufferedReader br = null;
        StringBuilder result = new StringBuilder();
        try {
            // 创建远程url连接对象
            URL url = new URL(URL);
            // 通过远程url连接对象打开一个连接,强转成HTTPURLConnection类
            conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("GET");
            // 设置连接超时时间和读取超时时间
            conn.setConnectTimeout(15000);
            conn.setReadTimeout(60000);
            conn.setRequestProperty("accept-encoding","gzip, deflate, br");
            conn.setRequestProperty("User-agent","Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.102 Safari/537.36 Edg/98.0.1108.62");
            // 发送请求
            conn.connect();
            // 通过conn取得输入流,并使用Reader读取
            if (200 == conn.getResponseCode()) {
                // 获取响应头content-encoding数据,如果是gzip就解压(以后可能要改成部分对比.contains()而不是全部对比)
                String contentEncoding = conn.getHeaderField("content-encoding");
                if((contentEncoding != null)&&(contentEncoding.equals("gzip"))){
                    is = new GZIPInputStream(conn.getInputStream());
                }else{
                    is = conn.getInputStream();
                }

                br = new BufferedReader(new InputStreamReader(is, "UTF-8"));
                String line;
                while ((line = br.readLine()) != null) {
                    result.append(line);
                    System.out.println(line);
                }
            } else {
                System.out.println("ResponseCode is an error code:" + conn.getResponseCode());
            }
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (br != null) {
                    br.close();
                }
                if (is != null) {
                    is.close();
                }
            } catch (IOException ioe) {
                ioe.printStackTrace();
            }
            conn.disconnect();
        }
        return result.toString();
    }

    public static void main(String[] args) {
        System.out.println(new HttpURLConnectionTools().doGet("https://api.66mz8.com/api/weather.php?location=%E5%8C%97%E4%BA%AC"));
        System.out.println(new HttpURLConnectionTools().doGet("http://api.wpbom.com/api/neran.php"));
    }
}
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最后修改:2022 年 06 月 12 日
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