百度翻譯api（接口）--使用post請求--java後臺--只需三步

一：前言

這篇文章主要是講給需要用百度翻譯api做產品的人，下面肯定不會將怎麼申請百度翻譯api，怎麼用，因爲這一些你在網上搜（百度等等）是有很多的，主要我是講在用百度翻譯api的時候，怎麼讓java使用post請求去請求百度翻譯的接口，從而避免get請求帶來的414和返回null

二：場景模擬

公司產品準備上線了，翻譯這一模塊是直接用百度翻譯提供的api的demo直接用，用戶某一天用一個超長的文本去翻譯，發現返回值爲null，查看後臺才知道是請求出錯414url地址過長，然後第一時間就想到不能get請求，要用post請求，當我去百度或者其他的搜索引擎去搜結果的時候，發現用java的post請求去請求百度翻譯api的寥寥無幾。就準備自己琢磨去修改一下代碼

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三：步驟分析

首先我們下載的demo有這三個核心文件，一個是負責請求的，一個負責加密，一個負者業務處理。

所以我們需要在HttpGet.java去增加一個post請求

步驟一：在HttpGet中增加一個post請求，當然這個你也可以自己去寫一個類HttpPost來寫post請求，這裏是直接在HttpGet.java中增加的post

1.post方法：主要是負責post請求，包括傳遞參數。

2.convertStreamToString方法：主要是對post請求返回的結果進行處理，轉換爲一個String對象

步驟二：編寫post方法，參數url主要是請求地址，param主要是需要傳遞的參數，我是一個map，你們自己可以爲String或者其他的，這裏主要是明白一下幾點

1.

httpURLConnection.setDoOutput(true);//此申明在申明請求方式爲post之前
httpURLConnection.setRequestMethod("POST");//申明請求爲post

2.

httpURLConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");//後面的application/x-www-form-urlencoded主要能我們傳遞參數的時候爲name=jc&age=54&sex=2這種get形式來傳遞參數
httpURLConnection.setRequestProperty("Content-Length", String.valueOf("5000"));//設置傳遞文件的長度

3.

outputStreamWriter.write(builder.toString());主要這裏是向請求地址去傳遞參數

步驟三：編寫convertStreamToString，主要一個參數就是inputStream，輸入流，來解析結果

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四：HttpGet.java完整代碼

package cn.cigit.contextquery.servlet;

import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;
import java.io.*;
import java.net.*;
import java.security.KeyManagementException;
import java.security.NoSuchAlgorithmException;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import java.util.Map;

class HttpGet {
    protected static final int SOCKET_TIMEOUT = 10000; // 10S
    protected static final String GET = "GET";
    protected static final String POST = "POST";

    public static String get(String host, Map<String, String> params) {
        try {
            System.out.println("開始處理");
            // 設置SSLContext
            SSLContext sslcontext = SSLContext.getInstance("TLS");
            sslcontext.init(null, new TrustManager[] { myX509TrustManager }, null);

            String sendUrl = getUrlWithQueryString(host, params);

            // System.out.println("URL:" + sendUrl);

            URL uri = new URL(sendUrl); // 創建URL對象
            URLConnection urlConnection=uri.openConnection();
            HttpURLConnection conn = (HttpURLConnection)urlConnection;
            if (conn instanceof HttpsURLConnection) {
                ((HttpsURLConnection) conn).setSSLSocketFactory(sslcontext.getSocketFactory());
            }

            conn.setDoOutput(true);
            conn.setRequestMethod("POST");
            conn.setRequestProperty("Accept-Charset", "utf-8");
            conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            conn.setRequestProperty("Content-Length", String.valueOf("1532"));
            conn.setConnectTimeout(10000);
            conn.setDoInput(true);
            int statusCode = conn.getResponseCode();
            if (statusCode != HttpURLConnection.HTTP_OK) {
                System.out.println("Http錯誤碼：" + statusCode);
            }

            // 讀取服務器的數據
            InputStream is = conn.getInputStream();
            BufferedReader br = new BufferedReader(new InputStreamReader(is));
            StringBuilder builder = new StringBuilder();
            String line = null;
            while ((line = br.readLine()) != null) {
                builder.append(line);
            }

            String text = builder.toString();

            close(br); // 關閉數據流
            close(is); // 關閉數據流
            conn.disconnect(); // 斷開連接

            return text;
        } catch (MalformedURLException e) {
            System.out.println(e.toString());
        } catch (IOException e) {
            System.out.println(e.toString());
        } catch (KeyManagementException e) {
            System.out.println(e.toString());
        } catch (NoSuchAlgorithmException e) {
            System.out.println(e.toString());
        }

        return null;
    }

    public static String getUrlWithQueryString(String url, Map<String, String> params) {
        if (params == null) {
            return url;
        }

        StringBuilder builder = new StringBuilder(url);
        if (url.contains("?")) {
            builder.append("&");
        } else {
            builder.append("?");
        }

        int i = 0;
        for (String key : params.keySet()) {
            String value = params.get(key);
            if (value == null) { // 過濾空的key
                continue;
            }

            if (i != 0) {
                builder.append('&');
            }

            builder.append(key);
            builder.append('=');
            builder.append(encode(value));

            i++;
        }

        return builder.toString();
    }

    protected static void close(Closeable closeable) {
        if (closeable != null) {
            try {
                closeable.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    public static String encode(String input) {
        if (input == null) {
            return "";
        }

        try {
            return URLEncoder.encode(input, "utf-8");
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }

        return input;
    }

    private static TrustManager myX509TrustManager = new X509TrustManager() {

        @Override
        public X509Certificate[] getAcceptedIssuers() {
            return null;
        }

        @Override
        public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {
        }

        @Override
        public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
        }
    };
    public static String post(String url, Map<String,String> param) throws Exception {

        URL localURL = new URL(url);
        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("5000"));
        httpURLConnection.setConnectTimeout(10000);

        OutputStream outputStream = null;
        OutputStreamWriter outputStreamWriter = null;
        InputStream inputStream = null;
        InputStreamReader inputStreamReader = null;
        BufferedReader reader = null;
        String resultBuffer = "";

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


            int i = 0;
            StringBuilder builder = new StringBuilder();
            for (String key : param.keySet()) {
                String value = param.get(key);
                if (value == null) { // 過濾空的key
                    continue;
                }

                if (i != 0) {
                    builder.append('&');
                }

                builder.append(key);
                builder.append('=');
                builder.append(encode(value));

                i++;
            }
            outputStreamWriter.write(builder.toString());
            outputStreamWriter.flush();

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

            inputStream = httpURLConnection.getInputStream();
            resultBuffer = convertStreamToString(inputStream);
            System.out.println(resultBuffer);

        } catch (Exception e) {
            e.printStackTrace();
        } 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;
    }

    public static String convertStreamToString(InputStream is) {
        StringBuilder sb1 = new StringBuilder();
        byte[] bytes = new byte[4096];
        int size = 0;

        try {
            while ((size = is.read(bytes)) > 0) {
                String str = new String(bytes, 0, size, "UTF-8");
                sb1.append(str);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return sb1.toString();
    }

}

注意你可能需要修改的地方，post請求中的param參數的類型，主要我是一個map數據，你可能是String，但是裏面組裝數據也需要修改。還有就是TransApi.java中把

HttpGet.get(TRANS_API_HOST, params);改爲HttpGet.post(TRANS_API_HOST, params);

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基本到這裏就結束了，不懂的小夥伴可以加我微信：y958231955

 

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