Java 百度翻译 API 中文转英文接入

业务上遇到了语言国际化的需求，需要将 中文的 json 字符串翻译成英文，通过百度翻译 API 接口来实现翻译功能。

1、平台认证

登录百度翻译开放平台，找到通用翻译模块，提交申请。

申请链接：http://api.fanyi.baidu.com/product/11

申请通过后，就能直接使用了，默认为标准版，完全免费：

2、Java demo 配置

翻译开放平台非常友好，提供了许多常用语言的 demo 下载，稍微修改下便能使用了。

页面下载链接： http://api.fanyi.baidu.com/doc/21

demo 配置好 appid 及密钥，运行便能看到控制台中文成功翻译成了英文：

3、封装接口

我的目标是将 一长串的中文 json 翻译成英文 json, 上面的 demo 是满足不了需求的，可以创建一个 springboot 项目，将 demo 代码迁移到项目中，封装一个接口实现业务需求。

项目结构如下：

3.1、自定义接口：

先引入 fastJson 依赖：

<!--fastJson-->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.70</version>
</dependency>

接口参数接收一长串的中文 json ，翻译完成后返回英文 json:

package com.lin.translate.controller;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.lin.translate.config.TransApi;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.util.List;
import java.util.Map;

@Controller
@RequestMapping("/com/lin")
public class TranslateController {

    // 在平台申请的APP_ID 详见 http://api.fanyi.baidu.com/api/trans/product/desktop?req=developer
    private static final String APP_ID = "";
    private static final String SECURITY_KEY = ";

    @GetMapping("/translate")
    @ResponseBody
    public Map<String, Map<String, String>> toTranslate(@RequestBody Map<String, Map<String, String>> map) throws InterruptedException {
        TransApi api = new TransApi(APP_ID, SECURITY_KEY);
        for(String  key : map.keySet()) {
            Map<String, String> childMap = map.get(key);
            StringBuilder builder = new StringBuilder();
            for (String childKey : childMap.keySet()) {
                //需要翻译的中文
                builder.append(childMap.get(childKey)).append("\n");
            }
            //创建线程
            Thread thread = new Thread() {
                @Override
                public void run() {
                    String result = api.getTransResult(builder.toString(), "auto", "en");
                    System.out.println(result);
                    //转成map
                    Map<String, String> mapResult = JSON.parseObject(result, Map.class);
                    List<Map<String, String>> transResult = (List<Map<String, String>>)JSONArray.parse(JSON.toJSONString(mapResult.get("trans_result")));
                    int i = 0;
                    for (String childKey : childMap.keySet()) {
                        //获取翻译结果
                        String transQuery = transResult.get(i).get("dst");
                        try {
                            //解码
                            transQuery= URLDecoder.decode(transQuery,"utf-8");
                        } catch (UnsupportedEncodingException e) {
                            e.printStackTrace();
                        }
                        childMap.put(childKey, transQuery);
                        i++;
                    }
                    try {
                        //睡眠一秒
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            };
            thread.start();
            //主线程阻塞，等待子线程结束
            thread.join();
        }
        return map;
    }
}

3.2、demo 配置类代码

HttpGet 类代码如下：

package com.baidu.translate.demo;

import java.io.BufferedReader;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;
import java.security.KeyManagementException;
import java.security.NoSuchAlgorithmException;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import java.util.Map;

import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;

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

    public static String get(String host, Map<String, String> params) {
        try {
            // 设置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); // 创建URL对象
            HttpURLConnection conn = (HttpURLConnection) uri.openConnection();
            if (conn instanceof HttpsURLConnection) {
                ((HttpsURLConnection) conn).setSSLSocketFactory(sslcontext.getSocketFactory());
            }

            conn.setConnectTimeout(SOCKET_TIMEOUT); // 设置相应超时
            conn.setRequestMethod(GET);
            int statusCode = conn.getResponseCode();
            if (statusCode != HttpURLConnection.HTTP_OK) {
                System.out.println("Http错误码：" + statusCode);
            }

            // 读取服务器的数据
            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); // 关闭数据流
            close(is); // 关闭数据流
            conn.disconnect(); // 断开连接

            return text;
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (KeyManagementException e) {
            e.printStackTrace();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }

        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) { // 过滤空的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();
            }
        }
    }

    /**
     * 对输入的字符串进行URL编码, 即转换为%20这种形式
     * 
     * @param input 原文
     * @return URL编码. 如果编码失败, 则返回原文
     */
    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 {
        }
    };
}

MD5 类代码如下：

package com.lin.translate.config;

import java.io.*;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * MD5编码相关的类
 * 
 * @author wangjingtao
 * 
 */
public class MD5 {
    // 首先初始化一个字符数组，用来存放每个16进制字符
    private static final char[] hexDigits = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd',
            'e', 'f' };

    /**
     * 获得一个字符串的MD5值
     * 
     * @param input 输入的字符串
     * @return 输入字符串的MD5值
     * 
     */
    public static String md5(String input) {
        if (input == null) {
            return null;
        }

        try {
            // 拿到一个MD5转换器（如果想要SHA1参数换成”SHA1”）
            MessageDigest messageDigest = MessageDigest.getInstance("MD5");
            // 输入的字符串转换成字节数组
            byte[] inputByteArray = input.getBytes("utf-8");
            // inputByteArray是输入字符串转换得到的字节数组
            messageDigest.update(inputByteArray);
            // 转换并返回结果，也是字节数组，包含16个元素
            byte[] resultByteArray = messageDigest.digest();
            // 字符数组转换成字符串返回
            return byteArrayToHex(resultByteArray);
        } catch (NoSuchAlgorithmException | UnsupportedEncodingException e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 获取文件的MD5值
     * 
     * @param file
     * @return
     */
    public static String md5(File file) {
        try {
            if (!file.isFile()) {
                System.err.println("文件" + file.getAbsolutePath() + "不存在或者不是文件");
                return null;
            }

            FileInputStream in = new FileInputStream(file);

            String result = md5(in);

            in.close();

            return result;

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        return null;
    }

    public static String md5(InputStream in) {

        try {
            MessageDigest messagedigest = MessageDigest.getInstance("MD5");

            byte[] buffer = new byte[1024];
            int read = 0;
            while ((read = in.read(buffer)) != -1) {
                messagedigest.update(buffer, 0, read);
            }

            in.close();

            String result = byteArrayToHex(messagedigest.digest());

            return result;
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        return null;
    }

    private static String byteArrayToHex(byte[] byteArray) {
        // new一个字符数组，这个就是用来组成结果字符串的（解释一下：一个byte是八位二进制，也就是2位十六进制字符（2的8次方等于16的2次方））
        char[] resultCharArray = new char[byteArray.length * 2];
        // 遍历字节数组，通过位运算（位运算效率高），转换成字符放到字符数组中去
        int index = 0;
        for (byte b : byteArray) {
            resultCharArray[index++] = hexDigits[b >>> 4 & 0xf];
            resultCharArray[index++] = hexDigits[b & 0xf];
        }

        // 字符数组组合成字符串返回
        return new String(resultCharArray);

    }
}

TransApi 类代码如下：

package com.lin.translate.config;

import java.util.HashMap;
import java.util.Map;

public class TransApi {
    private static final String TRANS_API_HOST = "http://api.fanyi.baidu.com/api/trans/vip/translate";

    private String appid;
    private String securityKey;

    public TransApi(String appid, String securityKey) {
        this.appid = appid;
        this.securityKey = securityKey;
    }

    public String getTransResult(String query, String from, String to) {
        Map<String, String> params = buildParams(query, from, to);
        return HttpGet.get(TRANS_API_HOST, params);
    }

    private Map<String, String> buildParams(String query, String from, String to) {
        Map<String, String> params = new HashMap<String, String>();
        params.put("q", query);
        params.put("from", from);
        params.put("to", to);

        params.put("appid", appid);

        // 随机数
        String salt = String.valueOf(System.currentTimeMillis());
        params.put("salt", salt);

        // 签名
        String src = appid + query + salt + securityKey; // 加密前的原文
        params.put("sign", MD5.md5(src));

        return params;
    }
}

3.3、结果示例

原中文 json：

{
  "login": {
    "login": "登录",
    "loginLoading": "登录中...",
    "account": "账号",
    "password": "密码",
    "lang": "语言",
    "setAddress": "设置服务地址",
    "more": "更多"
  },
  "mDns": {
    "local": "局域网",
    "localText": "内的XYMERP服务",
    "useAddress": "当前设置的地址",
    "addressUnAvailable": "无法连接此服务器",
    "setAddressTips": "未设置服务地址，立刻设置"
  }
}

翻译后的英文 json：

{
    "login": {
        "login": "Sign in",
        "loginLoading": "Logging in",
        "account": "account number",
        "password": "password",
        "lang": "language",
        "setAddress": "Set service address",
        "more": "more"
    },
    "mDns": {
        "local": "LAN",
        "localText": "Xymerp service in",
        "useAddress": "Currently set address",
        "addressUnAvailable": "Unable to connect to this server",
        "setAddressTips": "Service address not set, set now"
    }
}

以上结果满足我的需求了，不满足你们需求的就稍微修改下吧。