java调用http接口（含图片上传），java基础面试笔试题

其他 2019-04-30 23:13:33 阅读次数: 0


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调用http接口并实现图片传递的关键分为两部分

其一：创建servlet接口，加图片上传注解，用于接收传过来的图片等信息，并做进一步的处理后，返回json格式的结果

其二：创建htpclient，并且运用MultipartEntity对图片进行封装，调用http接口，获取返回值，进行下一步处理

下面就以人脸识别登录，来讲解带有图片的http接口的调用过程

1、创建jsp页面，用于获取到人脸信息

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

<!DOCTYPE html>

<html lang="ZH-CN">

<head>

  <meta charset="utf-8">

  <title>人脸识别登录</title>

  <style>

    .booth {

      width:340px;

     

      background:#ccc;

      border: 10px solid #ddd;

      margin: 0 auto;

    }

    .btn input[type=button] {

    width: 60px;

    height: 30px;

    line-height: 30px;

    margin: 3px;

}

  </style>

  <script type="text/javascript" src="js/jquery.js"></script>

</head>

<body>

  <div class="booth">

    <input type="button" value="登录" onclick="doLogin('login');">

        <video id="video" width="320" height="240"></video>

       <canvas id='canvas' style="display:none;"></canvas>

  </div>

 

  <script type="text/javascript">

    var video = document.getElementById('video'),

    canvas = document.getElementById('canvas'),

    vendorUrl = window.URL || window.webkitURL;

    

    //媒体对象

    navigator.getMedia = navigator.getUserMedia ||

                     navagator.webkitGetUserMedia ||

                     navigator.mozGetUserMedia ||

                     navigator.msGetUserMedia;

        navigator.getMedia({

            video: true, //使用摄像头对象

            audio: false  //不适用音频

        }, function(strem){

            console.log(strem);

            video.src = vendorUrl.createObjectURL(strem);

            video.play();

        }, function(error) {

            //error.code

            console.log(error);

        });

    

    

function doLogin(method) {

      //绘制canvas图形

        canvas.getContext('2d').drawImage(video, 0, 0, 320, 240);

        //把canvas图像转为img图片

        $.ajax({

            url : 'login.do?method='+method,

            type : "POST",

            dataType : 'json',

            async : false,

            data : {image : canvas.toDataURL("image/png")},

            success : function(data) {    

                alert(data.flag+'---'+data.message);

                var msg = data.message;

                if (msg != "success") {

                    resultflag=false;

                }

            },

            error : function(error) {

                tip('访问数据异常', '异常提示');

                return true;

            }

        });

}

    

    

  </script>

</body>

</html>

2、在loginController中编写创建httpclient的方法，并调用接口、

/**

     * 调用接口，实现人脸识别登录

     * @param req

     * @param resp

     * @param model

     * @throws IOException

     */

    @RequestMapping(value = "login_ai.do", method = RequestMethod.POST)

    public void login_ai(HttpServletRequest req, HttpServletResponse resp,

            ModelMap model) {

        try {

            resp.setContentType("application/text; charset=utf-8");

            String basePath = "upload/";

            String filePath = req.getSession().getServletContext()

                    .getRealPath("/")

                    + basePath;

            String fileName = getDate("yyyyMMddHHmmss") + ".png";

            // 默认传入的参数带类型等参数：data:image/png;base64,

            PrintWriter out = resp.getWriter();

            com.alibaba.fastjson.JSONObject loginInfo = new com.alibaba.fastjson.JSONObject();

            String imgStr = req.getParameter("image");

            if (null != imgStr) {

                imgStr = imgStr.substring(imgStr.indexOf(",") + 1);

            }

            // 每次上传文件之前，需要先将之前的文件删除掉

            File file = new File(filePath);

            if (file.isDirectory()) {

                for (File f : file.listFiles()) {

                    f.delete();

                }

            }

            // 文件上传到服务器

            Boolean flag = ImageCompressUtil.GenerateImage(imgStr, filePath,

                    fileName);

            String newfileName = fileName.substring(0, fileName.indexOf("."))

                    + "_bak" + fileName.substring(fileName.indexOf("."));

//            loginInfo = HttpUtil.sendPostWithImage(AIConstant.LOGIN_REGIST_URL

//                    + "?method=login", filePath+newfileName);



            HttpClient client = new DefaultHttpClient();

            HttpPost httpPost = new HttpPost(AIConstant.LOGIN_REGIST_URL

                    + "?method=login");// 通过post传递

            /** 绑定数据 这里需要注意 如果是中文 会出现中文乱码问题 但只要按设置好 */

            MultipartEntity muit = new MultipartEntity();

            File fileupload = new File(filePath+newfileName);

            FileBody fileBody = new FileBody(fileupload);

            muit.addPart("file", fileBody);

            httpPost.setEntity(muit);

            /** 发送请求 */

            try {

                HttpResponse response = client.execute(httpPost);

                // 判断师傅上传成功 返回200

                if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {

                    loginInfo = (com.alibaba.fastjson.JSONObject) com.alibaba.fastjson.JSONObject.parse(EntityUtils.toString(response

                            .getEntity()));

                }else{

                    loginInfo.put("flag", false);

                    loginInfo.put("message", "服务器相应异常！");

                }

            } catch (ClientProtocolException e) {

                e.printStackTrace();

            } catch (IOException e) {

                e.printStackTrace();

            }

            

            out.write(loginInfo.toString());

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

其中涉及到的图片压缩ImageCompressUtil.GenerateImage（）类及方法参见博客： http://www.cnblogs.com/guo-eric/p/8418626.html 有详细介绍
引入的三方文件有：

import org.apache.http.HttpResponse;

import org.apache.http.HttpStatus;

import org.apache.http.client.ClientProtocolException;

import org.apache.http.client.HttpClient;

import org.apache.http.client.methods.HttpPost;

import org.apache.http.entity.mime.MultipartEntity;

import org.apache.http.entity.mime.content.FileBody;

import org.apache.http.impl.client.DefaultHttpClient;

import org.apache.http.util.EntityUtils;

3、需要单独写一个web服务，发布http接口用的，在这里有第二步想要访问的接口，接口编写：

package com.hengyunsoft.face.login;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.OutputStream;

import java.io.PrintWriter;

import java.text.SimpleDateFormat;

import java.util.Date;

import javax.servlet.ServletException;

import javax.servlet.annotation.MultipartConfig;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.Part;

import org.json.JSONArray;

import org.json.JSONObject;

import sun.misc.BASE64Decoder;

import com.baidu.aip.face.AipFace;

import com.hengyunsoft.face.aip.FaceManage;

import com.hengyunsoft.face.util.ImageCompressUtil;

/**

 * Servlet implementation class UploadFile

 */

@WebServlet("/login.do")

@MultipartConfig

public class Login extends HttpServlet {

    private static final long serialVersionUID = 1L;

    // 设置APPID/AK/SK

    public static final String APP_ID = "10580034";

    public static final String API_KEY = "CUEBLydMIEhyHXGgjuBLMCDx";

    public static final String SECRET_KEY = "XXXXXX";

    /**

     * @see HttpServlet#HttpServlet()

     */

    public Login() {

        super();

        // TODO Auto-generated constructor stub

    }

    /**

     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse

     *      response)

     */

    protected void doGet(HttpServletRequest request,

            HttpServletResponse response) throws ServletException, IOException {

        try {

            String method = request.getParameter("method");

            switch (method) {

            case "login":

                login_regist_inter(request, response);// 接口调用

                break;

            case "reg":

                login_regist_inter(request, response);// 接口调用

                break;

            case "del":

                del_inter(request, response);// 接口调用

                break;

            default:

                break;

            }

            

        } catch (Exception e) {

             System.out.println("接口调用异常");

        }

    }

    /**

     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse

     *      response)

     */

    protected void doPost(HttpServletRequest request,

            HttpServletResponse response) throws ServletException, IOException {

        this.doGet(request, response);

    }

        /**

     * 登录和注册的接口

     * 

     * @param req

     * @param resp

     * @throws Exception

     */

    public void login_regist_inter(HttpServletRequest req,

            HttpServletResponse resp) throws Exception {

        resp.setContentType("application/text; charset=utf-8");

        PrintWriter out = resp.getWriter();

        // 接口返回值

        JSONObject returnValue = new JSONObject();

        returnValue.put("flag", true);

        // 图片上传路径

        String filePath = req.getSession().getServletContext()

                .getRealPath("/upload")

                + File.separator;

        String fileName = getDate("yyyyMMddHHmmss") + ".png";

        // 获取接口传递参数

        String uid = req.getParameter("uid");

        String method = req.getParameter("method");

        // 每次上传文件之前，需要先将之前的文件删除掉

        File file = new File(filePath);

        if (file.isDirectory()) {

            for (File f : file.listFiles()) {

                f.delete();

            }

        }

        // 文件夹位置固定，文件夹采用与上传文件的原始名字相同

        String fileSavingPath = filePath + fileName;

        // 如果存储上传文件的文件夹不存在，则创建文件夹

        File f = new File(filePath);

        if (!f.exists()) {

            f.mkdirs();

        }

        Part part = req.getPart("file");// 获取文件路径

        part.write(fileSavingPath);

        // 拿到base64编码的图片，就可以调用百度的API进行验证

        AipFace client = new AipFace(APP_ID, API_KEY, SECRET_KEY);

        if (method.equals("reg")) {

            register(filePath, fileName, returnValue, uid, client);

        } else if (method.equals("login")) {

            // 需要从返回的信息中取用户id

            login(filePath, fileName, returnValue, client);

        }

        out.write(returnValue.toString());

    }

    

    /**

     * 清除注册信息的接口

     * 

     * @param req

     * @param resp

     * @throws Exception

     */

    public void del_inter(HttpServletRequest req,

            HttpServletResponse resp) throws Exception {

        resp.setContentType("application/text; charset=utf-8");

        PrintWriter out = resp.getWriter();

        // 接口返回值

        JSONObject returnValue = new JSONObject();

        returnValue.put("flag", true);

        // 获取接口传递参数

        String uid = req.getParameter("uid");

        // 拿到base64编码的图片，就可以调用百度的API进行验证

        AipFace client = new AipFace(APP_ID, API_KEY, SECRET_KEY);

        try {

            FaceManage.deleteUser(client, uid);

            returnValue.put("message", "人脸信息删除成功！");

        } catch (Exception e) {

            returnValue.put("flag", false);

            returnValue.put("message", "人脸信息删除失败！");

        }

        out.write(returnValue.toString());

    }

    

    /**

     * 登录的第二种实现，人脸识别的方式，将注册用户的所有匹配度拿到，取最高

     * 

     * @param filePath

     * @param fileName

     * @param j

     * @param uid

     * @param client

     * @return

     */

    private void login(String filePath, String fileName, JSONObject aiInfo,

            AipFace client) {

        JSONObject aiJson = FaceManage

                .identifyUser(client, filePath + fileName);

        double tmp = 0.0, matchPercent = 0.0;

        String uid = "";

        try {

            JSONArray ja = aiJson.getJSONArray("result");

            double scores[] = new double[ja.length()]; // 声明数组

            matchPercent = scores[0];

            for (int i = 0; i < ja.length(); i++) {

                JSONObject json = ja.getJSONObject(i);

                tmp = Double.parseDouble(json.get("scores").toString()

                        .replace("[", "").replace("]", ""));

                if (tmp > matchPercent) {

                    // 判断最大值

                    matchPercent = tmp;

                    uid = json.get("uid").toString();

                }

                System.out.println(tmp);

            }

        } catch (Exception e) {

            matchPercent = 0.0;

        }

        if (matchPercent > 90) {

            System.out.println("验证成功，人脸匹配度是：" + matchPercent);

            aiInfo.put("uid", uid);

            aiInfo.put("matchPercent", matchPercent);

            aiInfo.put("flag", true);

            aiInfo.put("message", "验证成功，人脸匹配度是：" + matchPercent);

        } else {

            System.out.println("验证失败，人脸匹配度是：" + matchPercent);

            aiInfo.put("flag", false);

            aiInfo.put("uid", uid);

            aiInfo.put("matchPercent", matchPercent);

            aiInfo.put("message", "验证失败，人脸匹配度是：" + matchPercent);

        }

    }

    /**

     * 注册

     * 

     * @param filePath

     * @param fileName

     * @param j

     * @param uid

     * @param client

     * @return

     */

    private void register(String filePath, String fileName, JSONObject regInfo,

            String uid, AipFace client) {

        String message = "用户" + uid + "人脸注册失败！";

        int matchPercent = FaceManage.saveOrUpdateUser(client, filePath

                + fileName, uid);

        if (matchPercent == 1) {

            message = "用户" + uid + "人脸注册成功！";

            regInfo.put("flag", true);

        } else {

            regInfo.put("flag", false);

        }

        regInfo.put("message", message);

    }

    

    public String getDate(String pattern) {

        return new SimpleDateFormat(pattern).format(new Date());

    }

}

需要注意的是：

1）类上要加@MultipartConfig注解，该注解是用来保存上传图片的

2）需要引入Part类：javax.servlet.http.Part; 用来将上传图片写入文件中

3）调用的人脸识别接口可参考博客：http://www.cnblogs.com/guo-eric/p/8109411.html

至此就完成了人脸识别登录过程，登录系统和人脸识别处理接口的服务相分离的实现，欢迎了解。


转载：https://www.cnblogs.com/guo-eric/p/8465351.html

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