dsProject/dsGw/src/main/java/com/dsideal/gw/Handler/RouterHandler.java

package com.dsideal.gw.Handler;

import com.dsideal.gw.Bean.RetBean;
import com.dsideal.gw.GwApplication;
import com.dsideal.gw.Util.JwtUtil;
import com.dsideal.gw.Util.SessionKit;
import com.jfinal.handler.Handler;
import com.jfinal.kit.StrKit;
import com.jfinal.upload.MultipartRequest;
import com.jfinal.upload.UploadFile;
import io.jsonwebtoken.Claims;
import okhttp3.*;
import org.apache.commons.io.IOUtils;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.util.*;

/**
 * 测试用例：
 * GET
 * http://10.10.21.20:8000/dsBase/dm/getDmSchoolProperty
 * http://10.10.21.20:8000/dsBase/global/getGlobalList?page=1&limit=10
 * POST
 * http://10.10.21.20:8000/dsBase/global/testPost?a=100
 * 上传文件
 * http://10.10.21.20:8000/dsBase/global/testUpload
 * form-data
 * upfile --->参数值：选择一个文件 类型：file
 */

public class RouterHandler extends Handler {
    //OkHttp的实例，单例模式
    private static final OkHttpClient OK_HTTP_CLIENT = new OkHttpClient();

    /**
     * 功能：输出JSON文本串
     *
     * @param res
     */
    public void renderJson(HttpServletResponse res, String body) {
        res.setHeader("Access-Control-Allow-Origin", "*");
        res.setHeader("Cache-Control", "no-cache");
        res.setCharacterEncoding("UTF-8");
        res.setContentType("application/json");
        try {
            res.getWriter().println(body);
            res.getWriter().flush();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    //OkHttp的回调函数，同步执行
    private void executeRequest(Request request, HttpServletResponse res) throws IOException {
        Response response = OK_HTTP_CLIENT.newCall(request).execute();
        if (response.isSuccessful()) {
            ResponseBody body = response.body();
            if (body != null) {
                // 获取Content-Type
                String contentType = response.header("Content-Type");

                if (contentType != null && contentType.startsWith("image/")) {
                    // 处理图片响应
                    handleImageResponse(res, body, contentType);
                } else {
                    // 处理文本响应
                    handleTextResponse(res, body);
                }
            } else {
                renderJson(res, new RetBean(RetBean.ERROR, "响应体为空").toString());
            }
        } else {
            renderJson(res, new RetBean(RetBean.ERROR, "请求失败！").toString());
        }
    }

    // 处理图片响应
    private void handleImageResponse(HttpServletResponse res, ResponseBody body, String contentType) throws IOException {
        // 设置响应头
        res.setContentType(contentType);
        res.setHeader("Cache-Control", "no-store");
        res.setHeader("Pragma", "no-cache");
        res.setDateHeader("Expires", 0);

        // 将图片数据写入响应
        try (InputStream inputStream = body.byteStream()) {
            IOUtils.copy(inputStream, res.getOutputStream());
        }
    }

    // 处理文本响应
    private void handleTextResponse(HttpServletResponse res, ResponseBody body) throws IOException {
        String responseBody = body.string();
        renderJson(res, responseBody);
    }

    public static RequestBody createRequestBody(HttpServletRequest req) {
        FormBody.Builder formBodyBuilder = new FormBody.Builder();
        // 遍历请求中的参数
        Enumeration<String> parameterNames = req.getParameterNames();
        while (parameterNames.hasMoreElements()) {
            String paramName = parameterNames.nextElement();
            String paramValue = req.getParameter(paramName);
            formBodyBuilder.add(paramName, paramValue);
        }
        // 构建RequestBody
        return formBodyBuilder.build();
    }

    @Override
    public void handle(String target, HttpServletRequest req, HttpServletResponse res, boolean[] isHandled) {
        //可以正确获取到URL的完整路径
        String servletPath = req.getServletPath();
        String queryString = req.getQueryString();
        //对于根目录的访问，放行
        if (servletPath.equals("/")) {
            next.handle(target, req, res, isHandled);
            return;
        }
        //如果是白名单，不检查jwt,否则需要检查jwt
        if (!GwApplication.whiteSet.contains(servletPath)) {

            //微服务间的调用视为内部调用
            if (req.getServletPath().endsWith("_Internal")) {
                renderJson(res, new RetBean(RetBean.ERROR, "微服务间内部接口调用，是不需要走网关的！").toString());
                isHandled[0] = true; //停止filter
                return;
            }

            //是不是通过了登录检查？
            boolean canPass = true;
            //1、存在Session,检查是不是正确的Session
            String identity_id = SessionKit.get(req, res, "identity_id");
            String person_id = SessionKit.get(req, res, "person_id");
            String bureau_id = SessionKit.get(req, res, "bureau_id");
            String token = SessionKit.get(req, res, "token");

            //如果没有找到Session，那么直接不通过
            if (StrKit.isBlank(token) || StrKit.isBlank(bureau_id) || StrKit.isBlank(identity_id) || StrKit.isBlank(person_id)) {
                canPass = false;
            }

            if (!canPass) {
                //如果不存在Session,那么检查是不是存在JWT,并且JWT是不是正确的
                if (req.getHeader("Authorization") != null) {
                    String jwtToken = req.getHeader("Authorization");
                    Claims claims = JwtUtil.getClaims(jwtToken);
                    if (claims != null) {
                        canPass = true;
                    }
                }
            }


            if (!canPass) {
                renderJson(res, new RetBean(RetBean.ERROR, "登录已过期，请重新登录！").toString());
                isHandled[0] = true; //停止filter
                return;
            }
        }

        //路由到哪个微服务
        int xie1 = servletPath.indexOf('/'); // 找到第一个 '/' 的索引
        int xie2 = servletPath.indexOf('/', xie1 + 1); // 从第一个 '/' 之后开始找第二个 '/' 的索引

        //action名称
        String action = servletPath.substring(xie2 + 1);
        if (xie1 == -1 || xie2 == -1) {
            renderJson(res, new RetBean(RetBean.ERROR, "输入的字符串格式不正确，没有找到两个 '/'。").toString());
            isHandled[0] = true; //停止filter
            return;
        }

        String prefix = servletPath.substring(xie1 + 1, xie2); // 截取两个 '/' 之间的内容
        if (!GwApplication.routeList.containsKey(prefix)) {
            renderJson(res, new RetBean(RetBean.ERROR, prefix + "前缀没有找到合适的路由表，请检查是否请求正确！").toString());
            isHandled[0] = true; //停止filter
            return;
        }

        //路由到哪个微服务
        String FORWARD_URL = GwApplication.routeList.get(prefix) + "/" + prefix + "/" + action;

        //1、如果是上传文件
        if (req.getMethod().equals("POST") && req.getContentType() != null && req.getContentType().startsWith("multipart/form-data")) {
            // 指定文件类型
            MediaType mediaType = MediaType.parse("multipart/form-data");
            MultipartRequest mp = new MultipartRequest(req);
            List<UploadFile> files = mp.getFiles();
            if (files.isEmpty()) {
                renderJson(res, new RetBean(RetBean.ERROR, "没有上传文件！").toString());
                isHandled[0] = true;//停止filter
                return;
            }
            UploadFile uploadFile = files.getFirst();

            // 获取文件流
            RequestBody requestBody = RequestBody.create(uploadFile.getFile(), mediaType);
            // 构建MultipartBody
            MultipartBody body = new MultipartBody.Builder()
                    .setType(MultipartBody.FORM)
                    .addFormDataPart("file", uploadFile.getFileName(), requestBody)
                    .build();
            // 构建Request
            Request request = new Request.Builder()
                    .url(FORWARD_URL)
                    .post(body)
                    .build();
            try {
                executeRequest(request, res);
                isHandled[0] = true;//停止filter
                return;
            } catch (Exception e) {
                renderJson(res, new RetBean(RetBean.ERROR, "请求失败！" + e).toString());
                isHandled[0] = true;//停止filter
                return;
            }
        }

        //2、处理GET请求
        if (req.getMethod().equals("GET")) {
            //参数:queryString
            Request.Builder builder;
            if (queryString != null) {
                builder = new Request.Builder().url(FORWARD_URL + "?" + queryString);
            } else {
                builder = new Request.Builder().url(FORWARD_URL);
            }
            if (!StrKit.isBlank(req.getHeader("Authorization"))) {
                builder.addHeader("Authorization", req.getHeader("Authorization"));
                builder.addHeader("Accept", "application/json;odata=verbose");
            }
            Request request = builder.build();
            try {
                executeRequest(request, res);
                isHandled[0] = true;//停止filter
                return;
            } catch (IOException e) {
                renderJson(res, new RetBean(RetBean.ERROR, "请求失败！" + e).toString());
                isHandled[0] = true;//停止filter
                return;
            }
        }

        //3、处理POST请求
        if (req.getMethod().equals("POST")) {
            RequestBody body = createRequestBody(req);
            Request.Builder builder;
            if (queryString != null) {
                builder = new Request.Builder().url(FORWARD_URL + "?" + queryString);
            } else {
                builder = new Request.Builder().url(FORWARD_URL);
            }
            if (!StrKit.isBlank(req.getHeader("Authorization"))) {
                builder.addHeader("Authorization", req.getHeader("Authorization"));
                builder.addHeader("Accept", "application/json;odata=verbose");
            }
            builder.post(body);
            Request request = builder.build();
            try {
                executeRequest(request, res);
                isHandled[0] = true;//停止filter
                return;
            } catch (IOException e) {
                renderJson(res, new RetBean(RetBean.ERROR, "请求失败！" + e).toString());
                isHandled[0] = true;//停止filter
                return;
            }
        }
        //4、其它的OPTIONS
        renderJson(res, new RetBean(RetBean.ERROR, "系统只支持GET,POST，其它的OPTIONS不支持！文件上传请使用S3协议进行直传，不通过JAVA处理，JAVA只处理授权！").toString());
        //停止filter
        isHandled[0] = true;
    }
}