dsProject/ds-gw/src/main/java/com/dsideal/gw/Handler/RouterHandler.java

package com.dsideal.gw.Handler;

import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.dsideal.gw.GwApplication;
import com.jfinal.handler.Handler;
import okhttp3.*;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Enumeration;


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


    /**
     * 测试用例：
     * GET
     * http://10.10.21.20:8000/ds-base/dm/getDmSchoolProperty
     * http://10.10.21.20:8000/ds-base/global/getGlobalList?page=1&limit=10
     * <p>
     * POST
     * http://10.10.21.20:8000/ds-base/global/testPost?a=100
     */

    //OkHttp的实例，单例模式
    private static final OkHttpClient OK_HTTP_CLIENT = new OkHttpClient();

    //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()) {
            String responseBody = response.body().string();
            JSONObject jo = JSONUtil.parseObj(responseBody).put("success", true).put("code", response.code());
            renderJson(res, jo);
        } else {
            JSONObject jo = new JSONObject();
            jo.put("message", "请求失败！");
            jo.put("code", response.code());
            renderJson(res, jo);
        }
    }

    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)) {
            System.out.println("白名单内链接，不检查jwt!");
        } else {
            System.out.println("不包含在白名单内链接，检查jwt!");
        }

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

        //action名称
        String action = servletPath.substring(secondSlashIndex + 1);

        if (firstSlashIndex != -1 && secondSlashIndex != -1) {
            String prefix = servletPath.substring(firstSlashIndex + 1, secondSlashIndex); // 截取两个 '/' 之间的内容
            if (!GwApplication.routeList.containsKey(prefix)) {
                JSONObject jo = new JSONObject();
                jo.put("success", false);
                jo.put("message", prefix + "前缀没有找到合适的路由表，请检查是否请求正确！");
                renderJson(res, jo);
            } else {
                //路由到哪个微服务
                String FORWARD_URL = GwApplication.routeList.get(prefix) + "/" + action;
                //处理GET请求
                if (req.getMethod().equals("GET")) {
                    //参数:queryString
                    Request request;
                    if (queryString != null) {
                        request = new Request.Builder().url(FORWARD_URL + "?" + queryString).get().build();
                    } else {
                        request = new Request.Builder().url(FORWARD_URL).get().build();
                    }
                    try {
                        executeRequest(request, res);
                    } catch (IOException e) {
                        JSONObject jo = new JSONObject();
                        jo.put("success", false);
                        jo.put("message", "请求失败！" + e);
                        renderJson(res, jo);
                    }
                }//处理POST请求
                else if (req.getMethod().equals("POST")) {
                    RequestBody body = createRequestBody(req);
                    Request request;
                    if (queryString != null) {
                        request = new Request.Builder().url(FORWARD_URL + "?" + queryString).post(body).build();
                    } else {
                        request = new Request.Builder().url(FORWARD_URL).post(body).build();
                    }
                    try {
                        executeRequest(request, res);
                    } catch (IOException e) {
                        JSONObject jo = new JSONObject();
                        jo.put("success", false);
                        jo.put("message", "请求失败！" + e);
                        renderJson(res, jo);
                    }
                } else {
                    // MinIO - 服务端签名直传（前端 + 后端 + 效果演示）
                    //https://blog.csdn.net/CYK_byte/article/details/140254412
                    JSONObject jo = new JSONObject();
                    jo.put("success", false);
                    jo.put("message", "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！");
                    renderJson(res, jo);
                }
            }
        } else {
            JSONObject jo = new JSONObject();
            jo.put("success", false);
            jo.put("message", "输入的字符串格式不正确，没有找到两个 '/'。");
            renderJson(res, jo);
        }
        //停止filter
        isHandled[0] = true;
    }
}