HttpClient封装类：https://shentuzhigang.blog.csdn.net/article/details/104274609 

FineReportUtil 

package cn.edu.zstu.myzstu.spyder.ezstu;

import cn.edu.zstu.myzstu.utils.consts.Consts;
import cn.edu.zstu.myzstu.utils.httpclient.HttpClientUtils;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;

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

/**
 * @Author ShenTuZhiGang
 * @Version 1.0.0
 * @Date 2020-07-12 15:20
 */
public class FineReportUtil {

    public static String getSessionID(String url, String username, String viewlet) throws Exception {
        String sessionid = "";
        Map<String, String> header = new HashMap<>();
        header.put("User-Agent", Consts.AGENT);
        header.put("Host", Consts.EZLHOST);
        Map<String, String> params = new HashMap<>();
        params.put("viewlet", viewlet);
        params.put("__pi__", "true");
        params.put("op", "h5");
        params.put("username", username);
        String htmlText = HttpClientUtils.doGetRequest(url, header, params);
        Document doc = Jsoup.parse(htmlText, "UTF-8");
        Element element = doc.select("script").get(1);
        sessionid = element.toString().split("get")[7].split("'")[1];
        return sessionid;
    }
}

DEMO

package cn.edu.zstu.myzstu.spyder.ezstu.query;

import cn.edu.zstu.myzstu.model.lib.BookRecord;
import cn.edu.zstu.myzstu.spyder.ezstu.FineReportUtil;
import cn.edu.zstu.myzstu.utils.consts.Consts;
import cn.edu.zstu.myzstu.utils.httpclient.HttpClientUtils;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.springframework.stereotype.Component;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @Author ShenTuZhiGang
 * @Version 1.0.0
 * @Date 2020-07-12 15:18
 */
@Component
public class LibraryQuery {
    private static final String ezlUrl = Consts.PROTOCOL + Consts.EZLHOST +"/webroot/decision/view/report";
    public Map<String, List<BookRecord>> getBorrowList(String sid) throws Exception{
        Map<String, List<BookRecord>> res = new HashMap<>();
        List<BookRecord> borrowlist = new ArrayList<>();
        List<BookRecord> historylist = new ArrayList<>();
        String sessionid = FineReportUtil.getSessionID(ezlUrl,sid,"/yiban/S图书借阅情况查询.cpt");
        Map<String, String> header = new HashMap<>();
        header.put("User-Agent", Consts.AGENT);
        header.put("Host", Consts.EZLHOST);
        header.put("sessionID", sessionid);
        String htmlText = HttpClientUtils.doPostRequest(ezlUrl, header, inputGetForm(sessionid, "1")).getContent();
        //System.out.println(htmlText);
        JSONObject resjson = JSONObject.parseObject(htmlText);
        JSONArray bookjson = resjson.getJSONObject("pageContent").getJSONArray("detail").getJSONObject(0).getJSONObject("cellData").getJSONArray("rows");
        String sname = bookjson.getJSONObject(4).getJSONArray("cells").getJSONObject(2).getString("text");
        if(sname.equals("")) {
            throw new Exception("201|学号错误");
        }
        int pagenum = resjson.getInteger("reportTotalPage");
        int borrownum = Integer.parseInt(bookjson.getJSONObject(6).getJSONArray("cells").getJSONObject(2).getString("text"));
        int size =  pagenum == 1 ? bookjson.size() - 5 : bookjson.size();
        for(int k = 15; k < size; k ++) {
            JSONArray bookinfo = bookjson.getJSONObject(k).getJSONArray("cells");
            String bookname = bookinfo.getJSONObject(2).getString("text");
            String borrowdate = bookinfo.getJSONObject(5).getString("text");
            BookRecord bookRecord = new BookRecord();
            bookRecord.setBookName(bookname);
            bookRecord.setBorrowDate(borrowdate);
            if(borrowlist.size() < borrownum || k - 14 <= 2* borrownum) {
                if(borrowlist.size() == 0 || (borrowlist.size() > 0 && (!bookname.equals(borrowlist.get(borrowlist.size() - 1).getBookName()) || !borrowdate.equals(borrowlist.get(borrowlist.size() - 1).getBorrowDate())))) {
                    borrowlist.add(bookRecord);
                }
                else continue;
            }
            else{
                historylist.add(bookRecord);
            }

        }
        for(int i = 1; i < pagenum; i ++) {
            htmlText = HttpClientUtils.doPostRequest(ezlUrl, header, inputGetForm(sessionid, i+1+"")).getContent();
            resjson = JSONObject.parseObject(htmlText);
            bookjson = resjson.getJSONObject("pageContent").getJSONArray("detail").getJSONObject(0).getJSONObject("cellData").getJSONArray("rows");
            size = i + 1 < pagenum ? bookjson.size() : bookjson.size() - 4;
            for(int k = 0; k < size; k ++) {
                JSONArray bookinfo = bookjson.getJSONObject(k).getJSONArray("cells");
                String bookname = bookinfo.getJSONObject(2).getString("text");
                String borrowdate = bookinfo.getJSONObject(5).getString("text");
                BookRecord bookRecord = new BookRecord();
                bookRecord.setBookName(bookname);
                bookRecord.setBorrowDate(borrowdate);
                if(borrowlist.size() < borrownum) {
                    if(borrowlist.size() == 0 || (borrowlist.size() > 0 && (!bookname.equals(borrowlist.get(borrowlist.size() - 1).getBookName()) || !borrowdate.equals(borrowlist.get(borrowlist.size() - 1).getBorrowDate())))) {
                        borrowlist.add(bookRecord);
                    }
                }
                else {
                    historylist.add(bookRecord);
                }

            }
        }
        res.put("borrowlist", borrowlist);
        res.put("historylist", historylist);
        return res;
    }

    //填充请求信息
    private Map<String,String> inputGetForm(String sessionid, String pagenum) {
        Map<String,String > formData = new HashMap<>();
        formData.put("toVanCharts", "true");
        formData.put("dynamicHyperlink", "true");
        formData.put("op", "page_content");
        formData.put("cmd", "json");
        formData.put("sessionID", sessionid);
        formData.put("pn", pagenum);
        formData.put("__fr_locale__", "zh_CN");
        return formData;
    }

}

参考文章

https://blog.csdn.net/whyorg/article/details/54018060