这个就是我所说的有问题的

package com.liu.controller; import com.liu.pojo.Paper; import com.liu.service.PaperService; import com.sun.org.apache.xpath.internal.objects.XString; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RequestMapping; import java.util.List; /** * Create with IDEA * * @ClassName: PaperController * @Author : Liu Xingyu * @Create: 6/4/2021 * @Description: */ @Controller @RequestMapping("/paper") public class PaperController { @Autowired private PaperService paperService; @RequestMapping("/allPaper") public String list(Model model) { List<Paper> list = paperService.queryAllPaper(); model.addAttribute("list", list); return "allPaper"; } @RequestMapping("toAddPaper") public String toAddPaper() { return "addPaper"; } @RequestMapping("/addPaper") public String addPaper(Paper paper) { paperService.addPaper(paper); return "redirect:/paper/allPaper"; } @RequestMapping("/del/{paperId}") public String deletePaper(@PathVariable("paperId") int id) { paperService.deletePaperById(id); return "redirect:/paper/allPaper"; } @RequestMapping("toUpdatePaper") public String toUpdatePaper(Model model, int id) { model.addAttribute("paper", paperService.queryById(id)); return "updatePaper"; } @RequestMapping("/updatePaper") public String updatePaper(Model model, Paper paper) { paperService.updatePaper(paper); paper = paperService.queryById(paper.getPaperId()); model.addAttribute("paper", paper); return "redirect:/paper/allPaper"; } @GetMapping("ee") public String get(){ return "ee"; } }