springboot + html 專案報錯：

javax.servlet.ServletException: Circular view path [readingList]: would dispatch back to the current handler URL [/book/readingList] again. Check your ViewResolver setup!

controller 程式碼：

@RestController
@RequestMapping("/book")
public class ReadingListController {
    @Resource
 
private BookMapper bookMapper;
@RequestMapping(value="/{reader}",method = RequestMethod.GET)
    public ModelAndView readersBooks(@PathVariable("reader") String reader){
        ModelAndView modelAndView = new ModelAndView();
modelAndView.setViewName("/book/readingList.html");
List<Book> readingList = bookMapper
 
.findByReader(reader);
        if(readingList != null){
            modelAndView.addObject("books", readingList);
}
        return modelAndView;
}

}

專案路徑：

啟動專案：gradle bootRun

訪問：http://localhost:8080/book/pang

現象：一直error，javax.servlet.ServletException: Circular view path [readingList]: would dispatch back to the current handler URL [/book/readingList] again. Check your ViewResolver setup!

這個error是在InternalResourceView.prepareForRendering 方法中丟擲的

debug 發現這個請求會走兩次servlet，也就是會呼叫兩次InternalResourceView.prepareForRendering 方法，第一次呼叫success，第二次呼叫時丟擲異常

原因是：controller 返回的路徑 /book/readingList.html 因為和mapping 的路徑 @RequestMapping("/book") 重合，第一次返回response 後會再次匹配mapping，導致error。

解決方法：modelAndView.setViewName("/book/readingList.html"); 改成 modelAndView.setViewName("/page/readingList.html");

根本原因是什麼呢？