java - 需要 Errors/BindingResult 参数

Question

我正在学习 Spring MVC，我正在尝试验证表单。当用户搜索空白字符串时，它会显示错误。执行代码时出现以下错误

An Errors/BindingResult argument is expected to be immediately after the model attribute argument in the controller method signature: public java.lang.String com.mycompany.controller.catalog.SearchController.search(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse,java.lang.String,org.springframework.validation.BindingResult,org.springframework.ui.Model) throws javax.servlet.ServletException,java.io.IOException,org.broadleafcommerce.common.exception.ServiceException

package com.mycompany.controller.catalog;

import org.broadleafcommerce.common.exception.ServiceException;

import org.broadleafcommerce.core.web.controller.catalog.Mysearchcontroller;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import  org.springframework.web.method.support.ModelAndViewContainer;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

@Controller
@RequestMapping("/search")
public class SearchController extends Mysearchcontroller {


    @RequestMapping("")
    public String search(HttpServletRequest request, HttpServletResponse response,
            @RequestParam(value = "q") String q,BindingResult errors,Model model) throws ServletException, IOException, ServiceException {
        return search3(model, request,response, q ,errors);
    }

}

Answer 1

BindingResult 参数只能与 @ModelAttribute 带注释的方法结合使用。如果没有模型属性，就没有绑定(bind)，因此没有 BindingResult 实例可用。因此，在您的情况下，您必须删除 BindingResult 参数，因为由于缺少模型属性，它永远不会在您的情况下工作。

模型属性不与模型相同(正如所暗示的那样)。 model 属性是 Model 的一部分。