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简单的Java Web验证Bean名称“数字”的BindingResult和普通目标对象都不能用作请求属性

[英]Simple Java Web validation Neither BindingResult nor plain target object for bean name 'number' available as request attribute

我在验证简单的“ NumberValidate”对象时遇到问题

在这里,您可以看到JSP文件:

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@taglib uri="http://www.springframework.org/tags" prefix="spring"%>
<%@taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP Page</title>
    </head>
    <body>
        <h1>Vul een nummer in:</h1>
        <form:form action="form" modelAttribute="number" method="POST">
            <form:input path="number"/>
            <form:errors path="number"/>
            <input type="submit" value="submit"/>
        </form:form>

    </body>
</html>

控制器:

package controller;

import domain.NumberValidate;
import javax.validation.Valid;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
public class ValidationController {
    @RequestMapping(value = {"form"}, method = RequestMethod.GET)
    public String showHomePage(Model model){
        model.addAttribute("number", new NumberValidate());
        return "validation";
    }
    @RequestMapping(value = {"form"}, method = RequestMethod.POST)
    public String showHomePage(@Valid @ModelAttribute NumberValidate number, BindingResult result){
        if(result.hasErrors())
            return "validation";
        return "success";
    }
}

“ NumberValidate”类:

包域;

import javax.validation.constraints.Min;


public class NumberValidate {
    @Min(50)
    private int number;

    public int getNumber() {
        return number;
    }

    public void setNumber(int number) {
        this.number = number;
    }

}

当我运行该应用程序时,它会以文本框等正常启动。当我键入一个小于40的数字时,会出现错误:java.lang.IllegalStateException:BeanResult'number'的BindingResult或普通目标对象都不能用作请求属性

有人可以帮我解决这个问题吗?

如果验证有错误,则返回验证视图时需要在模型中添加数字属性。 代码段如下:

@RequestMapping(value = {"form"}, method = RequestMethod.POST) public String showHomePage(@Valid @ModelAttribute NumberValidate number, BindingResult result){ if(result.hasErrors()){ model.addAttribute("number", number); return "validation"; } return "success"; }

showHomePage方法中,更改为@ModelAttribute("number")并执行以下操作:

if(result.hasErrors()) {
    return "validation";
}
return "success";

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