Question

我有一个模型对象Person

 public class Person {

         public String firstName;
         public String lastName;

         public String country;
         public String sex;
         private Integer age;  


        public String getSex() {
            return sex;
        }

        public void setSex(String sex) {
            this.sex = sex;
        }

        public String getCountry() {
            return country;
        }

        public void setCountry(String country) {
            this.country = country;
        }

        public String getLastName() {
            return lastName;
        }

        public void setLastName(String lastName) {
            this.lastName = lastName;
        }



        public String getFirstName() {  
            return firstName;  
        }  

        public void setFirstName(String firstName) {  
            this.firstName = firstName;  
        }  

        public Integer getAge() {  
            return age;  
        }  

        public void setAge(Integer age) {  
            this.age = age;  
        }  

        public String toString(){
            return firstName + " " + sex;
        }

}

并在控制器i中填充以下方法

中的参考数据 countryList

 @ModelAttribute
    public void populateCountryList(Model model){
        System.out.println("inside populateCountryList");
        Map<String,String> country = new LinkedHashMap<String,String>();
        country.put("Select", "-----Select------");
        country.put("US", "United Stated");
        country.put("CHINA", "China");
        country.put("SG", "Singapore");
        country.put("MY", "Malaysia");
        country.put("MY1", "India");
        country.put("MY2", "UK");
        country.put("MY3", "SA");
        country.put("MY4", "Newzeland");

        model.addAttribute("countryList", country);     

    }

还在另一个方法中填充了 Person 对象

 @ModelAttribute
    public Person populateModel(){
        System.out.println("inside populateCountry");
        Person person = new Person();
        person.setCountry("India");
        person.setSex("M");
        return person;
    }

现在在jsp中我的组件是firstName，age，乡村下拉和性别单选按钮的文本框。我想要性别（M）的单选按钮，在下拉列表中默认选择国家“India”。我的jsp在下面。

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"  
    pageEncoding="ISO-8859-1"%>  
<%@taglib uri="http://www.springframework.org/tags/form" prefix="form"%>  
...  
<h1>Person page</h1>  
<p>This is Person page</p>  
<form:form method="POST" commandName="person" action="process-person.html">  
<table>  
    <tbody><tr>  
        <td><form:label path="firstName">Name:</form:label></td>  
        <td><form:input path="firstName"></form:input></td>  
    </tr>


    <tr>  
        <td><form:label path="age">Age:</form:label></td>  
        <td><form:input path="age"></form:input></td>  
    </tr> 

    <tr>
     <td><form:label path="country">Country:</form:label></td>  
     <td> 
       <form:select path="country">                   
                       <form:options items="${countryList}" />
       </form:select>       
      </td>
    </tr>

    <tr>
        <td>Sex :</td>
        <td><form:radiobutton path="sex" value="M" />Male 
             <form:radiobutton path="sex" value="F" />Female
        </td>
    </tr>

    <tr>  
        <td colspan="2">  
            <input type="submit" value="Submit">  
        </td>  
        <td></td>  
        <td></td>  
    </tr>  
</tbody></table>    
</form:form>

当我运行应用程序时，未选择默认值。我还尝试在jsp中打印Person对象，它正在打印Person对象的属性值为null。

请告诉我这个实施中有什么问题。

解在处理程序方法中，我编写了以下代码。

**@RequestMapping(value="/person-form")  
public ModelAndView personPage() {  
    return new ModelAndView("person-page", "person", new Person());  
}**

所以我已将代码更改为

**@RequestMapping(value="/person-form")  
public ModelAndView personPage() {  
    return new ModelAndView("person-page");  
}**

Answer 1

这是因为您需要在人物对象中设置KEY而不是Value：

person.setCountry("MY1");

Spring 3 MVC，无法访问JSP中的模型对象（已关闭）

1 个答案: