Spring mvc spring mvc多值选择下拉列表。作为域对象的值。如何实现这一点

下面的代码用于单值选择，它工作得非常好。但当我将attribue multiple=true添加到form:select标记时，当我在Jsp中选择多个值时，save方法中的country对象参数的值为null。为了在controller方法中获得country对象的列表，我必须在jsp中做什么更改。请告知

JSP代码 国家和国家级 _________________________

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如果我将country变量转换为在country类中列出country。jsp和控制器方法应该如何更改

根据给定的jsp，国家和州的模型Java类应如下所示

public class Country{
private List<State> stateList;
//getter and setters
}

/** State object**/
public class State{
    private long stateUniqueCode;
    private String stateName;
//getter and setters
}

您应该按如下方式在路径中绑定stateList属性

<form:form modelAttribute="country">    
<li>
    <form:label cssClass="mandatory" path="stateList">Select State</form:label>
        <form:select path="stateList" cssErrorClass="error">
             <form:option value="" label="Please Select..." />
                <c:forEach items="${listOfStates}" var="s">
                    <form:option value="${s.stateUniqueCode}" label="${s.stateName}"/>  
                </c:forEach>
        </form:select>
</li>

检查我的答案。也许对你有帮助

 /** Country object**/
    public class Country{
    private State state;
    //getter and setters
    }

    /** State object**/
    public class State{
        private long stateUniqueCode;
        private String stateName;
    //getter and setters
    }

public class Country{
private List<State> stateList;
//getter and setters
}

/** State object**/
public class State{
    private long stateUniqueCode;
    private String stateName;
//getter and setters
}

<form:form modelAttribute="country">    
<li>
    <form:label cssClass="mandatory" path="stateList">Select State</form:label>
        <form:select path="stateList" cssErrorClass="error">
             <form:option value="" label="Please Select..." />
                <c:forEach items="${listOfStates}" var="s">
                    <form:option value="${s.stateUniqueCode}" label="${s.stateName}"/>  
                </c:forEach>
        </form:select>
</li>