无法以 spring 形式绑定 属性

not able to bind property in spring form

我有class个User和userRole,我需要在User中绑定UserRole对象 我试过下面的代码

UserRole.java

public class UserRoleBean {
private Integer role_id;
private String roleName;
private String roleDesc;
//getter setter
}

User.java

public class UserBean {


private Integer userId;
private String firstName;
private String lastName;
private Date dob;
private String emailAddr;
private String mobileNo;
private Integer balance;
private String password;

private UserRoleBean roleBean;
//getter and setter;

}

AddUser.jsp

<form:form method="POST" action="saveUser.html" modelAttribute="userBean">
        <table>
            <tr>
                <td><form:label path="userId">User ID:</form:label></td>
                <td><form:input path="userId" value="${user.userId}" readonly="true"/></td>
            </tr>
            <tr>
                <td><form:label path="firstName">First Name:</form:label></td>
                <td><form:input path="firstName" value="${user.firstName}"/></td>
            </tr>
            <tr>
                <td><form:label path="lastName">Last Name :</form:label></td>
                <td><form:input path="lastName" value="${user.lastName}"/></td>
            </tr>
            <tr>
                <td><form:label path="emailAddr">Email Address :</form:label></td>
                <td><form:input path="emailAddr" value="${user.emailAddr}" readonly="false"/></td>
            </tr>
            <tr>

                <td><form:label path="dob">Date Of Birth:</form:label></td>
                 <td><form:input path="dob" /></td>
            </tr>
            <tr>
                <td><form:label path="mobileNo">Mobile No :</form:label></td>
                <td><form:input path="mobileNo" value="${user.mobileNo}"/></td>
            </tr>
            <tr>
                <td><form:label path="password">Password:</form:label></td>
                <td><form:password path="password" value="${user.password}"/></td>
            </tr>
            <tr>
                <td><form:label path="balance">Balance:</form:label></td>
                <td><form:input path="balance" value="${user.balance}"/></td>
            </tr>
             <tr>
                <td><form:label path="roleBean">Select Role:</form:label></td>
               <td>
            <form:select path="roleBean">
            <form:option value="0" label="Select" />
            <form:options items="${forRoles}" itemValue="role_id" itemLabel="roleName" />
            </form:select> 
                </td>

            </tr> 
       <tr>
     <td colspan="2"><input type="submit" value="${cap}"/></td>
    </tr>
        </table> 
    </form:form>

其他属性绑定了但是roleBean无法绑定,怎么办,
任何帮助将不胜感激

您必须分别设置 roleBean 中的每个 属性,就像您对 User 对象所做的那样。

在设置 roleBean 的任何 属性 时,对 Id 使用 roleBean.role_id,对 'roleName' 使用 `roleBean.roleName'。

就像你 roleName 的路径是 <form:select path="roleBean"> 但如果是 roleName 它应该是 <form:select path="roleBean.roleName">。其他属性也是如此。