Spring MVC将ArrayList传递回控制器

小编典典

Spring MVC将ArrayList传递回控制器

jsp

我是Spring的新手。我向用户显示一个列表。每行都有一个用于删除用户的复选框。

控制器：

@Controller
public class AdminController {

    @Autowired
    private UserDao userDao;

    @RequestMapping(value = "/admin", method = RequestMethod.GET)
    public ModelAndView adminPage() {
        ModelAndView model = new ModelAndView();
        model.addObject("users", userDao.findAll());
        model.setViewName("admin");
        return model;

    }

    @RequestMapping(value = "admin/remove", method = RequestMethod.POST)
    public ModelAndView removeUser(@ModelAttribute(value = "users") ArrayList<User> users) {
        ModelAndView model = new ModelAndView();
        //UPDATE USERS HERE 
        model.setViewName("redirect:/admin");
        return model;

    }

JSP：

<form:form action="/admin/remove" method="POST"  modelAttribute="users">
            <table class="table table-striped">
                <thead>
                    <tr>
                        <th>Firstname</th>
                        <th>Lastname</th>
                        <th>Email/login</th>
                        <th>Profession</th>
                        <th>Select<th>
                    </tr>
                </thead>
                <tbody>
                    <c:forEach var="user" items="${users}">
                        <tr>
                            <td>${user.firstName}</td>
                            <td>${user.lastName}</td>
                            <td>${user.login}</td>
                            <td>${user.profession}</td>
                            <td><input type="checkbox" value="${user.delete}"/></td>
                        </tr>
                    </c:forEach>
                </tbody>
            </table>            
            <input type="submit" value="Delete user(s)" class="btn-danger" />
            <input type="hidden" name="${_csrf.parameterName}" value="${_csrf.token}" />
            </form:form>

该列表显示正确。如果我按下“删除用户”按钮。@modelAttribute用户为空。我也尝试将列表包装在新类中，但得到的结果相同。

有任何想法吗？

阅读 257

2020-06-08

共1个答案

小编典典

多亏了奴才，我找到了答案

包装器：

public class UserListWrapper {

private ArrayList<User> users;

public ArrayList<User> getUsers() {
    return users;
}

public void setUsers(ArrayList<User> users) {
    this.users = users;
}

控制器：

@Controller
public class AdminController {

@Autowired
private UserDao userDao;

@RequestMapping(value = "/admin", method = RequestMethod.GET)
public ModelAndView adminPage() {
    ModelAndView model = new ModelAndView();
    UserListWrapper wrapper = new UserListWrapper();
    wrapper.setUsers(new ArrayList<User>(userDao.findAll()));
    model.addObject("userListWrapper",wrapper);

    model.setViewName("admin");
    return model;

}

@RequestMapping(value = "admin/remove", method = RequestMethod.POST)
public ModelAndView removeUser(@ModelAttribute(value = "userListWrapper") UserListWrapper userListWrapper) {
    ModelAndView model = new ModelAndView();
    userDao.removeFlaggedUsers(userListWrapper.getUsers());
    model.setViewName("redirect:/admin");
    return model;

}

}

视图：

<form:form action="/admin/remove" method="POST"  modelAttribute="userListWrapper">
        <table class="table table-striped">
            <thead>
                <tr>
                    <th>First name</th>
                    <th>Last name</th>
                    <th>Email/login</th>
                    <th>Profession</th>
                    <th>Select<th>
                </tr>
            </thead>
            <tbody>
                <c:forEach varStatus="us" var="user" items="${userListWrapper.users}" >
                    <tr>
                        <td><form:input type="hidden" path="users[${us.index}].firstName"/>${user.firstName}</td>
                        <td><form:input type="hidden" path="users[${us.index}].lastName"/> ${user.lastName}</td>
                        <td><form:input type="hidden" path="users[${us.index}].login"/>${user.login}</td>
                        <td><form:input type="hidden" path="users[${us.index}].profession"/>${user.profession}</td>
                        <td><form:checkbox path="users[${us.index}].delete" value="${user.delete}"/></td>
         <form:input type="hidden" path="users[${us.index}].id"/>
                    </tr>
                </c:forEach>
            </tbody>
        </table>            
        <input type="submit" value="Delete user(s)" class="btn-danger" />
        <input type="hidden" name="${_csrf.parameterName}" value="${_csrf.token}" />
        </form:form>

谢谢！

编辑：别忘了还要添加您未显示的字段。

例如：

如果不添加ID，则删除将不起作用，因为返回的User对象中的ID为NULL。

2020-06-08