Dropwizard 从 POST 方法更新视图

Question

我正在尝试验证我的 POST 注册新用户的方法中的表单。如果出现错误，例如已使用的用户名，我希望我的视图（从我的 GET 方法中检索到）更新错误。我正在使用 Dropwizard Views 和 Freemarker。到目前为止我的代码：

 public class SignUpView extends View {

    List<String> errors;

    public SignUpView() {
        super("signup.ftl");
        errors = new ArrayList<>();

    }

    public SignUpView(List<String> errors) {
        super("signup.ftl");
        this.errors = errors;

    }

}

signup.ftl:

<#-- @ftlvariable name="" type="com.tm.resources.views.SignUpView" -->
<#include "include/head.html">
<#include "include/header.html">

<br><br><br>

<form action="/signup" method="post">
  <div class="container">
    <h1>Sign Up</h1>
    <p>Please fill in this form to create an account.</p>
    <hr>
    <#if errors?has_content>
        <ul class="errorMessages">
             <#list errors as error>
                 <li>${error}</li>
             </#list>
        </ul>
    </#if>    
    <label><b>Full name</b></label>
    <input type="text" placeholder="full name" name="full_name" required>

    <label><b>Email</b></label>
    <input type="email" placeholder="Enter Email" name="email" required>

    <label><b>Password</b></label>
    <input type="password" placeholder="Enter Password" name="psw" required>

    <label><b>Repeat Password</b></label>
    <input type="password" placeholder="Repeat Password" name="psw-repeat" required>

    <label>
      <input type="checkbox" checked="checked" style="margin-bottom:15px"> Remember me
    </label>

    <p>By creating an account you agree to our <a href="#" style="color:dodgerblue">Terms & Privacy</a>.</p>

    <div class="clearfix">
      <button type="button" class="cancelbtn btn-form">Cancel</button>
      <button type="submit" class="signupbtn btn-form">Sign Up</button>
    </div>
  </div>
</form>


<#include "include/footer.html">

还有我的资源class：

@Path("/signup")
@Produces(MediaType.TEXT_HTML)
public class SignUpResource {

    // UserService
    private UserService userService;

    public SignUpResource(UserService userService) {
        this.userService = userService;
    }

    @GET
    public SignUpView getView() {

            return new SignUpView();
    }

    @POST
    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
    @Timed
    @UnitOfWork
    public Response registerUserInfo(@FormParam("full_name") String name, 
            @FormParam("email") String email,
            @FormParam("psw") String pwd,
            @FormParam("psw-repeat") String pwdRepeat){

        String responseString = "Successfully added user details, name: "+
                name+" and pwd: "+pwd;

        try {
            userService.addUser(name,email, pwd);
        } catch (ShowAbleException e) {
            // if adding triggered an error it must be displayed on the page
            List<String> errors = new ArrayList<String>();
            errors.add(e.getMessage());

            // HOW to go back to GET method with errors?? Or just display them?
        }

        try {
            //return Response.created(new URI("/")).entity(response).build();
            return Response.seeOther(new URI("/")).build(); // redirect back to homepage...
        } catch (URISyntaxException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            throw new RuntimeException(e.getMessage(), e);
        }
    } 
}

我看到 this 页面提供了一些指导，但我未能复制它，因为源未完全提供并且它不使用 Dropwizard 的视图功能。我还考虑过向我的 GET 方法添加参数并从 POST 方法重定向，但这对我来说似乎有点矫枉过正？

任何帮助将不胜感激。

Answer 1

我设法通过遇到 this thread 解决了这个问题，这表明可以发送一个新的 View 作为响应。因此，如果遇到错误，则会在 Response 中创建一个新的 View 并更新错误。代码如下：

 try {
            userService.addUser(name,email, pwd);
        } catch (ShowAbleException e) {
            // if adding triggered an error it must be displayed on the page
            List<String> errors = new ArrayList<String>();
            errors.add(e.getMessage());

            return Response.ok(new SignUpView(errors)).build();
        }

        try {
            //return Response.created(new URI("/")).entity(response).build();
            return Response.seeOther(new URI("/")).build(); // redirect back to homepage...
        } catch (URISyntaxException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            throw new RuntimeException(e.getMessage(), e);
        }

我还发现我的 SignUpView class 需要一个 getErrors 方法，以便 Freemarker 文件可以访问错误列表。所以我补充说：

public List<String> getErrors() {
    return errors;
}

Dropwizard 从 POST 方法更新视图

Dropwizard update View from POST method

java

freemarker

dropwizard

javax.ws.rs

dropwizard-templates