如何使用 struts2-json-plugin 将 JSON 绑定到 Struts2 中的 Java 对象 [英] How to bind JSON to Java object in Struts2 using struts2-json-plugin

问题描述

我想将 JSON 反序列化(绑定)到 java 对象.在 Struts2 中怎么做?

I want to deserialize (bind) JSON to java object. How to do it in Struts2?

我正在尝试使用 struts2-json-plugin 来执行此操作，如下面的代码所示，但是从前端发送的 JSON 未绑定到我的 java 对象.你能帮我吗，请问如何使这段代码正常工作?

I am trying to do it with struts2-json-plugin as you can see in code below, but sent JSON from frontend is not binding to my java object. Could you help me, please how to make this code to work correctly?

请看一下我的 Action 类，我不确定在这个 Action 中我是否正确处理了 JSON，或者我错过了什么?

Please take a look at my Action class, I am not sure if I'm handling JSON correctly in this Action, or maybe I missed something?

我试图绑定的 JSON:

{"data":[
    {"active":true,"color":"orange","date":"2008-01-01","id":1,"name":"Chris"},
    {"active":false,"color":"blue","date":"2013-03-03","id":2,"name":"Kate"},
    {"active":true,"color":"black","date":"2013-05-03","id":3,"name":"Blade"},
    {"active":false,"color":"yellow","date":"2013-01-01","id":4,"name":"Zack"}]
}

通过 Ajax 发送 JSON:

$.ajax({
  url: "../json/saveJSONDataAction.action",
  data: {"data": handsontable.getData()}, //returns all cells' data
  dataType: 'json',
  type: 'POST',
  success: function (res) {
    if (res.result === 'ok') {
      $console.text('Data saved');
    }
  }
});

在 Struts2 中接收 JSON:

我可以在调试中访问 execute() 方法，但不幸的是，data 字段始终为空.我应该怎么做才能使这个字段充满来自 JSON 的数据? JSON 的格式是否正确以绑定到 List<Report>数据?

I can reach execute() method in debug, but unfortunately, the data field is always null. What should I do to make this field filled with data from JSON? Is the JSON in correct format to bind to List<Report> data?

@ParentPackage("json-default")
@Action(value="saveJSONDataAction")
@Result(type="json")
public class JSONSaveAction extends ActionSupport {
    private static final long serialVersionUID = 1L;

    private List<Report> data;

    public JSONSaveAction(){
    }

    public String execute() {
        try {
            System.out.println(data);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return NONE;
    }

    public List<Report> getData() {
        return data;
    }

    public void setData(List<Report> data) {
        this.data = data;
    }
}

报告类:

public class Report {
    private int id;
    private String name;
    private boolean active;
    private String date;
    private String color;

    //getters and setters
}

struts.xml:

正如你在这里看到的，我添加了 <interceptor-ref name="json"> 和 <param name="enableSMD">true</param>.整个配置如下:

As you can see here I've added <interceptor-ref name="json"> with <param name="enableSMD">true</param>. Whole config below:

<struts>
<constant name="struts.action.extension" value="action,pdf" />
<constant name="struts.i18n.reload" value="true" />
<constant name="struts.configuration.xml.reload" value="true" />
<constant name="struts.custom.i18n.resources" value="i18n/ap,application" />
<constant name="struts.date.format" value="yyyy-MM-dd" />
<constant name="struts.serve.static" value="true" />
<constant name="struts.serve.static.browserCache" value="false" />

<package name="default" namespace="/ftl" extends="json-default">

    <result-types>
       <result-type name="rethrowException" class="com.myhome.commons.util.ExceptionRethrowResult" />
       <result-type name="poi-excel" class="com.myhome.commons.util.PoiExcelResult"/>
    </result-types>

    <interceptors>
        <interceptor name="businessException" class="com.myhome.commons.exception.BusinessExceptionInterceptor"></interceptor>
        <interceptor-stack name="defaultStack">
            <interceptor-ref name="exception" />
            <interceptor-ref name="alias" />
            <interceptor-ref name="servletConfig" />
            <interceptor-ref name="i18n" />
            <interceptor-ref name="chain" />

            <interceptor-ref name="scopedModelDriven" />
            <interceptor-ref name="modelDriven" />
            <interceptor-ref name="fileUpload">
                <param name="maximumSize">10485760</param>
            </interceptor-ref>
            <interceptor-ref name="checkbox" />
            <interceptor-ref name="staticParams" />
            <interceptor-ref name="params">
                <param name="excludeParams">dojo\..*</param>
            </interceptor-ref>
            <interceptor-ref name="json">
                <param name="enableSMD">true</param>
            </interceptor-ref>
            <interceptor-ref name="prepare" />
            <interceptor-ref name="conversionError" />
            <interceptor-ref name="businessException" />
            <interceptor-ref name="validation">
                <param name="includeMethods">save,search</param>
            </interceptor-ref>
            <interceptor-ref name="workflow">
                <param name="includeMethods">save,search</param>
            </interceptor-ref>
            <interceptor-ref name="tokenSession">
                <param name="includeMethods">save</param>
            </interceptor-ref>
        </interceptor-stack>

    </interceptors>
    <default-interceptor-ref name="defaultStack"/>

    <global-results>
        <result name="exception" type="chain">
            <param name="actionName">exception</param>
            <param name="namespace">/</param>
        </result>
        <result name="rethrowException">/applicationAccessDeniedPage.jsp</result>       
        <result name="applicationAccessDenied">/applicationAccessDeniedPage.jsp</result>
        <result name="unavailableResource">/unavailableResource.jsp</result>        
        <result name="pessimisticLock">/pessimisticLock.jsp</result>        
        <result name="goto-crud" type="redirect">/crud/index.action</result>
        <result name="goto-dict" type="redirect">/dictionaries/index.action</result>
        <result name="reportXls" type="poi-excel">
            <param name="contentDisposition">attachment; filename="${resultFileName}"</param>
            <param name="excelWorkbook">workbook</param>
        </result>

    </global-results>
    <global-exception-mappings>
        <exception-mapping exception="com.myhome.ap.service.exception.AuthorizationFailedException" result="rethrowException"/>
        <exception-mapping exception="com.myhome.ap.service.exception.ApplicationAccessDeniedException" result="applicationAccessDenied"/>
        <exception-mapping exception="org.hibernate.ObjectNotFoundException" result="unavailableResource" />
        <exception-mapping exception="com.myhome.ap.service.exception.model.EntityHasBeenDeletedException" result="unavailableResource" />
        <exception-mapping exception="com.myhome.ap.service.exception.PessimisticLockingException" result="pessimisticLock" />
        <exception-mapping exception="java.lang.Exception" result="exception"/>
     </global-exception-mappings>

    <action name="version" class="com.myhome.ap.web.action.VersionAction" />

</package>
</struts>

我做错了什么?你能给我推荐一些如何在 Struts2 中从 JSON 反序列化到 Java 的好例子/教程，因为我什至找不到一个在 Struts2 中使用 JSON 反序列化的正确完整示例，特别是将接收 JSON 并将其绑定到 Java 的 Action 代码示例.

What am I doing wrong? Can you suggest me some good examples/tutorial how to do deserialization from JSON to Java in Struts2, because I cannot find even one correct full example with JSON deserialization in Struts2, specially example of Action code which will receive the JSON and bind it to Java.

我是 Struts 的新手，所以我在理解一些问题和流程时遇到问题，例如如何在 Action 中接收和处理 JSON.有使用 struts2-json-plugin 进行序列化的示例，但是对于这个主题，我没有遇到任何麻烦.请帮帮我...

I am new in Struts at all, so that's why I have problems to understand some issues and flow, for example how to receive and handle JSON in Action. There are examples for serialization with struts2-json-plugin, but with this subject I had no trouble. Please help me...

推荐答案

我想通了.有遗漏:

contentType: 'application/json',

在我的 Ajax 请求中.

in my Ajax request.

这篇关于如何使用 struts2-json-plugin 将 JSON 绑定到 Struts2 中的 Java 对象的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！