无法从令牌中反序列化任务START_ARRAY实例

Question

从 EXTJS 存储发送的 JSON 文件中反序列化多个任务（数据）时遇到问题。在更新单个任务时，其工作正确。但是当我们更新多个任务时，它会显示

org.codehaus.jackson.map.JsonMappingException：无法反序列化 bryntum.com.gnt.model.Task 的实例START_ARRAY令牌

我正在使用Spring MVC和Hibernate。我的 Web 控制器代码是。

package bryntum.com.gnt.web;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.json.*;
import bryntum.com.gnt.model.Task;
import bryntum.com.gnt.model.TaskWrapper;
import bryntum.com.gnt.service.TaskService;
import bryntum.com.gnt.util.ReturnTasks;

@Controller
public class TaskController  {
    private TaskService taskService;

    @RequestMapping(value="/tasks/update.action")
    public @ResponseBody String update (@RequestBody TaskWrapper data) throws Exception {
        try{
                 TaskWrapper tw=(TaskWrapper)data;
            List<Task> tasks = taskService.update(tw.getData());
            return ReturnTasks.mapOK(tasks);
        } catch (Exception e) {
            return ReturnTasks.mapError("Error trying to update task. ");
        }
    }
    @Autowired
    public void setEventService(TaskService taskService) {
        this.taskService = taskService;
    }
}

服务类代码是..

    package bryntum.com.gnt.service;
import java.util.ArrayList;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import bryntum.com.gnt.dao.TaskDAO;
import bryntum.com.gnt.model.Task;
@Service
public class TaskService {
    private TaskDAO taskDAO;

    @Transactional
    public List<Task> update(Task record){
        List<Task> returnTasks = new ArrayList<Task>();
        returnTasks.add(taskDAO.saveTask(record));
        return returnTasks;
    }

    @Autowired
    public void setTaskDAO(TaskDAO taskDAO) {
        this.taskDAO = taskDAO;
    }
}

用于处理 JSON 的 Util 类代码。

package bryntum.com.gnt.util;
import java.io.IOException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.springframework.stereotype.Component;
import org.codehaus.jackson.JsonGenerationException;
import org.codehaus.jackson.map.JsonMappingException;
import org.codehaus.jackson.map.ObjectMapper;
import org.json.*;
import bryntum.com.gnt.model.Task;
import org.codehaus.jackson.map.DeserializationConfig;
@Component
public class ReturnTasks {
    private static JSONObject sortedByParentTasks = null;
    private static JSONArray tasksTree = null;
    private static JSONObject taskChildrenObject;
    /**
     * Generates JSON String to return in the modelAndView
     * @param tasks
     * @return
     * @throws JSONException 
     * @throws IOException 
     * @throws JsonMappingException 
     * @throws JsonGenerationException 
     */
    public static String mapOK(List<Task> tasks) throws JSONException, JsonGenerationException, JsonMappingException, IOException{
        tasksTree = null;
        tasksTree = new JSONArray();
        sortedByParentTasks = null;
        sortedByParentTasks = new JSONObject();
        tasksTree = makeTree(tasks);
        return tasksTree.toString();
    }
    private static JSONArray makeTree(List<Task> list) throws JSONException, JsonGenerationException, JsonMappingException, IOException{
             ObjectMapper om= new ObjectMapper();
        Iterator<Task> listIterator = list.iterator();
        String parentId;
        while(listIterator.hasNext()){
            om=om.configure(DeserializationConfig.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY, true);
            om.enable(DeserializationConfig.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY);
            Task task = listIterator.next();
            JSONArray equalParentId;
            parentId = ""+task.getParentId();
            String json = om.writeValueAsString(task);
            JSONObject taskJSON = new JSONObject(json);
            if (sortedByParentTasks.has(parentId)){
                sortedByParentTasks.accumulate(parentId, taskJSON);
            } else {
                equalParentId = new JSONArray();
                equalParentId.put(taskJSON);
                sortedByParentTasks.put(parentId, equalParentId);
            }
        }
        addNodes(sortedByParentTasks.getJSONArray("null"));
        return tasksTree;
    }
    private static void addNodes(JSONArray nodes) throws JSONException{
        for(int i=0, l=nodes.length(); i<l; i++){
            taskChildrenObject = nodes.getJSONObject(i);
            listHierarchy(taskChildrenObject);
            tasksTree.put(taskChildrenObject);
        }
    }
    private static void listHierarchy(JSONObject task) throws JSONException{
        JSONArray childrenArray = new JSONArray();
        JSONArray childNodes = new JSONArray();
        try {
            childNodes = sortedByParentTasks.getJSONArray(""+task.get("Id"));
        }catch(JSONException e){} 
        if (childNodes.length() > 0){
            for (int i=0, l=childNodes.length(); i<l; i++) {
                JSONObject childObject = childNodes.getJSONObject(i);
                childrenArray.put(childObject);
                try{
                    task.put("children", childrenArray);
                    task.put("leaf", false);
                }catch(JSONException e){}
                listHierarchy(childObject);
            }           
        }
    }
    /**
     * Generates modelMap to return in the modelAndView in case
     * of exception
     * @param msg message
     * @return
     */
    public static String mapError(String msg){
        Map<String,Object> modelMap = new HashMap<String,Object>(2);
        modelMap.put("message", msg);
        modelMap.put("success", false);
        return modelMap.toString();
    } 
}

模型类代码..

package bryntum.com.gnt.model;
import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
import org.codehaus.jackson.annotate.JsonAutoDetect;
import org.codehaus.jackson.annotate.JsonProperty;
import org.codehaus.jackson.annotate.JsonIgnoreProperties;
@JsonAutoDetect
@JsonIgnoreProperties(ignoreUnknown = true)
@Entity
@Table(name="events")
public class Task implements Serializable {
    @Id
    @GeneratedValue
    @Column(name="Id")
    private int id;
    @Column(name="Name", nullable=false)
    private String name;
    /*@Column(name="TASK", nullable=false)
    private String task;
    */
    @Column(name="StartDate", nullable=false)
    private String startDate;
    @Column(name="EndDate", nullable=false)
    private String endDate;
    @Column(name="parentId", nullable=true)
    private Integer parentId;
       /*
        and more fields
        */
        @JsonProperty("Id")
    public int getId() {
        return id;
    }
    @JsonProperty("Id")
    public void setId(int id) {
        this.id = id;
    }

    @JsonProperty("Name")
    public String getName() {
        return name;
    }
    @JsonProperty("Name")
    public void setName(String name) {
        this.name = name;
    }
    @JsonProperty("StartDate")
    public String getStartDate() {
        return startDate;
    }
    @JsonProperty("StartDate")
    public void setStartDate(String start) {
        this.startDate = start;
    }
    @JsonProperty("EndDate")
    public String getEndDate() {
        return endDate;
    }
    @JsonProperty("EndDate")
    public void setEndDate(String end) {
        this.endDate = end;
    }
    public Integer getParentId() {
        return parentId;
    }
    public void setParentId(Integer id) {
        this.parentId = id;
    }
}

和用于任务的包装器克拉斯

package bryntum.com.gnt.model;
import java.io.Serializable;
public class TaskWrapper implements Serializable{
    private Task data; 
    public Task getData() {
        return data;
    }
    public void setData(Task data) {
        this.data = data;
    }
}

Answer 1

在控制器中，如果要更新多个对象，则应将方法更改为使用List作为参数：

公共@ResponseBody字符串更新（@RequestBody列表<任务包装器>任务）引发异常

这也取决于您如何使用批处理操作将 extjs 代理配置为 true 或 true。查看文档：http://docs.sencha.com/extjs/4.2.3/#!/api/Ext.data.proxy.Proxy-cfg-batchActions