ssh 架构下 json 数据的产生概述

N没写博客了，也是来****公司后的第一博。呵呵

  今天绝大多数的Web  开发会涉及到ajax json。先从前台开始说起（基于Jquery）

（1） web 前台产生异步请求；jquery 比较常用的两个函数：

 1） 

 

  $.ajax({

    type:"post",

    url: addURL,

    dataType: "json",

    data:param,

       success: function (data){

        alert("dd"); 

    alert(data);

     

    }

    });

   其中addURL 处理该请求的后台Action，param表示请求的参数，是以键值对的显示出现，如：

 

   var  selcetedIdString =  "${param.selcetedIdString}";

    var  addURL = '${addURL}';

    var  param = {selcetedIdString:selcetedIdString};

2）第二种方法，利用jqurey 提供的函数

       $.getJSON(url,param,function(data){

        alert(data);

         });

参数意义与第一种一样，两者的唯一区别在于 返回的data 的类型，第一种是是返回对象不是json对象，要进过

eval 函数转化才能成json对象，第二种，返回的data直接是json数据。

前台大致情况是这样的，后台是 json数据的来源，下面来描述后台怎么样常识json 数据，基于ssh 开发，struts2 很好的集成了 对json 数据产生支持，利用struts2 产生json 数据，需要用到包为：

  json-lib-2.4-jdk15.jar；ezmorph-1.0.2.jar等。主要是利用import net.sf.json.*下的静态类，写入到请求里。其中主要的注意点，Action 里，请求处理成功后，是否有配置Result；

  1） Action 返回的是Void 

    Action中 

     public void sationMapQuery(){

Helper.logEntrance("sationMapQuery");

try {

Helper.checkNotNull("sationMapQuery_selcetedIdString", selcetedIdString, "sationMapQuery_selcetedIdString");

String idtemp = selcetedIdString;

selcetedId = null;

selcetedId =  new ArrayList<Long>();

if(idtemp.contains(",")){

String arrayID [] = idtemp.split(",");

for(String id:arrayID){

selcetedId.add(new Long(id));

}

}else {

selcetedId.add(new Long(idtemp));

}

List selectedList  = stationMapServer.queryByIDs(selcetedId);

String listjson = JsonUtil.getListToJsonData(selectedList);

System.out.println(listjson);

JsonUtil.sendJsonString(listjson);

} catch (IOException e) {

e.printStackTrace();

}

/*JSONObject jsonObject=new JSONObject();

try {

JsonUtil.sendCallbackMessage("true");

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

jsonObject.element("isSuccess", true);*/

Helper.logExit("sationMapQuery");

}

其中package com.zjpost.rural.util;

 

import java.io.IOException;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

 

import javax.servlet.http.HttpServletResponse;

 

import net.sf.json.JSONArray;

import net.sf.json.JSONObject;

import net.sf.json.JsonConfig;

 

import org.apache.struts2.ServletActionContext;

 

 

import com.zjpost.rural.model.intermedia.JsonColumn;

import com.zjpost.rural.model.intermedia.JsonTreeItem;

 

public class JsonUtil {

public static void sendJsonString(String content)throws IOException{      

if(content == null){

content = "";

}

        HttpServletResponse response = ServletActionContext.getResponse();      

        response.setCharacterEncoding("UTF-8");      

        response.setContentType("text/plain");

        response.getWriter().write(content);  

}

//message values:

// success : "true"

// error: "detail error message like : db connection exception"

// forword: "forword"

public static void sendCallbackMessage(String message) throws IOException{

JSONObject jsonMessage = new JSONObject();

jsonMessage.element("message", message);

HttpServletResponse response = ServletActionContext.getResponse();      

        response.setCharacterEncoding("UTF-8");      

        response.setContentType("text/plain");

        response.getWriter().write(jsonMessage.toString()); 

}

public static void sendHtmlCallbackMessage(String message) throws IOException{

JSONObject jsonMessage = new JSONObject();

jsonMessage.element("message", message);

HttpServletResponse response = ServletActionContext.getResponse();      

        response.setCharacterEncoding("UTF-8");      

        response.setContentType("text/html");

        response.getWriter().write(jsonMessage.toString()); 

}

public static String toJsonTable(JsonColumn[] columns, List<Object[]> rows, Long total){

return toJsonTable(columns, rows, total, null, false);

}

public static String toJsonTable(JsonColumn[] columns, List<Object[]> rows, Long total, String idColumnName,boolean needCheckbox){

JSONObject table = new JSONObject();

table.element("total", total);

table.element("columns", columns);

JSONArray rowArray = new JSONArray();

if(rows != null && rows.size() > 0){

for(Object[] objs: rows)

{

JSONObject  rowObj = new JSONObject();

int i=0;

if (needCheckbox) {

i = 1;

for (; i < columns.length ; i++) {

rowObj.element(columns[i].getField(), objs[i - 1]);

}

} else{

for(; i< columns.length;i++){

rowObj.element(columns[i].getField(), objs[i]);

}

}

if(idColumnName != null && !idColumnName.isEmpty()){

rowObj.element(idColumnName, objs[objs.length -1]);

}

rowArray.add(rowObj);

}

}

table.element("rows", rowArray);

return table.toString();

}

public static String toJsonTableWithColor(JsonColumn[] columns, List<Object[]> rows, Long total, String idColumnName,boolean needCheckbox,String colorColumnName){

JSONObject table = new JSONObject();

table.element("total", total);

table.element("columns", columns);

JSONArray rowArray = new JSONArray();

if(rows != null && rows.size() > 0){

for(Object[] objs: rows)

{

JSONObject  rowObj = new JSONObject();

int i=0;

if (needCheckbox) {

i = 1;

for (; i < columns.length ; i++) {

rowObj.element(columns[i].getField(), objs[i - 1]);

}

} else{

for(; i< columns.length;i++){

rowObj.element(columns[i].getField(), objs[i]);

}

}

if(idColumnName != null && !idColumnName.isEmpty()){

if(colorColumnName != null){

rowObj.element(idColumnName, objs[objs.length -2]);

rowObj.element(colorColumnName, objs[objs.length -1]);

}

else{

rowObj.element(idColumnName, objs[objs.length -1]);

}

}

rowArray.add(rowObj);

}

}

table.element("rows", rowArray);

return table.toString();

}

public static String toJsonTable(JsonColumn[] columns, List<Object[]> rows, Long total, String idColumnName){

return toJsonTable(columns, rows, total, idColumnName, true);

}

 

public static List<JsonTreeItem> makeTree(List<JsonTreeItem> items)

{

Map<Long, List<JsonTreeItem>> parentMap = new HashMap<Long, List<JsonTreeItem>>();

List<JsonTreeItem> rootItems = null;

if(items != null && items.size() >0){

for(JsonTreeItem item : items){

if(parentMap.containsKey(item.getParentId())){

parentMap.get(item.getParentId()).add(item);

}

else{

List<JsonTreeItem> children = new  ArrayList<JsonTreeItem>();

children.add(item);

parentMap.put(item.getParentId(), children);

}

}

rootItems = parentMap.get(0L);

if(rootItems != null && rootItems.size() > 0){

for(JsonTreeItem rootItem : rootItems){

setChildrenItem(rootItem, parentMap);

}

}

}

changeParentCheckStatus(rootItems);

return rootItems;

}

public static void changeParentCheckStatus(List<JsonTreeItem> items){

for(JsonTreeItem item : items){

if(item.getChildren().size() > 0)

{

item.setChecked(false);

changeParentCheckStatus(item.getChildren());

}

}

}

//递归set children

public static void setChildrenItem(JsonTreeItem parentItem, Map<Long, List<JsonTreeItem>> itemMap){

List<JsonTreeItem> children = null;

if(itemMap.containsKey(parentItem.getId())){

children  = itemMap.get(parentItem.getId());

for(JsonTreeItem item : children){

setChildrenItem(item, itemMap);

}

parentItem.setChildren(children);

}

}

public static String getListToJsonData(List<?> dataList) {

JSONArray jsonArray = null;

try{

jsonArray = JSONArray.fromObject(dataList);

}catch (Exception e) {

// TODO: handle exception

e.printStackTrace();

}

return jsonArray.toString();

}

}

 

 sturts 配置

<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.1//EN" "http://struts.apache.org/dtds/struts-2.1.dtd">

<struts>

<package name="getgps" namespace="" extends="default">

<!-- 网点地图获取经纬度 --> 

<action name="queryMapAction" class="stationMapQueryBean" method="sationMapQuery">

</action>

<action name="initMapQueryAction" class="stationMapQueryBean" method="initMapQuery">

<param name="selcetedIdString">${selcetedIdString}</param>

<result >

/npmap/statiomMap.jsp

</result>

</action>

<action name="initAction" class="stationMapQueryBean" method="init">

<result >

/npmap/stationMapQueryList.jsp

</result>

</action>

</package>  

</struts>

 

 

2）自己定义个结构类型，实现Result 

 

  <package name="kingee_ast_default"  namespace="/mobile" extends="struts-default" >

<result-types>

        <result-type name="json" class="JSONResult"/>

         </result-types>

        <action name="queryCtyTwn" class="mobileQueryCtyTwn"  method="getCityTown">

<result type="json"></result>

</action>

</package>

 

/**

 * zjpost

 

 */

package com.zjpost.npmis.struts2;

 

import com.opensymphony.xwork2.ActionInvocation;

import com.opensymphony.xwork2.Result;

 

/***

 * @author <a href="[e-mail]">XXX</a>

 * @version $Id: $

 */

public class MobileBaseResult implements Result {

 

@Override

public void execute(ActionInvocation arg0) throws Exception {

 

}

 

}

 

 

 

 /**

 * zjpost

 

 */

package com.zjpost.npmis.action.mobile;

 

import java.io.IOException;

 

import com.opensymphony.xwork2.ActionSupport;

import com.zjpost.npmis.service.mobile.IBusinesSiteServer;

import com.zjpost.rural.model.management.User;

import com.zjpost.rural.util.JsonUtil;

 

/***

 * @author <a href="[e-mail]">XXX</a>

 * @version $Id: $

 */

public class BusinesSiteAction  extends ActionSupport{

private   IBusinesSiteServer  businesSiteServer;

// private   User  usr;

public String getCityTown(){

// businesSiteServer.queryCtiyOrTown(usr, null);

     String temp = "{" +

      " \"posts\" : [{ \"usr_id\": \"1000010012342\"}]} ";

try {

JsonUtil.sendJsonString(temp);

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return SUCCESS;

}

public IBusinesSiteServer getBusinesSiteServer() {

return businesSiteServer;

}

 

public void setBusinesSiteServer(IBusinesSiteServer businesSiteServer) {

this.businesSiteServer = businesSiteServer;

}

 

}