学步园

网上看到好多人都是不知道Extjs的grid怎么分页,其中包括start 为0 的问题,有人提出过自己修改分页工具条控件,实现与后台无关的分页效果,这也是一种解决方法,但不是最标准的,下面我就说说最标准的解决方法!!

先看下面的类!

 package com.td.Common;</p> <p>import java.lang.reflect.Field;<br /> import java.util.Date;<br /> import java.util.List;</p> <p>import org.apache.commons.logging.Log;<br /> import org.apache.commons.logging.LogFactory;</p> <p>import com.td.bean.Caigou;</p> <p>import net.sf.json.JSONArray;<br /> import net.sf.json.JSONObject;<br /> import net.sf.json.JsonConfig;<br /> @SuppressWarnings({ "unchecked", "serial" })<br /> public class ObjectToJson {<br /> private static final Log log = LogFactory.getLog(Caigou.class);</p> <p> public String ObjectToJson(Object bean) {<br /> JSONObject jo= JSONObject.fromObject(bean);<br /> //JSONArray ja = JSONArray.fromObject(bean);<br /> return jo.toString();<br /> }</p> <p> public String ArrayToJson(Object bean) {</p> <p> JSONArray ja = JSONArray.fromObject(bean);<br /> return ja.toString();<br /> }</p> <p> private String ConvertJavaScriptType(String type) {<br /> // System.out.print(type);<br /> if ("String".equals(type))<br /> return "string";<br /> else if ("Integer".equals(type))<br /> return "int";<br /> else if ("Date".equals(type))<br /> return "date";// 本来应该是date类型但是应为这个json包转换成的数据结果是这样的:{"month":3,"day":2,"year":109,"nanos":0,"time":1239694471000,"seconds":31,"timezoneOffset":-480,"date":14,"hours":15,"minutes":34}<br /> else<br /> return "string";<br /> }</p> <p> public String ListToJson(List list, String key,int totalNumber,int start,int limit) {<br /> if (list!=null && list.size() > 0 )<br /> {<br /> Object obj = list.get(0);<br /> return this.ListToJson(obj, list, key,totalNumber, start,limit);<br /> } else {<br /> return "";<br /> }</p> <p> }</p> <p> /*<br /> * 最新的方法不需要Key但是需要在每个类里面加上如下的一个字段<br /> * public String KeyField="{每个对象对应表的主键}";<br /> * 例如:<br /> * public String KeyField="tableName";<br /> * */<br /> public String ListToJson(List list,int totalNumber, int start,int limit) {<br /> if (list!=null && list.size() > 0 )<br /> {<br /> Object obj = list.get(0);<br /> return this.ListToJson(obj, list,totalNumber, start, limit);<br /> } else {<br /> return "";<br /> }</p> <p> }</p> <p> //<br /> /*<br /> * @param Object bean 实体bean List list 包含数据的list, String key 当前实体的主键,start从第几页开始,limit每页多少行<br /> */<br /> public String ListToJson(Object bean, List list, String key,int totalNumber,int start,int limit)<br /> {</p> <p> StringBuilder sb = new StringBuilder();<br /> JsonConfig jsonConfig = new JsonConfig();</p> <p> jsonConfig.registerJsonValueProcessor(Date.class,<br /> new JsDateJsonValueProcessor());<br /> jsonConfig.registerJsonValueProcessor(java.sql.Date.class,<br /> new JsSqlDateJsonValueProcessor());</p> <p> JSONArray ja = JSONArray.fromObject(list, jsonConfig);<br /> Class clazz = bean.getClass();<br /> // clazz.getDeclaredFields()<br /> Field[] fields = clazz.getDeclaredFields();</p> <p> sb.append("{");<br /> sb.append("'metaData': {");<br /> sb.append("totalProperty: 'totalProperty',");<br /> sb.append("root: 'root',");<br /> sb.append(String.format("id: '%1$s',", key));<br /> sb.append("fields: [");</p> <p> for (int i = 0; i < fields.length; i++) {<br /> Field field = fields[i];<br /> String name = field.getName();<br /> String type = field.getType().getSimpleName();<br /> sb.append("{");<br /> sb.append(String.format("name: '%1$s', type: '%2$s'", name,<br /> ConvertJavaScriptType(type)));<br /> sb.append("},");<br /> }<br /> sb.replace(sb.length() - 1, sb.length(), "");<br /> sb.append("]");<br /> sb.append("},");<br /> sb.append("start:");<br /> sb.append(start);<br /> sb.append(",");<br /> sb.append("limit:");<br /> sb.append(limit);<br /> sb.append(",");<br /> sb.append(String.format("totalProperty:%1$s,", totalNumber));// 总共多少条记录<br /> sb.append("root:");<br /> sb.append(ja.toString());<br /> sb.append("}");<br /> log.debug(sb.toString());<br /> return sb.toString();<br /> }</p> <p> public String ListToJson(Object bean,List list,int totalNumber,int start,int limit) {</p> <p> StringBuilder sb = new StringBuilder();<br /> JsonConfig jsonConfig = new JsonConfig();</p> <p> jsonConfig.registerJsonValueProcessor(Date.class,<br /> new JsDateJsonValueProcessor());<br /> jsonConfig.registerJsonValueProcessor(java.sql.Date.class,<br /> new JsSqlDateJsonValueProcessor());</p> <p> JSONArray ja = JSONArray.fromObject(list, jsonConfig);<br /> Class clazz = bean.getClass();<br /> // clazz.getDeclaredFields()<br /> Field[] fields = clazz.getDeclaredFields();</p> <p> sb.append("{");<br /> sb.append("'metaData': {");<br /> sb.append("totalProperty: 'totalProperty',");<br /> sb.append("root: 'root',");<br /> try {<br /> //System.out.println( bean.getClass().getDeclaredField("KeyField").get(bean).toString());<br /> sb.append(String.format("id: '%1$s',", bean.getClass().getDeclaredField("KeyField").get(bean).toString()));<br /> } catch (IllegalArgumentException e) {<br /> e.printStackTrace();<br /> } catch (SecurityException e) {<br /> e.printStackTrace();<br /> } catch (IllegalAccessException e) {<br /> e.printStackTrace();<br /> } catch (NoSuchFieldException e) {<br /> e.printStackTrace();<br /> }<br /> sb.append("fields: [");</p> <p> for (int i = 0; i < fields.length; i++) {<br /> Field field = fields[i];<br /> String name = field.getName();<br /> String type = field.getType().getSimpleName();<br /> sb.append("{");<br /> sb.append(String.format("name: '%1$s', type: '%2$s'", name,<br /> ConvertJavaScriptType(type)));<br /> sb.append("},");<br /> }<br /> sb.replace(sb.length() - 1, sb.length(), "");<br /> sb.append("]");<br /> sb.append("},");<br /> sb.append("start:");<br /> sb.append(start);<br /> sb.append(",");<br /> sb.append("limit:");<br /> sb.append(limit);<br /> sb.append(",");<br /> sb.append(String.format("totalProperty:%1$s,",totalNumber));// 总共多少条记录<br /> sb.append("root:");<br /> sb.append(ja.toString());<br /> sb.append("}");<br /> log.debug(sb.toString());<br /> return sb.toString();<br /> }</p> <p> public String ListToTreeJson(List list) {<br /> JSONArray ja = JSONArray.fromObject(list);<br /> //System.out.println(ja.toString());<br /> log.debug(ja.toString());<br /> return ja.toString();<br /> }</p> <p>// public String JsonToBeanArray(String jsonString,Object obj) {<br /> //<br /> // JSONArray jsonArray = JSONArray.fromObject(jsonString);<br /> // JsonConfig jsonConfig = new JsonConfig();<br /> // jsonConfig.setArrayMode( JsonConfig.MODE_OBJECT_ARRAY );<br /> // jsonConfig.setRootClass(obj.getClass());<br /> // obj.getClass()[] users= JSONSerializer.toJava( jsonArray, jsonConfig );<br /> //<br /> //<br /> //<br /> // }<br /> // public String JsonToBean(String jsonString,Object obj) {<br /> //<br /> // JSONObject jsonPerson = JSONObject.fromObject(jsonString);<br /> // String[] dateFormats = new String[] {"yyyy/MM/dd"};<br /> // JSONUtils.getMorpherRegistry().registerMorpher(new DateMorpher(dateFormats));<br /> // Person person = (Person)JSONObject.toBean(jsonPerson, Person.class);<br /> //<br /> //<br /> //<br /> // }<br /> // </p> <p>}<br />

我们可以看到:

  sb.append("start:");
  sb.append(start);
  sb.append(",");
  sb.append("limit:");
  sb.append(limit);

这几行代码.这回你知道为什么你的grid不能分页了吗?

前台的分页工具条是根据后台传过去的数据内容分页的!