查询,分页封装

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一，后台查询，分页封装

1.BaseQuery.java:

import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;

public class BaseQuery implements Serializable {
private Integer pageSize = 5;

private Integer currentPage = 1;

private Integer startRow = 0;

public Integer getPageSize() {
return pageSize;
}

public void setPageSize(Integer pageSize) {
if(pageSize == null || pageSize <= 0) {
return;
}
this.pageSize = pageSize;
}

public Integer getCurrentPage() {
return currentPage;
}

public void setCurrentPage(Integer currentPage) {
if(currentPage == null || currentPage <= 0) {
return;
}
this.currentPage = currentPage;
}

public Integer getStartRow() {
if(currentPage == null || currentPage < 0 || pageSize == null && pageSize < 0) {
return 0;
}
startRow = (currentPage - 1) * pageSize;
return startRow;
}

public Map<String, Object> bulid() {
Map<String, Object> params = new HashMap<String, Object>();
params.put("pageSize", this.pageSize);
params.put("currentPage", this.currentPage);
params.put("startRow", this.getStartRow());

return params;
}
}

2.查询类继承BaseQuery,以UserQuery.java为例。

import java.util.Map;

public classUserQuery extends BaseQuery {

private Stringname;

public String getName() {

returnname;

}

public void setName(String name) {

this.name =name;

}

public Map<String, Object> build() {

Map<String, Object> params = super.bulid();

params.put("name",name);

returnparams;

}

public String queryString() {

StringBuilder sb =new StringBuilder();

sb.append("name=");

sb.append(name ==null ? "" :name);

return sb.toString();

}

3.QueryResult.java:

import java.io.Serializable;
import java.util.*;

/**
* 分页查询结果
* @param <T>
*/
public class QueryResult<T> implements Serializable {

private Integer totalPage;//总页数
private Integer amount;//总条数
private Collection<T> resultList = new ArrayList<T>();//当前页数据集合
private BaseQuery query;

public Integer getTotalPage() {
return totalPage;
}

public Integer getAmount() {
return amount;
}

public void setAmount(Integer amount) {
if (amount == null) {
return;
}
if (query == null) {
return;
}
int pageSize = query.getPageSize();
int mod = amount % pageSize;
int page = amount / pageSize;
totalPage = (mod == 0 ? page : page + 1);
this.amount = amount;
}

public Collection<T> getResultList() {
return resultList;
}

public void setResultList(Collection<T> resultList) {
this.resultList = resultList;
}

public BaseQuery getQuery() {
return query;
}

public void setQuery(BaseQuery query) {
this.query = query;
}

public Integer getNextPage() {
Integer nextPage = query.getCurrentPage() + 1;
return nextPage > totalPage ? -1 : nextPage;
}

public List<Integer> pageNumbers() {
if(totalPage == 0) {
return Collections.EMPTY_LIST;
}
List<Integer> pages = new ArrayList<Integer>();
for(int i = 1; i<= totalPage; i++) {
pages.add(i);
}
return pages;
}

//***************************utils*****************************//
public Map<String, Object> propertyMap() {
Map<String, Object> pm = new HashMap<String, Object>(5);
pm.put("amount", this.amount);
pm.put("totalPage", this.totalPage);
pm.put("resultList", this.resultList);
if (query != null) {
pm.putAll(query.build());
}
return pm;
}
}

二，前台用velocity的宏定义显示分页。

1.list_user.vm：

</form>

<td>借款人姓名</td>

</tr>

#foreach( $user in $!users )

<tr>

</tr>

#end

</table>

#pagination("list_user.jhtml?$!{query.queryString()}" $!queryResult)

</div>

2.macro.vm

#macro(pagination $targetUrl $queryResult)

//init

$(function(){

//生成分页

//有些参数是可选的，比如lang，若不传有默认值

kkpager.generPageHtml({

//当前页码

pno : $!{query.currentPage},

//总页码

total : $!{queryResult.totalPage},

//总数据条数

totalRecords : $!{queryResult.amount},

//链接前部

hrefFormer : '$targetUrl',

//链接尾部

hrefLatter : '',

getLink : function(n){

if (n == 1){

return this.hrefFormer;

}

return this.hrefFormer + "&page="+n;

}

});

</script>

#end

3.使用velocity配置引入macro.vm

a. 在spring-velocity.xml配置中加入macroHelper:

<beanid="viewResolver"class="org.springframework.web.servlet.view.velocity.VelocityLayoutViewResolver">

<propertyname="exposeSpringMacroHelpers"value="true"/>

</bean>

b. 在velocity.properties中加入：

velocimacro.library.autoreload=true

velocimacro.library=macro.vm

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