jdbcTemplate实现分页功能

package com.yadou.model;

/**
* 分页参数类
* Created by lv on 16-5-12.
*/
public class PageParam {
/**
* 起始页码
*/
private int page = 1;

/**
* 每页显示条数
*/
private int limit;
/**
* 默认为10条
*/
public static final int PAGE_SIZE = 10;
/**
* 排序字段
*/
private String sort;
/**
* asc or desc
*/
private String dir;

public int getPage() {
return page;
}

public void setPage(int page) {
this.page = page;
}

public String getSort() {
return sort;
}

public void setSort(String sort) {
this.sort = sort;
}

public String getDir() {
return dir;
}

public void setDir(String dir) {
this.dir = dir;
}

public int getLimit() {
return limit;
}

public void setLimit(int limit) {
this.limit = limit;
}
}

package com.yadou.util;

import com.yadou.model.PageParam;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.support.JdbcDaoSupport;

import java.util.List;

public class Pagination extends JdbcDaoSupport {
private static final Logger LOGGER = LogManager.getLogger(Pagination.class);
//一页显示的记录数
private int pageSize;
//记录总数
private int totalRows;
//总页数
private int totalPages;
//当前页码
private int currentPage;
//起始行数
private int startIndex;
//结束行数
private int lastIndex;
//结果集存放List
private List resultList;
//JdbcTemplate jTemplate
private JdbcTemplate jTemplate;

/**
* 分页构造函数
*
* @param sql       根据传入的sql语句得到一些基本分页信息
* @param params    参数列表
* @param pageParam 分页参数对象
* @param jTemplate JdbcTemplate实例
*/
public Pagination(String sql, Object[] params, PageParam pageParam, JdbcTemplate jTemplate) {
if (jTemplate == null) {
throw new IllegalArgumentException("com.deity.ranking.util.Pagination.jTemplate is null,please initial it first. ");
} else if (sql == null || sql.equals("")) {
throw new IllegalArgumentException("com.deity.ranking.util.Pagination.sql is empty,please initial it first. ");
}
//设置每页显示记录数
setPageSize(pageParam.getLimit());
//设置要显示的页数
setCurrentPage(pageParam.getPage());
//计算总记录数
StringBuffer totalSQL = new StringBuffer(" SELECT count(*) FROM ( ");
totalSQL.append(sql);
totalSQL.append(" ) totalTable ");
//给JdbcTemplate赋值
setJdbcTemplate(jTemplate);
//总记录数
setTotalRows(getJdbcTemplate().queryForObject(totalSQL.toString(), params, Integer.class));
//计算总页数
setTotalPages();

//计算起始行数
setStartIndex();
//计算结束行数
setLastIndex();
//装入结果集
setResultList(getJdbcTemplate().queryForList(getMySQLPageSQL(new StringBuilder(sql), pageParam), params));
}

/**
* 构造MySQL数据分页SQL
*
* @param queryString
* @return
*/
public String getMySQLPageSQL(StringBuilder queryString, PageParam pageParam) {
String resultSql = null;
if (pageParam != null && pageParam.getSort() != null && pageParam.getDir() != null) {
queryString.append(" order by ").append(pageParam.getSort()).append(" ").append(pageParam.getDir());
}
if (0 != pageSize) {
resultSql = queryString.append(" limit ").append(startIndex).append(",").append(pageSize).toString();
} else {
resultSql = queryString.toString();
}
LOGGER.info("page sql:{}", resultSql);
return resultSql;
}

public int getCurrentPage() {
return currentPage;
}

public void setCurrentPage(int currentPage) {
//如果当前页码<1，则默认加载第一页数据
if (currentPage < 0) {
this.currentPage = 1;
} else {
this.currentPage = currentPage;
}
}

public List getResultList() {
return resultList;
}

public void setResultList(List resultList) {
this.resultList = resultList;
}

public int getTotalPages() {
return totalPages;
}

//计算总页数
public void setTotalPages() {
if (pageSize == 0) {
totalPages = 0;
} else {
if (totalRows % pageSize == 0) {
this.totalPages = totalRows / pageSize;
} else {
this.totalPages = (totalRows / pageSize) + 1;
}
}
}

public int getTotalRows() {
return totalRows;
}

public void setTotalRows(int totalRows) {
this.totalRows = totalRows;
}

public int getStartIndex() {
return startIndex;
}

public void setStartIndex() {
//如果总页数>当前页,则默认加载最后一页
if (currentPage > totalPages) {
currentPage = totalPages;
}
this.startIndex = (currentPage - 1) * pageSize;
}

public int getLastIndex() {
return lastIndex;
}

public JdbcTemplate getJTemplate() {
return jTemplate;
}

public void setJTemplate(JdbcTemplate template) {
jTemplate = template;
}

public int getPageSize() {
return pageSize;
}

public void setPageSize(int pageSize) {
this.pageSize = pageSize;
}

//计算结束时候的索引
public void setLastIndex() {
LOGGER.debug("totalRows={}", totalRows);///////////
LOGGER.debug("pageSize={}", pageSize);///////////
if (pageSize != 0) {
if (totalRows < pageSize) {
this.lastIndex = totalRows;
} else if ((totalRows % pageSize == 0) || (totalRows % pageSize != 0 && currentPage < totalPages)) {
this.lastIndex = currentPage * pageSize;
} else if (totalRows % pageSize != 0 && currentPage == totalPages) {//最后一页
this.lastIndex = totalRows;
}
}
}

}

public Pagination find(BGoodsVO bGoodsVO, PageParam pageParam) {
List<Object> params = new ArrayList<>();
StringBuilder sqlBuilder = new StringBuilder("SELECT\n" +
"	g.*, s.shop_name\n" +
"FROM\n" +
"	b_goods g,\n" +
"	b_shop s\n" +
"WHERE\n" +
"	g.shopid = s.ID\n");
if (bGoodsVO != null) {
if (bGoodsVO.getState() != null) {
//状态
sqlBuilder.append(" and g.state = ?");
params.add(bGoodsVO.getState());
}
}
return new Pagination(sqlBuilder.toString(), params.toArray(), pageParam, super.getJdbcTemplate());
}