通用分页2
通用分页
实体类
package com.zhoujun.zj.entity;
import java.io.Serializable;
/**
* 实体类
* @author 周俊
*
*/
public class Book implements Serializable {
private static final long serialVersionUID = -1784556434207788044L;
private Integer bId;
private String bName;
private Float bPrice;
public Integer getbId() {
return bId;
}
public void setbId(Integer bId) {
this.bId = bId;
}
public String getbName() {
return bName;
}
public void setbName(String bName) {
this.bName = bName;
}
public Float getbPrice() {
return bPrice;
}
public void setbPrice(Float bPrice) {
this.bPrice = bPrice;
}
public Book() {}
public Book(Integer bId, String bName, Float bPrice) {
this.bId = bId;
this.bName = bName;
this.bPrice = bPrice;
}
@Override
public String toString() {
return "Book [bId=" + bId + ", bName=" + bName + ", bPrice=" + bPrice + "]";
}
}
dao方法
package com.zhoujun.zj.dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import com.zhoujun.zj.base.BaseDao;
import com.zhoujun.zj.entity.Book;
import com.zhoujun.zj.util.DBHelper;
import com.zhoujun.zj.util.PageBean;
import com.zhoujun.zj.util.StringUtils;
/**
* 数据访问层实现类
* @author 周俊
*
*/
//增加
public class BookDao extends BaseDao<Book> implements IBookDao {
@Override
public void add(Book book) {
// TODO Auto-generated method stub
Connection con = null;
PreparedStatement ps = null;
ResultSet rs = null;
String sql = "INSERT INTO tb_book(b_name,b_price) VALUES(?,?)";
con = DBHelper.getConnection();
try {
ps = con.prepareStatement(sql);
ps.setString(1, book.getbName());
ps.setFloat(2, book.getbPrice());
ps.executeUpdate();
} catch (SQLException e) {
// TODO Auto-generated catch block
throw new RuntimeException(e);
} finally{
DBHelper.close(con, ps, rs);
}
}
/**
* 不分页查询
*/
@Override
public List<Book> Search(Book book) {
// TODO Auto-generated method stub
Connection con = null;
PreparedStatement ps = null;
ResultSet rs = null;
String sql = "SELECT b_id,b_name,b_price FROM tb_book WHERE 1=1";
if(StringUtils.isNotBlank(book.getbName())) {
sql += " AND b_name LIKE '%"+book.getbName()+"%'";
}
List<Book> bookList = new ArrayList<Book>();
con = DBHelper.getConnection();
try {
ps = con.prepareStatement(sql);
rs = ps.executeQuery();
Book z = null;
while(rs.next()) {
z = new Book();
z.setbId(rs.getInt("b_id"));
z.setbName(rs.getString("b_name"));
z.setbPrice(rs.getFloat("b_price"));
bookList.add(z);
}
return bookList;
} catch (SQLException e) {
// TODO Auto-generated catch block
throw new RuntimeException(e);
} finally {
DBHelper.close(con, ps, rs);
}
}
/**
* 分页查询
*/
@Override
public List<Book> Search(Book book, PageBean pageBean) {
// TODO Auto-generated method stub
String sql = "SELECT b_id,b_name,b_price FROM tb_book WHERE 1=1";
if(StringUtils.isNotBlank(book.getbName())) {
sql += " AND b_name LIKE '%"+book.getbName()+"%'";
}
return this.executeQuery(sql, pageBean, new CallBack<Book>() {
@Override
public List<Book> forEachRs(ResultSet rs) throws SQLException {
// TODO Auto-generated method stub
List<Book> bookList = new ArrayList<Book>();
Book z = null;
while(rs.next()) {
z = new Book();
z.setbId(rs.getInt("b_id"));
z.setbName(rs.getString("b_name"));
z.setbPrice(rs.getFloat("b_price"));
bookList.add(z);
}
return bookList;
}
}
);
}
}
与数据库连接
定义tid文件
<tag>
<!-- 标签名 -->
<name>page</name>
<!-- 标签工具类 -->
<tag-class>com.cengke.paging.tag.PageTag</tag-class>
<!-- 标签的内容类型：empty表示空标签，jsp表示可以为任何合法的JSP元素 -->
<body-content>empty</body-content>
<!-- 自定义标签的属性定义,请注意一定要在标签类中提供对应的get/set方法 -->
<attribute>
<!-- 自定义标签的属性名称 -->
<name>pageBean</name>
<!-- true表示必填 -->
<required>true</required>
<!-- true支持动态值,可以向值里面填jsp表达式、EL表达式,false则不支持 -->
<rtexprvalue>true</rtexprvalue>
</attribute>
</tag>
jsp界面
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@taglib prefix="zz" uri="/zhoujun" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>书店首页</title>
</head>
<body>
<h1>首页</h1>
<form action="search.action" method="post">
<span>姓名：</span>
<input name="key" />
<input type="submit" value="查询" />
</form>
<table border="1px" width="100%">
<tr>
<td>序号</td>
<td>书名</td>
<td>价格</td>
</tr>
<c:forEach items="${bookList }" var="book" varStatus="vs">
<tr>
<td>${vs.index + 1 }</td>
<td>${book.bName }</td>
<td>${book.bPrice }</td>
<td>${book.bPrice }</td>
</tr>
</c:forEach>
</table>
<!-- 使用自定义标签 -->
<zz:page pageBean="${pageBean }"/>
</body>
</html>
核心代码
package com.zhoujun.zj.base;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
import com.zhoujun.zj.util.DBHelper;
import com.zhoujun.zj.util.PageBean;
public class BaseDao<C> {
/**
* 内部接口，用来遍历rs结果集
* @author 周俊
*
* @param
*/
public static interface CallBack<K>{
public List<K> forEachRs(ResultSet rs) throws SQLException;
}
@SuppressWarnings("unchecked")
public List<C> executeQuery(String sql, PageBean pageBean, @SuppressWarnings("rawtypes") CallBack callBack){
Connection con = null;
PreparedStatement ps = null;
ResultSet rs = null;
con = DBHelper.getConnection();
try {
/**
* 查询符合条件的总记录数
*/
//判断是否分页
if(null != pageBean && pageBean.isPagination()) {
String countSql = this.getCountSql(sql);
ps = con.prepareStatement(countSql);
rs = ps.executeQuery();
if(rs.next()) {
Object obj = rs.getInt(1);
pageBean.setTotal(obj.toString());
}
DBHelper.close(null, ps, rs);
}
/**
* 查询符合条件的记录
*/
//判断是否分页
if(null != pageBean && pageBean.isPagination()) {
sql = this.getPageSql(sql, pageBean);
}
ps = con.prepareStatement(sql);
rs = ps.executeQuery();
return callBack.forEachRs(rs);
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
DBHelper.close(con, ps, rs);
}
}
/**
* 得到查询总记录数的sql语句
* @param sql
* @return
*/
private String getCountSql(String sql) {
String countSql = "SELECT COUNT(*) FROM (" + sql + ")t1";
return countSql;
}
/**
* 得到查询满足条件的记录的sql
* @param sql
* @param pageBean
* @return
*/
private String getPageSql(String sql, PageBean pageBean) {
String pageSql = sql + " LIMIT " + pageBean.getStartIndex() + "," +pageBean.getRows();
return pageSql;
}
}