開源組件POI打印Excel報表

      首先將POI組件中的jar包放入項目中路徑下的WEB-INF/lib目錄中，而後即可以在JSP中使用POI組件了。

      新建一數據庫鏈接類Conn.java，代碼以下：

    

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
public class Conn {
	private final String dbDriver="com.mysql.jdbc.Driver" ;
	private final String url="jdbc:mysql://localhost:3306/employee";
	private final String userName = "root";
	private final String password = "ldm";
	private Connection con=null;
	Statement s=null;
    public Conn(){
    	try{
    		Class.forName(dbDriver);
    		con=DriverManager.getConnection(url,userName,password);
    		
    	}catch(Exception e){
    		System.out.println(e.getMessage());
    	}
    }
    
    public ResultSet executeQuery(String sql){
    	ResultSet rs=null;
    	try{
    		Conn conn=new Conn();
    		s=con.createStatement();
    		rs=s.executeQuery(sql);
    	}catch(Exception e){
    		e.printStackTrace();
    	}
    	return rs;
    }
    
    public void close(){
    	try{
    		if(s!=null||con!=null){
    			s.close();
    			con.close();
    		}
    	}catch(Exception e){
    		e.printStackTrace();
    	}
    }
}

           爲了將從數據庫中取出的數據放入List,建立JavaBean,命名爲POITest.java;這個JavaBean除了setXXX()和getXXX()方法以外，還有一個根據用戶須要顯示的行數從數據庫中取值ReadRecord(int rsRow)方法，它的返回值類型是List集合，程序代碼以下：

          

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.sql.ResultSet;
import java.util.List;
import java.util.ArrayList;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;

public class POITest {
    
	private int id;
	private String studentCode;
	private String name;
	private String sex;
	private String institute;
	private String department;
	private String classes;
	private String phone;
	private String address;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getStudentCode() {
		return studentCode;
	}
	public void setStudentCode(String studentCode) {
		this.studentCode = studentCode;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getSex() {
		return sex;
	}
	public void setSex(String sex) {
		this.sex = sex;
	}
	public String getInstitute() {
		return institute;
	}
	public void setInstitute(String institute) {
		this.institute = institute;
	}
	public String getDepartment() {
		return department;
	}
	public void setDepartment(String department) {
		this.department = department;
	}
	public String getClasses() {
		return classes;
	}
	public void setClasses(String classes) {
		this.classes = classes;
	}
	public String getPhone() {
		return phone;
	}
	public void setPhone(String phone) {
		this.phone = phone;
	}
	public String getAddress() {
		return address;
	}
	public void setAddress(String address) {
		this.address = address;
	}

	 
	 public static List ReadRecord(int rsRow){
		 Conn conn=new Conn();
		 String sql="select * from student where id<='"+rsRow+"'";
		 ResultSet rs=conn.executeQuery(sql);
		 List l=new ArrayList();
		 try{
			 while(rs.next()){
				 POITest p=new POITest();
				 p.setId(rs.getInt("id"));
				 p.setStudentCode(rs.getString("studentCode"));
				 p.setName(rs.getString("name"));
				 p.setSex(rs.getString("sex"));
				 p.setInstitute(rs.getString("institute"));
				 p.setDepartment(rs.getString("department"));
				 p.setClasses(rs.getString("classes"));
				 p.setPhone(rs.getString("phone"));
				 p.setAddress(rs.getString("address"));
				 l.add(p);
			 }
			 conn.close();
		 }catch(Exception e){
			 e.printStackTrace();
		 }
		 return l;
	 }
		
	 public static List ReadRecord(){
		 Conn conn=new Conn();                     //鏈接數據庫
		 String sql="select * from student";       //查詢學生信息
		 ResultSet rs=conn.executeQuery(sql);      //執行查詢
		 List l=new ArrayList();                   //定義List集合
		 
			try{	
				while(rs.next()){
					 POITest p=new POITest();       //實例化對象
					 p.setId(rs.getInt("id"));      //爲對象賦值
					 p.setStudentCode(rs.getString("studentCode"));
					 p.setName(rs.getString("name"));
					 p.setSex(rs.getString("sex"));
					 p.setInstitute(rs.getString("institute"));
					 p.setDepartment(rs.getString("department"));
					 p.setClasses(rs.getString("classes"));
					 p.setPhone(rs.getString("phone"));
					 p.setAddress(rs.getString("address"));
					 l.add(p);                      //將對象添加到List集合中
					
				}
				conn.close();                       //關閉數據庫
			}catch(Exception e){
				e.printStackTrace();
			}
			return l;                               //返回集合
			
	 }
	 /*
	  * 爲了添加工做表，必須建立一個HSSFSheet實例，使用POI組件中的createSheet("sheetname")建立工做表，根據顯示內容大小建立指定大小的單元格。
	  * 程序代碼以下：
	  * 
	  */
	 public void WriteCell(int rsRow){
		 HSSFWorkbook wb=new HSSFWorkbook();
		 HSSFSheet sheet=wb.createSheet("poiexample");//創建名爲poiexample的報表
		 sheet.setColumnWidth(0, 2500);
		 sheet.setColumnWidth(1, 6000);
		 sheet.setColumnWidth(2, 3500);
		 sheet.setColumnWidth(3, 9000);
		 sheet.setColumnWidth(4, 9000);
		 sheet.setColumnWidth(5, 8000);
		 sheet.setColumnWidth(6, 8000);
		 sheet.setColumnWidth(7, 9000);
		 sheet.setColumnWidth(8, 9000);
	     HSSFRow row=sheet.createRow(0);
		 HSSFCell cell[]=new HSSFCell[9];
		 for(int i=0;i<9;i++){                //遍歷每行的每列
			 cell[i]=row.createCell(i);
		 }
		 cell[0].setCellValue("id號");         //在單元格寫入文字
		 cell[1].setCellValue("學號");
		 cell[2].setCellValue("姓名");
		 cell[3].setCellValue("性別");
		 cell[4].setCellValue("系別");
		 cell[5].setCellValue("專業");
		 cell[6].setCellValue("班級");
		 cell[7].setCellValue("電話");
		 cell[8].setCellValue("地址");
		 
		 List l=POITest.ReadRecord(rsRow);
		 if(l.size()>0 && l!=null){
			 for(int i=0;i<l.size();i++){
				 POITest p2=(POITest)l.get(i);
				 HSSFRow datarow=sheet.createRow(i+1);
				 HSSFCell data[]=new HSSFCell[9];
				 for(int j=0;j<9;j++){
					 data[j]=datarow.createCell(j);
				 }
				 data[0].setCellValue(p2.getId());
				 data[1].setCellValue(p2.getStudentCode());
				 data[2].setCellValue(p2.getName());
				 data[3].setCellValue(p2.getSex());
				 data[4].setCellValue(p2.getInstitute());
				 data[5].setCellValue(p2.getDepartment());
				 data[6].setCellValue(p2.getClasses());
				 data[7].setCellValue(p2.getPhone());
				 data[8].setCellValue(p2.getAddress());
			 }
		 }
		 File file=new File("e:\\workbook.xls");
		 try{
			 FileOutputStream fileOut=new  FileOutputStream(file);
			 wb.write(fileOut);
			 fileOut.close();
		 }catch(IOException e){
			 e.printStackTrace();
		 }
	 }
}

  最後建立一JSP頁面，命名爲PoiTest.jsp;程序代碼以下：

 

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8" import="java.sql.*,com.wsy.POITest,java.io.*,java.io.FileOutputStream,
    org.apache.poi.hssf.usermodel.*,java.util.*,java.text.*"%>
      <jsp:useBean id="poi" scope="page" class="com.wsy.POITest"/> 
<!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>學生管理系統</title>
</head>
<script type="text/javascript" language="javascript">
      function fn1(){
         <%poi.WriteCell(9); %>
         alert("導出報表完畢！導出位置爲e:\\workbook.xls！！！");
      } 
</script>
<body>
<table border="1">
<tr><td>ID號</td><td>學號</td><td>姓名</td><td>性別</td><td>系別</td><td>專業</td><td>班級</td><td>電話</td><td>地址</td></tr>
<% List l=poi.ReadRecord();
for(int i=0;i<l.size();i++){
	POITest p2=(POITest)l.get(i);
%><tr>
<td><%=p2.getId() %><td>
<td><%=p2.getStudentCode() %></td>
<td><%=p2.getName()%></td>
<td><%=p2.getSex() %></td>
<td><%=p2.getInstitute() %></td>
<td><%=p2.getDepartment() %></td>
<td><%=p2.getClasses() %></td>
<td><%=p2.getPhone() %></td>
<td><%=p2.getAddress() %></td></tr>
<%  
}
%>
</table><br/>
<input type="button" value="導出報表" onClick='fn1()'/>
</body>
</html>

           重啓Tomcat服務器，在IE瀏覽器中運行JSP頁面；效果以下：

單擊「導出報表」按鈕，出現一個提示框

打開E盤，能夠看到已經生成一個名爲workbook.xls的文件，打開此文件，以下：