Java web--利用java操作excel文档

  在web应用程序的开发中，如果需要将Excel文档中的信息导入数据库或将数据库的信息导出到Excel文档中，需要应用程序访问Excel文件。目前，操作Excel文档的java组件主要有Jxl和POI两种。本篇博客主要讲通过Jxl对Excel的操作。

目录

 

  1.读取Excel文档

2.写入Excel文档

3.修改已有的Excel文档

4.java实现Excel表格的数据导入与导出

---

  1.读取Excel文档

  读取电子表时需要用电子工作簿创建Workbook对象，然后基于Workbook对象获取工作簿的工作表，形成sheet对象，最后由sheet对象获取工作表的行、列，并根据行列值完成对工作表单元的读操作。

Workbook workbook=Workbook.getWorkbook(new File("d:/student.xls"));//位置随意填写
Sheet sheet=workbook.getSheet(0);//第一个工作表
int r=sheet.getRows();
int c=sheet.getColumns();
for(int i=0;i<r;i++){
    for(int j=0;j<c;j++){
//getCell方法第一个参数是列，第二个参数是行
      System.out.println(sheet.getCell(j,i).getCounts()+"");
    System.out.println("");
    }
}

2.写入Excel文档

  写文档与读文档类似，写Excel文档时需要用电子工作簿创建Workbook对象，然后基于Workbook对象获取工作簿的工作表，形成sheet对象，在创建单元格并添加到sheet对象，最后将sheet对象写入Workbook对象中。

WritableWorkbook wwb=Workbook。createWorkbook(new File("位置"));
WritableSheet ws=wwb.createSheet("TESTSHEET1",0);
Label label=new Label(2,3,"abc");//3行4列
ws.addCell(label);
jxl.write.Number number=new jxl.write.Number(1,0,555.12541);
ws.addCell(number);
wwb.write();
wwb.close();

3.修改已有的Excel文档

  修改已有的Excel文档

Workbook wb=Workbook.getWorkbook(new File("位置"));
WritableWorkbook book=Workbook.createWorkbook(new File("位置")，wb);//位置可相同，可不同
WritableSheet sheet=book.getSheet(0);
sheet.addCell(new Label(4,1,"ab"));
sheet.addCell(new Label(5,1,"cd"));
sheet.addCell(new Label(4,2,"eg"));
sheet.addCell(new Label(5,2,"gh"));
book.write();
book.close();

4.java实现Excel表格的数据导入与导出

  导入功能：用户选择本地的Excel文件后将其上传到服务器，然后从服务器导入。

  导出功能：先将数据库数据导入服务器，在下载到客户端。

    Student.java--javabean组件

package bean;

public class Student {
private String id;
private String name;
private String sex;
public Student(String id, String name, String sex) {
	super();
	this.id = id;
	this.name = name;
	this.sex = sex;
}
public Student() {
	super();
	// TODO Auto-generated constructor stub
}
public String getId() {
	return id;
}
public void setId(String id) {
	this.id = id;
}
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;
}

}

     JdbcUtil.java--连接MySql

package bean;

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

public class JdbcUtil {
	private static String driver;
	private static String url;
	private static String user;
	private static String password;
	private static Properties pr=new Properties();
	public JdbcUtil(){
		super();
	}
	static 
	{
		try {
			pr.load(JdbcUtil.class.getClassLoader().getResourceAsStream("db.properties"));
		    driver=pr.getProperty("driver");
		    url=pr.getProperty("url");
		    user=pr.getProperty("user");
		    password=pr.getProperty("password");
		    try {
				Class.forName(driver);
			} catch (ClassNotFoundException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	public static Connection getConnection() throws SQLException
	{
		return DriverManager.getConnection(url,user,password);
	}
	public static void free(Connection conn,Statement pstmt,ResultSet rs) throws Exception
	{
		if(conn!=null){conn.close();}
		if(pstmt!=null){pstmt.close();}
		if(rs!=null){rs.close();}
	}
}

     db.properties--用来记录数据库的数据，用以JdbcUtil调用，与xml文件作用类似

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/ccc?useUnicode=true&characterEncoding=UTF-8
user=root
password=2411030483

     StudentDao.java--用以完成功能的书写

package bean;

import java.io.File;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import jxl.Sheet;
import jxl.Workbook;
import jxl.write.Label;
import jxl.write.WritableSheet;
import jxl.write.WritableWorkbook;

public class StudentDao {
	public void exportToexcel(File excelpath,String condition) throws Exception{
		Connection conn=JdbcUtil.getConnection();
		String sql="select id,name,sex from student"+condition;
		PreparedStatement pstmt=conn.prepareStatement(sql);
		ResultSet rs=pstmt.executeQuery();
		WritableWorkbook wwb=Workbook.createWorkbook(excelpath);
		WritableSheet ws=wwb.createSheet("student", 0);
		String[] titles={"学号","姓名","性别"};
		int columnCount=titles.length;
		for(int i=0;i<columnCount;i++){
			ws.addCell(new Label(i,0,titles[i]));
		}
		int count=1;
		while(rs.next()){
			for(int j=0;j<columnCount;j++){
				ws.addCell(new Label(j,count,rs.getString(j+1)));
			}
			count++;
		}
		wwb.write();
		if(wwb!=null)wwb.close();
		JdbcUtil.free(conn, pstmt, rs);
	}
	public void importFromexcel(File excelpath,int sheetno) throws Exception{
		Connection conn=JdbcUtil.getConnection();
		String sql="insert into student(id,name,sex) values(?,?,?)";
		PreparedStatement pstmt=conn.prepareStatement(sql);
		Workbook workbook=Workbook.getWorkbook(excelpath);
		Sheet sheet=workbook.getSheet(sheetno-1);
		int r=sheet.getRows();
		int c=sheet.getColumns();
		for(int i=0;i<r;i++){
			for(int j=1;j<=c;j++){
				pstmt.setString(j,sheet.getCell(j-1,i).getContents().trim());
			}
			pstmt.addBatch();
		}
		pstmt.executeBatch();
		if(workbook!=null)workbook.close();
		JdbcUtil.free(conn, pstmt, null);
	}
	public List<Student> query()throws Exception{
		List<Student> studentList=new ArrayList<Student>();
		Connection conn=JdbcUtil.getConnection();
		String sql="select * from student";
		PreparedStatement pstmt=conn.prepareStatement(sql);
		ResultSet rs=pstmt.executeQuery();
		while(rs.next()){
			Student student=new Student();
			student.setId(rs.getString("id"));
			student.setName(rs.getString("name"));
			student.setSex(rs.getString("sex"));
			studentList.add(student);
		}
		JdbcUtil.free(conn, pstmt, rs);
		return studentList;
	}
}

     Dao.java--servlet函数，用以完成最终功能调用

package bean;

import java.io.File;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.oreilly.servlet.MultipartRequest;
import com.oreilly.servlet.ServletUtils;

/**
 * Servlet implementation class Dao
 */
@WebServlet("/daorucaochu")
public class Dao extends HttpServlet {
	private static final long serialVersionUID = 1L;

	/**
	 * Default constructor.
	 */
	public Dao() {
		// TODO Auto-generated constructor stub
	}

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
	 *      response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		// TODO Auto-generated method stub
		String action = request.getParameter("action");
		StudentDao studentdao = new StudentDao();
		String saveDirectory = this.getServletContext().getRealPath("/file");
		if ("daoru".equals(action)) {
			int maxPostSize = 5 * 1024 * 1024;
			MultipartRequest multi = new MultipartRequest(request, saveDirectory, maxPostSize, "utf-8");
			File excelfile = multi.getFile("file1");
			if (excelfile != null) {
				try {
					studentdao.importFromexcel(excelfile, 1);
				} catch (Exception e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}}
				response.setCharacterEncoding("UTF-8");
				response.sendRedirect("daorudaochu.jsp");
			} else if ("daochu".equals(action)) {
				String fileName = "student.xls";
				try {
					studentdao.exportToexcel(new File(saveDirectory + "/" + fileName), "");
					String isofilename = new String(fileName.getBytes("gbk"), "iso-8859-1");
					response.setContentType("application/octet-stream");
					response.setHeader("Content-Disposition", "attachment;filename=" + isofilename);
					ServletOutputStream out = null;
					out = response.getOutputStream();
					System.out.println(saveDirectory + "/" + fileName);
					ServletUtils.returnFile(saveDirectory + "/" + fileName, out);
					new File(saveDirectory + "/" + fileName).delete();
				} catch (Exception e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				
			}
		}
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
	 *      response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}

     daorudaochu.jsp--jsp页面，用以获取显示信息

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@ page import="bean.StudentDao,java.util.List,bean.Student"%>
    <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!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>表格数据的导入和导出</title>
</head>
<body>
<%
request.setCharacterEncoding("UTF-8");
StudentDao studentdao=new StudentDao();
List<Student> studentList=studentdao.query();
pageContext.setAttribute("studentList",studentList);
%>
<%
    String path = request.getContextPath();
    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<table>
<tr><th>学号</th><th>姓名</th><th>性别</th></tr>
<c:forEach items="${studentList}" var="student">
<tr><td>${student.id}</td><td>${student.name}</td><td>${student.sex}</td></tr>
</c:forEach>
</table>
<form action="http://localhost:8080/java第十五周/daorucaochu?action=daoru" method="post" enctype="multipart/form-data">
<input type="file" name="file1"/>
<input type="submit" value="excel->mysql(导入)"/>
</form>
<a href="http://localhost:8080/java第十五周/daorucaochu?action=daochu">mysql->excel(导出)</a>
</body>
</html>

  当将信息导入服务器时，数据库会获取Excel中的信息并将其加入到数据库，jsp页面信息也会更新，导出时Excel中的信息也会更新到与数据库一致。