POI打印Excel报表

1.将POI组件中的jar包放入项目中路径下的WEB-INF/lib目录中

2.在javabean中创建一个poi的java文件,中间出了创建getXXX(),setXXX()方法外,加入readRecord(int rsRow)方法,返回值是list集合(需要遍历);

3.必须创建一个HSSFSheet实例，使用POI组件中的createSheet("sheetname")创建工作表，根据显示内容大小创建指定大小的单元格。

4.最后创建一JSP页面在看到合同的同时还能打印下载到Excel

首先将POI组件中的jar包放入项目中路径下的WEB-INF/lib目录中，然后便可以在JSP中使用POI组件了。

新建一数据库连接类Conn.java，代码如下：

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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();         }     } }

为了将从数据库中取出的数据放入List,创建JavaBean,命名为POITest.java;这个JavaBean除了setXXX()和getXXX()方法之外，还有一个根据用户需要显示的行数从数据库中取值ReadRecord(int rsRow)方法，它的返回值类型是List集合，程序代码如下：

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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();                     //连接数据库          String sql="select * from student";       //查询学生信息          ResultSet rs=conn.executeQuery(sql);      //执行查询          List l=new ArrayList();                   //定义List集合                        try{                    while(rs.next()){                      POITest p=new POITest();       //实例化对象                      p.setId(rs.getInt("id"));      //为对象赋值                      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);                      //将对象添加到List集合中                                       }                 conn.close();                       //关闭数据库             }catch(Exception e){                 e.printStackTrace();             }             return l;                               //返回集合                    }      /*       * 为了添加工作表，必须创建一个HSSFSheet实例，使用POI组件中的createSheet("sheetname")创建工作表，根据显示内容大小创建指定大小的单元格。       * 程序代码如下：       *       */      public void WriteCell(int rsRow){          HSSFWorkbook wb=new HSSFWorkbook();          HSSFSheet sheet=wb.createSheet("poiexample");//建立名为poiexample的报表          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++){                //遍历每行的每列              cell[i]=row.createCell(i);          }          cell[0].setCellValue("id号");         //在单元格写入文字          cell[1].setCellValue("学号");          cell[2].setCellValue("姓名");          cell[3].setCellValue("性别");          cell[4].setCellValue("系别");          cell[5].setCellValue("专业");          cell[6].setCellValue("班级");          cell[7].setCellValue("电话");          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();          }      } }

最后创建一JSP页面，命名为PoiTest.jsp;程序代码如下：

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<%@ 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>学生管理系统</title> </head> <script type="text/javascript" language="javascript">       function fn1(){          <%poi.WriteCell(9); %>          alert("导出报表完毕！导出位置为e:\\workbook.xls！！！");       } </script> <body> <table border="1"> <tr><td>ID号</td><td>学号</td><td>姓名</td><td>性别</td><td>系别</td><td>专业</td><td>班级</td><td>电话</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="导出报表" onClick='fn1()'/> </body> </html>

重启Tomcat服务器，在IE浏览器中运行JSP页面；效果如下：

单击“导出报表”按钮，出现一个提示框

打开E盘，可以看到已经生成一个名为workbook.xls的文件，打开此文件，如下：