java的poi技术写Excel的Sheet

在这之前写过关于java读，写Excel的blog如下：

Excel转Html

java的poi技术读，写Excel[2003-2007,2010]

java的poi技术读取Excel[2003-2007,2010]

java的poi技术读取Excel数据到MySQL

java的jxl技术导入Excel

java的poi技术读取和导入Excel

然而，这篇blog主要内容是关于Excel里面怎样去写Sheet数据。

那么在Excel里面什么叫做Sheet呢？如下图红色框里面的内容就是Excel的Sheet了。

我们需要知道怎样创建一个Sheet，下面是一个Sample：

 Workbook wb = new HSSFWorkbook();  // or new XSSFWorkbook();
 Sheet sheet1 = wb.createSheet("new sheet");
 Sheet sheet2 = wb.createSheet("second sheet");

 // You can use org.apache.poi.ss.util.WorkbookUtil#createSafeSheetName(String nameProposal)}
 // for a safe way to create valid names, this utility replaces invalid characters with a space (' ')
 String safeName = WorkbookUtil.createSafeSheetName("[O'Brien's sales*?]"); // returns " O'Brien's sales   "
 Sheet sheet3 = wb.createSheet(safeName);

 FileOutputStream fileOut = new FileOutputStream("workbook.xls");
 wb.write(fileOut);
 fileOut.close();

看了以后，会不会觉得So easy！这是因为Apache的poi给我们封装了很多方法，提供了很好的接口。

下面是我做的一个Demo，这个Demo的数据流如下：

MySQL数据库 -- > Demo 程序 -- > Excel 文件

我们的Demo程序会从MySQL数据库中读取数据，然后把数据写入到Excel文件中。

项目结构：

注意：红色框里面的jar包，你在下载源码后，这些jar包不会存放到源码里面，需要手动下载！

在MySQL数据库中，我们会用到两张表： t_school, t_student.

 -- Table "t_school" DDL

 CREATE TABLE `t_school` (
   `no` int(16) NOT NULL AUTO_INCREMENT,
   `name` varchar(50) COLLATE utf8_bin NOT NULL,
   `desc` varchar(500) COLLATE utf8_bin DEFAULT NULL,
   `ranking` int(3) DEFAULT NULL,
   `address` varchar(200) COLLATE utf8_bin DEFAULT NULL,
   PRIMARY KEY (`no`)
 ) ENGINE=InnoDB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8 COLLATE=utf8_bin;

 -- Table "t_student" DDL

 CREATE TABLE `t_student` (
   `student_no` int(16) NOT NULL AUTO_INCREMENT,
   `school_no` int(16) NOT NULL,
   `name` varchar(100) COLLATE utf8_bin DEFAULT NULL,
   `address` varchar(200) COLLATE utf8_bin DEFAULT NULL,
   `birthdate` varchar(15) COLLATE utf8_bin DEFAULT NULL,
   `phone` varchar(15) COLLATE utf8_bin DEFAULT NULL,
   PRIMARY KEY (`student_no`,`school_no`),
   KEY `school_no` (`school_no`),
   CONSTRAINT `school_no` FOREIGN KEY (`school_no`) REFERENCES `t_school` (`no`)
 ) ENGINE=InnoDB AUTO_INCREMENT=100000023 DEFAULT CHARSET=utf8 COLLATE=utf8_bin;

在Excel文件中，我们要做的是在'School Summary' Sheet里面写入School的信息，而对于其他的Sheet，我们会把Shool的名称命名为Sheet的Name，然后在每一个Sheet里面写入在这个Shool里面的Student的信息。

两张表里面数据，大家可以通过blog末尾的下载链接获得。

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代码部分

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/ExcelHandler/src/com/b510/hongten/client/Client.java

 package com.b510.hongten.client;

 import java.util.List;

 import com.b510.hongten.db.SchoolDAO;
 import com.b510.hongten.excel.WriteExcel;
 import com.b510.hongten.vo.School;

 /**
  * @author hongten
  * @created Jun 16, 2016
  */
 public class Client {

     public static void main(String[] args) {
         List<School> schools = SchoolDAO.getSchools();
         WriteExcel writeExcel = new WriteExcel();
         writeExcel.writeExcel(schools);
     }

 }

/ExcelHandler/src/com/b510/hongten/common/Common.java

 package com.b510.hongten.common;

 /**
  * @author hongten
  * @created Jun 16, 2016
  */
 public class Common {

     // MySQL database connection configuration, you could write in *.properties
     // file as also. For this demo, we write this configuration in this class
     // file. By the way, I don't recommend this way ^_^.
     public static String URL = "jdbc:mysql://localhost:3306/school";
     public static String USER_NAME = "root";
     public static String PASSWORD = "password1";

     public static String TARGET_FILE_PATH = "lib/excel_resources/school.xls";

     public static String SUMMARY = "Shool Summary";
     public static String[] TITLES = { "S/N", "Name", "Description", "Ranking", "Address" };
     public static String[] STUDENT_TITLE = { "S/N", "Name", "Birth Date", "Phone", "Address" };
 }

/ExcelHandler/src/com/b510/hongten/db/ConnectionUtil.java

 package com.b510.hongten.db;

 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.SQLException;

 import org.apache.log4j.Logger;

 import com.b510.hongten.common.Common;

 /**
  * @author hongten
  * @created Jun 16, 2016
  */
 public class ConnectionUtil {

     static Logger logger = Logger.getLogger(ConnectionUtil.class);

     public static Connection getConn() {
         logger.debug("-------- MySQL JDBC Connection Testing ------------");

         Connection connection = null;
         try {
             Class.forName("com.mysql.jdbc.Driver");
         } catch (ClassNotFoundException e) {
             logger.error("Where is your MySQL JDBC Driver?");
             e.printStackTrace();
         }

         logger.info("MySQL JDBC Driver Registered!");

         try {
             connection = DriverManager.getConnection(Common.URL, Common.USER_NAME, Common.PASSWORD);
             if(connection != null){
                 logger.info("connecte successfully!");
             }
         } catch (SQLException e) {
             logger.error("Connection Failed! Check output console");
             e.printStackTrace();
         }
         return connection;

     }

     public static void closeConn(Connection conn) {
         if (conn != null) {
             try {
                 logger.info("closing connection begin!");
                 conn.close();
                 logger.info("closing connection end!");
             } catch (SQLException e) {
                 e.printStackTrace();
             }
         } else {
             logger.info("connection is not null!");
         }
     }
 }

/ExcelHandler/src/com/b510/hongten/db/SchoolDAO.java

 package com.b510.hongten.db;

 import java.sql.Connection;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.List;

 import org.apache.log4j.Logger;

 import com.b510.hongten.vo.School;
 import com.b510.hongten.vo.Student;
 import com.mysql.jdbc.PreparedStatement;

 /**
  * @author hongten
  * @created Jun 16, 2016
  */
 public class SchoolDAO {

     static Logger logger = Logger.getLogger(SchoolDAO.class);

     public static List<School> getSchools() {
         Connection conn = null;
         PreparedStatement preparedStatement = null, preStat = null;
         ResultSet rs = null, rs_student = null;
         List<School> schools = new ArrayList<School>();

         try {
             conn = ConnectionUtil.getConn();
             String sql = "select * from t_school order by no";
             preparedStatement = (PreparedStatement) conn.prepareStatement(sql);
             rs = preparedStatement.executeQuery();
             while (rs.next()) {
                 int school_no = rs.getInt(1);
                 if (school_no > 0) {
                     School school = new School();
                     school.setNo(school_no);
                     school.setName(rs.getString("name"));
                     school.setAddrss(rs.getString("address"));
                     school.setDesc(rs.getString("desc"));
                     school.setRanking(rs.getString("ranking"));

                     String studentSQL = "select * from t_student where school_no = ? ";
                     preStat = (PreparedStatement) conn.prepareStatement(studentSQL);
                     preStat.setInt(1, school_no);
                     rs_student = preStat.executeQuery();
                     List<Student> students = new ArrayList<>();
                     while (rs_student.next()) {
                         Student student = new Student();
                         int std_no = rs_student.getInt(1);
                         student.setStudentNo(std_no);
                         student.setName(rs_student.getString("name"));
                         student.setBirthdate(rs_student.getString("birthdate"));
                         student.setPhone(rs_student.getString("phone"));
                         student.setAddress(rs.getString("address"));
                         students.add(student);
                     }
                     school.setStudents(students);
                     schools.add(school);
                 }
             }
         } catch (SQLException e) {
             e.printStackTrace();
             logger.error(e.getMessage());
         } finally {
             if (rs != null) {
                 try {
                     rs.close();
                 } catch (SQLException e) {
                     e.printStackTrace();
                 }
             }
             if (preparedStatement != null) {
                 try {
                     preparedStatement.close();
                 } catch (SQLException e) {
                     e.printStackTrace();
                 }
             }
             ConnectionUtil.closeConn(conn);
         }
         return schools;
     }
 }

/ExcelHandler/src/com/b510/hongten/excel/WriteExcel.java

 package com.b510.hongten.excel;

 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.util.List;

 import org.apache.log4j.Logger;
 import org.apache.poi.hssf.usermodel.HSSFWorkbook;
 import org.apache.poi.ss.usermodel.Cell;
 import org.apache.poi.ss.usermodel.Row;
 import org.apache.poi.ss.usermodel.Sheet;
 import org.apache.poi.ss.usermodel.Workbook;

 import com.b510.hongten.common.Common;
 import com.b510.hongten.vo.School;
 import com.b510.hongten.vo.Student;

 /**
  * @author hongten
  * @created Jun 13, 2016
  */
 public class WriteExcel {

     static Logger logger = Logger.getLogger(WriteExcel.class);

     public void writeExcel(List<School> schools) {
         if (schools == null || schools.size() == 0) {
             return;
         }
         FileOutputStream fileOut = null;
         Workbook wb = new HSSFWorkbook();
         Sheet shool_sheet = wb.createSheet(Common.SUMMARY);
         shool_sheet.setAutobreaks(true);
         // Create a row and put some cells in it. Rows are 0 based.
         Row row = shool_sheet.createRow(0);
         String[] titles = Common.TITLES;
         int num = 0;
         for (String title : titles) {
             // Create a cell
             Cell cell = row.createCell(num++);
             cell.setCellValue(title);
         }
         int rowNum = 1;
         for (School school : schools) {
             row = shool_sheet.createRow(rowNum++);
             Cell cell = row.createCell(0);
             cell.setCellValue(school.getNo());
             cell = row.createCell(1);
             cell.setCellValue(school.getName());
             cell = row.createCell(2);
             cell.setCellValue(school.getDesc());
             cell = row.createCell(3);
             cell.setCellValue(school.getRanking());
             cell = row.createCell(4);
             cell.setCellValue(school.getAddrss());

             List<Student> students = school.getStudents();
             if (students != null && students.size() > 0) {
                 Sheet student_sheet = wb.createSheet(school.getName());
                 student_sheet.setAutobreaks(true);
                 // Create a row and put some cells in it. Rows are 0 based.
                 Row student_row = student_sheet.createRow(0);
                 String[] student_titles = Common.STUDENT_TITLE;
                 num = 0;
                 for (String title : student_titles) {
                     // Create a cell
                     Cell student_cell = student_row.createCell(num++);
                     student_cell.setCellValue(title);
                 }
                 int stuRowNum = 1;
                 for (Student student : students) {
                     student_row = student_sheet.createRow(stuRowNum++);
                     Cell student_cell = student_row.createCell(0);
                     student_cell.setCellValue(student.getStudentNo());
                     student_cell = student_row.createCell(1);
                     student_cell.setCellValue(student.getName());
                     student_cell = student_row.createCell(2);
                     student_cell.setCellValue(student.getBirthdate());
                     student_cell = student_row.createCell(3);
                     student_cell.setCellValue(student.getPhone());
                     student_cell = student_row.createCell(4);
                     student_cell.setCellValue(student.getAddress());
                 }
             }
         }

         try {
             fileOut = new FileOutputStream(Common.TARGET_FILE_PATH);
         } catch (FileNotFoundException e) {
             e.printStackTrace();
         }
         try {
             wb.write(fileOut);
         } catch (IOException e1) {
             e1.printStackTrace();
         }
         try {
             fileOut.close();
         } catch (IOException e) {
             e.printStackTrace();
         }
         logger.info("done");
     }

 }

/ExcelHandler/src/com/b510/hongten/vo/School.java

 package com.b510.hongten.vo;

 import java.util.ArrayList;
 import java.util.List;

 /**
  * @author hongten
  * @created Jun 16, 2016
  */
 public class School {

     private int no;
     private String name;
     private String desc;
     private String ranking;
     private String addrss;

     private List<Student> students = new ArrayList<Student>();

     public int getNo() {
         return no;
     }

     public void setNo(int no) {
         this.no = no;
     }

     public String getName() {
         return name;
     }

     public void setName(String name) {
         this.name = name;
     }

     public String getDesc() {
         return desc;
     }

     public void setDesc(String desc) {
         this.desc = desc;
     }

     public String getRanking() {
         return ranking;
     }

     public void setRanking(String ranking) {
         this.ranking = ranking;
     }

     public String getAddrss() {
         return addrss;
     }

     public void setAddrss(String addrss) {
         this.addrss = addrss;
     }

     public List<Student> getStudents() {
         return students;
     }

     public void setStudents(List<Student> students) {
         this.students = students;
     }

 }

/ExcelHandler/src/com/b510/hongten/vo/Student.java

 package com.b510.hongten.vo;

 /**
  * @author hongten
  * @created Jun 16, 2016
  */
 public class Student {

     private int studentNo;
     private String name;
     private String address;
     private String birthdate;
     private String note;
     private String phone;

     public int getStudentNo() {
         return studentNo;
     }

     public void setStudentNo(int studentNo) {
         this.studentNo = studentNo;
     }

     public String getName() {
         return name;
     }

     public void setName(String name) {
         this.name = name;
     }

     public String getAddress() {
         return address;
     }

     public void setAddress(String address) {
         this.address = address;
     }

     public String getBirthdate() {
         return birthdate;
     }

     public void setBirthdate(String birthdate) {
         this.birthdate = birthdate;
     }

     public String getNote() {
         return note;
     }

     public void setNote(String note) {
         this.note = note;
     }

     public String getPhone() {
         return phone;
     }

     public void setPhone(String phone) {
         this.phone = phone;
     }

 }

/ExcelHandler/src/log4j.xml

 <?xml version="1.0" encoding="UTF-8" ?>
 <!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
 <log4j:configuration debug="true"
     xmlns:log4j='http://jakarta.apache.org/log4j/'>

     <appender name="console" class="org.apache.log4j.ConsoleAppender">
         <layout class="org.apache.log4j.PatternLayout">
         <param name="ConversionPattern"
           value="%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n" />
         </layout>
     </appender>

     <root>
         <level value="DEBUG" />
         <appender-ref ref="console" />
     </root>
 </log4j:configuration>

源码下载：

http://files.cnblogs.com/files/hongten/ExcelHandler.rar

测试数据下载：

http://files.cnblogs.com/files/hongten/t_shool_and_t_student_data.rar

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