java的poi技术写Excel的Sheet
Posted Hongten
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在这之前写过关于java读，写Excel的blog如下：
java的poi技术读，写Excel[2003-2007,2010]
java的poi技术读取Excel[2003-2007,2010]
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：
1 Workbook wb = new HSSFWorkbook(); // or new XSSFWorkbook(); 2 Sheet sheet1 = wb.createSheet("new sheet"); 3 Sheet sheet2 = wb.createSheet("second sheet"); 4 5 6 // You can use org.apache.poi.ss.util.WorkbookUtil#createSafeSheetName(String nameProposal)} 7 // for a safe way to create valid names, this utility replaces invalid characters with a space (\' \') 8 String safeName = WorkbookUtil.createSafeSheetName("[O\'Brien\'s sales*?]"); // returns " O\'Brien\'s sales " 9 Sheet sheet3 = wb.createSheet(safeName); 10 11 FileOutputStream fileOut = new FileOutputStream("workbook.xls"); 12 wb.write(fileOut); 13 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.
1 -- Table "t_school" DDL 2 3 CREATE TABLE `t_school` ( 4 `no` int(16) NOT NULL AUTO_INCREMENT, 5 `name` varchar(50) COLLATE utf8_bin NOT NULL, 6 `desc` varchar(500) COLLATE utf8_bin DEFAULT NULL, 7 `ranking` int(3) DEFAULT NULL, 8 `address` varchar(200) COLLATE utf8_bin DEFAULT NULL, 9 PRIMARY KEY (`no`) 10 ) ENGINE=InnoDB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8 COLLATE=utf8_bin; 11 12 -- Table "t_student" DDL 13 14 CREATE TABLE `t_student` ( 15 `student_no` int(16) NOT NULL AUTO_INCREMENT, 16 `school_no` int(16) NOT NULL, 17 `name` varchar(100) COLLATE utf8_bin DEFAULT NULL, 18 `address` varchar(200) COLLATE utf8_bin DEFAULT NULL, 19 `birthdate` varchar(15) COLLATE utf8_bin DEFAULT NULL, 20 `phone` varchar(15) COLLATE utf8_bin DEFAULT NULL, 21 PRIMARY KEY (`student_no`,`school_no`), 22 KEY `school_no` (`school_no`), 23 CONSTRAINT `school_no` FOREIGN KEY (`school_no`) REFERENCES `t_school` (`no`) 24 ) 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
1 package com.b510.hongten.client; 2 3 import java.util.List; 4 5 import com.b510.hongten.db.SchoolDAO; 6 import com.b510.hongten.excel.WriteExcel; 7 import com.b510.hongten.vo.School; 8 9 /** 10 * @author hongten 11 * @created Jun 16, 2016 12 */ 13 public class Client { 14 15 public static void main(String[] args) { 16 List<School> schools = SchoolDAO.getSchools(); 17 WriteExcel writeExcel = new WriteExcel(); 18 writeExcel.writeExcel(schools); 19 } 20 21 }
/ExcelHandler/src/com/b510/hongten/common/Common.java
1 package com.b510.hongten.common; 2 3 /** 4 * @author hongten 5 * @created Jun 16, 2016 6 */ 7 public class Common { 8 9 // MySQL database connection configuration, you could write in *.properties 10 // file as also. For this demo, we write this configuration in this class 11 // file. By the way, I don\'t recommend this way ^_^. 12 public static String URL = "jdbc:mysql://localhost:3306/school"; 13 public static String USER_NAME = "root"; 14 public static String PASSWORD = "password1"; 15 16 public static String TARGET_FILE_PATH = "lib/excel_resources/school.xls"; 17 18 public static String SUMMARY = "Shool Summary"; 19 public static String[] TITLES = { "S/N", "Name", "Description", "Ranking", "Address" }; 20 public static String[] STUDENT_TITLE = { "S/N", "Name", "Birth Date", "Phone", "Address" }; 21 }
/ExcelHandler/src/com/b510/hongten/db/ConnectionUtil.java
1 package com.b510.hongten.db; 2 3 import java.sql.Connection; 4 import java.sql.DriverManager; 5 import java.sql.SQLException; 6 7 import org.apache.log4j.Logger; 8 9 import com.b510.hongten.common.Common; 10 11 /** 12 * @author hongten 13 * @created Jun 16, 2016 14 */ 15 public class ConnectionUtil { 16 17 static Logger logger = Logger.getLogger(ConnectionUtil.class); 18 19 public static Connection getConn() { 20 logger.debug("-------- MySQL JDBC Connection Testing ------------"); 21 22 Connection connection = null; 23 try { 24 Class.forName("com.mysql.jdbc.Driver"); 25 } catch (ClassNotFoundException e) { 26 logger.error("Where is your MySQL JDBC Driver?"); 27 e.printStackTrace(); 28 } 29 30 logger.info("MySQL JDBC Driver Registered!"); 31 32 try { 33 connection = DriverManager.getConnection(Common.URL, Common.USER_NAME, Common.PASSWORD); 34 if(connection != null){ 35 logger.info("connecte successfully!"); 36 } 37 } catch (SQLException e) { 38 logger.error("Connection Failed! Check output console"); 39 e.printStackTrace(); 40 } 41 return connection; 42 43 } 44 45 public static void closeConn(Connection conn) { 46 if (conn != null) { 47 try { 48 logger.info("closing connection begin!"); 49 conn.close(); 50 logger.info("closing connection end!"); 51 } catch (SQLException e) { 52 e.printStackTrace(); 53 } 54 } else { 55 logger.info("connection is not null!"); 56 } 57 } 58 }
/ExcelHandler/src/com/b510/hongten/db/SchoolDAO.java
1 package com.b510.hongten.db; 2 3 import java.sql.Connection; 4 import java.sql.ResultSet; 5 import java.sql.SQLException; 6 import java.util.ArrayList; 7 import java.util.List; 8 9 import org.apache.log4j.Logger; 10 11 import com.b510.hongten.vo.School; 12 import com.b510.hongten.vo.Student; 13 import com.mysql.jdbc.PreparedStatement; 14 15 /** 16 * @author hongten 17 * @created Jun 16, 2016 18 */ 19 public class SchoolDAO { 20 21 static Logger logger = Logger.getLogger(SchoolDAO.class); 22 23 public static List<School> getSchools() { 24 Connection conn = null; 25 PreparedStatement preparedStatement = null, preStat = null; 26 ResultSet rs = null, rs_student = null; 27 List<School> schools = new ArrayList<School>(); 28 29 try { 30 conn = ConnectionUtil.getConn(); 31 String sql = "select * from t_school order by no"; 32 preparedStatement = (PreparedStatement) conn.prepareStatement(sql); 33 rs = preparedStatement.executeQuery(); 34 while (rs.next()) { 35 int school_no = rs.getInt(1); 36 if (school_no > 0) { 37 School school = new School(); 38 school.setNo(school_no); 39 school.setName(rs.getString("name")); 40 school.setAddrss(rs.getString("address")); 41 school.setDesc(rs.getString("desc")); 42 school.setRanking(rs.getString("ranking")); 43 44 String studentSQL = "select * from t_student where school_no = ? "; 45 preStat = (PreparedStatement) conn.prepareStatement(studentSQL); 46 preStat.setInt(1, school_no); 47 rs_student = preStat.executeQuery(); 48 List<Student> students = new ArrayList<>(); 49 while (rs_student.next()) { 50 Student student = new Student(); 51 int std_no = rs_student.getInt(1); 52 student.setStudentNo(std_no); 53 student.setName(rs_student.getString("name")); 54 student.setBirthdate(rs_student.getString("birthdate")); 55 student.setPhone(rs_student.getString("phone")); 56 student.setAddress(rs.getString("address")); 57 students.add(student); 58 } 59 school.setStudents(students); 60 schools.add(school); 61 } 62 } 63 } catch (SQLException e) { 64 e.printStackTrace(); 65 logger.error(e.getMessage()); 66 } finally { 67 if (rs != null) { 68 try { 69 rs.close(); 70 } catch (SQLException e) { 71 e.printStackTrace(); 72 } 73 } 74 if (preparedStatement != null) { 75 try { 76 preparedStatement.close(); 77 } catch (SQLException e) { 78 e.printStackTrace(); 79 } 80 } 81 ConnectionUtil.closeConn(conn); 82 } 83 return schools; 84 } 85 }
/ExcelHandler/src/com/b510/hongten/excel/WriteExcel.java
1 package com.b510.hongten.excel; 2 3 import java.io.FileNotFoundException; 4 import java.io.FileOutputStream; 5 import java.io.IOException; 6 import java.util.List; 7 8 import org.apache.log4j.Logger; 9 import org.apache.poi.hssf.usermodel.HSSFWorkbook; 10 import org.apache.poi.ss.usermodel.Cell; 11 import org.apache.poi.ss.usermodel.Row; 12 import org.apache.poi.ss.usermodel.Sheet; 13 import org.apache.poi.ss.usermodel.Workbook; 14 15 import com.b510.hongten.common.Common; 16 import com.b510.hongten.vo.School; 17 import com.b510.hongten.vo.Student; 18 19 /** 20 * @author hongten 21 * @created Jun 13, 2016 22 */ 23 public class WriteExcel { 24 25 static Logger logger = Logger.getLogger(WriteExcel.class); 26 27 public void writeExcel(List<School> schools) { 28 if (schools == null || schools.size() == 0) { 29 return; 30 } 31 FileOutputStream fileOut = null; 32 Workbook wb = new HSSFWorkbook(); 33 Sheet shool_sheet = wb.createSheet(Common.SUMMARY); 34 shool_sheet.setAutobreaks(true); 35 // Create a row and put some cells in it. Rows are 0 based. 36 Row row = shool_sheet.createRow(0); 37 String[] titles = Common.TITLES; 38 int num = 0; 39 for (String title : titles) { 40 // Create a cell 41 Cell cell = row.createCell(num++); 42 cell.setCellValue(title); 43 } 44 int rowNum = 1; 45 for (School school : schools) { 46 row = shool_sheet.createRow(rowNum++); 47 Cell cell = row.createCell(0); 48 cell.setCellValue(school.getNo()); 49 cell = row.createCell(1); 50 cell.setCellValue(school.getName()); 51 cell = row.createCell(2); 52 cell.setCellValue(school.getDesc()); 53 cell = row.createCell(3); 54 cell.setCellValue(school.getRanking()); 55 cell = row.createCell(4); 56 cell.setCellValue(school.getAddrss()); 57 58 List<Student> students = school.getStudents(); 59 if (students != null && students.size() > 0) { 60 Sheet student_sheet = wb.createSheet(school.getName()); 61 student_sheet.setAutobreaks(true); 62 // Create a row and put some cells in it. Rows are 0 based. 63 Row student_row = student_sheet.createRow(0); 64 String[] student_titles = Common.STUDENT_TITLE; 65 num = 0; 66 for (String title : student_titles) { 67 // Create a cell 68 Cell student_cell = student_row.createCell(num++); 69 student_cell.setCellValue(title); 70 } 71 int stuRowNum = 1; 72 for (Student student : students) { 73 student_row = student_sheet.createRow(stuRowNum++); 74 Cell student_cell = student_row.createCell(0); 75 student_cell.setCellValue(student.getStudentNo()); 76 student_cell = student_row.createCell(1); 77 student_cell.setCellValue(student.getName()); 78 student_cell = student_row.createCell(2); 79 student_cell.setCellValue(student.getBirthdate()); 80 student_cell = student_row.createCell(3); 81 student_cell.setCellValue(student.getPhone()); 82 student_cell = student_row.createCell(4); 83 student_cell.setCellValue(student.getAddress()); 84 } 85 } 86 } 87 88 try { 89 fileOut = new FileOutputStream(Common.TARGET_FILE_PATH); 90 } catch (FileNotFoundException e) { 91 e.printStackTrace(); 92 } 93 try { 94 wb.write(fileOut); 95 } catch (IOException e1) { 96 e1.printStackTrace(); 97 } 98 try { 99 fileOut.close(); 100 } catch (IOException e) { 101 e.printStackTrace(); 102 } 103 logger.info("done"); 104 } 105 106 }
/ExcelHandler/src/com/b510/hongten/vo/School.java
1 package com.b510.hongten.vo; 2 3 import java.util.ArrayList; 4 import java.util.List; 5 6 /** 7 * @author hongten 8 * @created Jun 16, 2016 9 */ 10 public class School { 11 12 private int no; 13 private String name; 14 private String desc; 15 private String ranking; 16 private String addrss; 17 18 private List<Student> students = new ArrayList<Student>(); 19 20 public int getNo() { 21 return no; 22 } 23 24 public void setNo(int no) { 25 this.no = no; 26 } 27 28 public String getName() { 29 return name; 30 } 31 32 public void setName(String name) { 33 this.name = name; 34 } 35 36 public String getDesc() { 37 return desc; 38 } 39 40 public void setDesc(String desc) { 41 this.desc = desc; 42 } 43 44 public String getRanking() { 45 return ranking; 46 } 47 48 public void setRanking(String ranking) { 49 this.ranking = ranking; 50 } 51 52 public String getAddrss() { 53 return addrss; 54 } 55 56 public void setAddrss(String addrss) { 57 this.addrss = addrss; 58 } 59 60 public List<以上是关于java的poi技术写Excel的Sheet的主要内容，如果未能解决你的问题，请参考以下文章
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