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

---------------------------------------------

/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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I'm Hongten



E | hongtenzone@foxmail.com B | http://www.cnblogs.com/hongten

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