poi 学习之使用 Apche poi 读取数据库中的数据并写入Excel

Apche  poi  读取数据库中的数据并写入  Excel

之前写了一篇 poi 读写 excel 的简单demo，但考虑到实际项目中，主要还是对将数据库中的数据进行写入excel，所以练习了一个也是比较简单的demo。

首先：

数据库：

创建一个数据库连接的Util类

DBConnectionUtil.java

package com.poi.org;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;public class DBConnectionUtil {private static Connection conn = null;private static String Driver = "com.mysql.jdbc.Driver";private static String url = "jdbc:mysql://localhost/quechao?useUnicode=true&characterEncoding=utf8";private static String userName = "root";private static String password = "123456";public static Connection getConnection(){try {Class.forName(Driver);conn = DriverManager.getConnection(url, userName, password);} catch (ClassNotFoundException e) {e.printStackTrace();}catch (SQLException e) {e.printStackTrace();}return conn;}public static void closeDB(ResultSet rs, Statement st, Connection conn){try {if(rs != null) rs.close(); rs = null;if(st != null) st.close(); st = null;if(conn != null) conn.close(); conn = null;} catch (SQLException e) {e.printStackTrace();}}}

实体类 Hospital.java

package com.poi.model;public class Hospital {private Integer id;    private String hospitalOn;    private String province;    private String city;    private String title;public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getHospitalOn() {return hospitalOn;}public void setHospitalOn(String hospitalOn) {this.hospitalOn = hospitalOn;}public String getProvince() {return province;}public void setProvince(String province) {this.province = province;}public String getCity() {return city;}public void setCity(String city) {this.city = city;}public String getTitle() {return title;}public void setTitle(String title) {this.title = title;}}

测试类QueryHospital.java

package com.poi.test;import java.io.File;import java.io.FileOutputStream;import java.sql.Connection;import java.sql.ResultSet;import java.sql.Statement;import java.util.ArrayList;import java.util.List;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;import com.poi.model.Hospital;import com.poi.org.DBConnectionUtil;public class QueryHospital {public static List<Hospital> selectHospital()throws Exception{Connection conn = null;ResultSet rs = null;Statement st = null;String sql = "select * from hospital";conn = DBConnectionUtil.getConnection();List<Hospital> list = new ArrayList<Hospital>();try {st = conn.createStatement();rs = st.executeQuery(sql);while(rs.next()){Hospital hospital = new Hospital();//hospital.setId(rs.getInt("id"));hospital.setId(rs.getInt(1));//hospital.setHospitalOn(String.valueOf(rs.getInt("hospitalOn")));hospital.setHospitalOn(rs.getString(2));hospital.setProvince(rs.getString(3));hospital.setCity(rs.getString(4));//hospital.setTitle(String.valueOf(rs.getInt("title")));hospital.setTitle(rs.getString(5));list.add(hospital);}} catch (Exception e) {e.printStackTrace();}finally{DBConnectionUtil.closeDB(rs, st, conn);}return list;}public void createExcel()throws Exception{HSSFWorkbook workBook = new HSSFWorkbook();HSSFSheet sheet = workBook.createSheet("第一页");sheet.setColumnWidth(0, 2500);sheet.setColumnWidth(1, 5000);HSSFRow row = sheet.createRow(0);HSSFCell cell[] = new HSSFCell[5];for(int i = 0; i < 5; i++){cell[i] = row.createCell(i);}cell[0].setCellValue("id");cell[1].setCellValue("hospitalOn");cell[2].setCellValue("province");cell[3].setCellValue("city");cell[4].setCellValue("title");List<Hospital> list = QueryHospital.selectHospital();if(list != null && list.size() > 0){for(int i = 0; i < list.size(); i++){Hospital hospital = list.get(i);HSSFRow dataRow = sheet.createRow(i+1);HSSFCell dataCell[] = new HSSFCell[5];for(int j = 0; j < 5; j++){dataCell[j] = dataRow.createCell(j);}dataCell[0].setCellValue(hospital.getId());dataCell[1].setCellValue(hospital.getHospitalOn());dataCell[2].setCellValue(hospital.getProvince());dataCell[3].setCellValue(hospital.getCity());dataCell[4].setCellValue(hospital.getTitle());File file = new File("E:\\hospital.xls");FileOutputStream fos = new FileOutputStream(file);workBook.write(fos);fos.close();}}}public static void main(String[] args)throws Exception {QueryHospital queryHospital = new QueryHospital();queryHospital.createExcel();}}

考虑到每个人项目中用的持久层技术（Hibernate、Mybatis等）会有不同，所以这里用的jdbc，后续抽时间会再写一个读取Excel并写入数据库的demo。

注：以上所写部分来自网络以及自己学习时所记录，若有高人指点，必虚心学习。