java poi 对excel的读写

package com.ming.poi;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.poifs.filesystem.POIFSFileSystem;

public class ToExcel {
public static void main(String[] args) throws Exception {
//      ToExcel.writeExcel();
ToExcel.readExcel();
}

public static List<Student> getStudent() throws Exception {
Student student = null;
List<Student> list = new ArrayList<Student>();
for (int i = 0; i < 10; i++) {
student = new Student(i + "", "小明" + i, 80 + i + "");
list.add(student);
}
return list;
}

public static void writeExcel() throws Exception {
// 1.创建一个webbook，对应一个excel
HSSFWorkbook workbook = new HSSFWorkbook();
// 2.在webbook中添加一个sheet,对应Excel文件中的sheet
HSSFSheet sheet = workbook.createSheet();
// 3.创建表头
HSSFRow row = sheet.createRow(0);
// 4.创建单元格，并设置值表头 设置表头居中
HSSFCellStyle style = workbook.createCellStyle();
style.setAlignment(HSSFCellStyle.ALIGN_CENTER);// 单元格居中
HSSFCell cell = null;
String[] header = { "学号", "姓名", "成绩" };
for (int i = 0; i < header.length; i++) {
cell = row.createCell(i);
cell.setCellStyle(style);
cell.setCellValue(header[i]);
}
List<Student> list = ToExcel.getStudent();
for (int i = 0; i < list.size(); i++) {
row = sheet.createRow(i + 1);
Student student = list.get(i);
// 5.创建单元格,存数据
row.createCell(0).setCellValue(student.getSno());
;
row.createCell(1).setCellValue(student.getSname());
;
row.createCell(2).setCellValue(student.getSgrade());
;
}
OutputStream stream = new FileOutputStream("e://ming.xls");
// 6.导出excel
workbook.write(stream);
stream.flush();
stream.close();
}

public static void readExcel() {
FileInputStream in;
List<Student> list = new ArrayList<Student>();
Student student = null;
try {
// 通过流，读取excel文件 ，转化成excel
in = new FileInputStream("e://ming.xls");
HSSFWorkbook workbook = new HSSFWorkbook(in);
for (int i = 0; i < workbook.getNumberOfSheets(); i++) {
HSSFSheet sheet = workbook.getSheetAt(i);
if (sheet == null) {
continue;
}
for (int j = 0; j <=sheet.getLastRowNum(); j++) {
HSSFRow row = sheet.getRow(j);
if (row != null) {
student = new Student(row.getCell(0)
.getStringCellValue(), row.getCell(1)
.getStringCellValue(), row.getCell(2)
.getStringCellValue());
list.add(student);
}
}

}
for (Student stu : list) {
System.out.println(stu.getSname());
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}

}
}

package com.ming.poi;

import java.io.Serializable;

publ
d52b
ic class Student implements Serializable {
private String sno;
private String sname;
private String sgrade;

public Student() {
}
public Student(String sno, String sname, String sgrade) {
super();
this.sno = sno;
this.sname = sname;
this.sgrade = sgrade;
}
public String getSno() {
return sno;
}
public void setSno(String sno) {
this.sno = sno;
}
public String getSname() {
return sname;
}
public void setSname(String sname) {
this.sname = sname;
}
public String getSgrade() {
return sgrade;
}
public void setSgrade(String sgrade) {
this.sgrade = sgrade;
}

}