转自：https://www.jb51.net/article/95526.htm
介绍
Jakarta POI 是一套用于访问微软格式文档的Java API。Jakarta POI有很多组件组成，其中有用于操作Excel格式文件的HSSF和用于操作Word的HWPF，在各种组件中目前只有用于操作Excel的HSSF相对成熟。官方主页http://poi.apache.org/index.html，API文档http://poi.apache.org/apidocs/index.html
实现
已经在代码中加入了完整的注释。
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import
java.io.FileInputStream;
import
java.io.FileOutputStream;
import
java.io.InputStream;
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;
public
class
ExcelOperate {
public
static
void
main(String[] args) {
// 创建Excel表格
createExcel(getStudent());
// 读取Excel表格
List<Student> list = readExcel();
System.out.println(list.toString());
}
/**
* 初始化数据
*
* @return 数据
*/
private
static
List<Student> getStudent() {
List<Student> list =
new
ArrayList<Student>();
Student student1 =
new
Student(
"小明"
,
8
,
"二年级"
);
Student student2 =
new
Student(
"小光"
,
9
,
"三年级"
);
Student student3 =
new
Student(
"小花"
,
10
,
"四年级"
);
list.add(student1);
list.add(student2);
list.add(student3);
return
list;
}
/**
* 创建Excel
*
* @param list
* 数据
*/
private
static
void
createExcel(List<Student> list) {
// 创建一个Excel文件
HSSFWorkbook workbook =
new
HSSFWorkbook();
// 创建一个工作表
HSSFSheet sheet = workbook.createSheet(
"学生表一"
);
// 添加表头行
HSSFRow hssfRow = sheet.createRow(
0
);
// 设置单元格格式居中
HSSFCellStyle cellStyle = workbook.createCellStyle();
cellStyle.setAlignment(HSSFCellStyle.ALIGN_CENTER);
// 添加表头内容
HSSFCell headCell = hssfRow.createCell(
0
);
headCell.setCellValue(
"姓名"
);
headCell.setCellStyle(cellStyle);
headCell = hssfRow.createCell(
1
);
headCell.setCellValue(
"年龄"
);
headCell.setCellStyle(cellStyle);
headCell = hssfRow.createCell(
2
);
headCell.setCellValue(
"年级"
);
headCell.setCellStyle(cellStyle);
// 添加数据内容
for
(
int
i =
0
; i < list.size(); i++) {
hssfRow = sheet.createRow((
int
) i +
1
);
Student student = list.get(i);
// 创建单元格，并设置值
HSSFCell cell = hssfRow.createCell(
0
);
cell.setCellValue(student.getName());
cell.setCellStyle(cellStyle);
cell = hssfRow.createCell(
1
);
cell.setCellValue(student.getAge());
cell.setCellStyle(cellStyle);
cell = hssfRow.createCell(
2
);
cell.setCellValue(student.getGrade());
cell.setCellStyle(cellStyle);
}
// 保存Excel文件
try
{
OutputStream outputStream =
new
FileOutputStream(
"D:/students.xls"
);
workbook.write(outputStream);
outputStream.close();
}
catch
(Exception e) {
e.printStackTrace();
}
}
/**
* 读取Excel
*
* @return 数据集合
*/
private
static
List<Student> readExcel() {
List<Student> list =
new
ArrayList<Student>();
HSSFWorkbook workbook =
null
;
try
{
// 读取Excel文件
InputStream inputStream =
new
FileInputStream(
"D:/students.xls"
);
workbook =
new
HSSFWorkbook(inputStream);
inputStream.close();
}
catch
(Exception e) {
e.printStackTrace();
}
// 循环工作表
for
(
int
numSheet =
0
; numSheet < workbook.getNumberOfSheets(); numSheet++) {
HSSFSheet hssfSheet = workbook.getSheetAt(numSheet);
if
(hssfSheet ==
null
) {
continue
;
}
// 循环行
for
(
int
rowNum =
1
; rowNum <= hssfSheet.getLastRowNum(); rowNum++) {
HSSFRow hssfRow = hssfSheet.getRow(rowNum);
if
(hssfRow ==
null
) {
continue
;
}
// 将单元格中的内容存入集合
Student student =
new
Student();
HSSFCell cell = hssfRow.getCell(
0
);
if
(cell ==
null
) {
continue
;
}
student.setName(cell.getStringCellValue());
cell = hssfRow.getCell(
1
);
if
(cell ==
null
) {
continue
;
}
student.setAge((
int
) cell.getNumericCellValue());
cell = hssfRow.getCell(
2
);
if
(cell ==
null
) {
continue
;
}
student.setGrade(cell.getStringCellValue());
list.add(student);
}
}
return
list;
}
}
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附上Student类的代码
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public
class
Student {
private
String name;
private
int
age;
private
String grade;
public
Student() {
}
public
Student(String name,
int
age, String grade) {
super
();
this
.name = name;
this
.age = age;
this
.grade = grade;
}
public
String getName() {
return
name;
}
public
void
setName(String name) {
this
.name = name;
}
public
int
getAge() {
return
age;
}
public
void
setAge(
int
age) {
this
.age = age;
}
public
String getGrade() {
return
grade;
}
public
void
setGrade(String grade) {
this
.grade = grade;
}
@Override
public
String toString() {
return
"Student [name="
+ name +
", age="
+ age +
", grade="
+ grade
+
"]"
;
}
}
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测试结果
导出的Excel表格
students
打印读取的Excel数据
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1
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[Student [name=小明, age=
8
, grade=二年级], Student [name=小光, age=
9
, grade=三年级], Stu
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