本篇文章主要介绍了Java通过apache poi生成excel实例代码，小编觉得挺不错的，现在分享给大家，也给大家做个参考。一起跟随小编过来看看吧
首先,jar
maven 添加依赖
<!-- https://mvnrepository.com/artifact/org.apache.poi/poi-ooxml --> <dependency> <groupId>org.apache.poi</groupId> <artifactId>poi-ooxml</artifactId> <version>3.15</version> </dependency>
开始以为是poi，然后就直接加poi的依赖，谁知道并没有所需要的类。查了查才发现是poi-ooxml
要用到的类
XSSFWorkbook ， 代表一个excel文档
XSSFSheet ， 代表文档中的一个sheet
XSSFRow ， 代表sheet中的一行
XSSFCell ， 代表row中的每一项的值
最最基本的使用
//创建excel文档
XSSFWorkbook workbook = new XSSFWorkbook();
//创建sheet
XSSFSheet sheet = workbook.createSheet("sheetName");
int rownum=0;
//创建首行
XSSFRow firstrow = sheet.createRow(rownum++);
int cellnum = 0;
//把保存在titles中的各个列名，分别在row中创建cell
for(String key : titles){
XSSFCell cell = firstrow.createCell(cellnum++);
cell.setCellValue(key);
}
//下面可以继续创建行
//把excel写到要写的outputStream中
workbook.write(output);
//最后关闭
workbook.close();小例子一枚
利用反射，把bean类中各属性（用getXxx取出），写入到excel中
ExcelUtil.java
package me.paul.excelDemo;
import java.io.IOException;
import java.io.OutputStream;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
public class ExcelUtil {
public <T> void getExcel(List<T> list,Class<T> c,OutputStream output) throws IOException, IllegalAccessException, IllegalArgumentException, InvocationTargetException{
Map<String,Method> methodMap = new LinkedHashMap<>();
Method[] methods = c.getDeclaredMethods();
for(int i=0;i<methods.length;i++){
Method method = methods[i];
String name = method.getName();
Pattern pattern = Pattern.compile("get(.*)");
Matcher matcher = null;
if((matcher = pattern.matcher(name)).matches()){
name = matcher.group(1);
char ch = name.charAt(0);
char newch = (char) (ch + 32);
name = name.replace(ch,newch);
methodMap.put(name, method);
}
}
XSSFWorkbook workbook = new XSSFWorkbook();
XSSFSheet sheet = workbook.createSheet(c.getCanonicalName());
int rownum=0;
XSSFRow firstrow = sheet.createRow(rownum++);
int cellnum = 0;
for(String key : methodMap.keySet()){
XSSFCell cell = firstrow.createCell(cellnum++);
cell.setCellValue(key);
}
for(T t : list){
XSSFRow row = sheet.createRow(rownum++);
cellnum = 0;
for(String key:methodMap.keySet()){
Method method = methodMap.get(key);
//设置可访问，之前不知道这方法，所以关于反射那篇文章有错误，见谅见谅
method.setAccessible(true);
Object obj = method.invoke(t);
XSSFCell cell = row.createCell(cellnum++);
cell.setCellValue(obj== null ? "":obj.toString());
}
}
workbook.write(output);
workbook.close();
}
}App.java 进行测试使用
package me.paul.excelDemo;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.List;
public class App {
public static void main(String[] args) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException, IOException {
List<User> list = new ArrayList<>();
User u = new User();
u.setId(1);
u.setName("Paul");
u.setAge(18);
list.add(u);
u = new User();
u.setId(2);
u.setName("Johnson");
u.setAge(20);
list.add(u);
u = new User();
u.setId(3);
u.setName("David");
u.setAge(22);
list.add(u);
OutputStream output = new FileOutputStream("/home/paul/user.xlsx");
new ExcelUtil().getExcel(list, User.class,output);
output.close();
}
}测试结果截图
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