Java通过apache poi生成excel实例代码

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();

									 }

									}