通过注解反射对导出excel进行封装

1：先定义excel导出的注解

package com.example.demo.Annotation;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
public @interface Exceld {
	public String name() default "";
}

2：创建对应实体类

package com.example.demo.Main;

import java.util.Date;

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import com.example.demo.Annotation.Exceld;

//EasyExcl学生表

public class Student {
	public Student(){
		
	}
	public Student(Integer id,String name,Integer age){
		this.id=id;
		this.name=name;
		this.age=age;
	}
	@TableId(value = "id",type = IdType.AUTO)
	private Integer id;
	
	@Exceld(name="姓名")
	private String name;
	
	@Exceld(name="年龄")
	private Integer age;

	
	@Exceld(name="生日")
	private Date date;
	
	public Integer getId() {
		return id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	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 Date getDate() {
		return date;
	}
	public void setDate(Date date) {
		this.date = date;
	}
	
}

3：核心代码一:解析传入的list为List<List<Object>>只对时间类型进行yyyy-MM-dd进行转化，可以自行根据情况进行调整
 

public static List<List<Object>> getList(List<?> list) throws IllegalArgumentException, IllegalAccessException {
		SimpleDateFormat df=new SimpleDateFormat("yyyy-MM-dd");
		List<List<Object>> objlist = new ArrayList<>();
		List<Object> obj0 = new ArrayList<>();
		for (Field field : list.get(0).getClass().getDeclaredFields()) {
			Exceld e = field.getAnnotation(Exceld.class);
			if (e == null) {
				continue;
			}
			obj0.add(e == null ? "" : e.name());
		}
		objlist.add(obj0);
		Iterator<?> iter = list.iterator();
		while (iter.hasNext()) {
			Object obj = iter.next();
			final List<Object> obj1 = new ArrayList<>();
			for (Field field : obj.getClass().getDeclaredFields()) {
				field.setAccessible(true);
				Exceld e = field.getAnnotation(Exceld.class);
				if (e == null) {
					continue;
				}
				
				Object Value = field.get(obj);
				if(field.getType()==Date.class&&Value!=null){
					Value=df.format((Date)Value);
				}
				Value = Value == null ? "" : Value;
				obj1.add(Value);
			}
			objlist.add(obj1);
		}
		return  objlist;
	}

4：创建excl ，LIst<List<Object>插入excl表中，样式可以根据需求自己调整
 

public static CellStyle getCellStyleTitle(HSSFWorkbook workbook){
		CellStyle cellStyleTitle = workbook.createCellStyle();
		HSSFFont fontTitle = workbook.createFont();
		fontTitle.setFontHeightInPoints((short) 25); //字体大小
		fontTitle.setFontName("宋体"); //字体
	    fontTitle.setBold(true);
		cellStyleTitle.setFont(fontTitle);
		cellStyleTitle.setAlignment(HorizontalAlignment.CENTER); //水平布局：居中
		cellStyleTitle.setWrapText(true);//设置自动换行
		return cellStyleTitle;
	}
	
	public static CellStyle getCellStyle(HSSFWorkbook workbook){
		CellStyle cellStyle= workbook.createCellStyle();
		HSSFFont font = workbook.createFont();
		font.setFontHeightInPoints((short) 15); //字体大小
		font.setFontName("宋体"); //字体
		cellStyle.setFont(font);
		cellStyle.setFillForegroundColor(IndexedColors.LIME.getIndex());
		cellStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);
		return cellStyle;
	}
	

	public static HSSFWorkbook oupt1(List<?> list) throws Exception {	
		HSSFWorkbook workbook = new HSSFWorkbook();	
		CellStyle cellStyleTitle=getCellStyleTitle(workbook);  //获取大标题样式
		CellStyle cellStyle=getCellStyle(workbook);			   //获取小标题样式
		HSSFSheet sheet = workbook.createSheet("学生表");
		List<List<Object>> lists = getList(list);
		int hb=lists.get(0).size()-1;
		CellRangeAddress region = new CellRangeAddress(0, 0, 0, hb);
		Row rowtitle = sheet.createRow(0);
		rowtitle.createCell(0).setCellValue("学生表");
		rowtitle.getCell(0).setCellStyle(cellStyleTitle);
		sheet.addMergedRegion(region);
		for (int i = 0; i < lists.size(); i++) {
			int line=i+1;
			Row row = sheet.createRow(line);
			for (int j = 0; j < lists.get(i).size(); j++) {
				row.createCell(j).setCellValue(lists.get(i).get(j).toString());			
				if(i==0){
				System.out.println(lists.get(i).get(j).toString());
				row.getCell(j).setCellStyle(cellStyle);	
				}
			
			}

		}
		return workbook;
	}

5：最后一步运行Main方法导出
 

public static void main(String[] args) throws Exception {
		Student stu = new Student(1, "张三", 33);
		Student stu1 = new Student(2, "李四", 22);
		Student stu2 = new Student(3, null, 33);
		Student stu3 = new Student(4, "孙六", 24);
		stu.setDate(new Date());
		List<Student> stus = new ArrayList<Student>();
		stus.add(stu);
		stus.add(stu1);
		stus.add(stu2);
		stus.add(stu3);
		//getField(stus);
		HSSFWorkbook work = oupt1(stus);
		work.write(new File("d:/x.xls"));

	}