Java: Excel导入导出

【相关文档】:EasyPoi教程

1. 依赖

        <dependency>
            <groupId>cn.afterturn</groupId>
            <artifactId>easypoi-spring-boot-starter</artifactId>
            <version>4.4.0</version>
        </dependency>

2. 常用注解

@ExcelTarget("xxx")
public class TestPo {

    @Excel(name = "excel中的列名", needMerge = true, dict = "dictName", orderNum = "-3",width = 20)
    private String name;

    @ExcelCollection(name = "子列表")
    private List<ChildPo> list;
}

• ExcelTarget: 用于标记实体对象
• name: 该字段在excel中的列名
• orderNum: 列的顺序根据该属性的值进行确定,值越小,该列越靠前
• 列的宽度
• dict: 字典项,若字段为字典类型,且需要在字典名称和字典值做转换, 需要实现 IExcelDictHandler 接口,并在导入导出时设置该参数
• ExcelCollection: 标识该字段为集合属性
• needMerge: 若包含集合属性的字段时, 该列是否需要进行纵向合并

3.示例

1. 实体类及控制层

@RequestMapping("excel")
@RestController
public class ExcelController {
	
	@Resource
	private MyExcelUtil excelUtil;
	
	@GetMapping("export")
	public void export(HttpServletResponse response) {
		MyClass myClass1 = new MyClass("一版","jingying");
		MyClass myClass2 = new MyClass("六班","putong");
		List<MyClass> childList = new ArrayList<>();
		childList.add(myClass1);
		childList.add(myClass2);
		List<MySchool> list = new ArrayList<>();
		list.add(new MySchool("凤翔中学","emphasis",childList));
		list.add(new MySchool("柳林中学","general",childList));
		excelUtil.exportExcel(response,"测试标题","花名册", MySchool.class,list);
	}
	
}

@Data
@AllArgsConstructor
public class MySchool {
  
  @Excel(name = "学校名称", needMerge = true, orderNum = "1", width = 10 )
  private String name;
  
  @Excel(name = "学校类型", needMerge = true, dict = "school_type", orderNum = "2", width = 10 )
  private String type;
  
  @ExcelCollection(name = "班级列表", orderNum = "3")
  private List<MyClass> list;
  
}

@Data
@AllArgsConstructor
public class MyClass {
	
	@Excel(name = "班级名称", orderNum = "1", width = 10)
	private String name;
	
	@Excel(name = "班级类型", dict = "class_type",orderNum = "2", width = 10)
	private String type;
}

2. DictHandler

@Component
public class DictHandler implements IExcelDictHandler {
	
	public Map<String, Map<String, String>> dictMap = new ConcurrentHashMap<>();
	
	{
		Map<String, String> dictLength = new ConcurrentHashMap<>();
		dictLength.put("重点学校", "emphasis");
		dictLength.put("普通学校", "general");
		dictMap.put("school_type", dictLength);
		Map<String, String> dictSize = new ConcurrentHashMap<>();
		dictSize.put("精英班", "jingying");
		dictSize.put("普通班", "putong");
		dictMap.put("class_type", dictSize);
	}
	
	/**
	 * 从值翻译到名称
	 *
	 * @param dict  字典Key
	 * @param obj   对象
	 * @param name  属性名称
	 * @param value 属性值
	 * @return
	 */
	@Override
	public String toName(String dict, Object obj, String name, Object value) {
		Map<String, String> map = dictMap.get(dict);
		for (String key : map.keySet()) {
			if (map.get(key).equals(value)) {
				return key;
			}
		}
		return null;
	}
	
	/**
	 * 从名称翻译到值
	 *
	 * @param dict  字典Key
	 * @param obj   对象
	 * @param name  属性名称
	 * @param value 属性值
	 * @return
	 */
	@Override
	public String toValue(String dict, Object obj, String name, Object value) {
		Map<String, String> map = dictMap.get(dict);
		for (String key : map.keySet()) {
			if (key.equals(name)) {
				return map.get(name);
			}
		}
		return null;
	}
}

3. 导出Excel

@Component
public class MyExcelUtil {
	
	@Resource
	private DictHandler dictHandler;
	
	public void exportExcel(HttpServletResponse response, String title, String sheetName, Class clazz, List<? extends Object> list) {
		try {
			ExportParams exportParams = new ExportParams(title, sheetName, ExcelType.XSSF);
			exportParams.setCreateHeadRows(true);
			exportParams.setDictHandler(dictHandler);
			Workbook workbook = ExcelExportUtil.exportExcel(exportParams, clazz, list);
			OutputStream out = response.getOutputStream();
			response.setCharacterEncoding(StandardCharsets.UTF_8.name());
			response.setHeader("content-type", "application/vnd.ms-excel");
			response.setHeader("content-disposition", "attachment;filename=" + URLEncoder.encode(sheetName + "." + "xlsx", StandardCharsets.UTF_8.name()));
			workbook.write(out);
			out.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}

4. 导出效果