浅析EasyExcel如何导出自动回显中文

@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface ExcelSelected {
    /**
     * 码表类型（如 trans_status）
     */
    String codeField();
}

CREATE TABLE sys_dict (
    type VARCHAR(50) COMMENT '码表类型（如trans_status）',
    code VARCHAR(20) COMMENT '码值',
    name VARCHAR(50) COMMENT '显示名称'
);

public class GlobalCodeConverter implements Converter<String> {

    private static final Map<String, Map<String, String>> CACHE = new ConcurrentHashMap<>();

    @Override
    public Class<String> supportJavaTypeKey() {
        return String.class;
    }

    @Override
    public CellDataTypeEnum supportExcelTypeKey() {
        return CellDataTypeEnum.STRING;
    }

    // 读取Excel时的转换（中文->码值）
    @Override
    public String convertToJavaData(ReadConverterContext<?> context) {
        String cellValue = context.getReadCellData().getStringValue();
        Field field = context.getContentProperty().getField();
        ExcelSelected annotation = field.getAnnotation(ExcelSelected.class);

        if (annotation != null) {
            Map<String, String> codeMap = getCodeMap(annotation.codeField());
            return codeMap.entrySet().stream()
                    .filter(entry -> entry.getValue().equals(cellValue))
                    .map(Map.Entry::getKey)
                    .findFirst()
                    .orElse(null);
        }
        return cellValue;
    }

    // 写入Excel时的转换（码值->中文）
    @Override
    public WriteCellData<String> convertToExcelData(WriteConverterContext<String> context) {
        String value = context.getValue();
        Field field = context.getContentProperty().getField();
        ExcelSelected annotation = field.getAnnotation(ExcelSelected.class);

        if (annotation != null) {
            Map<String, String> codeMap = getCodeMap(annotation.codeField());
            return new WriteCellData<>(codeMap.get(value));
        }
        return new WriteCellData<>(value);
    }

    // 获取码表数据
    private Map<String, String> getCodeMap(String codeType) {
        // 带缓存的码表查询
        return CACHE.computeIfAbsent(codeType, k -> {
            // 实际查询数据库的代码（示例）
            Map<String, String> map = new HashMap<>();
            map.put("1", "进行中");
            map.put("2", "已完成");
            map.put("3", "已取消");
            return map;
        });
    }
}

public class OrderVO {
    @ExcelProperty("订单状态")
    @ExcelSelected(codeField = "trans_status")
    private String transStatus;
}

// 导出
EasyExcel.write(fileName, OrderVO.class)
         .registerConverter(new GlobalCodeConverter())
         .sheet().doWrite(orders);
// 导入
EasyExcel.read(fileName, OrderVO.class, new PageReadListener<>(list -> {}))
         .registerConverter(new GlobalCodeConverter())
         .sheet().doRead();