EasyExcel Dynamic Column【Implementation of Dynamic Columns】Supports Dynamic Date and Time Formats

# 1. Introduction to EasyExcel Dynamic Columns

## 1.1 What is the EasyExcel Library?
This section will introduce the definition and function of the EasyExcel library, as well as its application scenarios and advantages in practical development.

## 1.2 Overview of EasyExcel Dynamic Columns
This part will provide a detailed explanation of what EasyExcel dynamic columns are, and the importance and practicality of dynamic columns in data processing.

## 1.3 Advantages and Characteristics of EasyExcel
This section will explain the advantages and characteristics of EasyExcel compared to other Excel processing libraries, and why to choose EasyExcel for the implementation of dynamic columns.

# 2. Principles of Dynamic Column Implementation

In this chapter, we will delve into the principles behind the implementation of EasyExcel dynamic columns, including the definition and function of dynamic columns, the main methods of implementing dynamic columns, and the importance of dynamic columns in data processing. Let us begin our in-depth exploration.

# 3. Support for Dynamic Date Formats

During the data processing process, date formatting is a very common and important operation. EasyExcel provides functionality to support dynamic date formats, making it easy for users to handle data in various date formats, meeting different needs.

#### 3.1 Introduction to Date Formatting

Date formatting is the operation of displaying or outputting date data in a certain format. In practical applications, we often need to present date data in different forms, such as "yyyy-MM-dd", "MM/dd/yyyy", and so on. Date formatting can make data more intuitive and readable, and also meet display requirements in different scenarios.

#### 3.2 How EasyExcel Supports Dynamic Date Formats

In EasyExcel, we can achieve dynamic display of dates by specifying different date formats. By setting the `@DateTimeFormat` annotation or `converter` configuration, it can be easily handled to process date type data in the specified format.

@Data
public class UserData {
     @DateTimeFormat("yyyy-MM-dd")
     private Date birthDate;
     private String name;
     private Integer age;
}

ExcelWriter excelWriter = EasyExcel.write("output.xlsx", UserData.class).build();
WriteSheet writeSheet = EasyExcel.writerSheet("sheet1").build();
List<UserData> dataList = new ArrayList<>();
// Add data to dataList
excelWriter.write(dataList, writeSheet);
excelWriter.finish();

In the code above, we specify the date format as "yyyy-MM-dd" through the `@DateTimeFormat` annotation, and it will be displayed according to the specified format when writing to Excel.

#### 3.3 Application Scenarios and Practical Cases of Date Formatting

Date formatting is widely used in daily development, such as exporting data reports, data display, and other scenarios. Through dynamic date formatting, different user needs can be better met, making data display more flexible and customizable.

In practical cases, we can dynamically display date