Spring Integration Guide

This chapter introduces how to integrate and use FastExcel in the Spring framework to handle Excel files uploaded by users.

Overview

By creating RESTful API endpoints, users can upload Excel files using HTTP requests, and the server uses FastExcel to parse the data.

Environment Dependencies

Maven

Ensure the necessary dependencies are included in your pom.xml file:

<dependency>
    <groupId>cn.idev.excel</groupId>
    <artifactId>fastexcel</artifactId>
    <version>{version.number}</version>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
</dependency>

Creating Upload Endpoints

POJO Class

First, define a POJO class for mapping Excel data:

@Getter
@Setter
@ToString
public class UploadData {
    private String string;
    private Date date;
    private Double doubleData;
}

Data Listener

Create a listener to handle each row of data:

@Slf4j
public class UploadDataListener extends AnalysisEventListener<UploadData> {
    private final List<UploadData> list = new ArrayList<>();

    @Override
    public void invoke(UploadData data, AnalysisContext context) {
        log.info("Read one record: {}", JSON.toJSONString(data));
        list.add(data);
    }

    @Override
    public void doAfterAllAnalysed(AnalysisContext context) {
        log.info("All data reading completed!");
        // Data storage operations can be performed here, such as saving to database
    }
}

Spring Controller

Create a controller to handle file upload requests:

@RestController
@RequestMapping("/excel")
public class ExcelController {

    @PostMapping("/upload")
    public ResponseEntity<String> upload(@RequestParam("file") MultipartFile file) {
        if (file.isEmpty()) {
            return ResponseEntity.badRequest().body("Please select a file to upload!");
        }

        try {
            FastExcel.read(file.getInputStream(), UploadData.class, new UploadDataListener())
                    .sheet()
                    .doRead();
            return ResponseEntity.ok("File uploaded and processed successfully!");
        } catch (IOException e) {
            log.error("File processing failed", e);
            return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body("File processing failed");
        }
    }
}

Complex Scenarios

Multi-Template Parsing

By defining multiple different model classes and processing methods within the same listener, you can extend support for multi-template parsing as needed.

Exception Handling

To improve user experience and ensure program robustness, exception handling logic needs to be added during data processing. You can override the onException method in custom listeners for detailed exception handling.

Practical Applications

In real-world scenarios, parsed data may be stored in a database. Database interaction logic can be implemented in the doAfterAllAnalysed method to ensure data persistence.