为什么我可以通过 Postman 将图像上传到我的 S3 存储桶，但不能通过 Node.js 上传图像？

Question

I'm trying to create a basic page that uploads images to S3. I have my S3 credentials and methods for the upload running on port 8080 in Springboot and the front end running in Angular on port 4200. I'm able to make a POST request in Postman to http://localhost:8080/storage/uploadFile which successfully uploads an image to my S3 bucket. But when I try to do the same through Angular/my application, I get a 404. Here's my code:

Angular:
```import { Component } from '@angular/core';
import { HttpClient } from '@angular/common/http';

@Component ({
    selector: 'upload-images',
    templateUrl: './upload-images.html',
    styleUrls: ['./upload-images.css']
})

export class UploadImagesComponent {
    selectedFile: File = null;

    constructor(private http: HttpClient) {}

    onFileSelected(event) {
        this.selectedFile = <File>event.target.files[0];
    }

    onUpload() {
        const formData = new FormData();
        formData.append('image', this.selectedFile, this.selectedFile.name);
        this.http.post('http://localhost:4200/storage/uploadFile', formData)
        .subscribe(res => {
            console.log(res);
        });
    }
}```

Springboot:

```package inno.garage.june19.bucket;

import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.model.CannedAccessControlList;
import com.amazonaws.services.s3.model.DeleteObjectRequest;
import com.amazonaws.services.s3.model.PutObjectRequest;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;

import javax.annotation.PostConstruct;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Date;

@Service
public class AmazonClient {

    private AmazonS3 s3client;

    @Value("${amazonProperties.endpointUrl}")
    private String endpointUrl;
    @Value("${amazonProperties.bucketName}")
    private String bucketName;
    @Value("${amazonProperties.accessKey}")
    private String accessKey;
    @Value("${amazonProperties.secretKey}")
    private String secretKey;

    @PostConstruct
    private void initializeAmazon() {
        AWSCredentials credentials = new BasicAWSCredentials(this.accessKey, this.secretKey);
        this.s3client = new AmazonS3Client(credentials);
    }

    public String uploadFile(MultipartFile multipartFile) {
        String fileUrl = "";
        try {
            File file = convertMultiPartToFile(multipartFile);
            String fileName = generateFileName(multipartFile);
            fileUrl = endpointUrl + "/" + bucketName + "/" + fileName;
            uploadFileTos3bucket(fileName, file);
            file.delete();
        } catch (Exception e) {
           e.printStackTrace();
        }
        return fileUrl;
    }

    private File convertMultiPartToFile(MultipartFile file) throws IOException {
        File convFile = new File(file.getOriginalFilename());
        FileOutputStream fos = new FileOutputStream(convFile);
        fos.write(file.getBytes());
        fos.close();
        return convFile;
    }

    private String generateFileName(MultipartFile multiPart) {
        return new Date().getTime() + "-" + multiPart.getOriginalFilename().replace(" ", "_");
    }

    private void uploadFileTos3bucket(String fileName, File file) {
        s3client.putObject(new PutObjectRequest(bucketName, fileName, file)
                .withCannedAcl(CannedAccessControlList.PublicRead));
    }

    public String deleteFileFromS3Bucket(String fileUrl) {
        String fileName = fileUrl.substring(fileUrl.lastIndexOf("/") + 1);
        s3client.deleteObject(new DeleteObjectRequest(bucketName, fileName));
        return "Successfully deleted";
    }

}
```

Java Controller:
```package inno.garage.june19.bucket;

import inno.garage.june19.bucket.AmazonClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

@RestController
@RequestMapping("/storage")
public class BucketController {

    private AmazonClient amazonClient;

    @Autowired
    BucketController(AmazonClient amazonClient) {
        this.amazonClient = amazonClient;
    }

    @PostMapping("/uploadFile")
    public String uploadFile(@RequestPart(value = "file") MultipartFile file) {
        return this.amazonClient.uploadFile(file);
    }

    @DeleteMapping("/deleteFile")
    public String deleteFile(@RequestPart(value = "url") String fileUrl) {
        return this.amazonClient.deleteFileFromS3Bucket(fileUrl);
    }
}```

Answer 1

You are call wrong API Endpoint here

onUpload() {
    const formData = new FormData();
    formData.append('image', this.selectedFile, this.selectedFile.name);
    this.http.post('http://localhost:8080/storage/uploadFile', formData)
    .subscribe(res => {
        console.log(res);
    });
}

You are calling http://localhost:4200 not http://localhost:8080