AmazonS3文件简单上传下载_java amazons3 下载大文件

1.前言

基于项目的不同规范写法上会有不同，最近项目中需要适配AmazonS3的文件存储。由于对于上传下载的方法都是在同一个类里面，所以我将初始化S3client的方法单独写成了一个工具类静态访问，不需要属性注入，减少了配置文件，同时由于有多种文件存储系统的实现，避免了在不需要使用S3的时候去注入。

2.引入依赖

避免引进的一整个sdk过于庞大，单独引入了四个依赖

            <dependency>
                <groupId>com.amazonaws</groupId>
                <artifactId>aws-java-sdk-s3</artifactId>
                <version>1.12.445</version>
            </dependency>
            <dependency>
                <groupId>com.amazonaws</groupId>
                <artifactId>aws-java-sdk-core</artifactId>
                <version>1.12.445</version>
            </dependency>
            <dependency>
                <groupId>com.amazonaws</groupId>
                <artifactId>aws-java-sdk-kms</artifactId>
                <version>1.12.445</version>
            </dependency>
            <dependency>
                <groupId>com.amazonaws</groupId>
                <artifactId>jmespath-java</artifactId>
                <version>1.12.445</version>
            </dependency>
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3.工具类

由于上传下载是一个非常频繁的动作，所以为了避免重复创建对象和安全性，用了单例模式创建对象

import com.amazonaws.ClientConfiguration;
import com.amazonaws.Protocol;
import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.AWSCredentialsProvider;
import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.client.builder.AwsClientBuilder;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3Client;

/**
 * @Author: lsy
 * @Description:
 * @DateTime: 2023/5/15 10:29
 **/
public class AswUtil {
    private volatile static AmazonS3 s3;
    private AswUtil(){};

    public static AmazonS3 getInstance(String accessKey,String secretKey,String endPoint){
        if(null == s3){
            synchronized (AswUtil.class){
                if (null == s3){
                    ClientConfiguration config = new ClientConfiguration();
                    config.setProtocol(Protocol.HTTP);
                    AwsClientBuilder.EndpointConfiguration endpointConfig =
                            new AwsClientBuilder.EndpointConfiguration(endPoint, Regions.CN_NORTH_1.getName());
                    AWSCredentials awsCredentials = new BasicAWSCredentials(accessKey, secretKey);
                    AWSCredentialsProvider awsCredentialsProvider = new AWSStaticCredentialsProvider(awsCredentials);
                    s3 = AmazonS3Client.builder()
                            .withEndpointConfiguration(endpointConfig)
                            .withClientConfiguration(config)
                            .withCredentials(awsCredentialsProvider)
                            .disableChunkedEncoding()
                            .withPathStyleAccessEnabled(true)
                            .build();
                }
            }
        }
        return s3;
    }
}

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4.业务代码

根据业务逻辑不同，参数和实现方法自行调整

上传方法：

    private Boolean upload(File file,Map map,String path,String fileName) {
        String endPointUrl = Strings.getString(map.get("endPoint"));
        String accessKey = Strings.getString(map.get("accessKey"));
        String accessKeySecret = Strings.getString(map.get("accessKeySecret"));
        String path = Strings.getString(map.get("path"));
        String bucket = Strings.getString(map.get("bucket"));
        AmazonS3 s3 = AswUtil.getInstance(accessKey, accessKeySecret, endPointUrl);
        ftpPath = formatPath(path + "/" + ftpPath);
        String objectName = Strings.trim(ftpPath + "/" + fileName, "/");
        return putObject(s3, file, bucket,objectName);
    }
	    
	private Boolean putObject(AmazonS3 s3, File file, String bucketName,String objectName) {
        try {
            com.amazonaws.services.s3.model.ObjectMetadata objectMetadata = new com.amazonaws.services.s3.model.ObjectMetadata();
            objectMetadata.setContentType("application/octet-stream");
            objectMetadata.setContentLength(file.length());
            com.amazonaws.services.s3.model.PutObjectResult putObjectResult = s3.putObject(new PutObjectRequest(bucketName, objectName, new FileInputStream(file), objectMetadata));
            if (null != putObjectResult) {
                return true;
            }
        } catch (Exception e) {
            log.error("上传文件失败,失败原因:{}",e.getMessage(),e);
        }
        return false;
    }
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下载方法

    private Boolean downLoad(String remotePath, String localPath, String remoteFileName, Map map){
        String endPointUrl = Strings.getString(map.get("endPoint"));
        String accessKey = Strings.getString(map.get("accessKey"));
        String accessKeySecret = Strings.getString(map.get("accessKeySecret"));
        String path = Strings.getString(map.get("path"));
        String bucket = Strings.getString(map.get("bucket"));
        remotePath = formatPath(path + "/" + remotePath);
        String objectName = Strings.trim(remotePath + "/" + remoteFileName, "/");
        AmazonS3 s3 = AswUtil.getInstance(accessKey, accessKeySecret, endPointUrl);
        return getObject(s3,objectName,bucket,localPath);
    }
    private Boolean getObject(AmazonS3 s3, String key,String bucketName,String localPath) {
        try {
            S3Object object = s3.getObject(bucketName, key);
            S3ObjectInputStream objectContent = object.getObjectContent();
            FileOutputStream fos = new FileOutputStream(new File(localPath));
            byte[] read_buf = new byte[1024];
            int read_len = 0;
            while ((read_len = objectContent.read(read_buf)) > 0) {
                fos.write(read_buf, 0, read_len);
            }
            objectContent.close();
            fos.close();
            return true;
        } catch (AmazonServiceException | IOException e) {
            log.error("下载文件失败,失败原因:{}",e.getMessage(),e);
            return false;
        }
    }
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总结

之前也是想要用http的方式直接访问AmazonS3的RestApi接口，但是组装参数过于麻烦，同时相关文档支持又不太具体，于是还是使用了引入jdk的方式来实现。