使用 AWS SDK for Java 获取对象

使用 AWS SDK for Java 获取对象

使用的maven包是

     	<dependency>
            <groupId>org.apache.httpcomponentsgroupId>
            <artifactId>httpclientartifactId>
            <version>4.5.6version>
        dependency>
        <dependency>
            <groupId>com.amazonawsgroupId>
            <artifactId>aws-java-sdk-s3artifactId>
            <version>1.11.347version>
        dependency>

通过AWS SDK for Java下载某个对象

• 当您通过AWS SDK for Java下载某个对象时，Amazon S3 将返回该对象的所有元数据以及从中读取该对象
  的内容的输入流。
• 下面的例子通过三种方式从 Amazon S3 存储桶中检索对象：作为完整的对象、作为来自该对象的一系列字
  节以及作为包含被覆盖的响应标头值的完整对象。

最后附上官网自带的使用java连接S3的案例demo。

import com.amazonaws.AmazonServiceException;
import com.amazonaws.SdkClientException;
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.GetObjectRequest;
import com.amazonaws.services.s3.model.ResponseHeaderOverrides;
import com.amazonaws.services.s3.model.S3Object;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

// Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: MIT-0 (For details, see https://github.com/awsdocs/amazon-s3-
public class AwsS3Demo {


    public static void main(String[] args) throws IOException {
        String clientRegion = "*** Client region ***";
        String bucketName = "*** Bucket name ***";
        String key = "*** Object key ***";
        S3Object fullObject = null, objectPortion = null, headerOverrideObject = null;

        try {
            AmazonS3 s3Client = AmazonS3ClientBuilder.standard()
                    .withRegion(clientRegion)
                    .withCredentials(new ProfileCredentialsProvider())
                    .build();

            // Get an object and print its contents.
            System.out.println("Downloading an object");
            fullObject = s3Client.getObject(new GetObjectRequest(bucketName, key));
            System.out.println("Content-Type: " +  fullObject.getObjectMetadata().getContentType());
            System.out.println("Content: ");
            displayTextInputStream(fullObject.getObjectContent());

            // Get a range of bytes from an object and print the bytes.
            GetObjectRequest rangeObjectRequest = new GetObjectRequest(bucketName, key).withRange(0,9);
            objectPortion = s3Client.getObject(rangeObjectRequest);
            System.out.println("Printing bytes retrieved.");
            displayTextInputStream(objectPortion.getObjectContent());


          // Get an entire object, overriding the specified response headers, and print the object's content.
            ResponseHeaderOverrides headerOverrides = new ResponseHeaderOverrides()
                    .withCacheControl("No-cache")
                    .withContentDisposition("attachment; filename=example.txt");
            GetObjectRequest getObjectRequestHeaderOverride = new
                    GetObjectRequest(bucketName, key)
                    .withResponseHeaders(headerOverrides);
            headerOverrideObject = s3Client.getObject(getObjectRequestHeaderOverride);

            displayTextInputStream(headerOverrideObject.getObjectContent());
        } catch(AmazonServiceException e) {
            // The call was transmitted successfully, but Amazon S3 couldn't process
            // it, so it returned an error response.
            e.printStackTrace();
        } catch(SdkClientException e) {
            // Amazon S3 couldn't be contacted for a response, or the client
            // couldn't parse the response from Amazon S3.
            e.printStackTrace();
        } finally {
            // To ensure that the network connection doesn't remain open, close any open input streams.
            if(fullObject != null) {
                fullObject.close();
            }
            if(objectPortion != null) {
                objectPortion.close();
            }
            if(headerOverrideObject != null) {
                headerOverrideObject.close();
            }
        }
    }


    /**
     * @param input
     * @throws IOException
     */
    private static void displayTextInputStream(InputStream input) throws IOException {
        // Read the text input stream one line at a time and display each line.
        BufferedReader reader = new BufferedReader(new InputStreamReader(input));
        String line = null;
        while ((line = reader.readLine()) != null) {
            System.out.println(line);
        }
        System.out.println();
    }

使用 AWS SDK for Java 上传对象

Example:

• 以下示例将创建两个对象。第一个对象将一个文本字符串作为数据，第二对象是一个文件。
• 该示例通过在对 AmazonS3Client.putObject() 的调用中直接指定存储桶名称、对象键和文本数据来创建第一个对象。该示例通过使用指定存储桶、对象键和文件路径的 PutObjectRequest 来创建第二个对象。PutObjectRequest 还指定 ContentType 标头和标题元数据。

// Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: MIT-0 (For details, see https://github.com/awsdocs/amazon-s3-
import com.amazonaws.AmazonServiceException;
import com.amazonaws.SdkClientException;
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.ObjectMetadata;
import com.amazonaws.services.s3.model.PutObjectRequest;

import java.io.File;
import java.io.IOException;


public class UploadObjectS3Demo {
    public static void main(String[] args) throws IOException {
        String clientRegion = "*** Client region ***";
        String bucketName = "*** Bucket name ***";
        String stringObjKeyName = "*** String object key name ***";
        String fileObjKeyName = "*** File object key name ***";
        String fileName = "*** Path to file to upload ***";
        try {
            AmazonS3 s3Client = AmazonS3ClientBuilder.standard()
                    .withRegion(clientRegion)
                    .withCredentials(new ProfileCredentialsProvider())
                    .build();

            // Upload a text string as a new object.
            s3Client.putObject(bucketName, stringObjKeyName, "Uploaded String Object");
            
            // Upload a file as a new object with ContentType and title specified.
            PutObjectRequest request = new PutObjectRequest(bucketName, fileObjKeyName, new
                    File(fileName));
            ObjectMetadata metadata = new ObjectMetadata();
            metadata.setContentType("plain/text");
            metadata.addUserMetadata("x-amz-meta-title", "someTitle");
            request.setMetadata(metadata);
            s3Client.putObject(request);
        } catch (AmazonServiceException e) {
            // The call was transmitted successfully, but Amazon S3 couldn't process
            // it, so it returned an error response.
            e.printStackTrace();
        } catch (SdkClientException e) {
            // Amazon S3 couldn't be contacted for a response, or the client
            // couldn't parse the response from Amazon S3.
            e.printStackTrace();
        }
    }
}