• Amazon AWS S3 操作手册


    Install the SDK

    The recommended way to use the AWS SDK for Java in your project is to consume it from Maven. Import the aws-java-sdk-bom and specify the SDK Maven modules that your project needs in the dependencies.

    Importing the BOM
    <dependencyManagement>
      <dependencies>
        <dependency>
          <groupId>com.amazonaws</groupId>
          <artifactId>aws-java-sdk-bom</artifactId>
          <version>1.11.63</version>
          <type>pom</type>
          <scope>import</scope>
        </dependency>
      </dependencies>
    </dependencyManagement>
    Using the SDK Maven modules
    <dependencies>
      <dependency>
        <groupId>com.amazonaws</groupId>
        <artifactId>aws-java-sdk-ec2</artifactId>
      </dependency>
      <dependency>
        <groupId>com.amazonaws</groupId>
        <artifactId>aws-java-sdk-s3</artifactId>
      </dependency>
      <dependency>
        <groupId>com.amazonaws</groupId>
        <artifactId>aws-java-sdk-dynamodb</artifactId>
      </dependency>
    </dependencies>
    See the Set up the AWS SDK for Java section of the developer guide for more information about installing the SDK through other means.

    Features

    • Provides easy-to-use HTTP clients for all supported AWS services, regions, and authentication protocols.

    • Client-Side Data Encryption for Amazon S3 - Helps improve the security of storing application data in Amazon S3.

    • Amazon DynamoDB Object Mapper - Uses Plain Old Java Object (POJOs) to store and retrieve Amazon DynamoDB data.

    • Amazon S3 Transfer Manager - With a simple API, achieve enhanced the throughput, performance, and reliability by using multi-threaded Amazon S3 multipart calls.

    • Amazon SQS Client-Side Buffering - Collect and send SQS requests in asynchronous batches, improving application and network performance.

    • Automatically uses IAM Instance Profile Credentials on configured Amazon EC2 instances.

    • And more!

    Building From Source

    Once you check out the code from GitHub, you can build it using Maven. To disable the GPG-signing in the build, use:

    mvn clean install -Dgpg.skip=true

    Supported Versions

    • 1.11.x - Recommended.

    • 1.10.x - Approved. Only major critical bugs will be fixed. To get the new features, upgrade to 1.11.x version of the SDK.

    https://github.com/helloworldtang/aws-sdk-java

    /*
     * Copyright 2010-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
     *
     * Licensed under the Apache License, Version 2.0 (the "License").
     * You may not use this file except in compliance with the License.
     * A copy of the License is located at
     *
     *  http://aws.amazon.com/apache2.0
     *
     * or in the "license" file accompanying this file. This file is distributed
     * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
     * express or implied. See the License for the specific language governing
     * permissions and limitations under the License.
     */
    import java.io.BufferedReader;
    import java.io.File;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.InputStreamReader;
    import java.io.OutputStreamWriter;
    import java.io.Writer;
    import java.util.UUID;
    
    import com.amazonaws.AmazonClientException;
    import com.amazonaws.AmazonServiceException;
    import com.amazonaws.auth.AWSCredentials;
    import com.amazonaws.auth.profile.ProfileCredentialsProvider;
    import com.amazonaws.regions.Region;
    import com.amazonaws.regions.Regions;
    import com.amazonaws.services.s3.AmazonS3;
    import com.amazonaws.services.s3.AmazonS3Client;
    import com.amazonaws.services.s3.model.Bucket;
    import com.amazonaws.services.s3.model.GetObjectRequest;
    import com.amazonaws.services.s3.model.ListObjectsRequest;
    import com.amazonaws.services.s3.model.ObjectListing;
    import com.amazonaws.services.s3.model.PutObjectRequest;
    import com.amazonaws.services.s3.model.S3Object;
    import com.amazonaws.services.s3.model.S3ObjectSummary;
    
    /**
     * This sample demonstrates how to make basic requests to Amazon S3 using the
     * AWS SDK for Java.
     * <p>
     * <b>Prerequisites:</b> You must have a valid Amazon Web Services developer
     * account, and be signed up to use Amazon S3. For more information on Amazon
     * S3, see http://aws.amazon.com/s3.
     * <p>
     * Fill in your AWS access credentials in the provided credentials file
     * template, and be sure to move the file to the default location
     * (~/.aws/credentials) where the sample code will load the credentials from.
     * <p>
     * <b>WARNING:</b> To avoid accidental leakage of your credentials, DO NOT keep
     * the credentials file in your source directory.
     *
     * http://aws.amazon.com/security-credentials
     */
    public class S3Sample {
    
        public static void main(String[] args) throws IOException {
    
            /*
             * The ProfileCredentialsProvider will return your [default]
             * credential profile by reading from the credentials file located at
             * (~/.aws/credentials).
             */
            AWSCredentials credentials = null;
            try {
                credentials = new ProfileCredentialsProvider().getCredentials();
            } catch (Exception e) {
                throw new AmazonClientException(
                        "Cannot load the credentials from the credential profiles file. " +
                        "Please make sure that your credentials file is at the correct " +
                        "location (~/.aws/credentials), and is in valid format.",
                        e);
            }
    
            AmazonS3 s3 = new AmazonS3Client(credentials);
            Region usWest2 = Region.getRegion(Regions.US_WEST_2);
            s3.setRegion(usWest2);
    
            String bucketName = "my-first-s3-bucket-" + UUID.randomUUID();
            String key = "MyObjectKey";//key可以以目录的形式出现a/b,则会在a目录下创建b文件
    
            System.out.println("===========================================");
            System.out.println("Getting Started with Amazon S3");
            System.out.println("===========================================
    ");
    
            try {
                /*
                 * Create a new S3 bucket - Amazon S3 bucket names are globally unique,
                 * so once a bucket name has been taken by any user, you can't create
                 * another bucket with that same name.
                 *
                 * You can optionally specify a location for your bucket if you want to
                 * keep your data closer to your applications or users.
                 */
                System.out.println("Creating bucket " + bucketName + "
    ");
                s3.createBucket(bucketName);
    
                /*
                 * List the buckets in your account
                 */
                System.out.println("Listing buckets");
                for (Bucket bucket : s3.listBuckets()) {
                    System.out.println(" - " + bucket.getName());
                }
                System.out.println();
    
                /*
                 * Upload an object to your bucket - You can easily upload a file to
                 * S3, or upload directly an InputStream if you know the length of
                 * the data in the stream. You can also specify your own metadata
                 * when uploading to S3, which allows you set a variety of options
                 * like content-type and content-encoding, plus additional metadata
                 * specific to your applications.
                 */
                System.out.println("Uploading a new object to S3 from a file
    ");
                s3.putObject(new PutObjectRequest(bucketName, key, createSampleFile()));
    
                /*
                 * Download an object - When you download an object, you get all of
                 * the object's metadata and a stream from which to read the contents.
                 * It's important to read the contents of the stream as quickly as
                 * possibly since the data is streamed directly from Amazon S3 and your
                 * network connection will remain open until you read all the data or
                 * close the input stream.
                 *
                 * GetObjectRequest also supports several other options, including
                 * conditional downloading of objects based on modification times,
                 * ETags, and selectively downloading a range of an object.
                 */
                System.out.println("Downloading an object");
                S3Object object = s3.getObject(new GetObjectRequest(bucketName, key));
                System.out.println("Content-Type: "  + object.getObjectMetadata().getContentType());
                displayTextInputStream(object.getObjectContent());
    
                /*
                 * List objects in your bucket by prefix - There are many options for
                 * listing the objects in your bucket.  Keep in mind that buckets with
                 * many objects might truncate their results when listing their objects,
                 * so be sure to check if the returned object listing is truncated, and
                 * use the AmazonS3.listNextBatchOfObjects(...) operation to retrieve
                 * additional results.
                 */
                System.out.println("Listing objects");
                ObjectListing objectListing = s3.listObjects(new ListObjectsRequest()
                        .withBucketName(bucketName)
                        .withPrefix("My"));
                for (S3ObjectSummary objectSummary : objectListing.getObjectSummaries()) {
                    System.out.println(" - " + objectSummary.getKey() + "  " +
                                       "(size = " + objectSummary.getSize() + ")");
                }
                System.out.println();
    
                /*
                 * Delete an object - Unless versioning has been turned on for your bucket,
                 * there is no way to undelete an object, so use caution when deleting objects.
                 */
                System.out.println("Deleting an object
    ");
                s3.deleteObject(bucketName, key);
    
                /*
                 * Delete a bucket - A bucket must be completely empty before it can be
                 * deleted, so remember to delete any objects from your buckets before
                 * you try to delete them.
                 */
                System.out.println("Deleting bucket " + bucketName + "
    ");
                s3.deleteBucket(bucketName);//非空bucketName不能删除
            } catch (AmazonServiceException ase) {
                System.out.println("Caught an AmazonServiceException, which means your request made it "
                        + "to Amazon S3, but was rejected with an error response for some reason.");
                System.out.println("Error Message:    " + ase.getMessage());
                System.out.println("HTTP Status Code: " + ase.getStatusCode());
                System.out.println("AWS Error Code:   " + ase.getErrorCode());
                System.out.println("Error Type:       " + ase.getErrorType());
                System.out.println("Request ID:       " + ase.getRequestId());
            } catch (AmazonClientException ace) {
                System.out.println("Caught an AmazonClientException, which means the client encountered "
                        + "a serious internal problem while trying to communicate with S3, "
                        + "such as not being able to access the network.");
                System.out.println("Error Message: " + ace.getMessage());
            }
        }
    
        /**
         * Creates a temporary file with text data to demonstrate uploading a file
         * to Amazon S3
         *
         * @return A newly created temporary file with text data.
         *
         * @throws IOException
         */
        private static File createSampleFile() throws IOException {
            File file = File.createTempFile("aws-java-sdk-", ".txt");
            file.deleteOnExit();
    
            Writer writer = new OutputStreamWriter(new FileOutputStream(file));
            writer.write("abcdefghijklmnopqrstuvwxyz
    ");
            writer.write("01234567890112345678901234
    ");
            writer.write("!@#$%^&*()-=[]{};':',.<>/?
    ");
            writer.write("01234567890112345678901234
    ");
            writer.write("abcdefghijklmnopqrstuvwxyz
    ");
            writer.close();
    
            return file;
        }
    
        /**
         * Displays the contents of the specified input stream as text.
         *
         * @param input
         *            The input stream to display as text.
         *
         * @throws IOException
         */
        private static void displayTextInputStream(InputStream input) throws IOException {
            BufferedReader reader = new BufferedReader(new InputStreamReader(input));
            while (true) {
                String line = reader.readLine();
                if (line == null) break;
    
                System.out.println("    " + line);
            }
            System.out.println();
        }
    
    }


    https://github.com/aws/aws-sdk-java/blob/master/src/samples/AmazonS3/S3Sample.java

    Exception in thread "main" com.amazonaws.services.s3.model.AmazonS3Exception: The bucket you tried to delete is not empty (Service: Amazon S3; Status Code: 409; Error Code: BucketNotEmpty; Request ID: EFBEEBCD746B48C3), S3 Extended Request ID: PPZs8QJiKDUjcETOTr/501ymr1XYKSy+9Q4fxsma/cyo2TIcHZCSW1gZezXp461A9HvQ4zudx/Y=
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.handleErrorResponse(AmazonHttpClient.java:1545)
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeOneRequest(AmazonHttpClient.java:1183)
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeHelper(AmazonHttpClient.java:964)
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.doExecute(AmazonHttpClient.java:676)
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeWithTimer(AmazonHttpClient.java:650)
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.execute(AmazonHttpClient.java:633)
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.access$300(AmazonHttpClient.java:601)
        at com.amazonaws.http.AmazonHttpClient$RequestExecutionBuilderImpl.execute(AmazonHttpClient.java:583)
        at com.amazonaws.http.AmazonHttpClient.execute(AmazonHttpClient.java:447)
        at com.amazonaws.services.s3.AmazonS3Client.invoke(AmazonS3Client.java:4137)
        at com.amazonaws.services.s3.AmazonS3Client.deleteBucket(AmazonS3Client.java:1534)
        at com.amazonaws.services.s3.AmazonS3Client.deleteBucket(AmazonS3Client.java:1520)


    获取可用的短连接:

    s3Client.putObject(new PutObjectRequest("your-bucket", "some-path/some-key.jpg", new File("somePath/someKey.jpg")).withCannedAcl(CannedAccessControlList.PublicRead))
    s3Client.getResourceUrl("your-bucket", "some-path/some-key.jpg");



    http://stackoverflow.com/questions/10975475/amazon-s3-upload-file-and-get-url




    /*
     * Obtain the Content length of the Input stream for S3 header
     */
    try {
        InputStream is = event.getFile().getInputstream();
        contentBytes = IOUtils.toByteArray(is);
    } catch (IOException e) {
        System.err.printf("Failed while reading bytes from %s", e.getMessage());
    } 
    
    Long contentLength = Long.valueOf(contentBytes.length);
    
    ObjectMetadata metadata = new ObjectMetadata();
    metadata.setContentLength(contentLength);
    
    /*
     * Reobtain the tmp uploaded file as input stream
     */
    InputStream inputStream = event.getFile().getInputstream();
    
    /*
     * Put the object in S3
     */
    try {
    
        s3client.putObject(new PutObjectRequest(bucketName, keyName, inputStream, metadata));
    
    } catch (AmazonServiceException ase) {
        System.out.println("Error Message:    " + ase.getMessage());
        System.out.println("HTTP Status Code: " + ase.getStatusCode());
        System.out.println("AWS Error Code:   " + ase.getErrorCode());
        System.out.println("Error Type:       " + ase.getErrorType());
        System.out.println("Request ID:       " + ase.getRequestId());
    } catch (AmazonClientException ace) {
        System.out.println("Error Message: " + ace.getMessage());
    } finally {
        if (inputStream != null) {
            inputStream.close();
        }
    }

    http://stackoverflow.com/questions/8351886/amazons3-putobject-with-inputstream-length-example

    CREATING A CONNECTION

    This creates a connection so that you can interact with the server.

    String accessKey = "insert your access key here!";
    String secretKey = "insert your secret key here!";
    
    AWSCredentials credentials = new BasicAWSCredentials(accessKey, secretKey);
    AmazonS3 conn = new AmazonS3Client(credentials);
    conn.setEndpoint("objects.dreamhost.com");
    accessKey 和secretKey的获取方式
    服务---安全、身份与合规 分组下的 IAM----用户----安全证书----创建访问密钥
    
    To get your access key ID and secret access key
    Open the IAM console.
    In the navigation pane, choose Users.
    Choose your IAM user name (not the check box).
    Choose the Security Credentials tab and then choose Create Access Key.
    To see your access key, choose Show User Security Credentials. Your credentials will look something like this:
    Access Key ID: AKIAIOSFODNN7EXAMPLE
    Secret Access Key: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
    Choose Download Credentials, and store the keys in a secure location.
    
    Your secret key will no longer be available through the AWS Management Console; you will have the only copy. 
    Keep it confidential in order to protect your account, and never email it. 
    Do not share it outside your organization, even if an inquiry appears to come from AWS or Amazon.com. 
    No one who legitimately represents Amazon will ever ask you for your secret key.
    http://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSGettingStartedGuide/AWSCredentials.html
    
    安全证书
    https://console.aws.amazon.com/iam/home?#/users/zhao.zhibo?section=security_credentials
    
    成功
    这是 仅有的 一次查看或下载私有访问密钥的机会。以后您无法恢复它们。不过,您随时可以创建新的访问密钥。


    CHANGE AN OBJECT’S ACL

    This makes the object hello.txt to be publicly readable, and secret_plans.txt to be private.

    conn.setObjectAcl(bucket.getName(), "hello.txt", CannedAccessControlList.PublicRead);
    conn.setObjectAcl(bucket.getName(), "secret_plans.txt", CannedAccessControlList.Private);
            //获取一个request
            GeneratePresignedUrlRequest urlRequest = new GeneratePresignedUrlRequest(bucketName, key);
            //生成公用的url
            URL url = s3.generatePresignedUrl(urlRequest);
        /**
         * <p>
         * Returns a pre-signed URL for accessing an Amazon S3 resource.
         * </p>
         * <p>
         * Pre-signed URLs allow clients to form a URL for an Amazon S3 resource,
         * and then sign it with the current AWS security credentials.
         * The pre-signed URL
         * can be shared to other users, allowing access to the resource without
         * providing an account's AWS security credentials.
         * </p>
         * <p>
         * Pre-signed URLs are useful in many situations where AWS security
         * credentials aren't available from the client that needs to make the
         * actual request to Amazon S3.
         * </p>
         * <p>
         * For example, an application may need remote users to upload files to the
         * application owner's Amazon S3 bucket, but doesn't need to ship the
         * AWS security credentials with the application. A pre-signed URL
         * to PUT an object into the owner's bucket can be generated from a remote
         * location with the owner's AWS security credentials, then the pre-signed
       URL can be passed to the end user's application to use.
         * </p>
         * <p>
         * If you are generating presigned url for <a
         * href="http://aws.amazon.com/kms/">AWS KMS</a>-encrypted objects, you need to
         * specify the correct region of the bucket on your client and configure AWS
         * Signature Version 4 for added security. For more information on how to do
         * this, see
         * http://docs.aws.amazon.com/AmazonS3/latest/dev/UsingAWSSDK.html#
         * specify-signature-version
         * </p>
         *
         * @param bucketName
         *            The name of the bucket containing the desired object.
         * @param key
         *            The key in the specified bucket under which the desired object
         *            is stored.
         * @param expiration
         *            The time at which the returned pre-signed URL will expire.
         * @param method
         *            The HTTP method verb to use for this URL
         *
         * @return A pre-signed URL which expires at the specified time, and can be
         *         used to allow anyone to download the specified object from S3,
         *         without exposing the owner's AWS secret access key.
         *
         * @throws SdkClientException
         *             If there were any problems pre-signing the request for the
         *             specified S3 object.
         *
         * @see AmazonS3#generatePresignedUrl(String, String, Date)
         * @see AmazonS3#generatePresignedUrl(GeneratePresignedUrlRequest)
         */
        public URL generatePresignedUrl(String bucketName, String key, Date expiration, HttpMethod method)
                throws SdkClientException;

    https://aws.amazon.com/articles/3002109349624271

    Upload an Object Using a Pre-Signed URL (AWS SDK for Java)

    The following tasks guide you through using the Java classes to upload an object using a pre-signed URL.

    import java.io.IOException;
    import java.io.OutputStreamWriter;
    import java.net.HttpURLConnection;
    import java.net.URL;
    
    import com.amazonaws.AmazonClientException;
    import com.amazonaws.AmazonServiceException;
    import com.amazonaws.HttpMethod;
    import com.amazonaws.auth.profile.ProfileCredentialsProvider;
    import com.amazonaws.services.s3.AmazonS3;
    import com.amazonaws.services.s3.AmazonS3Client;
    import com.amazonaws.services.s3.model.GeneratePresignedUrlRequest;
    
    public class GeneratePresignedUrlAndUploadObject {
        private static String bucketName = "*** bucket name ***"; 
        private static String objectKey  = "*** object key ***";
    
        public static void main(String[] args) throws IOException {
            AmazonS3 s3client = new AmazonS3Client(new ProfileCredentialsProvider());
    
            try {
                System.out.println("Generating pre-signed URL.");
                java.util.Date expiration = new java.util.Date();
                long milliSeconds = expiration.getTime();
                milliSeconds += 1000 * 60 * 60; // Add 1 hour.
                expiration.setTime(milliSeconds);
    
                GeneratePresignedUrlRequest generatePresignedUrlRequest = 
                        new GeneratePresignedUrlRequest(bucketName, objectKey);
                generatePresignedUrlRequest.setMethod(HttpMethod.PUT); 
                generatePresignedUrlRequest.setExpiration(expiration);
    
                URL url = s3client.generatePresignedUrl(generatePresignedUrlRequest); 
    
                UploadObject(url);
    
                System.out.println("Pre-Signed URL = " + url.toString());
            } catch (AmazonServiceException exception) {
                System.out.println("Caught an AmazonServiceException, " +
                        "which means your request made it " +
                        "to Amazon S3, but was rejected with an error response " +
                "for some reason.");
                System.out.println("Error Message: " + exception.getMessage());
                System.out.println("HTTP  Code: "    + exception.getStatusCode());
                System.out.println("AWS Error Code:" + exception.getErrorCode());
                System.out.println("Error Type:    " + exception.getErrorType());
                System.out.println("Request ID:    " + exception.getRequestId());
            } catch (AmazonClientException ace) {
                System.out.println("Caught an AmazonClientException, " +
                        "which means the client encountered " +
                        "an internal error while trying to communicate" +
                        " with S3, " +
                "such as not being able to access the network.");
                System.out.println("Error Message: " + ace.getMessage());
            }
        }
    
        public static void UploadObject(URL url) throws IOException
        {
            HttpURLConnection connection=(HttpURLConnection) url.openConnection();
            connection.setDoOutput(true);
            connection.setRequestMethod("PUT");
            OutputStreamWriter out = new OutputStreamWriter(
                    connection.getOutputStream());
            out.write("This text uploaded as object.");
            out.close();
            int responseCode = connection.getResponseCode();
            System.out.println("Service returned response code " + responseCode);
    
        }
    }

    http://docs.aws.amazon.com/AmazonS3/latest/dev/PresignedUrlUploadObjectJavaSDK.html

    设置Amazon AWS S3上object的权限

    在创建资源时设置 ACL

    String bucketName     = "bucket-name";
    String keyName        = "object-key";
    String uploadFileName = "file-name";
    
    AmazonS3 s3client = new AmazonS3Client(new ProfileCredentialsProvider());
    
    AccessControlList acl = new AccessControlList();
    acl.grantPermission(new CanonicalGrantee("d25639fbe9c19cd30a4c0f43fbf00e2d3f96400a9aa8dabfbbebe1906Example"), Permission.ReadAcp);
    acl.grantPermission(GroupGrantee.AllUsers, Permission.Read);
    acl.grantPermission(new EmailAddressGrantee("user@email.com"), Permission.WriteAcp);
    
    File file = new File(uploadFileName);
    s3client.putObject(new PutObjectRequest(bucketName, keyName, file).withAccessControlList(acl));

    在请求中创建一个存储桶并指定一个 LogDeliveryWrite 标准 ACL,以将写入权限授予 Amazon S3 LogDelivery 组。

    String bucketName     = "bucket-name";
    AmazonS3 s3client = new AmazonS3Client(new ProfileCredentialsProvider());
    
    s3client.createBucket(new CreateBucketRequest (bucketName).withCannedAcl(CannedAccessControlList.LogDeliveryWrite));

    更新现有资源上的 ACL

    String bucketName     = "bucket-name";
    String keyName        = "object-key";
    
    AmazonS3 s3client = new AmazonS3Client(new ProfileCredentialsProvider());
    
    AccessControlList acl = new AccessControlList();
    acl.grantPermission(new CanonicalGrantee("d25639fbe9c19cd30a4c0f43fbf00e2d3f96400a9aa8dabfbbebe1906Example"), Permission.ReadAcp);
    acl.grantPermission(GroupGrantee.AuthenticatedUsers, Permission.Read);
    acl.grantPermission(new EmailAddressGrantee("user@email.com"), Permission.WriteAcp);
    Owner owner = new Owner();
    owner.setId("852b113e7a2f25102679df27bb0ae12b3f85be6f290b936c4393484beExample");
    owner.setDisplayName("display-name");
    acl.setOwner(owner);
    
    s3client.setObjectAcl(bucketName, keyName, acl);

    http://docs.amazonaws.cn/AmazonS3/latest/dev/acl-using-java-sdk.html

            s3.setObjectAcl(bucketName, key, CannedAccessControlList.PublicRead);


    http://docs.ceph.com/docs/master/radosgw/s3/java/#creating-a-connection

    http://abc08010051.iteye.com/blog/2082956

    http://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/index.html

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  • 原文地址:https://www.cnblogs.com/softidea/p/6141710.html
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