Spring Boot项目集成AWS SDK连接到AWS S3,实现上传下载功能

本文主要描写在Spring Boot项目里集成AWS SDK连接到AWS S3,实现上传下载功能的具体代码和注意事项。如有不足和错误之处，欢迎指正。

AWS S3相关介绍

AWS S3(官网): https://www.amazonaws.cn/s3/
AWS SDK for Java(官网):https://docs.aws.amazon.com/sdk-for-java/v2/developer-guide/signup-create-iam-user.html
aws-doc-sdk-examples(官方github):https://github.com/awsdocs/aws-doc-sdk-examples/blob/master/javav2/example_code/s3
aws-s3-java-sample(个人github):https://github.com/maolikui/aws-s3-java-sample

具体配置实现代码及注意事项

Spring Boot项目pom.xml文件配置

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.javasample.s3</groupId>
    <artifactId>SpringS3Amazon</artifactId>
    <version>0.0.1</version>
    <packaging>jar</packaging>
    <name>SpringS3Amazon</name>
    <description>SpringS3Amazon</description>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.4.RELEASE</version>
    </parent>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>software.amazon.awssdk</groupId>
                <artifactId>bom</artifactId>
                <version>2.0.0-preview-12</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
        </dependency>
        <dependency>
            <groupId>software.amazon.awssdk</groupId>
            <artifactId>s3</artifactId>
            <version>2.0.0-preview-12</version>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <fork>true</fork>
                    <executable>
                        C:\Program Files\Java\jdk1.8.0_171\bin\javac.exe
                    </executable>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

注意事项：
pom.xml文件中的关于software.amazon.awssdk的version要保持一致，即以下两处：

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>software.amazon.awssdk</groupId>
                <artifactId>bom</artifactId>
                <version>2.0.0-preview-12</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

  <dependency>
            <groupId>software.amazon.awssdk</groupId>
            <artifactId>s3</artifactId>
            <version>2.0.0-preview-12</version>
        </dependency>

Spring Boot项目application.properties文件配置

server.port=9001
server.servlet.path=/rest/services
spring.servlet.multipart.max-file-size=2500MB
spring.servlet.multipart.max-request-size=2500MB

aws.access_key_id=your access key
aws.secret_access_key=your secret access key
aws.s3.bucket=your bucket name
aws.s3.region=cn-northwest-1

aws.s3.filename=/666666/test123/photo.zip

注意事项：
1.如果上传的文件过大，需要设置spring.servlet.multipart.max-file-size和spring.servlet.multipart.max-request-size的值。
2.access_key_id和secret_access_key是通过IAM账户创建生成的。
3.bucket和region要对应。

S3Client bean配置

package com.javasample.s3.config;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import software.amazon.awssdk.auth.credentials.AwsBasicCredentials;
import software.amazon.awssdk.auth.credentials.StaticCredentialsProvider;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;

@Configuration
public class S3Config {
    @Value("${aws.access_key_id}")
    private String awsId;
    @Value("${aws.secret_access_key}")
    private String awsKey;
    @Value("${aws.s3.region}")
    private String region;

    @Bean
    public S3Client s3client() {
        AwsBasicCredentials awsCreds = AwsBasicCredentials.create(
                awsId,
                awsKey);
        S3Client s3Client = S3Client.builder().region(Region.of(region)).credentialsProvider(StaticCredentialsProvider.create(awsCreds)).build();
        return s3Client;
    }
}

上传下载核心代码配置

package com.javasample.s3.services.impl;

import com.javasample.s3.services.S3Services;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;
import software.amazon.awssdk.core.ResponseInputStream;
import software.amazon.awssdk.core.sync.RequestBody;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.GetObjectRequest;
import software.amazon.awssdk.services.s3.model.GetObjectResponse;
import software.amazon.awssdk.services.s3.model.PutObjectRequest;
import software.amazon.awssdk.services.s3.model.PutObjectResponse;

@Service
public class S3ServicesImpl implements S3Services {
    private Logger logger = LoggerFactory.getLogger(S3ServicesImpl.class);
    @Value("${aws.s3.bucket}")
    private String bucketName;
    @Value("${aws.s3.filename}")
    private String fileName;
    @Autowired
    private S3Client s3Client;

    @Override
    public ResponseInputStream<GetObjectResponse> downloadFile(String keyName) {
        ResponseInputStream<GetObjectResponse> responseInputStream = null;
        try {
            logger.info("---------------- START DOWNLOAD FILE ----------------");
            logger.info("Downloading to bucket '" + bucketName);
            responseInputStream = s3Client.getObject(GetObjectRequest.builder().bucket(bucketName).key(keyName).build());
            logger.info("===================== Download File - Done! =====================");
        } catch (Exception e) {
            logger.info("Exception e:" + e.toString());
        }
        return responseInputStream;
    }

    @Override
    public PutObjectResponse uploadFile(MultipartFile file) {
        PutObjectResponse putObjectResponse = null;
        try {
            logger.info("---------------- START UPLOAD FILE ----------------");
            logger.info("Uploading to bucket '" + bucketName);
            putObjectResponse = s3Client.putObject(PutObjectRequest.builder().bucket(bucketName).key(fileName).build(), RequestBody.fromBytes(file.getBytes()));
            logger.info("===================== Upload File - Done! =====================");
        } catch (Exception e) {
            logger.info("Exception e:" + e.toString());
        }
        return putObjectResponse;
    }
}

注意事项：
在上传和下载的方法里，方法key的参数指的是存储在AWS S3上的文件名。如果是路径字符串格式，S3服务器上会自动创建对应路径的文件夹。
例如：该例application.properties中的aws.s3.filename=/666666/test123/photo.zip，如果key的参数为/666666/test123/photo.zip，那么S3存储桶下就会有路径为/666666/test123/photo.zip的文件，该文件就是上传的文件。