java利用oss实现下载功能
本文实例为大家分享了如何利用oss实现下载功能的具体代码,供大家参考,具体内容如下
目前我接触的实现下载功能有3种方式。第一种,就是把要下载的内容写到本地目录,然后把目录返回给前端,利用a标签下载。第二种,本地不允许访问,挂载目录,使目录可以对外访问,同样的,把目录返给前端下载。第三种,使用第三方存储,其中阿里云oss就是一种可以用来实现的对象存储。
首先,导入依赖包
<dependency> <groupId>com.aliyun.oss</groupId> <artifactId>aliyun-sdk-oss</artifactId> <version>3.6.0</version> </dependency>
参数类
public class OssParams { public static final String endpoint = "oss-cn-hangzhou.aliyuncs.com"; public static final String accessKeyId = ""; public static final String accessKeySecret = ""; public static final String bucketName = ""; public static final String rootName = "";//根目录 }
工具类
import com.aliyun.oss.ClientException; import com.aliyun.oss.OSS; import com.aliyun.oss.OSSClientBuilder; import com.aliyun.oss.OSSException; import com.aliyun.oss.model.AppendObjectRequest; import com.aliyun.oss.model.ObjectMetadata; import org.joda.time.DateTime; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.ByteArrayInputStream; import java.net.URL; import java.util.Date; import java.util.concurrent.atomic.AtomicLong; import static OssParams.bucketName; /** * 先做单例对象调用,防止多线程并发bug * 后期加入线程锁控制后,做成公共utils */ public class WriteLeadsOssUtils { private static Logger LOG = LoggerFactory.getLogger(WriteLeadsOssUtils.class.getName()); private static final String fileSub = ".csv"; private AtomicLong atomicLong = new AtomicLong(0L); private WriteLeadsOssUtils() { } private static class BuildWriteOSS { private static final WriteLeadsOssUtils instance = new WriteLeadsOssUtils(); } public static WriteLeadsOssUtils getInstance() { return BuildWriteOSS.instance; } private OSS getOssClient() { return new OSSClientBuilder().build(OssParams.endpoint, OssParams.accessKeyId, OssParams.accessKeySecret); } public URL writeJSONObjectFile(String content,String fileName) { // 创建OSSClient实例。 OSS ossClient = getOssClient(); try { DateTime currentTime = new DateTime(System.currentTimeMillis()); // String objectName = OssParams.rootName + currentTime.toString("yyyy-MM-dd-HH") + fileSub; String objectName = OssParams.rootName + fileName; // AppendObjectRequest appendObjectRequest = null; String data = content; ossClient.putObject(bucketName, objectName, new ByteArrayInputStream(content.getBytes())); Date expiration = new Date(System.currentTimeMillis() + 3600L * 1000 * 24 * 180); URL url = ossClient.generatePresignedUrl(bucketName, objectName, expiration); LOG.info("{} saved to OSS, url={}", objectName,url.toString()); // for (IngestLeadingRequest param : params) { // String jsonStr = JSONObject.toJSONString(param); // JSONObject object = JSONObject.parseObject(jsonStr); // data += object.toJSONString() + "\n"; // } //文件不存在 // if (!ossClient.doesObjectExist(OssParams.bucketName, objectName)) { // atomicLong.set(0L); // appendObjectRequest = getAppendObjectRequest(data, true, objectName); // appendObjectRequest.setPosition(0L); // } else { // appendObjectRequest = getAppendObjectRequest(data, false, objectName); // } // AppendObjectResult appendObjectResult = ossClient.appendObject(appendObjectRequest); // atomicLong.set(appendObjectResult.getNextPosition()); // System.gc(); return url; } catch (OSSException e) { e.printStackTrace(); return null; } catch (ClientException e) { e.printStackTrace(); return null; } finally { ossClient.shutdown(); } } /** * flag标志位,true为新文件,false为追加文件 * * @param data * @param flag * @param objectName * @return */ private AppendObjectRequest getAppendObjectRequest(String data, Boolean flag, String objectName) { ObjectMetadata meta = new ObjectMetadata(); // 指定上传的内容类型。 meta.setContentType("text/plain;charset=utf-8"); if (flag == true) { return new AppendObjectRequest(bucketName, objectName, new ByteArrayInputStream(data.getBytes()), meta); } else { return new AppendObjectRequest(bucketName, objectName, new ByteArrayInputStream(data.getBytes()), meta).withPosition(atomicLong.get()); } } }
调用方法
WriteLeadsOssUtils.getInstance().writeJSONObjectFile("hello"); //将hello作为内容存入oss,并获得可以下载的url
利用上述方式,可以直接将可以下载的url返回给前端,直接用窗口打开就可以下载。
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持我们。
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