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脚本之家。
