Merge pull request #191 from tencentyun/dev/update_demo

Dev/update demo

Author: Dzkol

src/main/java/com/qcloud/cos/demo/GetObjectDemo.java

@@ -1,27 +1,40 @@
 package com.qcloud.cos.demo;
 
 import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
 
 import com.qcloud.cos.COSClient;
 import com.qcloud.cos.ClientConfig;
 import com.qcloud.cos.auth.BasicCOSCredentials;
 import com.qcloud.cos.auth.COSCredentials;
+import com.qcloud.cos.exception.CosClientException;
+import com.qcloud.cos.exception.CosServiceException;
+import com.qcloud.cos.model.COSObject;
 import com.qcloud.cos.model.GetObjectRequest;
 import com.qcloud.cos.model.ObjectMetadata;
 import com.qcloud.cos.region.Region;
+import com.qcloud.cos.utils.IOUtils;
 
 public class GetObjectDemo {
+    private static COSClient cosClient = createClient();
+
     public static void main(String[] args) {
         getObjectToFileDemo();
     }
 
-    private static void getObjectToFileDemo() {
+    private static COSClient createClient() {
         // 初始化用户身份信息(secretId, secretKey)
         COSCredentials cred = new BasicCOSCredentials("AKIDXXXXXXXX","1A2Z3YYYYYYYYYY");
         // 设置bucket的区域, COS地域的简称请参照 https://www.qcloud.com/document/product/436/6224
         ClientConfig clientConfig = new ClientConfig(new Region("ap-guangzhou"));
         // 生成cos客户端
         COSClient cosclient = new COSClient(cred, clientConfig);
+
+        return cosclient;
+    }
+
+    private static void getObjectToFileDemo() {
         String key = "test/my_test.json";
         String bucketName = "mybucket-12500000000";
         boolean useTrafficLimit = false;
@@ -30,8 +43,36 @@ private static void getObjectToFileDemo() {
             getObjectRequest.setTrafficLimit(8*1024*1024);
         }
         File localFile = new File("my_test.json");
-        ObjectMetadata objectMetadata = cosclient.getObject(getObjectRequest, localFile);
+        ObjectMetadata objectMetadata = cosClient.getObject(getObjectRequest, localFile);
         System.out.println(objectMetadata.getContentLength());
     }
+
+    private static void getObjectDemo() throws IOException {
+        String key = "test/my_test.json";
+        String bucketName = "mybucket-12500000000";
+        GetObjectRequest getObjectRequest = new GetObjectRequest(bucketName, key);
+        InputStream cosObjectInput = null;
+
+        try {
+            COSObject cosObject = cosClient.getObject(getObjectRequest);
+            cosObjectInput = cosObject.getObjectContent();
+        } catch (CosServiceException e) {
+            e.printStackTrace();
+        } catch (CosClientException e) {
+            e.printStackTrace();
+        }
+
+        // 处理下载到的流
+        // 这里是直接读取，按实际情况来处理
+        byte[] bytes = null;
+        try {
+            bytes = IOUtils.toByteArray(cosObjectInput);
+        } catch (IOException e) {
+            e.printStackTrace();
+        } finally {
+            // 用完流之后一定要调用 close()
+            cosObjectInput.close();
+        }
+    }
 }