我是 Java 新手并且处于学习曲线中。我有一个阿里云集成，我正在创建一个 java 函数计算。
我需要连接到密钥管理服务 (KMS) 以获取密钥。如果 KMS 不可用或无法通过功能连接，那么我需要在 MNS 的主题中创建事件消息。我想知道如何处理这个错误？
代码片段如下。
public class SFTP14 implements StreamRequestHandler, FunctionInitializer {
public void initialize(Context context) throws IOException {
}
public void handleRequest( InputStream inputStream
, OutputStream outputStream
, Context context) throws IOException
{
// Get values from Environment varaible of function
String bucketname = System.getenv("BUCKET_NAME");
String endpoint = System.getenv("ENDPOINT");
String kmssecret = System.getenv("KMSSECRET");
String MNSEndpoint="http://mns.cn-shanghai.aliyuncs.com/";
outputStream.write(new String("Bucket Name:"+bucketname +" \n").getBytes());
outputStream.write(new String("End Point Name:"+endpoint +" \n").getBytes());
// Get credential from Funcion compute service
Credentials creds = context.getExecutionCredentials();
String AccessID= creds.getAccessKeyId();
String AccessKey= creds.getAccessKeySecret();
String SecurityToken =creds.getSecurityToken();
//outputStream.write(new String("Secret AccessID:"+AccessID +" \n").getBytes());
//outputStream.write(new String("Secret AccessKey:"+AccessKey +" \n").getBytes());
//DefaultProfile profile = DefaultProfile.getProfile("cn-shanghai", accessKeyId, accessKeySecret);
DefaultProfile profile = DefaultProfile.getProfile("cn-shanghai", AccessID, AccessKey,SecurityToken);
IAcsClient client = new DefaultAcsClient(profile);
// Get secret data from KMS
GetSecretValueRequest request = new GetSecretValueRequest();
request.setSecretName(kmssecret);
CloudAccount account = new CloudAccount(AccessID,AccessKey,ServiceSettings.getMNSAccountEndpoint(),SecurityToken);
//DefaultMNSClient MNSclient = new DefaultMNSClient(creds.getAccessKeyId(), creds.getAccessKeySecret(),MNSEndpoint) ;
CloudTopic topic = MNSclient.getTopicRef("myTopic");
try
{
GetSecretValueResponse response = client.getAcsResponse(request);
**if (response== null)
{
throw new Exception("Cant connect to KMS");
}**
JSONObject obj= new JSONObject(response);
String SecretData = obj.getString("secretData");
JSONObject SecretData1= new JSONObject(SecretData);
String user = SecretData1.getString("username");
String password = SecretData1.getString("password");
String host = SecretData1.getString("host");
String port1 = SecretData1.getString("port");
int port=Integer.parseInt(port1);
String remotePath = SecretData1.getString("remotepath");
// Print values got from KMS Secret
outputStream.write(new String("Secret UserName:"+user +" \n").getBytes());
outputStream.write(new String("Secret Password:"+password +" \n").getBytes());
outputStream.write(new String("Secret Host:"+host +" \n").getBytes());
outputStream.write(new String("Secret Port:"+port1 +" \n").getBytes());
outputStream.write(new String("Secret remotePath:"+remotePath +" \n\n").getBytes());
//TopicMessage msg1 = new TopicMessage(); // You can specify whether to perform Base64 encoding on topic messages.
TopicMessage msg = new RawTopicMessage();
//TopicMessage msg1 = new RawTopicMessage();
outputStream.write(new String("hello world to AliCloud\n").getBytes());
// Create an OSSClient instance.
outputStream.write(new String("Start to create OSS client\n").getBytes());
// OSS ossClient = new OSSClientBuilder().build(endpoint, accessKeyId, accessKeySecret);
OSS ossClient = new OSSClientBuilder().build(endpoint, creds.getAccessKeyId(), creds.getAccessKeySecret() ,creds.getSecurityToken());
outputStream.write(new String("OSS client created.\n").getBytes());
JSch jsch = new JSch();
outputStream.write(new String("Jsch instanciated\n").getBytes());
Session session = jsch.getSession(user, host, port);
session.setPassword(password);
// rational
session.setConfig("StrictHostKeyChecking", "no");
outputStream.write(new String("Jsch session created, Establishing Connection...\n").getBytes());
session.connect();
outputStream.write(new String("...Connection established\n").getBytes());
outputStream.write(new String("establish sftp channel...\n").getBytes());
ChannelSftp sftpChannel = (ChannelSftp) session.openChannel("sftp");
sftpChannel.connect();
outputStream.write(new String("...sftp channel established\n").getBytes());
sftpChannel.cd(remotePath);
outputStream.write(new String("...changed directory\n").getBytes());
Vector lsVector = sftpChannel.ls("*");
outputStream.write(new String("ls vector created\n").getBytes());
Enumeration en = lsVector.elements();
outputStream.write(new String("ls elements are:\n").getBytes());
String filename;
ChannelSftp.LsEntry LsEntry;
if(lsVector.isEmpty()==true)
{
outputStream.write(new String("Publish Message \n").getBytes());
//msg.setMessageBody("hello world!") ;
msg.setMessageBody(("hello bytes with tag! ").getBytes());
msg = topic.publishMessage(msg);
throw new Exception("No File Found");
}
else
{
while(en.hasMoreElements())
{
LsEntry = (ChannelSftp.LsEntry)en.nextElement();
filename = LsEntry.getFilename();
// else {
outputStream.write(new String(filename+" \n").getBytes());
InputStream fileIS = sftpChannel.get(filename);
// filename with extension ?
ossClient.putObject(bucketname, filename, fileIS);
// remove remote file from FTP server
sftpChannel.rm(filename);
// }
}
}
// Shut down the OSSClient instance.
ossClient.shutdown();
sftpChannel.disconnect();
outputStream.write(new String("sftp channel disconnected\n").getBytes());
session.disconnect();
outputStream.write(new String("disconnected from session\n").getBytes());
}
catch(Exception e)
{
outputStream.write(new String("Error Message:"+e.getMessage() +" \n\n").getBytes());
}
}
}
基本上我想捕获运行时出现的错误并基于此执行一些操作。
例如：
if exception=Forbidden.NoPermission
then
Publish a message in topic with the error message occurs.
阿里云 KMS 的错误描述在此处详细说明
https://error-center.alibabacloud.com/status/product/Kms?spm=a2c69.11428812.home.32.1f39bb9amMIo4u
有人可以帮我发现错误并在 MNS 中发布消息吗？
谢谢， 安多