Java 尝试动态实例化类
我正试图使用这个类与服务器建立连接。此类获取对HashMaps中的图像执行操作所需的参数列表。然后在doInBackground中,我对图像逐个执行所需的操作。下面还粘贴了OVFImage部署器类的代码Java 尝试动态实例化类,java,inheritance,casting,factory-pattern,jsch,Java,Inheritance,Casting,Factory Pattern,Jsch,我正试图使用这个类与服务器建立连接。此类获取对HashMaps中的图像执行操作所需的参数列表。然后在doInBackground中,我对图像逐个执行所需的操作。下面还粘贴了OVFImage部署器类的代码 public class ImageDeployer extends SwingWorker<Boolean,String> { public ImageDeployer(){ } public ImageDeployer(HashMap<Str
public class ImageDeployer extends SwingWorker<Boolean,String> {
public ImageDeployer(){
}
public ImageDeployer(HashMap<String, String> volIDMap, HashMap<String, String> osMap) {
// TODO Auto-generated constructor stub
this.volIDMap = volIDMap;
this.osMap = osMap;
System.out.println(volIDMap);
System.out.println(osMap);
makeAConnection();
try {
doInBackground();
System.out.println("Do In Background");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void makeAConnection(){
inputFile = RESTEngine.getFilePath();
Properties defaultProps = new Properties();
try {
fin = new FileInputStream(inputFile);
defaultProps.load(fin);
fin.close();
}
catch(FileNotFoundException e1){
System.out.println("The properties file supposed to contain Authorization parameters was not found.");
e1.printStackTrace();
System.exit(-1);
}
catch(IOException e1){
System.out.println("An exception occured while trying to open the properties file");
e1.printStackTrace();
System.exit(-1);
}
// assign variables from Input file with default value as null
user = defaultProps.getProperty("UserID", null);
host = defaultProps.getProperty("PowerVC_IP_ADDRESS", null);
password = defaultProps.getProperty("UserPass" ,null );
jsch = new JSch();
try {
session = jsch.getSession(user, host, 22);
session.setPassword(password);
java.util.Properties config = new java.util.Properties();
config.put("StrictHostKeyChecking", "no");
session.setConfig(config);
session.connect();
channel=session.openChannel("exec");
channel.setInputStream(null);
try {
in = channel.getInputStream();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("Connection Successful");
} catch (JSchException e) {
// TODO Auto-generated catch block
System.out.println("Unable to connect");
e.printStackTrace();
}
}
@Override
protected Boolean doInBackground() throws Exception {
ImageDeployer imageDeployer = new ImageDeployer();
imageDeployer.makeAConnection();
for(String imageName : volIDMap.keySet()){
String volID = volIDMap.get(imageName);
String oS = osMap.get(imageName);
if (oS.equalsIgnoreCase("aix")){
imageDeployer = new OVFImageDeployer(volID, oS, imageName);
}
// Other Cases depending upon the OS Type
}
return null;
}
}
现在,当我运行代码时,我在((ChannelExec)channel.setCommand(command)
行上得到一个NullPointerException
。
我知道,如果我在
OVFImageDeployer
中的try块后放置makeAConnection
,代码将正常工作,但我不想一次又一次地建立连接。我希望只初始化一次连接,并且只使用该连接执行所有操作。您应该从ImageDeployer
的构造函数中删除对doInBackground
的调用:
public ImageDeployer(HashMap<String, String> volIDMap, HashMap<String, String> osMap) {
....
makeAConnection();
//doInBackground();
...
}
public OVFImageDeployer(String VolID,String oS,String imageName, Channel channel){
this.channel = channel;
...
}
@Override
protected Boolean doInBackground() throws Exception {
//ImageDeployer imageDeployer = new ImageDeployer();
//imageDeployer.makeAConnection();
...
ImageDeployer imageDeployer = new OVFImageDeployer(volID, oS, imageName, channel);
...
}
这将使用ImageDeployer
实例中存在的channel
创建一个OVFImageDeployer
实例。您需要从doInBackground
方法中删除这两条语句,并在构造OVFImageDeployer
实例时传递channel
以及其他参数:
public ImageDeployer(HashMap<String, String> volIDMap, HashMap<String, String> osMap) {
....
makeAConnection();
//doInBackground();
...
}
public OVFImageDeployer(String VolID,String oS,String imageName, Channel channel){
this.channel = channel;
...
}
@Override
protected Boolean doInBackground() throws Exception {
//ImageDeployer imageDeployer = new ImageDeployer();
//imageDeployer.makeAConnection();
...
ImageDeployer imageDeployer = new OVFImageDeployer(volID, oS, imageName, channel);
...
}
现在,客户端代码可以创建ImageDeployer
的实例,并可以在其上执行doInBackground
:
ImageDeployer imageDeployer = new ImageDeployer();
imageDeployer.doInBackground();
这样,每次在
doInBackground
方法中创建OVFImageDeployer
的实例时,在构造ImageDeployer
实例时,可以使用由makeAConnection
方法创建的相同的channel
。应该从ImageDeployer
的构造函数中删除对doInBackground
的调用:
public ImageDeployer(HashMap<String, String> volIDMap, HashMap<String, String> osMap) {
....
makeAConnection();
//doInBackground();
...
}
public OVFImageDeployer(String VolID,String oS,String imageName, Channel channel){
this.channel = channel;
...
}
@Override
protected Boolean doInBackground() throws Exception {
//ImageDeployer imageDeployer = new ImageDeployer();
//imageDeployer.makeAConnection();
...
ImageDeployer imageDeployer = new OVFImageDeployer(volID, oS, imageName, channel);
...
}
这将使用ImageDeployer
实例中存在的channel
创建一个OVFImageDeployer
实例。您需要从doInBackground
方法中删除这两条语句,并在构造OVFImageDeployer
实例时传递channel
以及其他参数:
public ImageDeployer(HashMap<String, String> volIDMap, HashMap<String, String> osMap) {
....
makeAConnection();
//doInBackground();
...
}
public OVFImageDeployer(String VolID,String oS,String imageName, Channel channel){
this.channel = channel;
...
}
@Override
protected Boolean doInBackground() throws Exception {
//ImageDeployer imageDeployer = new ImageDeployer();
//imageDeployer.makeAConnection();
...
ImageDeployer imageDeployer = new OVFImageDeployer(volID, oS, imageName, channel);
...
}
现在,客户端代码可以创建ImageDeployer
的实例,并可以在其上执行doInBackground
:
ImageDeployer imageDeployer = new ImageDeployer();
imageDeployer.doInBackground();
这样,每次在
doInBackground
方法中创建OVFImageDeployer
实例时,您都可以使用与构建ImageDeployer
实例时由makeAConnection
方法创建的相同的channel
属性定义在哪里?是否在PowerVCImageDeployer中?是的,通道是通道类型的变量,是公共变量。我已经确保它不是特定于方法的,并在公共类ImageDeployer extends SwingWorker上面声明了它。并且您希望在构造ImageDeployer
的实例时初始化channel
,并且ImageDeployer
实例上的所有方法调用都应该使用相同的channel
?我说的对吗?是的,一次又一次地创建频道需要花费大量的时间和资源。您正在从内部ImageDeployer
构造函数调用doInBackground
,并且再次创建ImageDeployer
内部doInBackground
方法的实例。令人困惑您能解释一下原因吗?您的频道属性定义在哪里?是否在PowerVCImageDeployer中?是的,通道是通道类型的变量,是公共变量。我已经确保它不是特定于方法的,并在公共类ImageDeployer extends SwingWorker上面声明了它。并且您希望在构造ImageDeployer
的实例时初始化channel
,并且ImageDeployer
实例上的所有方法调用都应该使用相同的channel
?我说的对吗?是的,一次又一次地创建频道需要花费大量的时间和资源。您正在从内部ImageDeployer
构造函数调用doInBackground
,并且再次创建ImageDeployer
内部doInBackground
方法的实例。令人困惑你能解释一下原因吗?Thanx,这很有魅力。但现在它给了我一个新问题。SwingWorker只能执行一次。因此OVFImageDeployer只工作一次,不管for循环运行多少次(String-imageName:volIDMap.keySet())这个循环是nowThanx的新谜题,它就像一个符咒一样工作。但现在它给了我一个新问题。SwingWorker只能执行一次。因此OVFImageDeployer只工作一次,不管for循环运行多少次(字符串imageName:volIDMap.keySet())这个循环现在是新的难题