gwt连接数据库总是报错

Question

下面的代码只不过是将eclipse或用webAppCreator产生的service类的方法体变了一下,然后错误就开始了,
mysql与sqlserver都报错,说是没有权限访问.请问如何解决啊(不要说什么让我换个驱动,不通过gwt是可以正常取到数据的).
public class GreetingServiceImpl extends RemoteServiceServlet implements
GreetingService {

public String greetServer(String input) {
    try {
        Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
        Connection conn = DriverManager.getConnection("jdbc:sqlserver://localhost:1433;DatabaseName=zg", "sa", "sa");
        List<String> userList = new ArrayList<String>();
         Statement stmt = null;
         ResultSet rs = null;
         try {
           stmt = conn.createStatement();
           rs = stmt.executeQuery("select * from user");
           while (rs.next()) {
             userList.add(rs.getString(1) + "  " + rs.getString(2) + "  " + rs.getString(3));
             System.out.println(rs.getString(1) + "  " + rs.getString(2) + "  " + rs.getString(3));
           }
         }
         catch (SQLException e) {
           e.printStackTrace();
         }
         return userList.get(0);
    } catch (ClassNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return null;
}

}
异常:
SEVERE: [1262763541078000] javax.servlet.ServletContext log: Exception while dispatching incoming RPC call
com.google.gwt.user.server.rpc.UnexpectedException: Service method 'public abstract java.lang.String org.zengge.gwt.demo.client.GreetingService.greetServer(java.lang.String)' threw an unexpected exception: java.security.AccessControlException: access denied (java.net.SocketPermission localhost:1433 connect,resolve)
at com.google.gwt.user.server.rpc.RPC.encodeResponseForFailure(RPC.java:378)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:581)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:188)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java:224)
at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:713)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:806)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1093)
at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:51)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:121)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:360)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:712)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)
at com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:70)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:139)
at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:352)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:139)
at org.mortbay.jetty.Server.handle(Server.java:313)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:506)
at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:844)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:644)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:211)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:381)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:396)
at org.mortbay.thread.BoundedThreadPool$PoolThread.run(BoundedThreadPool.java:442)
Caused by: java.security.AccessControlException: access denied (java.net.SocketPermission localhost:1433 connect,resolve)
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at com.google.appengine.tools.development.DevAppServerFactory$CustomSecurityManager.checkPermission(DevAppServerFactory.java:151)
at java.lang.SecurityManager.checkConnect(Unknown Source)
at com.microsoft.sqlserver.jdbc.SQLServerConnectionSecurityManager.checkConnect(Unknown Source)
at com.microsoft.sqlserver.jdbc.SQLServerConnection.connect(Unknown Source)
at com.microsoft.sqlserver.jdbc.SQLServerDriver.connect(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at org.zengge.gwt.demo.server.GreetingServiceImpl.greetServer(GreetingServiceImpl.java:25)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.appengine.tools.development.agent.runtime.Runtime.invoke(Runtime.java:100)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:562)
... 30 more

Answer 1

是gwt的类库没有java.net.SocketPermission访问权限
可能是
\jre\lib\security\java.policy里设置了限制吧