Uma ajuda em conexao!

11/09/2008 11:13:29 javax.faces.webapp._ErrorPageWriter handleException
SEVERE: An exception occurred
javax.faces.FacesException: Error calling action method of component with id maind:addprod
	at org.apache.myfaces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:69)
	at javax.faces.component.UICommand.broadcast(UICommand.java:121)
	at org.ajax4jsf.component.AjaxViewRoot.processEvents(AjaxViewRoot.java:316)
	at org.ajax4jsf.component.AjaxViewRoot.broadcastEvents(AjaxViewRoot.java:291)
	at org.ajax4jsf.component.AjaxViewRoot.processPhase(AjaxViewRoot.java:248)
	at org.ajax4jsf.component.AjaxViewRoot.processApplication(AjaxViewRoot.java:461)
	at org.apache.myfaces.lifecycle.InvokeApplicationExecutor.execute(InvokeApplicationExecutor.java:32)
	at org.apache.myfaces.lifecycle.LifecycleImpl.executePhase(LifecycleImpl.java:103)
	at org.apache.myfaces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:76)
	at javax.faces.webapp.FacesServlet.service(FacesServlet.java:148)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:147)
	at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:276)
	at org.ajax4jsf.Filter.doFilter(Filter.java:175)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
	at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
	at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
	at java.lang.Thread.run(Unknown Source)
Caused by: javax.faces.el.EvaluationException: org.apache.jasper.el.JspELException: /index.jsp(18,4) '#{produto.mostrarConexaoString}' java.lang.NullPointerException
	at javax.faces.component._MethodExpressionToMethodBinding.invoke(_MethodExpressionToMethodBinding.java:79)
	at org.apache.myfaces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:54)
	... 26 more
Caused by: org.apache.jasper.el.JspELException: /index.jsp(18,4) '#{produto.mostrarConexaoString}' java.lang.NullPointerException
	at org.apache.jasper.el.JspMethodExpression.invoke(JspMethodExpression.java:77)
	at javax.faces.component._MethodExpressionToMethodBinding.invoke(_MethodExpressionToMethodBinding.java:75)
	... 27 more
Caused by: java.lang.NullPointerException
	at br.com.classes.Produto.mostrarConexaoString(Produto.java:99)
	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 org.apache.el.parser.AstValue.invoke(AstValue.java:152)
	at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:276)
	at org.apache.jasper.el.JspMethodExpression.invoke(JspMethodExpression.java:68)
	... 28 more

public String mostrarConexaoString() throws SQLException{
		System.out.println("conexao");
		
		try{
			conn= Conexao.getConexao();
			System.out.println("conexao feita");
		}
		catch (Exception e) {
			System.out.println("nao conseguio");
			System.out.println(e.toString());
		}finally{
			conn.close();
		}
		return "";

public static Connection getConexao() {
		
		System.out.println("slkf");
		
		try{
			Class.forName("org.postgresql.Driver");
			
			conn = DriverManager.getConnection("jdbc:postgresql://localhost:5432/projeto_pessoal","postgres","123456");
			
			System.out.println("Conexao com banco");
			
		}catch (SQLException e) {
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
		return conn;
		
	}

public static Connection criarConexao(){
		String driver, url, user, pass;		
		driver= "oracle.jdbc.OracleDriver";
		url= "jdbc:oracle:thin:hr/master@//localhost:1521/xe";				
		//Nesse código eu não precisei usar user e pass porque o Oracle trabalha de um modo diferente
		try{
			Class.forName(driver);
			Connection c= DriverManager.getConnection(url);
			//No caso do postgres você vai usar Driver.getConnection(url,user,pass);
			System.out.println("Conectado!");
			return c;
		}
		catch(ClassNotFoundException e){
			System.out.println("Driver não encontrado!");
			e.printStackTrace();
			return null;
		}
		catch(SQLException e){
			System.out.println("Banco de Dados não encontrado!");
			e.printStackTrace();
			return null;
		}
	}