JSF 中使用PreparedStatement的setString问题
下面用户登陆验证代码运行后，把正确的用户名和密码输入后，与数据库存放的用户名和密码核对总是不成功，请老师知道一下：

14. public class UserBean {

15. private String name;

16. private String password;

17. private boolean loggedIn;

18. private Logger logger = Logger.getLogger( "com.corejsf ");

19.
public void doLogin() throws SQLException, NamingException {

50. Context ctx = new InitialContext();

51. if (ctx == null) throw new NamingException( "No initial context ");


53. DataSource ds = (DataSource) ctx.lookup ( "java:comp/env/jdbc/mydb ");

54. if (ds == null) throw new NamingException( "No data source ");


56. Connection conn = ds.getConnection();

57. if (conn == null) throw new SQLException( "No connection ");


59. try {

60. PreparedStatement passwordQuery = conn.prepareStatement(

61. "SELECT password from Users WHERE username = ? ");


63. passwordQuery.setString(1, name);


65. ResultSet result = passwordQuery.executeQuery();


67. if (!result.next()) return;

68. String storedPassword = result.getString( "password ");

69. loggedIn = password.equals(storedPassword.trim());

70. }

71. finally {

72. conn.close();

73. }

74. }

75. }


但将 "SELECT password from Users WHERE username = ? " 改为 "SELECT password from Users WHERE username = 'name ' ",并且去掉 passwordQuery.setString(1, name);这行后，就可以和数据库存放的用户名和密码核对成功。 这是为什么？谢谢大家！

[解决办法]
the value of name is null