Java 如何将文本字段和密码字段与字符串值进行比较?
这是我使用JDBC连接的登录表单的代码。代码没有错误,但当我运行它时,它总是转到else语句Java 如何将文本字段和密码字段与字符串值进行比较?,java,mysql,jdbc,jtextfield,jpasswordfield,Java,Mysql,Jdbc,Jtextfield,Jpasswordfield,这是我使用JDBC连接的登录表单的代码。代码没有错误,但当我运行它时,它总是转到else语句 Connection con; Statement st; ResultSet rs; try{ Class.forName("java.sql.Driver"); con=DriverManager.getConnection ("jdbc:mysql://localhost/database","root","password");
Connection con;
Statement st;
ResultSet rs;
try{
Class.forName("java.sql.Driver");
con=DriverManager.getConnection ("jdbc:mysql://localhost/database","root","password");
st=con.createStatement();
rs=st.executeQuery("select * from users;");
while(rs.next()){
String userID=rs.getString("userID");
String password=rs.getString("password");
if(userID.equals(txtuserID.getText())
&& (password.equals(txtpassword.getPassword())) {
// ***HERE IS MY PROBLEM I WANT TO CHECK IF WHATS IN THE
// TEXT FIELD OR PASSWORD FIELD IS THE SAME FROM MySQL***
JOptionPane.showMessageDialog(null,"you have logged in");
new MainForm().setVisible(true);
} else {
JOptionPane.showMessageDialog(null,"Incorrect username and password");
}
}
} catch(Exception e) {
JOptionPane.showMessageDialog(null,"Error in Connectivity: " +e.getMessage());
}
JPasswordField getPassword()方法返回char[]。比较前转换为字符串:(实际使用这些字符构造一个新字符串…)
关于chenchuk的回答,将字符数组保留为字符数组,而不将其转换为字符串会更安全,因为字符串更容易被盗 因此,不要像chenchuk的回答那样将密码的char[]转换为字符串:
if(userID.equals(txtuserID.getText()) &&
(password.equals(new String((txtpassword.getPassword()))) {
}
使用java.util.Arrays.equals(…)
方法更安全:
if(userID.equals(txtuserID.getText())
&& Arrays.equals(txtpassword.getPassword(), password.toCharArray())) {
// your code goes here
}
什么是
txtpassword
?这是非常正确的,但是,如果这是您的问题,您仍然没有正确处理它。看见
if(userID.equals(txtuserID.getText())
&& Arrays.equals(txtpassword.getPassword(), password.toCharArray())) {
// your code goes here
}