Question

java TextField里面取出字符串作比较

textfeild里面取出的字符串和别的字符串比较没有效果 闷昂 java达人们帮帮忙额～

主要看加注释的地方就好了
//log.java
import java.awt.*;
import java.awt.event.*;
import java.util.*;

import java.io.*;

import javax.swing.*;

import javax.swing.event.*;

public class log extends Frame
{

private class WindowCloser extends WindowAdapter

{

public void windowClosing( WindowEvent we )

{

System.exit(0);

}

}

String[][] user_group = {{"root","sirenia"},{"administrator","admin"}};//user_group[0][0]的出处
int user_count = 2;

boolean flag = false;

JButton login = new JButton("login");
JButton exit = new JButton("exit");

Label user = new Label("username:");
Label psw = new Label("password：");
TextField _user = new TextField(13); //TextField
TextField _psw = new TextField(13);

log()
{
super("login...");
setSize(230, 180);
setLocation(200,200);

show();
setLayout(null);
setBackground(new Color(255,255,255));

add(user);
user.setSize(80,20);
user.setLocation(5,30);

add(psw);
psw.setSize(80,20);
psw.setLocation(5,70);

add(_user);
_user.setSize(120,25);
_user.setLocation(100,25);

add(_psw);
_psw.setSize(120,25);
_psw.setLocation(100,65);
_psw.setEchoChar('*');
add(login);
login.setSize(80,50);
login.setLocation(25,110);
login.addActionListener
(
new java.awt.event.ActionListener()
{
public void actionPerformed(java.awt.event.ActionEvent e)
{

if(_user.getText() == user_group[0][0]) //为什么这个不好使
JOptionPane.showMessageDialog(null,"fuck_java_1");
else if("root"== _user.getText()) //还有这个不好使
JOptionPane.showMessageDialog(null,"fuck_java_2");
else if("root" == user_group[0][0]) //这个好使
JOptionPane.showMessageDialog(null,"fuck_java_3");
_user.setText(_user.getText()+"_fuckjava"); //这个又好使
}
}
);

add(exit);
exit.setSize(80,50);
exit.setLocation(130,110);
exit.addActionListener
(
new java.awt.event.ActionListener()
{
public void actionPerformed(java.awt.event.ActionEvent e)
{
System.exit(0);
}
}
);

validate();
addWindowListener(new WindowCloser());

}

public static void main(String args[])
{
log fr = new log();

}
}

Answer 1

getText()返回是String，所以"root".equals(_user.getText())就可以了

Answer 2

一个是实参，另一个是引用的。故而两个比较就不好使了。