java用户名管理代码 java中用户名和密码不正常请重新输入

登录界面的java代码,分别有教师登录,管理员登录,学生登录,右边是用户名和密码,见图。

分三个包,自己建个包,导进去就ok了,数据库是access的。

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package 登录;

import java.awt.EventQueue;

public class Cilent {

private JFrame frame;

private JTextField textField;

private JPasswordField passwordField;

/**

* Launch the application.

*/

public static void main(String[] args) {

EventQueue.invokeLater(new Runnable() {

public void run() {

try {

Cilent window = new Cilent();

window.frame.setVisible(true);

} catch (Exception e) {

e.printStackTrace();

}

}

});

}

/**

* Create the application.

*/

public Cilent() {

initialize();

}

/**

* Initialize the contents of the frame.

*/

private void initialize() {

frame = new JFrame();

frame.setTitle("登陆界面");

frame.setBounds(100, 100, 450, 300);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.getContentPane().setLayout(null);

frame.setResizable(false);

JLabel lblNewLabel = new JLabel("用户名");

lblNewLabel.setBounds(38, 43, 80, 34);

frame.getContentPane().add(lblNewLabel);

textField = new JTextField();

textField.setBounds(155, 42, 227, 37);

frame.getContentPane().add(textField);

textField.setColumns(10);

JLabel label = new JLabel("密 码");

label.setBounds(38, 115, 80, 34);

frame.getContentPane().add(label);

passwordField = new JPasswordField();

passwordField.setBounds(155, 115, 227, 37);

frame.getContentPane().add(passwordField);

JButton btnNewButton = new JButton("登 录");

btnNewButton.setBounds(60, 187, 115, 34);

frame.getContentPane().add(btnNewButton);

btnNewButton.addActionListener(new ActionListener() {

@Override

public void actionPerformed(ActionEvent arg0) {

// TODO Auto-generated method stub

UserCheck UC=new UserCheck(textField.getText(),String.valueOf(passwordField.getPassword()));

if(UC.getI()!=0) //有此用户

{

frame.setVisible(false);

}

else

{

textField.setText("");

passwordField.setText("");

}

}

});

JButton button = new JButton("取 消");

button.setBounds(242, 187, 115, 34);

frame.getContentPane().add(button);

button.addActionListener(new ActionListener() {

@Override

public void actionPerformed(ActionEvent arg0) {

// TODO Auto-generated method stub

textField.setText("");

passwordField.setText("");

}

});

}

}

/*****************************************************************/

package 登录;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

import 操作处理.UsersCL;

/**@author 20111024

* 检测登录的用户在数据库中有无,若没有,则提示没有此用户,

* 若有,则判断级别:普通用户还是管理员。

*/

public class UserCheck {

private int i=0; //用户级别:0不是用户、1是管理员、2是普通用户

UserCheck(String name ,String password)

{

String jdriver="sun.jdbc.odbc.JdbcOdbcDriver";

String connectDB="jdbc:odbc:Students";

Statement stmt=null;

ResultSet rs=null;

Connection con=null;

try {

Class.forName(jdriver);

con=DriverManager.getConnection(connectDB);

stmt=con.createStatement();

String query="select * from users where name='"+name+"' and passwd='"+password+"'";

rs=stmt.executeQuery(query);

if(rs.next())

{

//数据库中有此用户,访问成功

i=Integer.parseInt(rs.getString(3));

UsersCL UL=new UsersCL(i);

}

else

{

i=0; //没有用户是默认是0级

}

} catch (ClassNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

public int getI() {

return i;

}

}

/********************************************************************************************/

package 操作处理;

import java.awt.EventQueue;

public class UsersCL implements ActionListener{

private JFrame frame;

private JTextField textField;

private JTextField textField_1;

private JTextField textField_2;

private JTextField textField_3;

private int i=0;

private JLabel label_3;

private JTextField textField_4;

public UsersCL(int i) {

this.i=i;

frame = new JFrame();

frame.setTitle("用户处理界面");

frame.setBounds(100, 100, 450, 300);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.getContentPane().setLayout(null);

frame.setResizable(false);

frame.setVisible(true);

JLabel lblNewLabel = new JLabel("学 号");

lblNewLabel.setBounds(24, 32, 74, 29);

frame.getContentPane().add(lblNewLabel);

JLabel label = new JLabel("姓 名");

label.setBounds(24, 71, 74, 29);

frame.getContentPane().add(label);

JLabel label_1 = new JLabel("年 龄");

label_1.setBounds(24, 110, 74, 29);

frame.getContentPane().add(label_1);

label_3 = new JLabel("性 别");

label_3.setBounds(24, 149, 74, 29);

frame.getContentPane().add(label_3);

JLabel label_2 = new JLabel("状 态");

label_2.setBounds(24, 195, 74, 29);

frame.getContentPane().add(label_2);

textField = new JTextField();

textField.setBounds(101, 34, 113, 25);

frame.getContentPane().add(textField);

textField.setColumns(10);

textField_1 = new JTextField();

textField_1.setColumns(10);

textField_1.setBounds(101, 73, 113, 25);

frame.getContentPane().add(textField_1);

textField_2 = new JTextField();

textField_2.setColumns(10);

textField_2.setBounds(101, 112, 113, 25);

frame.getContentPane().add(textField_2);

textField_3 = new JTextField();

textField_3.setEditable(false);

textField_3.setColumns(10);

textField_3.setBounds(101, 199, 288, 25);

frame.getContentPane().add(textField_3);

textField_4 = new JTextField();

textField_4.setColumns(10);

textField_4.setBounds(101, 149, 113, 25);

frame.getContentPane().add(textField_4);

if(1==i)

{

JButton btnNewButton = new JButton("追 加");

btnNewButton.setBounds(276, 41, 113, 29);

frame.getContentPane().add(btnNewButton);

btnNewButton.addActionListener(this);

btnNewButton.setActionCommand("追加");

JButton button_1 = new JButton("删 除");

button_1.setBounds(276, 145, 113, 29);

frame.getContentPane().add(button_1);

button_1.addActionListener(this);

button_1.setActionCommand("删除");

}

JButton button = new JButton("查 询");

button.setBounds(276, 91, 113, 29);

frame.getContentPane().add(button);

button.addActionListener(this);

button.setActionCommand("查询");

}

@Override

public void actionPerformed(ActionEvent e) {

// TODO Auto-generated method stub

String name,age,sex,query=null;

int num,age1,count=0;

num=Integer.parseInt(textField.getText());

name=textField_1.getText();

age1=Integer.parseInt(textField_2.getText());

sex=textField_4.getText();

if(e.getActionCommand().equals("追加"))

{

query="insert into students values("+num+","+"'"+name+"',"+age1+",'"+sex+"');";

count=1;

}

else if(e.getActionCommand().equals("查询"))

{

query="select * from students where XSB="+num+";";

count=2;

}

else if(e.getActionCommand().equals("删除"))

{

query="delete from students where XSB="+num+" and name="+"'"+name+"'";

count=3;

}

Statement stmt=null;

ResultSet rs=null;

Connection con=null;

String jdriver="sun.jdbc.odbc.JdbcOdbcDriver";

String connectDB="jdbc:odbc:Students";

String query1=null;

try {

Class.forName(jdriver);

con=DriverManager.getConnection(connectDB);

stmt=con.createStatement();

if(count==1)

{

query1="select * from students where XSB="+num+";";

rs=stmt.executeQuery(query1);

if(rs.next())

textField_3.setText("已经由此记录,不能追加!");

else

{

stmt.executeUpdate(query);

textField_3.setText("已经追加完成!");

}

}

else if(2==count)

{

stmt.executeQuery(query);

rs=stmt.executeQuery(query);

if(rs.next())

{

textField_3.setText("已查找到此记录!");

}

else

{

textField_3.setText("没有此记录,可以追加!");

}

}

else if(3==count)

{

query1="select * from students where XSB="+num+" and name="+"'"+name+"'";

rs=stmt.executeQuery(query1);

if(rs.next())

{

stmt.executeUpdate(query);

textField_3.setText("已删除此记录!");

}

else

textField_3.setText("无此记录!");

}

} catch (ClassNotFoundException e1) {

// TODO Auto-generated catch block

e1.printStackTrace();

} catch (SQLException e1) {

// TODO Auto-generated catch block

e1.printStackTrace();

}

finally{

//关闭资源

if(stmt!=null){

try {

stmt.close();

} catch (Exception e2) {

// TODO: handle exception

}

stmt=null;

}

if(con!=null){

try {

con.close();

} catch (Exception e2) {

// TODO: handle exception

}

con=null;

}

}

}

}

求Java编的登录界面代码:登录后分别进入管理员界面及用户界面,依据是数据库中的用户名和密码

分三个包,自己建个包,导进去就ok了,数据库是access的。

package 登录;

import java.awt.EventQueue;

public class Cilent {

private JFrame frame;

private JTextField textField;

private JPasswordField passwordField;

/**

* Launch the application.

*/

public static void main(String[] args) {

EventQueue.invokeLater(new Runnable() {

public void run() {

try {

Cilent window = new Cilent();

window.frame.setVisible(true);

} catch (Exception e) {

e.printStackTrace();

}

}

});

}

/**

* Create the application.

*/

public Cilent() {

initialize();

}

/**

* Initialize the contents of the frame.

*/

private void initialize() {

frame = new JFrame();

frame.setTitle("登陆界面");

frame.setBounds(100, 100, 450, 300);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.getContentPane().setLayout(null);

frame.setResizable(false);

JLabel lblNewLabel = new JLabel("用户名");

lblNewLabel.setBounds(38, 43, 80, 34);

frame.getContentPane().add(lblNewLabel);

textField = new JTextField();

textField.setBounds(155, 42, 227, 37);

frame.getContentPane().add(textField);

textField.setColumns(10);

JLabel label = new JLabel("密 码");

label.setBounds(38, 115, 80, 34);

frame.getContentPane().add(label);

passwordField = new JPasswordField();

passwordField.setBounds(155, 115, 227, 37);

frame.getContentPane().add(passwordField);

JButton btnNewButton = new JButton("登 录");

btnNewButton.setBounds(60, 187, 115, 34);

frame.getContentPane().add(btnNewButton);

btnNewButton.addActionListener(new ActionListener() {

@Override

public void actionPerformed(ActionEvent arg0) {

// TODO Auto-generated method stub

UserCheck UC=new UserCheck(textField.getText(),String.valueOf(passwordField.getPassword()));

if(UC.getI()!=0) //有此用户

{

frame.setVisible(false);

}

else

{

textField.setText("");

passwordField.setText("");

}

}

});

JButton button = new JButton("取 消");

button.setBounds(242, 187, 115, 34);

frame.getContentPane().add(button);

button.addActionListener(new ActionListener() {

@Override

public void actionPerformed(ActionEvent arg0) {

// TODO Auto-generated method stub

textField.setText("");

passwordField.setText("");

}

});

}

}

/*****************************************************************/

package 登录;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

import 操作处理.UsersCL;

/**@author 20111024

* 检测登录的用户在数据库中有无,若没有,则提示没有此用户,

* 若有,则判断级别:普通用户还是管理员。

*/

public class UserCheck {

private int i=0; //用户级别:0不是用户、1是管理员、2是普通用户

UserCheck(String name ,String password)

{

String jdriver="sun.jdbc.odbc.JdbcOdbcDriver";

String connectDB="jdbc:odbc:Students";

Statement stmt=null;

ResultSet rs=null;

Connection con=null;

try {

Class.forName(jdriver);

con=DriverManager.getConnection(connectDB);

stmt=con.createStatement();

String query="select * from users where name='"+name+"' and passwd='"+password+"'";

rs=stmt.executeQuery(query);

if(rs.next())

{

//数据库中有此用户,访问成功

i=Integer.parseInt(rs.getString(3));

UsersCL UL=new UsersCL(i);

}

else

{

i=0; //没有用户是默认是0级

}

} catch (ClassNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

public int getI() {

return i;

}

}

/********************************************************************************************/

package 操作处理;

import java.awt.EventQueue;

public class UsersCL implements ActionListener{

private JFrame frame;

private JTextField textField;

private JTextField textField_1;

private JTextField textField_2;

private JTextField textField_3;

private int i=0;

private JLabel label_3;

private JTextField textField_4;

public UsersCL(int i) {

this.i=i;

frame = new JFrame();

frame.setTitle("用户处理界面");

frame.setBounds(100, 100, 450, 300);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.getContentPane().setLayout(null);

frame.setResizable(false);

frame.setVisible(true);

JLabel lblNewLabel = new JLabel("学 号");

lblNewLabel.setBounds(24, 32, 74, 29);

frame.getContentPane().add(lblNewLabel);

JLabel label = new JLabel("姓 名");

label.setBounds(24, 71, 74, 29);

frame.getContentPane().add(label);

JLabel label_1 = new JLabel("年 龄");

label_1.setBounds(24, 110, 74, 29);

frame.getContentPane().add(label_1);

label_3 = new JLabel("性 别");

label_3.setBounds(24, 149, 74, 29);

frame.getContentPane().add(label_3);

JLabel label_2 = new JLabel("状 态");

label_2.setBounds(24, 195, 74, 29);

frame.getContentPane().add(label_2);

textField = new JTextField();

textField.setBounds(101, 34, 113, 25);

frame.getContentPane().add(textField);

textField.setColumns(10);

textField_1 = new JTextField();

textField_1.setColumns(10);

textField_1.setBounds(101, 73, 113, 25);

frame.getContentPane().add(textField_1);

textField_2 = new JTextField();

textField_2.setColumns(10);

textField_2.setBounds(101, 112, 113, 25);

frame.getContentPane().add(textField_2);

textField_3 = new JTextField();

textField_3.setEditable(false);

textField_3.setColumns(10);

textField_3.setBounds(101, 199, 288, 25);

frame.getContentPane().add(textField_3);

textField_4 = new JTextField();

textField_4.setColumns(10);

textField_4.setBounds(101, 149, 113, 25);

frame.getContentPane().add(textField_4);

if(1==i)

{

JButton btnNewButton = new JButton("追 加");

btnNewButton.setBounds(276, 41, 113, 29);

frame.getContentPane().add(btnNewButton);

btnNewButton.addActionListener(this);

btnNewButton.setActionCommand("追加");

JButton button_1 = new JButton("删 除");

button_1.setBounds(276, 145, 113, 29);

frame.getContentPane().add(button_1);

button_1.addActionListener(this);

button_1.setActionCommand("删除");

}

JButton button = new JButton("查 询");

button.setBounds(276, 91, 113, 29);

frame.getContentPane().add(button);

button.addActionListener(this);

button.setActionCommand("查询");

}

@Override

public void actionPerformed(ActionEvent e) {

// TODO Auto-generated method stub

String name,age,sex,query=null;

int num,age1,count=0;

num=Integer.parseInt(textField.getText());

name=textField_1.getText();

age1=Integer.parseInt(textField_2.getText());

sex=textField_4.getText();

if(e.getActionCommand().equals("追加"))

{

query="insert into students values("+num+","+"'"+name+"',"+age1+",'"+sex+"');";

count=1;

}

else if(e.getActionCommand().equals("查询"))

{

query="select * from students where XSB="+num+";";

count=2;

}

else if(e.getActionCommand().equals("删除"))

{

query="delete from students where XSB="+num+" and name="+"'"+name+"'";

count=3;

}

Statement stmt=null;

ResultSet rs=null;

Connection con=null;

String jdriver="sun.jdbc.odbc.JdbcOdbcDriver";

String connectDB="jdbc:odbc:Students";

String query1=null;

try {

Class.forName(jdriver);

con=DriverManager.getConnection(connectDB);

stmt=con.createStatement();

if(count==1)

{

query1="select * from students where XSB="+num+";";

rs=stmt.executeQuery(query1);

if(rs.next())

textField_3.setText("已经由此记录,不能追加!");

else

{

stmt.executeUpdate(query);

textField_3.setText("已经追加完成!");

}

}

else if(2==count)

{

stmt.executeQuery(query);

rs=stmt.executeQuery(query);

if(rs.next())

{

textField_3.setText("已查找到此记录!");

}

else

{

textField_3.setText("没有此记录,可以追加!");

}

}

else if(3==count)

{

query1="select * from students where XSB="+num+" and name="+"'"+name+"'";

rs=stmt.executeQuery(query1);

if(rs.next())

{

stmt.executeUpdate(query);

textField_3.setText("已删除此记录!");

}

else

textField_3.setText("无此记录!");

}

} catch (ClassNotFoundException e1) {

// TODO Auto-generated catch block

e1.printStackTrace();

} catch (SQLException e1) {

// TODO Auto-generated catch block

e1.printStackTrace();

}

finally{

//关闭资源

if(stmt!=null){

try {

stmt.close();

} catch (Exception e2) {

// TODO: handle exception

}

stmt=null;

}

if(con!=null){

try {

con.close();

} catch (Exception e2) {

// TODO: handle exception

}

con=null;

}

}

}

}

java用户管理的代码中查询不了是哪出问题了

一)[DLS_DEAD_LOCAL_STORE]

描述: Dead store to 未使用的局部变量

解决方法:局部变量定义后未使用;实例化对象后又重新对该对象赋值

(二) [ST_WRITE_TO_STATIC_FROM_INSTANCE_METHOD]

描述:Write to static field 通过实例方法更新静态属性

常见于常量类,直接通过类名.常量名获取的方式违背了封装的原则,findbugs不提倡使用,而如果将常量改成静态成员变量,又因为spring不支持静态注入导致不能实现,解决方法是非静态的setter调用静态的setter方法给静态成员变量赋值。

解决方法:

常量类F:

class F{

public static String a = “123”;

}

常量a改为静态成员变量,通过F.getA()获取,且由于spring不支持静态注入,改为:

class F{

private static String a;

public static Integer getA() {

return a;

}

public void setA(String a) {

setAValue(a);

}

public static void setAValue(String a) {

F.a = a;

}

}

(三) [BX_UNBOXING_IMMEDIATELY_REBOXED]

描述: Boxed value is unboxed and then immediately reboxed 装箱的值被拆箱,然后立刻重新装箱了

常见的是三目运算时,同时存在基本类型和包装类型。

解决方法:

Integer a = null;

//...

a = (a == null)?0:a;

此问题在于a不为null时,会被拆箱,赋值时再装箱。这是自动装箱拆箱的特性,只要运算中有不同类型,当涉及到类型转换时,编译器就会向下转型,再进行运算。修改方法,统一类型:

Integer a = null;

//...

a = (a == null)?Integer.valueOf(0):a;

(四) [SE_BAD_FIELD]

描述: Non-transient non-serializable instance field in serializable class在可序列化的类中存在不能序列化或者不能暂存的数据

解决方法:

方法1:序列化该对象

方法2:当采用struts2框架开发,不可避免的此问题会大量出现,因为ActionSupport实现了序列化接口,action继承了此类,而 service没序列化,所以在action中引用service对象时提示此错误,最简单的解决方法是将service对象声明成transient, 即service不需要序列化

方法3(未验证):To avoid java serialization you need to implement writeObject() and readObject() method in your Class and need to throw NotSerializableExceptionfrom those method.(action中实现这两个方法?)

private void writeObject(java.io.ObjectOutputStream stream) throws java.io.IOException {

throw new java.io.NotSerializableException( getClass().getName() );

}

private void readObject(java.io.ObjectInputStream stream) throws java.io.IOException, ClassNotFoundException {

throw new java.io.NotSerializableException( getClass().getName() );

}

(五) [NP_LOAD_OF_KNOWN_NULL_VALUE]

描述: Load of known null value加载已知是null的值

解决方法:已知方法参数为null是,直接传递null而不是参数名

(六) [REC_CATCH_EXCEPTION]

描述: Exception is caught when Exception is not thrown 过泛地捕获异常或捕获异常后未做任何处理

解决方法:异常分类捕获(至少要打印出此异常对象)

(七) [NP_NULL_PARAM_DEREF]

描述: Null passed for nonnull parameter 把空值传给了非空的参数

解决方法:增加非空判断

(八) [NP_IMMEDIATE_DEREFERENCE_OF_READLINE]

描述: Immediate dereference of the result of readLine() 立即引用了readLine()的结果

解决方法:判断readLine的结果是否为空

(九) [EI_EXPOSE_REP] 恶意代码漏洞

描述:may expose internal representation by returning getter方法返回引用类型

eclipse自动生成的引用类型(Object、数组、Date等)的getter、setter方法会得到或通过对可变对象的引用操作而暴露代码内部实现,解决方法很多,只要返回的或赋值的对象不是原引用对象即可。

解决方法:

以Date类型为例:

public Date getHappenTime() {

if(happenTime != null){

return (Date) happenTime.clone();

}

return null;

}

(十) [ EI_EXPOSE_REP2] 恶意代码漏洞

描述:may expose internal representation by storing an externally mutable object into setter方法返回引用类型

eclipse自动生成的引用类型(Object、数组、Date等)的getter、setter方法会得到或通过对可变对象的引用操作而暴露代码内部实现,解决方法很多,只要返回的或赋值的对象不是原引用对象即可。

解决方法:

以Date类型为例:

public void setHappenTime(Date happenTime) {

if(happenTime != null){

this.happenTime = (Date) happenTime.clone();

}else{

this.happenTime = null;

}

}


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