Java开学考（用户注册与登录部分）

.java文件：

package xuanke;
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 java.util.Scanner;

public class Xuanke {
public Xuanke(){}
public boolean Zhuce(String username,String pwd,String name) throws Exception
{
Statement st=null;
ResultSet rs=null;
PreparedStatement ps=null;
Connection conn=null;
int count=0;
Class.forName("com.mysql.cj.jdbc.Driver");
String url="jdbc:mysql://localhost:3306/form?serverTimezone=GMT%2B8";
String user="root";
String password="963123963123";
conn=DriverManager.getConnection(url, user, password);
st=conn.createStatement();
String sql="select username from yonghu where username= ? and password = ?";
// sql语句进行预编译
ps=conn.prepareStatement(sql);
// 对sql语句进行赋值
ps.setString(1, name);
ps.setString(2, pwd);
rs=ps.executeQuery();
boolean flag=false;
try{
if(rs.next())
{
flag=true;
}
if(!flag)
{
sql="insert into yonghu(name,username,password) values('"+name+"','"+username+"','"+pwd+"')";
count=st.executeUpdate(sql);
}
}catch (SQLException e) {
e.printStackTrace();
}finally
{
if(st!=null)
{
st.close();
}
if(conn!=null)
{
conn.close();
}
}
if(count==1)
{
return true;
}
else
{
return false;
}
}

public boolean Denglu (String name, String pwd) throws Exception {
// 普通用户登陆
ResultSet rs=null;
PreparedStatement ps=null;

Class.forName("com.mysql.jdbc.Driver");
String url = "jdbc:mysql://localhost:3306/form?serverTimezone=GMT%2B8";
String username = "root";
String Password = "963123963123";

Connection conn= DriverManager.getConnection(url, username, Password);
java.sql.Statement stmt = conn.createStatement();

String sql="select username from yonghu where username= ? and password = ?";
//sql语句进行预编译
ps=conn.prepareStatement(sql);
//对sql语句进行赋值
ps.setString(1, name);
ps.setString(2, pwd);
rs=ps.executeQuery();
boolean flag=false;
try{
if(rs.next())
{
flag=true;
}
} catch (SQLException e) {
e.printStackTrace();
}finally
{
if(rs!=null)
{
rs.close();
}
if(ps!=null)//st!=null
{
//st.close();
ps.close();
}
if(conn!=null)
{
conn.close();
}
}
return flag;
}
public boolean Denglu_2 (String name, String pwd) throws Exception {
// 管理员登陆
ResultSet rs=null;
PreparedStatement ps=null;

Class.forName("com.mysql.jdbc.Driver");
String url = "jdbc:mysql://localhost:3306/form?serverTimezone=GMT%2B8";
String username = "root";
String Password = "963123963123";

Connection conn= DriverManager.getConnection(url, username, Password);
java.sql.Statement stmt = conn.createStatement();

String sql="select username from guanli where username= ? and password = ?";
//sql语句进行预编译
ps=conn.prepareStatement(sql);
//对sql语句进行赋值
ps.setString(1, name);
ps.setString(2, pwd);
rs=ps.executeQuery();
boolean flag=false;
try{
if(rs.next())
{
flag=true;
}
} catch (SQLException e) {
e.printStackTrace();
}finally
{
if(rs!=null)
{
rs.close();
}
if(ps!=null)//st!=null
{
//st.close();
ps.close();
}
if(conn!=null)
{
conn.close();
}
}
return flag;
}
public boolean Denglu_3 (String name, String pwd) throws Exception {
// 撰稿人登陆
ResultSet rs=null;
PreparedStatement ps=null;

Class.forName("com.mysql.jdbc.Driver");
String url = "jdbc:mysql://localhost:3306/form?serverTimezone=GMT%2B8";
String username = "root";
String Password = "963123963123";

Connection conn= DriverManager.getConnection(url, username, Password);
java.sql.Statement stmt = conn.createStatement();

String sql="select username from zhuangao where username= ? and password = ?";
//sql语句进行预编译
ps=conn.prepareStatement(sql);
//对sql语句进行赋值
ps.setString(1, name);
ps.setString(2, pwd);
rs=ps.executeQuery();
boolean flag=false;
try{
if(rs.next())
{
flag=true;
}
} catch (SQLException e) {
e.printStackTrace();
}finally
{
if(rs!=null)
{
rs.close();
}
if(ps!=null)
{
ps.close();
}
if(conn!=null)
{
conn.close();
}
}
return flag;
}
}

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