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1021上课演练----SQL注入与避免(银行系统)
package com.bank; import java.sql.CallableStatement; import java.sql.Connection; import java.sql.DatabaseMetaData; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; //封装银行卡数据库操作类 public class CardDAO { //添加卡 //返回卡号 public String addCard (String userid,String username,String password) { String rtn=null; //生成卡号 String cardid =(int)(Math.random()*1000000)+""; try { //保存数据 //1.加载驱动 Class.forName("oracle.jdbc.driver.OracleDriver"); //2.获得连接 Connection conn=DriverManager.getConnection("jdbc:oracle:thin:@127.0.0.1:1521:orcl", "test0816", "123456"); //3.创建声明 Statement st=conn.createStatement(); //4.执行语句 String sql ="insert into t_bankcard (cardid,user_id,user_name,password,times)" +" values(‘"+cardid+"‘,‘"+userid+"‘,‘"+username+"‘,‘"+password+"‘,sysdate)"; if(st.executeUpdate(sql)==1) { rtn=cardid; } //5.释放资源 st.close(); conn.close(); } catch(Exception e) { e.printStackTrace(); } return rtn; } //修改余额 //可以完成取款和存款的功能 //卡号,余额 public boolean updateBalance(String cardid,double yue) throws Exception { boolean rtn =false; //验证余额 if(yue<0) { throw new Exception("余额数据异常"); } try { //保存数据 //1.加载驱动 Class.forName("oracle.jdbc.driver.OracleDriver"); //2.获得连接 Connection conn=DriverManager.getConnection("jdbc:oracle:thin:@127.0.0.1:1521:orcl", "test0816", "123456"); //3.创建声明 Statement st=conn.createStatement(); //4.执行语句 String sql ="update t_bankcard set yue= " +yue+"where cardid=‘"+cardid+"‘"; rtn=st.executeUpdate(sql)==1; //5.释放资源 st.close(); conn.close(); } catch(Exception e) { e.printStackTrace(); } return rtn; } //登入 //登入 public boolean login(String cardid,String password) { boolean rtn=false; try{ //保存数据 //1.加载驱动 Class.forName("oracle.jdbc.driver.OracleDriver"); //2.获得链接 Connection conn=DriverManager. getConnection("jdbc:oracle:thin:@localhost:1521:orcl","test0816","123456"); //3.创建声明 Statement st=conn.createStatement(); //4.执行语句 //这种方式会造成SQL注入 String sql="select * from t_bankcard where cardid=‘"+cardid +"‘"+"and password=‘"+password+"‘"; //遍历结果集 ResultSet rs=st.executeQuery(sql); rtn=rs.next(); //5.释放资源 st.close(); conn.close(); } catch(Exception e) { e.printStackTrace(); } return rtn; } //验证登录 public boolean login2 (String cardid,String password) { boolean rtn =false; try { Class.forName("oracle.jdbc.driver.OracleDriver"); Connection conn=DriverManager.getConnection( "jdbc:oracle:thin:@127.0.0.1:1521:orcl", "test0816", "123456"); //带有?占位符的语句 String sql= "select * from t_bankcard where " + "cardid=? and" + " password=? and state=?"; //预编译的声明 //优点:1.执行效率高 //2.避免SQL注入 PreparedStatement ps= conn.prepareStatement(sql); //替换占位符 ps.setString(1, cardid); ps.setString(2, password); ps.setString(3, "1"); //查询结果集 ResultSet rs = ps.executeQuery(); rtn=rs.next();//如果有数据就验证通过 //调用存储过程 //不怎么用 //CallableStatement cs=conn.prepareCall("{call存储过程(?,?)}"); //获得数据库的元数据 DatabaseMetaData dmd= conn.getMetaData(); System.out.println(dmd.getURL()); System.out.println("getUserName()"+dmd.getUserName()); System.out.println("getDatabaseProductName="+dmd.getDatabaseProductName()); //结果集的元数据 ResultSetMetaData rsmd= rs.getMetaData(); System.out.println("getColumnCount="+rsmd.getColumnCount()); System.out.println("getColumnName="+rsmd.getColumnName(1)); rs.close(); conn.close(); } catch(Exception e) { e.printStackTrace(); } return rtn; } //查询 }
package com.bank; import static org.junit.Assert.*; public class Test { @org.junit.Test public void testInsert() { //测试发卡 CardDAO cd =new CardDAO (); String cardid=cd.addCard("1234567890", "张三", "123456"); if(cardid !=null) { System.out.println("发卡成功"+cardid); } else { System.out.println("发卡失败"); } } //测试修改余额 @org.junit.Test public void testEdit() { CardDAO cd =new CardDAO (); boolean b=false; try { b=cd.updateBalance("148102", 100); } catch (Exception e) { // TODO 自动生成的 catch 块 e.printStackTrace(); } if(b) { System.out.println("修改余额成功"); } else { System.out.println("修改余额失败"); } } //登入 @org.junit.Test public void testLogin() { CardDAO cd=new CardDAO(); if(cd.login("‘or 1=1--","14"))//SQL注入 { System.out.println("登陆成功"); } else{ System.out.println("登录失败"); } } @org.junit.Test //避免SQL注入的测试登入 public void testLogin2() { CardDAO cd=new CardDAO(); if(cd.login2("148102","123456")) { System.out.println("登陆成功"); } else{ System.out.println("登录失败"); } } }
1021上课演练----SQL注入与避免(银行系统)
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