JDBC基础二

1.配置文件：dbinfo.properties

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driverClass=com.mysql.jdbc.Driver url=jdbc:mysql://127.0.0.1:3306/test username=root password=root

2.DBUtils.java

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package com.mf.util; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.Statement; import java.util.ResourceBundle; public class DBUtils {     private static String driverClass;     private static String url;     private static String username;     private static String password;     static{         //此对象是用于加载properties文件数据的         ResourceBundle rb = ResourceBundle.getBundle("dbinfo");         driverClass = rb.getString("driverClass");         url = rb.getString("url");         username = rb.getString("username");         password = rb.getString("password");         try {             Class.forName(driverClass);         } catch (ClassNotFoundException e) {             e.printStackTrace();         }     }       //得到连接的方法     public static Connection getConnection() throws Exception{         return DriverManager.getConnection(url, username, password);     }     //关闭资源的方法     public static void closeAll(ResultSet rs,Statement stmt,Connection conn){         //关闭资源         if(rs!=null){             try {                 rs.close();             } catch (Exception e) {                 e.printStackTrace();             }             rs = null;         }         if(stmt!=null){             try {                 stmt.close();             } catch (Exception e) {                 e.printStackTrace();             }             stmt = null;         }         if(conn!=null){             try {                 conn.close();             } catch (Exception e) {                 e.printStackTrace();             }             conn = null;         }     } }

3.解决sql注入问题

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public class DoLogin {           /**      * 根据用户名和密码查询用户对象信息      * @param name      * @param pwd      * @return u      */     public User findUser(String name,String pwd){         Connection conn = null;         PreparedStatement stmt = null;         ResultSet rs = null;         User u = null;         try {             conn = DBUtils.getConnection();//得到连接对象Connection             String sql ="SELECT * FROM users WHERE NAME=? AND PASSWORD=?";             stmt = conn.prepareStatement(sql);//得到执行sql语句的对象Statement             //给？赋值             stmt.setString(1, name);                           rs = stmt.executeQuery();//执行sql语句             if(rs.next()){                 u = new User();                 u.setId(rs.getInt(1));                 u.setName(rs.getString(2));                 u.setPassword(rs.getString(3));                 u.setEmail(rs.getString(4));                 u.setBirthday(rs.getDate(5));             }         } catch (SQLException e) {             e.printStackTrace();         }finally{             DBUtils.closeAll(rs, stmt, conn);         }         return u;     }

　　

 https://www.cnblogs.com/fzz9/p/8970210.html