JDBC连接数据库

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import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.sql.*;public class JDBC {    public static void main(String[] args) {        Connection conn = getConnection("sa", "wcvr123");        System.out.println("Please enter the SQL statement you want to execute:");        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));        String Sql = null;        try {            Sql = br.readLine();        } catch (IOException e) {            e.printStackTrace();        }        char[] S =  Sql.toCharArray();        switch (S[0]) {            case 's':                query(conn,Sql);                break;            case 'i':                insert(conn,Sql);                break;            case 'u':                update(conn,Sql);                break;            case 'd':                delete(conn,Sql);                break;            default:                System.out.println("you entered the wrong statement");                break;        }        releaseConnection(conn);    }    //数据库连接    public static Connection getConnection(String userName, String password){        Connection conn = null;        String driver = "com.microsoft.sqlserver.jdbc.SQLServerDriver";        String url = "jdbc:sqlserver://localhost:1433;DatabaseName=Student";        try {            Class.forName(driver);            conn = DriverManager.getConnection(url, userName, password);            System.out.println("connect succeed!");        } catch (ClassNotFoundException e) {            e.printStackTrace();            System.out.println("connect failed");        } catch (SQLException e) {            e.printStackTrace();            System.out.println("connect failed");        }        return conn;    }    public static void query(Connection conn, String Sql){        Statement stmt;        try {            stmt = conn.createStatement();            ResultSet rs = stmt.executeQuery(Sql);            while(rs.next()){                System.out.println("sno:" + rs.getString("sno") + " cno:" + rs.getString("cno") + " grade:" + rs.getString("grade"));            }            if(rs != null){                try {                    rs.close();                } catch (SQLException e) {                    e.printStackTrace();                }            }            if(stmt != null){                try {                    stmt.close();                } catch (Exception e) {                    e.printStackTrace();                }            }        } catch (SQLException e) {            e.printStackTrace();        }    }    public static void insert(Connection conn, String Sql){        try {            Statement stmt = conn.createStatement();            int count = stmt.executeUpdate(Sql);            System.out.println("you have successfully inserted " + count + " data into the table");            if(stmt != null){                try {                    stmt.close();                } catch (Exception e) {                    e.printStackTrace();                }            }        } catch (SQLException e) {            e.printStackTrace();        }    }    public static void update(Connection conn,String Sql){        try {            Statement stmt = conn.createStatement();            stmt.executeUpdate(Sql);            System.out.println("update succeed");            if(stmt != null){                try {                    stmt.close();                } catch (Exception e) {                    e.printStackTrace();                }            }        } catch (SQLException e) {            e.printStackTrace();        }    }    public static void delete(Connection conn, String Sql){        try {            Statement stmt = conn.createStatement();            stmt.executeUpdate(Sql);            System.out.println("delete succeed");            if(stmt != null){                try {                    stmt.close();                } catch (Exception e) {                    e.printStackTrace();                }            }        } catch (SQLException e) {            e.printStackTrace();        }    }    public static void releaseConnection(Connection conn){        if(conn != null)            try {                conn.close();                System.out.println("release succeed!");            } catch (SQLException e) {                e.printStackTrace();            }    }}
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