conndb.java~12~

是一个用jsp做前台

package core;

import java.sql.*;
import java.util.Properties;
import java.io.*;

public class ConnDB {
    public Connection conn=null;
    public ResultSet rs=null;
    public Statement stmt=null;
    private static String propFileName="connDB.properties";
    private static Properties prop=new Properties();
    private static String dbClassName =
    "com.mysql.jdbc.Driver";
    private static String dbUrl =
    "jdbc:mysql://127.0.0.1:3306/db_library";
    private static String dbUser = "admin";
    private static String dbPwd = "111";

    private static void loadProperty() {
        try {
            prop.load(new FileInputStream(propFileName)); //通过文件输入流对象加载Properties文件
            dbClassName = prop.getProperty("DB_CLASS_NAME");
            dbUrl = prop.getProperty("DB_URL",
                                     "jdbc:mysql://127.0.0.1:3306/db_library");
            dbUser = prop.getProperty("DB_USER", "admin");
            dbPwd = prop.getProperty("DB_PWD", "111");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    public static Connection getConnection() {
      Connection conn = null;
      loadProperty();
      try {
        Class.forName(dbClassName).newInstance();
        conn = DriverManager.getConnection(dbUrl, dbUser, dbPwd);
      }
      catch (Exception ee) {
        ee.printStackTrace();
      }
      if (conn == null) {
        System.err.println(
            "警告: DbConnectionManager.getConnection() 获得数据库链接失败.\r\n\r\n链接类型:" +
            dbClassName + "\r\n链接位置:" + dbUrl + "\r\n用户/密码" + dbUser + "/" +
            dbPwd);
      }
      return conn;
    }
    /*
 *功能：执行查询语句
 */
public ResultSet executeQuery(String sql) {
  try {
    conn = getConnection();
    stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
                                ResultSet.CONCUR_READ_ONLY);
    rs = stmt.executeQuery(sql);
  }
  catch (SQLException ex) {
    System.err.println(ex.getMessage());
  }
  return rs;
}

/*
 *功能:执行更新操作
 */
public int executeUpdate(String sql) {
  int result = 0;
  try {
    conn = getConnection();
    stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
                                ResultSet.CONCUR_READ_ONLY);
    result = stmt.executeUpdate(sql);
  }
  catch (SQLException ex) {
    result = 0;
  }
  try {
    stmt.close();
  }
  catch (SQLException ex1) {
  }
  return result;
}

public int executeUpdate_id(String sql) {
  int result = 0;
  try {
    conn = getConnection();
    stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
                                ResultSet.CONCUR_READ_ONLY);
    result = stmt.executeUpdate(sql);
    String ID = "select @@IDENTITY as id";
    rs = stmt.executeQuery(ID);
    if (rs.next()) {
      int autoID = rs.getInt("id");
      result = autoID;
    }
  }
  catch (SQLException ex) {
    result = 0;
  }
  return result;
}
    /*
     *功能:关闭数据库的连接
     */
    public void close() {
      try {
        if (rs != null) {
          rs.close();
        }
      }
      catch (Exception e) {
        e.printStackTrace(System.err);
      }
      try {
        if (stmt != null) {
          stmt.close();
        }
      }
      catch (Exception e) {
        e.printStackTrace(System.err);
      }
      try {
        if (conn != null) {
          conn.close();
        }
      }
      catch (Exception e) {
        e.printStackTrace(System.err);
      }
  }
}