dbutil.java

JavaBean+Jsp 开发的《手机商城系统》

package com.test.ps.util;

import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
import java.sql.Connection;
import java.sql.SQLException;

public class DBUtil {

	static String drivername = "com.mysql.jdbc.Driver";
	static String url = "jdbc:mysql://localhost:3306/phoneshop";
	static String username = "root";
	static String password = "1234";
	static Connection conn = null;
	static PreparedStatement pstmt = null;
	static Statement stmt = null;
	static ResultSet rs = null;

	/*
	 * 加载数据库驱动并连接
	 */
	public static Connection getConnection() {
		try {
			Class.forName(drivername);
			conn = DriverManager.getConnection(url, username, password);
			return conn;
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}
	}

	public static PreparedStatement prepare(Connection conn, String sql) {
		PreparedStatement pstmt = null;
		try {
			if (conn != null) {
				pstmt = conn.prepareStatement(sql);
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return pstmt;
	}

	public static Statement getStatement(Connection conn) {
		Statement stmt = null;
		try {
			if (conn != null) {
				stmt = conn.createStatement();
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return stmt;
	}

	public static ResultSet getResultSet(Statement stmt, String sql) {
		ResultSet rs = null;
		try {
			if (stmt != null) {
				rs = stmt.executeQuery(sql);
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return rs;
	}

	/*
	 * 处理插入或查询语句
	 */

	public static void executeUpdate(Statement stmt, String sql) {
		try {
			if (stmt != null) {
				stmt.executeUpdate(sql);
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}

	public static int executeUpdate(String sql) {
		int result = 0;
		try {
			conn = getConnection();
			stmt = conn.createStatement();
			result = stmt.executeUpdate(sql);
		} catch (SQLException ex) {
			result = 0;
		}
		try {
			stmt.close();
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return result;
	}

	public static ResultSet getResult(String SQL) {
		Connection con = getConnection();
		try {
			Statement stmt = con.createStatement();
			rs = stmt.executeQuery(SQL);
			//stmt.close();
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return rs;
	}
	
	/*
	 * 搜索功能 -查询数据方法
	 */
	public static  ResultSet executeQuery(String sql)
	{
		Connection conn= DBUtil.getConnection();
		try {
			Statement stmt =conn.createStatement();
			rs =  stmt.executeQuery(sql);
			//rs.last();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return rs;
	}
	
	/*
	 * 关闭数据库连接
	 */
	public static 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);
		}
	}

	/*
	 * 关闭结果集
	 */
	public static void closeConnection(Connection conn) {
		if (conn != null) {
			try {
				conn.close();

			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
		if (pstmt != null) {
			try {
				pstmt.close();

			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
		if (stmt != null) {
			try {
				stmt.close();

			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}

	/*
	 * 关闭结果集
	 */
	public static void CloseResultSet(ResultSet rs) {
		try {
			if (rs != null)
				rs.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public static void close(Connection conn) {
		try {
			if (conn != null) {
				conn.close();
				conn = null;
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}

	public static void close(Statement stmt) {
		try {
			if (stmt != null) {
				stmt.close();
				stmt = null;
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}

	public static void close(ResultSet rs) {
		try {
			if (rs != null) {
				rs.close();
				rs = null;
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}
}