工具类4

落日映苍穹つ 2022-08-09 02:11 110阅读 0赞

package cn.itcast.jdbc;
    
    import java.io.InputStream;
    import java.sql.Connection;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.sql.Statement;
    import java.util.Properties;
    
    import javax.sql.DataSource;
    
    import org.apache.commons.dbcp.BasicDataSourceFactory;
    
    public final class JdbcUtils { 
    
        private static DataSource myDataSource = null;
    
        private JdbcUtils() {
        }
    
        static {
            try {
                Properties prop = new Properties();
                InputStream is = JdbcUtils.class.getClassLoader()
                        .getResourceAsStream("dbcpconfig.properties");
                prop.load(is);
                myDataSource = BasicDataSourceFactory.createDataSource(prop); // 屏蔽了创建数据源的过程
            } catch (Exception e) {
                throw new ExceptionInInitializerError(e);
            }
        }
    
        public static Connection getConnection() throws SQLException {
            // return DriverManager.getConnection(url, user, password);
            return myDataSource.getConnection(); // 取连接
        }
    
        public static void free(ResultSet rs, Statement st, Connection conn) {
            try {
                if (rs != null)
                    rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            } finally {
                try {
                    if (st != null)
                        st.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                } finally {
                    try {
                        if (conn != null)
                            conn.close();
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    }