java实现数据库连接的工具类
第一种 (带事务)
package com.china.util; import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; public class BaseDao { protected Connection conn = null; /** * 创建数据库连接 * @throws ClassNotFoundException * @throws SQLException */ protected void openconnection() throws ClassNotFoundException,SQLException{ try { if( conn == null || conn.isClosed() ){ Class.forName("oracle.jdbc.driver.OracleDriver"); conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:xe","xx","xx"); //mysql //Class.forName("com.mysql.jdbc.Driver"); // conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/xe", "root", "root"); } } catch (ClassNotFoundException e) { throw e; } catch (SQLException e) { throw e; } } /** * 手动提交事务 * @throws Exception */ public void beginTransaction() throws Exception{ this.openconnection(); conn.setAutoCommit(false); } /** * 事务回滚 * @throws Exception */ public void rollback() throws Exception{ if(conn != null){ conn.rollback(); } } /** * 事务提交 * @throws Exception */ public void commit() throws Exception{ if(conn != null){ conn.commit(); } } /** * 关闭数据库 * @throws Exception */ public void closeResource() throws Exception{ if(conn != null){ conn.close(); } } }
第二种(mysql和oracle无事务)推荐!
package com.smn.toolsbean; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; public class DB { private final String url = "jdbc:mysql://127.0.0.1:3306/blog"; private final String userName = "root"; private final String password = "toor"; private Connection con = null; private Statement stm=null; /* 通过构造方法加载数据库驱动 */ public DB(){ try { Class.forName("com.mysql.jdbc.Driver"); } catch (Exception e) { e.printStackTrace(); System.out.println("加载数据库驱动失败!"); } } /* 创建数据库连接 */ public void createCon() { try { con = DriverManager.getConnection(url, userName, password); } catch (Exception e) { e.printStackTrace(); System.out.println("获取数据库连接失败!"); } } /* 获取Statement对象 */ public void getStm(){ createCon(); try { stm=con.createStatement(); } catch (SQLException e) { e.printStackTrace(); System.out.println("创建Statement对象失败!"); } } /** * @功能 对数据库的增加、修改和删除的操作 * @参数 sql为要执行的SQL语句 * @返回值 boolean型值 */ public boolean executeUpdate(String sql) { System.out.println(sql); boolean mark=false; try { getStm(); int iCount = stm.executeUpdate(sql); if(iCount>0) mark=true; else mark=false; } catch (Exception e) { e.printStackTrace(); mark=false; } return mark; } /* 查询数据库 */ public ResultSet executeQuery(String sql) { ResultSet rs=null; try { getStm(); try { rs = stm.executeQuery(sql); } catch (Exception e) { e.printStackTrace(); System.out.println("查询数据库失败!"); } } catch (Exception e) { e.printStackTrace(); } return rs; } /* 关闭数据库的操作 */ public void closed() { if(stm!=null) try { stm.close(); } catch (SQLException e) { e.printStackTrace(); System.out.println("关闭stm对象失败!"); } if(con!=null) try { con.close(); } catch (SQLException e) { e.printStackTrace(); System.out.println("关闭con对象失败!"); } } }
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