c3p0 一个数据库链接的例子

首先需要准备三个依赖包 c3p0-0.9.5.2.jar、mchange-commons-java-0.2.11.jar、mysql-connector-java-5.1.47.jar

下载链接 https://files.cnblogs.com/files/ruber/lib.rar

 public class testMysql implements myRoot{
     private ComboPooledDataSource dataSource = null;
 //    private Connection connection = null;
     @Override
     public void done() {
         initMysql();

         Connection connection = getConnection();//获取自动提交数据库连接
         setAutoCommit(connection, true);

         String name = doSql(connection, String.class, "select playerName from t_player where playerId = ?", 2);
         System.out.println("name = " + name);

         tplayer player = doSql(connection, tplayer.class, "select * from t_player where playerId = ?", 2);

         System.out.println("getPlayerId = " + player.getPlayerId());
         System.out.println("getPlayerName = " + player.getPlayerName());
         System.out.println("getCreateTime = " + player.getCreateTime());
         System.out.println("getLoginTime = " + player.getLoginTime());
         System.out.println("getLogoutTime = " + player.getLogoutTime());

         //--------批量提交sql-------------

         String Ary[] = new String[2];
         Ary[0] = "UPDATE t_player SET playerName = \"ccc\" WHERE playerId = 3;";
         Ary[1] = "UPDATE t_player SET playerName = \"ddd\" WHERE playerId = 4;";

         batchSql(connection, Ary);
         closeConnection(connection);//关闭连接

     }
     //批量提交处理事务
     public void batchSql(Connection connection, String []Ary){
         Statement st = null;
         try {
             setAutoCommit(connection, false);//必须为false,否则java.sql.SQLException: Can't call commit when autocommit=true
             st = connection.createStatement();

             int c=0;
             for(String sql:Ary){
                 st.addBatch(sql);
                 c++;
                 if(c == 1000){//防止内存溢出，一次不要提交太多条,暂设1000条
                     st.executeBatch();
                     commit(connection);
                     st.clearBatch();
                     c=0;
                 }
                 if(c>0){
                     st.executeBatch();
                     commit(connection);
                     st.clearBatch();
                 }
             }

         } catch (SQLException e) {
             e.printStackTrace();
         }finally{
             setAutoCommit(connection, true);
             closeStateMent(st);
         }
     }

     /**
      * @param cls 返回类型类
      * @param sql sql语句
      * @param paramter sql语句参数
      * @return cls实例
      */
     @SuppressWarnings("unchecked")
     public <T>T doSql(Connection connection, Class<?> cls, String sql, Object... paramter){
         PreparedStatement pst = null;
         ResultSet rs = null;

         Object obj = null;
         try {
             pst = connection.prepareStatement(sql);//创建一个 PreparedStatement 对象来将参数化的 SQL 语句发送到数据库
             if(paramter != null && paramter.length  > 0){
                 int i=1;//从1开始
                 for(Object parm: paramter){
                     pst.setObject(i++, parm);//为sql语句设置参数
                 }
             }
             rs = pst.executeQuery();//执行语句，返回ResultSet结果
             while(rs.next()){
                 if(cls.getSimpleName().toLowerCase().equals("string")){//标准类型
                     obj = rs.getString(1);
                 }else{//自定义类型
                     obj = cls.newInstance();//创建自定义类型
                     ResultSetMetaData resultsetmetadata = rs.getMetaData();//整行列信息
                     int count = resultsetmetadata.getColumnCount();//列数量
                     for(int i=1; i<=count; i++){//从1开始
                         String columnlabel = resultsetmetadata.getColumnLabel(i);//当前列标头
                         String methName = "set" + columnlabel.substring(0, 1).toUpperCase() + columnlabel.substring(1);//自定义类型的方法名，次数为set方法

                         Method[] methods = cls.getDeclaredMethods();//自定义类型的方法数组
                         int methodsSize = methods.length;//方法数量
                         for(int j=0; j<methodsSize; j++){
                             if(methods[j].getName().equals(methName)){
                                 Parameter[] parameterAry = methods[j].getParameters();//获取方法参数数组
                                 Class<?> type = parameterAry[0].getType();//第一个参数类型 从0开始
                                 String typeName = type.getSimpleName().toLowerCase();//参数类型的名字
 //                                String typeName = methods[j].getParameters()[0].getType().getSimpleName().toLowerCase();//这种写法不被推荐
                                 //反射调用
                                 if(typeName.equals("int")){
                                     methods[j].invoke(obj, rs.getInt(i));
                                 }else if(typeName.equals("string")){
                                     methods[j].invoke(obj, rs.getString(i));
                                 }
                             }
                         }
                     }
                 }
             }
         } catch (Exception e) {
             e.printStackTrace();
         }finally{
             try {
                 if(pst != null){ pst.close(); }
                 if( rs != null){ rs.close();  }
             } catch (SQLException e) {
                 e.printStackTrace();
             }
         }
         return (T) obj;
     }
     public void initMysql(){

         dataSource = new ComboPooledDataSource();
         try {
             dataSource.setDriverClass("com.mysql.jdbc.Driver");//com.mysql.jdbc.Driver
         } catch (PropertyVetoException e) {
             e.printStackTrace();
         }
         dataSource.setJdbcUrl("jdbc:mysql://192.168.50.229:3306/banzhan_tplayer?autoReconnect=true&rewriteBatchedStatements=true&useUnicode=true&characterEncoding=utf-8&useSSL=false");//
         dataSource.setUser("root");//root
         dataSource.setPassword("123456");//
         dataSource.setInitialPoolSize(1);//5 数量机器相关
         dataSource.setMinPoolSize(1);
         dataSource.setMaxPoolSize(1);
         dataSource.setTestConnectionOnCheckin(true);        //每次获取connection测试其有效性
         dataSource.setAutomaticTestTable("C3P0TestTable");    //测试表
         dataSource.setIdleConnectionTestPeriod(360);        //每N秒检查一次空闲连接
         dataSource.setMaxIdleTime(720);
     }

     public Connection getConnection(){
         Connection connection = null;
         if(dataSource != null){
             try {
                 connection =  dataSource.getConnection();
             } catch (SQLException e) {
                 e.printStackTrace();
             }
         }
         return connection;
     }

     public void setAutoCommit(Connection connection, boolean autoCommit){

         try {
             connection.setAutoCommit(autoCommit);
         } catch (SQLException e) {
             e.printStackTrace();
         }

     }

     public void commit(Connection connection){
         try {
             connection.commit();
         } catch (SQLException e) {
             e.printStackTrace();
         }
     }
     public void closeStateMent(Statement pst){
         if(pst != null){
             try {
                 pst.close();
             } catch (SQLException e) {
                 e.printStackTrace();
             }
         }
     }

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