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");//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();
        }
    }
}