事务处理中如何获取同一个connection 对象

时间:2022-10-26 19:26:45

运用线程内部的map属性,将对象绑定到ThreadLocal中:

具体实现:

1.新建一个绑定Connection对象的单例类

public class ConnectionBind {
    private ConnectionBind(){}
    private static ConnectionBind instance=new ConnectionBind();
    public static ConnectionBind getInstance() {
        return instance;
    }    
    private ThreadLocal<Connection> threadLocal=new ThreadLocal<>();
    
    //线程绑定
    public void bind(Connection connection){
        threadLocal.set(connection);
    }
    
    //获取绑定的线程对象
    public Connection get(){
        return threadLocal.get();
    }
    
    //解出绑定
    public void remove(){
        threadLocal.remove();
    }    
}

2.新建一个ThreadLocationFilter过滤器,对所有的请求过滤,在doFilter方法中做如下实现:

public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        Connection connection=null;
        try {
            //1.获取连接
            connection =JdbcUtils.getConnection();
            
            //2.开启事务
            connection.setAutoCommit(false);
            
            //3.利用ThreadLocal把当前连接和当前线程绑定
            ConnectionBind.getInstance().bind(connection);
            
            //4.把请求转给目标Servlet
            chain.doFilter(request, response);
//5.提交事务 connection.commit(); } catch (Exception e) { //6.回滚事务 try { connection.rollback(); } catch (SQLException e1) { e1.printStackTrace(); }
       //重定向到错误页面 HttpServletRequest request2
=(HttpServletRequest) request; HttpServletResponse response2=(HttpServletResponse) response; response2.sendRedirect(request2.getContextPath()+"/error-1.jsp"); }finally{ //7.解出绑定 ConnectionBind.getInstance().remove(); //8.关闭数据库连接 JdbcUtils.releaseConnection(connection); } }

3.获取同一个Connection连接对象

Connection connection=null;
connection=ConnectionBind.getInstance().get();