package com.aff.bookstore.web;

import java.sql.Connection;

public class ConnectionContext {

    private static ConnectionContext insetance = new ConnectionContext();

    public static ConnectionContext getInsetance() {

        return insetance;

    }

    private ThreadLocal<Connection> connectionThreadLocal = new ThreadLocal<>();

    public void bind(Connection connection) {

        connectionThreadLocal.set(connection);

    }

    public Connection get() {

        return connectionThreadLocal.get();

    }

    public void remove() {

        connectionThreadLocal.remove();

    }

}

package com.aff.bookstore.filter;

import java.io.IOException;

import java.sql.Connection;

import java.sql.SQLException;

import javax.servlet.Filter;

import javax.servlet.FilterChain;

import javax.servlet.FilterConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletRequest;

import javax.servlet.ServletResponse;

import javax.servlet.annotation.WebFilter;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.aff.bookstore.db.JDBCUtils;

import com.aff.bookstore.web.ConnectionContext;

@WebFilter("/*")

public class TranactionFilter implements Filter {

    public TranactionFilter() {

    }

    public void destroy() {

    }

    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 把连接和当前线程绑定

            ConnectionContext.getInsetance().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) {

            e.printStackTrace();

            // 6.回滚事务

            try {

                connection.rollback();

            } catch (SQLException e1) {

                e1.printStackTrace();

            }

            HttpServletResponse resp = (HttpServletResponse) response;

            HttpServletRequest req = (HttpServletRequest) request;

            resp.sendRedirect(req.getContextPath()+"/errror-1.jsp");

        } finally {

            // 7.解除连接

            ConnectionContext.getInsetance().remove();

            // 8.关闭连接

            JDBCUtils.release(connection);

        }

    }

    public void init(FilterConfig fConfig) throws ServletException {

    }

}