一. 资源文件（resources）

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--跟标签beans，里面配置一个又一个的bean子标签，每一个bean子标签都代表一个类的配置-->
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/tx
        https://www.springframework.org/schema/tx/spring-tx.xsd
">


    <!--id标识对象，class是类的全限定类名-->

    <!--scope：定义bean的作用范围

                singleton：单例，IOC容器中只有一个该类对象，默认为singleton
                prototype：原型(多例)，每次使用该类的对象（getBean），都返回给你一个新的对象，Spring只创建对象，不管理对象
    -->
    <bean id="accountDao" class="com.lagou.edu.dao.impl.JdbcAccountDaoImpl" scope="singleton" init-method="init" destroy-method="destory">


    <bean id="transferService" class="com.lagou.edu.service.impl.TransferServiceImpl">
        <!--set+ name 之后锁定到传值的set方法了，通过反射技术可以调用该方法传入对应的值-->
        <property name="AccountDao" ref="accountDao"></property>
    </bean>




    <!--事务管理器-->
    <bean id="transactionManager" class="com.lagou.edu.utils.TransactionManager">
        <property name="ConnectionUtils" ref="connectionUtils"/>
    </bean>

    <!--代理对象工厂-->
    <bean id="proxyFactory" class="com.lagou.edu.factory.ProxyFactory">
        <property name="TransactionManager" ref="transactionManager"/>
    </bean>


    <!--Spring ioc 实例化Bean的三种方式-->
    <!--方式一：使用无参构造器（推荐）-->
    <bean id="connectionUtils" class="com.lagou.edu.utils.ConnectionUtils"></bean>

    <!--另外两种方式是为了我们自己new的对象加入到SpringIOC容器管理-->
    <!--方式二：静态方法-->
    <!--<bean id="connectionUtils" class="com.lagou.edu.factory.CreateBeanFactory" factory-method="getInstanceStatic"/>-->
    <!--方式三：实例化方法-->
    <!--<bean id="createBeanFactory" class="com.lagou.edu.factory.CreateBeanFactory"></bean>
    <bean id="connectionUtils" factory-bean="createBeanFactory" factory-method="getInstance"/>-->



    <!--lazy-init默认为false立即加载-->
    <bean id="accountPojo" class="com.lagou.edu.pojo.Account" lazy-init="true"/>


</beans>

jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/bank
jdbc.username=root
jdbc.password=123456

二. 工具类

ConnectionUtils

package com.lagou.edu.utils;

import com.alibaba.druid.pool.DruidDataSource;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;

/**
 * @author 应癫
 */
public class ConnectionUtils {


   
    private ThreadLocal<Connection> threadLocal = new ThreadLocal<>(); // 存储当前线程的连接

    /**
     * 从当前线程获取连接
     */
    public Connection getCurrentThreadConn() throws SQLException {
        /**
         * 判断当前线程中是否已经绑定连接，如果没有绑定，需要从连接池获取一个连接绑定到当前线程
          */
        Connection connection = threadLocal.get();
        if(connection == null) {
            // 从连接池拿连接并绑定到线程
            connection = DruidUtils.getInstance().getConnection();
            // 绑定到当前线程
            threadLocal.set(connection);
        }
        return connection;

    }
}

JsonUtils

package com.lagou.edu.utils;

import java.util.List;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;

/**
 * JSON工具类（使用的是jackson实现的）
 * @author 应癫
 */
public class JsonUtils {

    private static final ObjectMapper MAPPER = new ObjectMapper();

    /**
     * 将对象转换成json字符串。
     * @param data
     * @return
     */
    public static String object2Json(Object data) {
    	try {
			String string = MAPPER.writeValueAsString(data);
			return string;
		} catch (JsonProcessingException e) {
			e.printStackTrace();
		}
    	return null;
    }
    
    /**
     * 将json结果集转化为对象
     * 
     * @param jsonData json数据
     * @param beanType 对象中的object类型
     * @return
     */
    public static <T> T json2Pojo(String jsonData, Class<T> beanType) {
        try {
            T t = MAPPER.readValue(jsonData, beanType);
            return t;
        } catch (Exception e) {
        	e.printStackTrace();
        }
        return null;
    }
    
    /**
     * 将json数据转换成pojo对象list
     * @param jsonData
     * @param beanType
     * @return
     */
    public static <T>List<T> json2List(String jsonData, Class<T> beanType) {
    	JavaType javaType = MAPPER.getTypeFactory().constructParametricType(List.class, beanType);
    	try {
    		List<T> list = MAPPER.readValue(jsonData, javaType);
    		return list;
		} catch (Exception e) {
			e.printStackTrace();
		}
    	
    	return null;
    }
    
}

TransactionManager

package com.lagou.edu.utils;

import java.sql.SQLException;

/**
 * @author 应癫
 *
 * 事务管理器类：负责手动事务的开启、提交、回滚
 */
public class TransactionManager {

    private ConnectionUtils connectionUtils;

    public void setConnectionUtils(ConnectionUtils connectionUtils) {
        this.connectionUtils = connectionUtils;
    }




    // 开启手动事务控制
    public void beginTransaction() throws SQLException {
        connectionUtils.getCurrentThreadConn().setAutoCommit(false);
    }


    // 提交事务
    public void commit() throws SQLException {
        connectionUtils.getCurrentThreadConn().commit();
    }


    // 回滚事务
    public void rollback() throws SQLException {
        connectionUtils.getCurrentThreadConn().rollback();
    }
}

三. 实体类

Account

package com.lagou.edu.pojo;

/**
 * @author 应癫
 */
public class Account {

    private String cardNo;
    private String name;
    private int money;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getMoney() {
        return money;
    }

    public void setMoney(int money) {
        this.money = money;
    }

    public String getCardNo() { return cardNo; }

    public void setCardNo(String cardNo) { this.cardNo = cardNo;}

    @Override
    public String toString() {
        return "Account{" +
                "cardNo='" + cardNo + '\'' +
                ", name='" + name + '\'' +
                ", money=" + money +
                '}';
    }
}

四. 工厂类

ProxyFactory

package com.lagou.edu.factory;

import com.lagou.edu.pojo.Account;
import com.lagou.edu.utils.TransactionManager;
import net.sf.cglib.proxy.Enhancer;
import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

/**
 * @author 应癫
 *
 *
 * 代理对象工厂：生成代理对象的
 */

public class ProxyFactory {


    private TransactionManager transactionManager;

    public void setTransactionManager(TransactionManager transactionManager) {
        this.transactionManager = transactionManager;
    }





    /**
     * Jdk动态代理
     * @param obj  委托对象
     * @return   代理对象
     */
    public Object getJdkProxy(Object obj) {

        // 获取代理对象
        return  Proxy.newProxyInstance(obj.getClass().getClassLoader(), obj.getClass().getInterfaces(),
                new InvocationHandler() {
                    @Override
                    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                        Object result = null;

                        try{
                            // 开启事务(关闭事务的自动提交)
                            transactionManager.beginTransaction();

                            result = method.invoke(obj,args);

                            // 提交事务

                            transactionManager.commit();
                        }catch (Exception e) {
                            e.printStackTrace();
                            // 回滚事务
                            transactionManager.rollback();

                            // 抛出异常便于上层servlet捕获
                            throw e;

                        }

                        return result;
                    }
                });

    }


    /**
     * 使用cglib动态代理生成代理对象
     * @param obj 委托对象
     * @return
     */
    public Object getCglibProxy(Object obj) {
        return  Enhancer.create(obj.getClass(), new MethodInterceptor() {
            @Override
            public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
                Object result = null;
                try{
                    // 开启事务(关闭事务的自动提交)
                    transactionManager.beginTransaction();

                    result = method.invoke(obj,objects);

                    // 提交事务

                    transactionManager.commit();
                }catch (Exception e) {
                    e.printStackTrace();
                    // 回滚事务
                    transactionManager.rollback();

                    // 抛出异常便于上层servlet捕获
                    throw e;

                }
                return result;
            }
        });
    }
}

五. DAO层

JdbcAccountDaoImpl

package com.lagou.edu.dao.impl;

import com.lagou.edu.pojo.Account;
import com.lagou.edu.dao.AccountDao;
import com.lagou.edu.utils.ConnectionUtils;
import com.lagou.edu.utils.DruidUtils;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.Map;
import java.util.Properties;
import java.util.Set;

/**
 * @author 应癫
 */
public class JdbcAccountDaoImpl implements AccountDao {

    private ConnectionUtils connectionUtils;


    public void setConnectionUtils(ConnectionUtils connectionUtils) {
        this.connectionUtils = connectionUtils;
    }


    public void init() {
        System.out.println("初始化方法.....");
    }

    public void destory(){
        System.out.println("销毁方法.....");
    }

    @Override
    public Account queryAccountByCardNo(String cardNo) throws Exception {
        //从连接池获取连接
        // Connection con = DruidUtils.getInstance().getConnection();
        Connection con = connectionUtils.getCurrentThreadConn();
        String sql = "select * from account where cardNo=?";
        PreparedStatement preparedStatement = con.prepareStatement(sql);
        preparedStatement.setString(1,cardNo);
        ResultSet resultSet = preparedStatement.executeQuery();

        Account account = new Account();
        while(resultSet.next()) {
            account.setCardNo(resultSet.getString("cardNo"));
            account.setName(resultSet.getString("name"));
            account.setMoney(resultSet.getInt("money"));
        }

        resultSet.close();
        preparedStatement.close();
        //con.close();

        return account;
    }

    @Override
    public int updateAccountByCardNo(Account account) throws Exception {

        // 从连接池获取连接
        // 改造为：从当前线程当中获取绑定的connection连接
        //Connection con = DruidUtils.getInstance().getConnection();
        Connection con = connectionUtils.getCurrentThreadConn();
        System.out.println("=======================con::::" + con);
        String sql = "update account set money=? where cardNo=?";
        PreparedStatement preparedStatement = con.prepareStatement(sql);
        preparedStatement.setInt(1,account.getMoney());
        preparedStatement.setString(2,account.getCardNo());
        int i = preparedStatement.executeUpdate();

        preparedStatement.close();
        //con.close();
        return i;
    }
}

六. service层

TransferServiceImpl

package com.lagou.edu.service.impl;

import com.lagou.edu.dao.AccountDao;
import com.lagou.edu.pojo.Account;
import com.lagou.edu.service.TransferService;
import com.lagou.edu.utils.ConnectionUtils;
import com.lagou.edu.utils.TransactionManager;

/**
 * @author 应癫
 */
public class TransferServiceImpl implements TransferService {



    // 最佳状态
    private AccountDao accountDao;

    // 构造函数传值/set方法传值

    public void setAccountDao(AccountDao accountDao) {
        this.accountDao = accountDao;
    }


    @Override
    public void transfer(String fromCardNo, String toCardNo, int money) throws Exception {


            Account from = accountDao.queryAccountByCardNo(fromCardNo);
            Account to = accountDao.queryAccountByCardNo(toCardNo);

            from.setMoney(from.getMoney()-money);
            to.setMoney(to.getMoney()+money);

            accountDao.updateAccountByCardNo(to);
            int c = 1/0;
            accountDao.updateAccountByCardNo(from);





    }
}

七. 启动

（一）JAVA环境

import com.lagou.edu.dao.AccountDao;


import org.junit.Test;

import org.springframework.context.support.ClassPathXmlApplicationContext;


/**
 * @author 应癫
 */
public class IoCTest {


    @Test
    public void testIoC() throws Exception {

        // 通过读取classpath下的xml文件来启动容器（xml模式SE应用下推荐）
        ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("classpath:applicationContext.xml");

        // 不推荐使用
        //ApplicationContext applicationContext1 = new FileSystemXmlApplicationContext("文件系统的绝对路径");


        // 第一次getBean该对象
        Object accountPojo = applicationContext.getBean("accountPojo");

        AccountDao accountDao = (AccountDao) applicationContext.getBean("accountDao");

        accountDao.queryAccountByCardNo("1111111");
        System.out.println("accountDao：" + accountDao);
        AccountDao accountDao1 = (AccountDao) applicationContext.getBean("accountDao");
        System.out.println("accountDao1：" + accountDao1);


        Object connectionUtils = applicationContext.getBean("connectionUtils");
        System.out.println(connectionUtils);

        applicationContext.close();




    }

}

（二）WEB环境

web.xml

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
  <display-name>Archetype Created Web Application</display-name>


  <!--配置Spring ioc容器的配置文件-->
  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:applicationContext.xml</param-value>
  </context-param>
  <!--使用监听器启动Spring的IOC容器-->
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>
</web-app>

index.html

<!doctype html>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>转账汇款</title>

    <script type="text/javascript" src="js/jquery-3.4.1.min.js"></script>


    <style type="text/css">
        body {
            background-color:#00b38a;
            text-align:center;
        }

        .lp-login {
            position:absolute;
            width:500px;
            height:300px;
            top:50%;
            left:50%;
            margin-top:-250px;
            margin-left:-250px;
            background: #fff;
            border-radius: 4px;
            box-shadow: 0 0 10px #12a591;
            padding: 57px 50px 35px;
            box-sizing: border-box
        }


        .lp-login .submitBtn {
            display:block;
            text-decoration:none;
            height: 48px;
            width: 150px;
            line-height: 48px;
            font-size: 16px;
            color: #fff;
            text-align: center;
            background-image: -webkit-gradient(linear, left top, right top, from(#09cb9d), to(#02b389));
            background-image: linear-gradient(90deg, #09cb9d, #02b389);
            border-radius: 3px
        }


        input[type='text'] {
            height:30px;
            width:250px;
        }

        span {
            font-style: normal;
            font-variant-ligatures: normal;
            font-variant-caps: normal;
            font-variant-numeric: normal;
            font-variant-east-asian: normal;
            font-weight: normal;
            font-stretch: normal;
            font-size: 14px;
            line-height: 22px;
            font-family: "Hiragino Sans GB", "Microsoft Yahei", SimSun, Arial, "Helvetica Neue", Helvetica;
        }

    </style>
    <script type="text/javascript">
        $(function(){
            $(".submitBtn").bind("click",function(){
                var fromAccount = $("#fromAccount").val();
                var toAccount = $("#toAccount").val();
                var money = $("#money").val();

                if(money == null || $.trim(money).length == 0){
                    alert("sorry,必须输入转账金额~");
                    return;
                }

                $.ajax({
                    url:'/transferServlet',
                    type:'POST',    //GET
                    async:false,    //或false,是否异步
                    data:{
                        fromCardNo:fromAccount.split(' ')[1],
                        toCardNo:toAccount.split(' ')[1],
                        money:money
                    },
                    timeout:5000,    //超时时间
                    dataType:'json', //返回的数据格式：json/xml/html/script/jsonp/text
                    success:function(data){
                        if("200" == data.status){
                            alert("转账成功~~~");
                        }else{
                            alert("转账失败~~~,message:" + data.message);
                        }
                    }
                })
            })
        })

        //检查输入值是否为整数
        function checkFormat(obj){
            var reg = /^[0-9]+[0-9]*]*$/;
            if($.trim($(obj).val()).length>0){
                if(!reg.test($(obj).val())){
                    alert("输入格式错误！请输整数！");
                    $(obj).val("");
                }else{
                    $(obj).val(parseInt($(obj).val()));
                }
            }
        }
    </script>
</head>
<body>


<form>
    <table class="lp-login">
        <tr>
            <td align="right"><span>收款账户</span></td>
            <td align="center">
                <input type="text" id="toAccount" value="韩梅梅 6029621011001" disabled></input>
            </td>
        </tr>
        <tr>
            <td align="right"><span>付款账户</span></td>
            <td align="center">
                <input type="text" id="fromAccount" value="李大雷 6029621011000" disabled></input>
            </td>
        </tr>
        <tr>
            <td align="right"><span>转账金额</span></td>
            <td align="center">
                <input type="text" id="money" onblur="checkFormat(this)"></input>
            </td>
        </tr>
        <tr align="center">
            <td colspan="2">
                <a href="javasrcipt:void(0)" class="submitBtn"><span>转 出</span></a>
            </td>
        </tr>
    </table>
</form>

</body>
</html>

TransferServlet

package com.lagou.edu.servlet;

import com.lagou.edu.factory.ProxyFactory;
import com.lagou.edu.utils.JsonUtils;
import com.lagou.edu.pojo.Result;
import com.lagou.edu.service.TransferService;
import org.springframework.web.bind.support.WebExchangeBindException;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * @author 应癫
 */
@WebServlet(name="transferServlet",urlPatterns = "/transferServlet")
public class TransferServlet extends HttpServlet {


    private TransferService transferService = null ;


    @Override
    public void init() throws ServletException {
        WebApplicationContext webApplicationContext = WebApplicationContextUtils.getWebApplicationContext(this.getServletContext());
        transferService = (TransferService) webApplicationContext.getBean("transferService");


    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        // 设置请求体的字符编码
        req.setCharacterEncoding("UTF-8");

        String fromCardNo = req.getParameter("fromCardNo");
        String toCardNo = req.getParameter("toCardNo");
        String moneyStr = req.getParameter("money");
        int money = Integer.parseInt(moneyStr);

        Result result = new Result();

        try {

            // 2. 调用service层方法
            transferService.transfer(fromCardNo,toCardNo,money);
            result.setStatus("200");
        } catch (Exception e) {
            e.printStackTrace();
            result.setStatus("201");
            result.setMessage(e.toString());
        }

        // 响应
        resp.setContentType("application/json;charset=utf-8");
        resp.getWriter().print(JsonUtils.object2Json(result));
    }
}