简易SSM框架转账

编译器：IDEA

数据库：Mysql 8.0

项目要求：实现张三给李四转账

如果自己有项目，可以根据本篇文章修改

一、导入数据库

-- 因为我们项目的目标只是实现一个简单的转账，所以我们只使用一个user表，一共三个字段，id，名字，余额

可以自己搭，也可以用下面的


SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------
-- Table structure for user
-- ----------------------------
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user`  (
  `user_id` int(11) NOT NULL,
  `user_name` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL,
  `user_money` float(50, 0) NULL DEFAULT NULL,
  PRIMARY KEY (`user_id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci ROW_FORMAT = Dynamic;

-- ----------------------------
-- Records of user
-- ----------------------------
INSERT INTO `user` VALUES (1, '张三', 90);
INSERT INTO `user` VALUES (2, '李四', 20);
INSERT INTO `user` VALUES (3, '王五', 90);
INSERT INTO `user` VALUES (4, '赵六', 0);

SET FOREIGN_KEY_CHECKS = 1;

清楚自己需要做什么功能，准备对应的sql语句

二、创建工程

（一）创建目录结构及类

控制器，Dao，实体，服务

（是类，是接口）

然后添加一个汤姆猫

三、导包

打开pom.xml，粘贴后记得刷一下如果刷不了可以右键 --> meven -->Reload project

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.fix</groupId>
  <artifactId>hellossm</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>hellossm Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <!-- 统一 spring 版本  -->
  <properties>
    <spring.version>5.1.8.RELEASE</spring.version>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-test</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <!--    日志-->
    <dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>1.2.17</version>
    </dependency>
    <!--    测试-->
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
      <scope>test</scope>
    </dependency>

    <!-- spring   -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <!-- 切入点解析 -->
    <dependency>
      <groupId>org.aspectj</groupId>
      <artifactId>aspectjweaver</artifactId>
      <version>1.8.7</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <!-- springmvc 返回json数据   -->
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.9.8</version>
    </dependency>
    <!-- servlet,jsp ,jstl -->
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>3.1.0</version>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>javax.servlet.jsp</groupId>
      <artifactId>jsp-api</artifactId>
      <version>2.0</version>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>jstl</artifactId>
      <version>1.2</version>
    </dependency>

    <!--    这里装的是mysql5的话可以换成5-->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>8.0.15</version>
    </dependency>
    <!--  阿里的连接池 -->
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid</artifactId>
      <version>1.1.10</version>
    </dependency>
    <!-- mybatis 依赖  -->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.3.0</version>
    </dependency>
    <!-- mybatis 跟spring整合 依赖  -->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>1.2.3</version>
    </dependency>
    <!-- 分页插件 pagehelper -->
    <dependency>
      <groupId>com.github.pagehelper</groupId>
      <artifactId>pagehelper</artifactId>
      <version>5.1.8</version>
    </dependency>

    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <version>1.18.12</version>
    </dependency>
  </dependencies>
</project>

四、配置文件

（一）创建配置文件

在目录下 resources 目录下创建五个文件

jdbc.properties mybatis-config.xml spring-dao.xml spring-web-xml

userMapper.xml (要在resources中建mapper包，并放在包里)

jdbc.properties

(替换自己的mysql账户密码跟数据库名)

jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/up?useUnicode=true&characterEncoding=utf8&serverTimezone=Asia/Shanghai
jdbc.username=root
jdbc.password=a123

mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <settings>
        <!-- 使用jdbc 获取数据库自增主键 -->
        <setting name="useGeneratedKeys" value="true"/>
<!--    驼峰命名转换-->
<!--        <setting name="mapUnderscoreToCamelCase"  value="true"/>-->
        <!-- 打印查询语句 打印mybatis使用的sql语句 -->
        <setting name="logImpl" value="STDOUT_LOGGING" />
    </settings>
</configuration>

spring-dao.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
 http://www.springframework.org/schema/beans/spring-beans.xsd
 http://www.springframework.org/schema/context
 http://www.springframework.org/schema/context/spring-context.xsd
 http://www.springframework.org/schema/tx
 http://www.springframework.org/schema/tx/spring-tx.xsd">

    <!-- 扫描service 包下所有使用注解的类 -->
    <context:component-scan base-package="com.an"/>

    <!-- 配置整合 mybatis 过程 -->
    <context:property-placeholder location="classpath:jdbc.properties"/>

    <!-- 数据库连接池 -->
    <bean id="dataSource"
          class="com.alibaba.druid.pool.DruidDataSource" destroy-method="close">
        <!-- 数据库连接相关信息 -->
        <property name="url" value="${jdbc.url}"/>
        <property name="driverClassName" value="${jdbc.driver}"/>
        <property name="username" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>
    </bean>

    <bean id="sessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!-- 注入连接池 -->
        <property name="dataSource" ref="dataSource"/>
        <!-- 配置mybatis 全局配置文件 mybatis-config.xml -->
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
        <!-- 扫描entity  -->
        <property name="typeAliasesPackage" value="com.an.entity"/>
        <!-- 扫描 mapper   -->
        <property name="mapperLocations" value="classpath:mapper/*.xml"/>
    </bean>

    <!-- 配置扫描dao 接口包，动态实现DAO 接口，注入spring 容器 -->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <!-- 注入 sessionFactory -->
        <property name="sqlSessionFactoryBeanName" value="sessionFactory"/>
        <!-- 给出扫描dao 接口包 -->
        <property name="basePackage" value="com.an.dao"/>
    </bean>

    <!-- 事务管理器 -->
    <bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <!--  注入连接池  -->
        <property name="dataSource" ref="dataSource"/>
    </bean>
    <!-- 基于注解的声明式事务  -->
    <tx:annotation-driven transaction-manager="txManager"/>

</beans>

spring-web.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!-- 扫描service 包下所有使用注解的类 -->
    <context:component-scan base-package="com.an"/>

    <!-- 配置springmvc  开启注解-->
    <mvc:default-servlet-handler/>

<!--    中文乱码问题解决-->
    <mvc:annotation-driven>
        <mvc:message-converters>
            <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                <property name="supportedMediaTypes">
                    <list>
                        <value>text/plain;charset=UTF-8</value>
                        <value>text/html;charset=UTF-8</value>
                        <value>application/json;charset=UTF-8</value>
                    </list>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>

    <!-- 视图解析器   -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/pages/"></property>
        <property name="suffix" value=".jsp"></property>
    </bean>

</beans>

userMapper.xml

这里填sql语句 #{ }是占位符

<mapper namespace="com.an.dao.UserDao">指定接口，mapper标签里面的标签id指定接口方法，占位符内映射为方法传入的参数

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.an.dao.UserDao">
    <select id="selectUser" resultType="User">
        select * from user where user_id = #{uid}
    </select>

    <update id="updateUserMoney">
        update user set user_money = #{money} where user_id = #{uid}
    </update>

</mapper>

（二）web.xml,开启spring

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
         id="WebApp_ID" version="3.0">

  <display-name>ssm</display-name>

<--  开启spring -->
  <servlet>
    <servlet-name>spring</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:spring-*.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>spring</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>

</web-app>

三、类

如果按照之前的建好包了，那么就可以开始着手写类了

（一）实体

所在包：entity

User

实体类中的变量名与数据库的名字一样（避免不必要的冲突）

这里使用了lombok动态生成get set

package com.an.entity;

import lombok.Data;

@Data
public class User {
    int user_id;
    String user_name;
    float user_money;
}

（二）Dao

UserDao

类型接口，用与与mapper交涉

package com.an.dao;
import com.an.entity.User;
import org.apache.ibatis.annotations.Param;

import java.util.List;

public interface UserDao {
     User selectUser(int uid);
//    查询某人

     int updateUserMoney(@Param("uid") int uid,@Param("money") float money);
//    修改余额,这里用@param是因为要映射到mapper，之前试了不写就会说匹配不到参数
}

（三）服务以及服务实现

UserService

跟Userdao写一样就行（别把类名也写一样了）

     package com.an.service;
     import com.an.entity.User;
     import java.util.List;
     
     public interface UserService {
          User selectUser(int uid);
     //    查询某人
     
          int updateUserMoney(int uid,float money);
     //    修改余额
     }

UserServiceImpl

最后这四个字母是大写的挨 I 按亩m 批p 爱奥 l

package com.an.service.Impl;

import com.an.dao.UserDao;
import com.an.entity.User;
import com.an.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service
public class UserServiceImpl implements UserService {

    @Autowired
    UserDao userdao;

    @Override
    public User selectUser(int uid) {
        System.out.println("selectUser  进入服务层");
        User userAll = userdao.selectUser(uid);
        return userAll;
    }

    @Override
    public int updateUserMoney(int uid,float money) {
        System.out.println("updateUserMoney  进入服务层  uid  -->" +uid  +";  money --> "+ money);
        int succ = userdao.updateUserMoney(uid,money);
        return succ;
    }
}

四、测试

写完就可以进入测试流程了

我们可以在dao这里创建一个测试类

选择junit4，把下面两个方法勾上

测试类会放在这个地方，不会被运行编译，方法单独运行

UserDaoTest

开始测试

package com.an.dao;

import com.an.entity.User;
import com.an.service.Impl.UserServiceImpl;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:spring-dao.xml")
//这里直接把spring配置进去，因为要装配一个容器
public class UserDaoTest {

    @Autowired
    ApplicationContext context;
//装配容器

    @Test
    public void selectUser() {
        UserServiceImpl userService = context.getBean(UserServiceImpl.class);
//        拿取实现类
        User u = userService.selectUser(1);
        System.out.println(u);

    }

    @Test
    public void updateUserMoney() {
        UserServiceImpl userService = context.getBean(UserServiceImpl.class);
        int succ = userService.updateUserMoney(1,100);
        System.out.println("影响行  --> "+succ);
    }
}

均测试成功

（一）控制类

UserController

测试成功之后就可以写控制类了

package com.an.controller;

import com.an.entity.User;
import com.an.service.Impl.UserServiceImpl;
import org.apache.ibatis.annotations.Param;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
public class UserController {

    @Autowired
    UserServiceImpl userService;
//    这里直接注入服务实现类

    @RequestMapping("view")
    public String selectUserAll(){
        System.out.println("进入视图");
//        这里直接跳转到user.jsp
        return "tomoney";
//        返回users   ，usersjsp的名字，在spring-web中配置了视图解析器，返回jsp名就会被解析并实现视图
    }

    @RequestMapping("toFoMoney")
    @ResponseBody//不跳转页面,只是返回字符串
    public String updateUserMoney(@Param("uid") int uid,@Param("money")float money,@Param("touid") int touid){
        System.out.println("进入修改余额");
        User u1 =  userService.selectUser(uid);
        float u1moeny = u1.getUser_money();
        float _u1money;//u1转账后的余额
        float _u2money;//u2转账后的余额
//转账人的余额

        User u2 = userService.selectUser(touid);
        float u2money = u2.getUser_money();
//收款人的余额

        if(u1moeny>=money){
            //判断转账人是否满足转账金额,如果余额大于或等于正在转账的金额，那么直接进入转账
            _u1money = u1moeny - money;
             userService.updateUserMoney(uid,_u1money);
            System.out.println(_u1money+" u1转账后余额");
            //            u1新的余额

            _u2money = u2money += money;
            userService.updateUserMoney(touid,_u2money);
            System.out.println(_u1money+" u2收款后余额");
            //            u2新的余额
        }else{
            return "转账失败"+u1.getUser_name()+"的钱不够"+money+"无法转账给"+u2.getUser_name();
        }
        return "转账成功"+u1.getUser_name()+"成功给"+u2.getUser_name()+"转账"+money+"  转账人" + u1.getUser_name()+"余额还有"+_u1money+" 收款人"+u2.getUser_name()+"余额还有"+_u2money;
    }

}

创建jsp路径，这里也是本篇文章最后的定版结构了

index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<a href="view">转账</a>
</body>
</html>

tomoney.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<form action="toFoMoney">
    <p>转账人id：<input type="number" name="uid">   转账金额<input type="number" name="money" placeholder="转账金额"></p>
    <p>收款人：<input type="number" name="touid">  </p>
    <p><button type="submit">转账</button> </p>
</form>

</body>
</html>

最后打开汤姆猫

最终效果：

点击转账进入控制器的 view