1.JDBC编程步骤：

1.拼写SQL语句
2.定义预处理事务集
3.获取连接
4.传参
5.执行更新操作
6.关闭连接

模式：

1.单例模式
2.代理模式
3.工厂模式
4.装饰器模式
5.适配器模式

2.关于SpringAOP的理解

• AOP的使用场景
  1.日志
  2.数据库事务

3.Hello的前置增强练习

• pom.xml中添加AOP相关依赖

<?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.spring</groupId>
    <artifactId>aop</artifactId>
    <version>1.0-SNAPSHOT</version>

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

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
        <spring.version>5.1.5.RELEASE</spring.version>
        <aspectj.version>1.9.2</aspectj.version>
        <junit.version>4.12</junit.version>
        <log4j.version>1.2.17</log4j.version>
        <slf4j.version>1.7.12</slf4j.version>
    </properties>

    <dependencies>
        <!--spring-context依赖-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--spring-aop依赖-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--aspectj依赖-->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjrt</artifactId>
            <version>${aspectj.version}</version>
        </dependency>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>${aspectj.version}</version>
        </dependency>
        <!--spring-test依赖-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--junit依赖-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>${junit.version}</version>
            <scope>test</scope>
        </dependency>
        <!-- log4j日志依赖 -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>${log4j.version}</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
    </dependencies>

    <build>
        <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
            <plugins>
                <!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
                <plugin>
                    <artifactId>maven-clean-plugin</artifactId>
                    <version>3.1.0</version>
                </plugin>
                <!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
                <plugin>
                    <artifactId>maven-resources-plugin</artifactId>
                    <version>3.0.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.8.0</version>
                </plugin>
                <plugin>
                    <artifactId>maven-surefire-plugin</artifactId>
                    <version>2.22.1</version>
                </plugin>
                <plugin>
                    <artifactId>maven-jar-plugin</artifactId>
                    <version>3.0.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-install-plugin</artifactId>
                    <version>2.5.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-deploy-plugin</artifactId>
                    <version>2.8.2</version>
                </plugin>
                <!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
                <plugin>
                    <artifactId>maven-site-plugin</artifactId>
                    <version>3.7.1</version>
                </plugin>
                <plugin>
                    <artifactId>maven-project-info-reports-plugin</artifactId>
                    <version>3.0.0</version>
                </plugin>
            </plugins>
        </pluginManagement>
    </build>
</project>

• Hello接口和实现类

package com.spring.aop;

public interface Hello {
    String sayHello();
}

package com.spring.aop;

public class HelloImpl implements Hello {
    @Override
    public String sayHello() {
        return "Spring AOP";
    }
}

• MyBefore类

package com.spring.aop;

/**
 * 用戶自定义前置增强类
 */
public class MyBefore {
    public void beforeMethod() {
        System.out.println("This is a before method...");
    }
 }

• 配置文件

    <bean id="hello" class="com.spring.aop.HelloImpl"/>
    <bean id="myBefore" class="com.spring.aop.MyBefore"/>
    <aop:config>
        <aop:aspect id="before" ref="myBefore">
            <aop:pointcut id="myPointcut" expression="execution(* com.spring.aop.*.*(..))"/>
            <aop:before method="beforeMethod" pointcut-ref="myPointcut"/>
        </aop:aspect>
    </aop:config>

• 应用主类

package com.spring.aop;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class HelloApp {
    public static void main(String[] args) {
        ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
        Hello hello = (Hello) ac.getBean("hello");
        System.out.println(hello.sayHello());
    }
}

• 运行结果

image.png