Spring 教程03

Posted 2020-10-05 c0

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spring-3
1.    Xml


<!-- \src\applicationContext-xml.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:aop="http://www.springframework.org/schema/aop"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd">

    <!-- 配置 bean -->
    <bean id="arithmeticCalculator" 
        class="com.atguigu.spring.aop.xml.ArithmeticCalculatorImpl"></bean>

    <!-- 配置切面的 bean. -->
    <bean id="loggingAspect"
        class="com.atguigu.spring.aop.xml.LoggingAspect"></bean>

    <bean id="vlidationAspect"
        class="com.atguigu.spring.aop.xml.VlidationAspect"></bean>

    <!-- 配置 AOP -->
    <aop:config>
        <!-- 配置切点表达式 -->
        <aop:pointcut expression="execution(* com.atguigu.spring.aop.xml.ArithmeticCalculator.*(int, int))" 
            id="pointcut"/>
        <!-- 配置切面及通知 -->
        <aop:aspect ref="loggingAspect" order="2">
            <aop:before method="beforeMethod" pointcut-ref="pointcut"/>
            <aop:after method="afterMethod" pointcut-ref="pointcut"/>
            <aop:after-throwing method="afterThrowing" pointcut-ref="pointcut" throwing="e"/>
            <aop:after-returning method="afterReturning" pointcut-ref="pointcut" returning="result"/>
            <!--  
            <aop:around method="aroundMethod" pointcut-ref="pointcut"/>
            -->
        </aop:aspect>   
        <aop:aspect ref="vlidationAspect" order="1">
            <aop:before method="validateArgs" pointcut-ref="pointcut"/>
        </aop:aspect>
    </aop:config>

</beans>

<!-- \src\applicationContext.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:aop="http://www.springframework.org/schema/aop"
    xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
        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-4.0.xsd">

    <!-- 配置自动扫描的包 -->
    <context:component-scan base-package="com.atguigu.spring.aop"></context:component-scan>
    
    <!-- 配置自动为匹配 aspectJ 注解的 Java 类生成代理对象 -->
    <aop:aspectj-autoproxy></aop:aspectj-autoproxy>
    
</beans>

2.    Java


// \src\com\atguigu\spring\aop\ArithmeticCalculator.java
package com.atguigu.spring.aop;

public interface ArithmeticCalculator {

    int add(int i, int j);
    int sub(int i, int j);
    
    int mul(int i, int j);
    int div(int i, int j);
    
}

// \src\com\atguigu\spring\aop\ArithmeticCalculatorImpl.java
package com.atguigu.spring.aop;

import org.springframework.stereotype.Component;

@Component("arithmeticCalculator")
public class ArithmeticCalculatorImpl implements ArithmeticCalculator {

    @Override
    public int add(int i, int j) {
        int result = i + j;
        return result;
    }

    @Override
    public int sub(int i, int j) {
        int result = i - j;
        return result;
    }

    @Override
    public int mul(int i, int j) {
        int result = i * j;
        return result;
    }

    @Override
    public int div(int i, int j) {
        int result = i / j;
        return result;
    }

}

// \src\com\atguigu\spring\aop\LoggingAspect.java
package com.atguigu.spring.aop;

import java.util.Arrays;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

/**
 * 可以使用 @Order 注解指定切面的优先级, 值越小优先级越高
 */
@Order(2)
@Aspect
@Component
public class LoggingAspect {
    
    /**
     * 定义一个方法, 用于声明切入点表达式. 一般地, 该方法中再不需要添入其他的代码. 
     * 使用 @Pointcut 来声明切入点表达式. 
     * 后面的其他通知直接使用方法名来引用当前的切入点表达式. 
     */
    @Pointcut("execution(public int com.atguigu.spring.aop.ArithmeticCalculator.*(..))")
    public void declareJointPointExpression(){}
    
    /**
     * 在 com.atguigu.spring.aop.ArithmeticCalculator 接口的每一个实现类的每一个方法开始之前执行一段代码
     */
    @Before("declareJointPointExpression()")
    public void beforeMethod(JoinPoint joinPoint){
        String methodName = joinPoint.getSignature().getName();
        Object [] args = joinPoint.getArgs();
        
        System.out.println("The method " + methodName + " begins with " + Arrays.asList(args));
    }
    
    /**
     * 在方法执行之后执行的代码. 无论该方法是否出现异常
     */
    @After("declareJointPointExpression()")
    public void afterMethod(JoinPoint joinPoint){
        String methodName = joinPoint.getSignature().getName();
        System.out.println("The method " + methodName + " ends");
    }
    
    /**
     * 在方法法正常结束受执行的代码
     * 返回通知是可以访问到方法的返回值的!
     */
    @AfterReturning(value="declareJointPointExpression()",
            returning="result")
    public void afterReturning(JoinPoint joinPoint, Object result){
        String methodName = joinPoint.getSignature().getName();
        System.out.println("The method " + methodName + " ends with " + result);
    }
    
    /**
     * 在目标方法出现异常时会执行的代码.
     * 可以访问到异常对象; 且可以指定在出现特定异常时在执行通知代码
     */
    @AfterThrowing(value="declareJointPointExpression()",
            throwing="e")
    public void afterThrowing(JoinPoint joinPoint, Exception e){
        String methodName = joinPoint.getSignature().getName();
        System.out.println("The method " + methodName + " occurs excetion:" + e);
    }
    
    /**
     * 环绕通知需要携带 ProceedingJoinPoint 类型的参数. 
     * 环绕通知类似于动态代理的全过程: ProceedingJoinPoint 类型的参数可以决定是否执行目标方法.
     * 且环绕通知必须有返回值, 返回值即为目标方法的返回值
     */
    /*
    @Around("execution(public int com.atguigu.spring.aop.ArithmeticCalculator.*(..))")
    public Object aroundMethod(ProceedingJoinPoint pjd){
        
        Object result = null;
        String methodName = pjd.getSignature().getName();
        
        try {
            //前置通知
            System.out.println("The method " + methodName + " begins with " + Arrays.asList(pjd.getArgs()));
            //执行目标方法
            result = pjd.proceed();
            //返回通知
            System.out.println("The method " + methodName + " ends with " + result);
        } catch (Throwable e) {
            //异常通知
            System.out.println("The method " + methodName + " occurs exception:" + e);
            throw new RuntimeException(e);
        }
        //后置通知
        System.out.println("The method " + methodName + " ends");
        
        return result;
    }
    */
}

// \src\com\atguigu\spring\aop\Main.java
package com.atguigu.spring.aop;

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

public class Main {
    
    public static void main(String[] args) {
        
        ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
        ArithmeticCalculator arithmeticCalculator = (ArithmeticCalculator) ctx.getBean("arithmeticCalculator");
        
        System.out.println(arithmeticCalculator.getClass().getName());
        
        int result = arithmeticCalculator.add(1, 2);
        System.out.println("result:" + result);
        
        result = arithmeticCalculator.div(1000, 10);
        System.out.println("result:" + result);
    }
    
}

// \src\com\atguigu\spring\aop\VlidationAspect.java
package com.atguigu.spring.aop;

import java.util.Arrays;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

@Order(1)
@Aspect
@Component
public class VlidationAspect {

    @Before("com.atguigu.spring.aop.LoggingAspect.declareJointPointExpression()")
    public void validateArgs(JoinPoint joinPoint){
        System.out.println("-->validate:" + Arrays.asList(joinPoint.getArgs()));
    }
    
}

// \src\com\atguigu\spring\aop\xml\ArithmeticCalculator.java
package com.atguigu.spring.aop.xml;

public interface ArithmeticCalculator {

    int add(int i, int j);
    int sub(int i, int j);
    
    int mul(int i, int j);
    int div(int i, int j);
    
}

// \src\com\atguigu\spring\aop\xml\ArithmeticCalculatorImpl.java
package com.atguigu.spring.aop.xml;


public class ArithmeticCalculatorImpl implements ArithmeticCalculator {

    @Override
    public int add(int i, int j) {
        int result = i + j;
        return result;
    }

    @Override
    public int sub(int i, int j) {
        int result = i - j;
        return result;
    }

    @Override
    public int mul(int i, int j) {
        int result = i * j;
        return result;
    }

    @Override
    public int div(int i, int j) {
        int result = i / j;
        return result;
    }

}

// \src\com\atguigu\spring\aop\xml\LoggingAspect.java
package com.atguigu.spring.aop.xml;

import java.util.Arrays;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;

public class LoggingAspect {
    
    public void beforeMethod(JoinPoint joinPoint){
        String methodName = joinPoint.getSignature().getName();
        Object [] args = joinPoint.getArgs();
        
        System.out.println("The method " + methodName + " begins with " + Arrays.asList(args));
    }
    
    public void afterMethod(JoinPoint joinPoint){
        String methodName = joinPoint.getSignature().getName();
        System.out.println("The method " + methodName + " ends");
    }
    
    public void afterReturning(JoinPoint joinPoint, Object result){
        String methodName = joinPoint.getSignature().getName();
        System.out.println("The method " + methodName + " ends with " + result);
    }
    
    public void afterThrowing(JoinPoint joinPoint, Exception e){
        String methodName = joinPoint.getSignature().getName();
        System.out.println("The method " + methodName + " occurs excetion:" + e);
    }
    
    @Around("execution(public int com.atguigu.spring.aop.ArithmeticCalculator.*(..))")
    public Object aroundMethod(ProceedingJoinPoint pjd){
        
        Object result = null;
        String methodName = pjd.getSignature().getName();
        
        try {
            //前置通知
            System.out.println("The method " + methodName + " begins with " + Arrays.asList(pjd.getArgs()));
            //执行目标方法
            result = pjd.proceed();
            //返回通知
            System.out.println("The method " + methodName + " ends with " + result);
        } catch (Throwable e) {
            //异常通知
            System.out.println("The method " + methodName + " occurs exception:" + e);
            throw new RuntimeException(e);
        }
        //后置通知
        System.out.println("The method " + methodName + " ends");
        
        return result;
    }
}

// \src\com\atguigu\spring\aop\xml\Main.java
package com.atguigu.spring.aop.xml;

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

public class Main {
    
    public static void main(String[] args) {
        
        ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext-xml.xml");
        ArithmeticCalculator arithmeticCalculator = (ArithmeticCalculator) ctx.getBean("arithmeticCalculator");
        
        System.out.println(arithmeticCalculator.getClass().getName());
        
        int result = arithmeticCalculator.add(1, 2);
        System.out.println("result:" + result);
        
        result = arithmeticCalculator.div(1000, 0);
        System.out.println("result:" + result);
    }
    
}

// \src\com\atguigu\spring\aop\xml\VlidationAspect.java
package com.atguigu.spring.aop.xml;

import java.util.Arrays;

import org.aspectj.lang.JoinPoint;

public class VlidationAspect {

    public void validateArgs(JoinPoint joinPoint){
        System.out.println("-->validate:" + Arrays.asList(joinPoint.getArgs()));
    }
    
}

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