1、AOP（面向切面编程）是Spring提供的重要技术工具，其主要功能是对业务层的方法调用进行拦截处理。SpringBoot默认情况下并没有配置AOP拦截器，需要在项目中手动引入spring-boot-starter-aop依赖库后才可以使用。
修改pom.xml配置文件，配置spring-boot-starter-aop依赖库，如下所示：
代码语言：javascript复制 1 <?xml version="1.0" encoding="UTF-8"?>
2 <project xmlns="http://maven.apache.org/POM/4.0.0"
3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
5 https://maven.apache.org/xsd/maven-4.0.0.xsd">
6 <modelVersion>4.0.0</modelVersion>
7 <parent>
8 <groupId>org.springframework.boot</groupId>
9 <artifactId>spring-boot-starter-parent</artifactId>
10 <version>2.3.5.RELEASE</version>
11 <relativePath /> <!-- lookup parent from repository -->
12 </parent>
13 <groupId>com.example</groupId>
14 <artifactId>demo</artifactId>
15 <version>0.0.1-SNAPSHOT</version>
16 <name>demo</name>
17 <description>Demo project for Spring Boot</description>
18
19 <properties>
20 <java.version>1.8</java.version>
21 <maven-jar-plugin.version>3.1.1</maven-jar-plugin.version>
22 </properties>
23
24 <dependencies>
25 <dependency>
26 <groupId>org.springframework.boot</groupId>
27 <artifactId>spring-boot-starter-web</artifactId>
28 </dependency>
29
30 <dependency>
31 <groupId>org.springframework.boot</groupId>
32 <artifactId>spring-boot-starter-test</artifactId>
33 <scope>test</scope>
34 <exclusions>
35 <exclusion>
36 <groupId>org.junit.vintage</groupId>
37 <artifactId>junit-vintage-engine</artifactId>
38 </exclusion>
39 </exclusions>
40 </dependency>
41 <!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-validator -->
42 <dependency>
43 <groupId>org.hibernate</groupId>
44 <artifactId>hibernate-validator</artifactId>
45 <version>6.1.0.Final</version>
46 </dependency>
47 <dependency>
48 <groupId>org.springframework.boot</groupId>
49 <artifactId>spring-boot-starter-thymeleaf</artifactId>
50 </dependency>
51 <!-- aop -->
52 <dependency>
53 <groupId>org.springframework.boot</groupId>
54 <artifactId>spring-boot-starter-aop</artifactId>
55 </dependency>
56 </dependencies>
57
58 <build>
59 <plugins>
60 <plugin>
61 <groupId>org.springframework.boot</groupId>
62 <artifactId>spring-boot-maven-plugin</artifactId>
63 </plugin>
64 </plugins>
65 <resources>
66 <resource>
67 <directory>src/main/resources</directory>
68 <includes>
69 <include>**/*.properties</include>
70 <include>**/*.yml</include>
71 <include>**/*.xml</include>
72 <include>**/*.p12</include>
73 <include>**/*.html</include>
74 <include>**/*.jpg</include>
75 <include>**/*.png</include>
76 </includes>
77 </resource>
78 </resources>
79 </build>
80
81 </project>搞一个业务层接口，然后搞一个业务层接口实现子类。
代码语言：javascript复制1 package com.demo.service;
2
3 public interface UserService {
4
5 public String login(String username, String password);
6 } 1 package com.demo.service.impl;
2
3 import org.springframework.stereotype.Service;
4
5 import com.demo.service.UserService;
6
7 @Service
8 public class UserServiceImpl implements UserService {
9
10 @Override
11 public String login(String username, String password) {
12 if (username.equals("admin") && password.equals("123456")) {
13 return "success!!!";
14 }
15 return "fail!!!";
16 }
17
18 }定义AOP程序类，对业务方法进行拦截，这里使用环绕通知处理。
代码语言：javascript复制 1 package com.demo.aop;
2
3 import java.util.Arrays;
4
5 import org.aspectj.lang.ProceedingJoinPoint;
6 import org.aspectj.lang.annotation.Around;
7 import org.aspectj.lang.annotation.Aspect;
8 import org.slf4j.Logger;
9 import org.slf4j.LoggerFactory;
10 import org.springframework.stereotype.Component;
11
12 /**
13 * 定义业务层拦截
14 *
15 * @author Aiyufei
16 *
17 */
18 @Component
19 @Aspect
20 public class ServiceAspect {
21
22 private Logger log = LoggerFactory.getLogger(ServiceAspect.class);
23
24 /**
25 * 环绕通知
26 *
27 * @param point
28 * @return
29 * @throws Throwable
30 */
31 @Around("execution(* com.demo.service..*.*(..))")
32 public Object arroudInvoke(ProceedingJoinPoint point) throws Throwable {
33 this.log.info("the before 执行参数： " Arrays.toString(point.getArgs()));
34 Object proceed = point.proceed(point.getArgs());
35 this.log.info("the after 返回结果：" proceed);
36 return proceed;
37 }
38
39 }搞一个控制层类，如下所示：
代码语言：javascript复制 1 package com.demo.controller;
2
3 import org.springframework.beans.factory.annotation.Autowired;
4 import org.springframework.stereotype.Controller;
5 import org.springframework.web.bind.annotation.RequestMapping;
6 import org.springframework.web.bind.annotation.RequestParam;
7 import org.springframework.web.bind.annotation.ResponseBody;
8
9 import com.demo.service.UserService;
10
11 @Controller
12 public class SpringBootController {
13
14 @Autowired
15 private UserService userService;
16
17 @RequestMapping(value = "/login")
18 @ResponseBody
19 public String hello(@RequestParam(value = "username") String username,
20 @RequestParam(value = "password") String password) {
21 System.out.println("hello world!!!");
22 String login = userService.login(username, password);
23 return login;
24 }
25
26 }使用postman测试一下，如下所示：
由于将切入点设置在了所有的业务层上，所以在调用UserService接口方法时会自动执行AOP拦截。
