关于java:Guice-AOP进阶版

本教程次要具体解说 Guice 的一些 AOP 形式, 通过该简略教程让咱们能够疾速应用 Guice 进行 AOP 开发, 后续咱们会更深刻解说更多 Guice 中的 AOP.

根底环境

初始化我的项目

• 初始化我的项目

mvn archetype:generate -DgroupId=io.edurt.lc.guice -DartifactId=guice-aop-senior -DarchetypeArtifactId=maven-archetype-quickstart -Dversion=1.0.0 -DinteractiveMode=false

• 批改 pom.xml 减少 Guice 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">

    <parent>
        <artifactId>lc-guice</artifactId>
        <groupId>io.edurt.lc.guice</groupId>
        <version>1.0.0</version>
    </parent>

    <modelVersion>4.0.0</modelVersion>

    <artifactId>guice-aop-senior</artifactId>
    <name>Learning Center for Guice AOP(Senior)</name>

    <properties>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>com.google.inject</groupId>
            <artifactId>guice</artifactId>
            <version>4.2.3</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

</project>

初始化 Service

首先咱们定义服务 Service，这个服务有一个简略的办法println.

• 在 src/main/java 目录下新建 io.edurt.lc.guice.GuiceAopSeniorService 类文件, 在文件输出以下内容

package io.edurt.lc.guice;

import com.google.inject.ImplementedBy;
import org.aopalliance.intercept.MethodInvocation;

@ImplementedBy(value = GuiceAopSeniorServiceImpl.class)
public interface GuiceAopSeniorService
{void before(MethodInvocation invocation);
}

• 在 src/main/java 目录下新建 io.edurt.lc.guice.GuiceAopSeniorServiceImpl 类文件, 在文件输出以下内容

package io.edurt.lc.guice;

import org.aopalliance.intercept.MethodInvocation;

public class GuiceAopSeniorServiceImpl
        implements GuiceAopSeniorService
{
    @Override
    public void before(MethodInvocation invocation)
    {System.out.println(String.format("Before method [%s]", invocation.getMethod().getName()));
    }
}

AOP 注入依赖

Guice 容许在关联 AOP 之前将 AOP 的依赖都注入到容器中!

• 在 src/main/java 目录下新建 io.edurt.lc.guice.GuiceAopInjectionMethodInterceptor 类文件, 在文件输出以下内容

package io.edurt.lc.guice;

import com.google.inject.Inject;
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;

public class GuiceAopInjectionMethodInterceptor
        implements MethodInterceptor
{
    @Inject
    private GuiceAopSeniorService service;

    @Override
    public Object invoke(MethodInvocation invocation)
            throws Throwable
    {service.before(invocation);
        Object response;
        try {response = invocation.proceed();
        }
        finally {System.out.println(String.format("After [%s]", invocation.getMethod().getName()));
        }
        return response;
    }
}

• 在 src/main/java 目录下新建 io.edurt.lc.guice.PrintlnService 类文件, 在文件输出以下内容

package io.edurt.lc.guice;

import com.google.inject.ImplementedBy;

@ImplementedBy(value = PrintlnServiceImpl.class)
public interface PrintlnService
{void println(String input);
}

• 在 src/main/java 目录下新建 io.edurt.lc.guice.PrintlnServiceImpl 类文件, 在文件输出以下内容

package io.edurt.lc.guice;

import com.google.inject.name.Named;

public class PrintlnServiceImpl
        implements PrintlnService
{
    @Override
    @Named(value = "println")
    public void println(String input)
    {System.out.println(input);
    }
}

PrintlnService和 PrintlnServiceImpl 用于测试新的服务产出.

• 接下来在 src/test/java 目录创立 io.edurt.lc.guice.TestGuiceAopSenior 类文件进行定义的服务进行测试, 增加以下代码

package io.edurt.lc.guice;

import com.google.inject.Guice;
import com.google.inject.Inject;
import com.google.inject.Injector;
import com.google.inject.matcher.Matchers;
import com.google.inject.name.Names;
import org.junit.Test;

public class TestGuiceAopSenior
{
    @Inject
    private PrintlnService printlnService;

    @Test
    public void test()
    {
        Injector injector = Guice.createInjector(binder -> {GuiceAopInjectionMethodInterceptor injectionMethodInterceptor = new GuiceAopInjectionMethodInterceptor();
            binder.requestInjection(injectionMethodInterceptor);
            binder.bindInterceptor(Matchers.any(), Matchers.annotatedWith(Names.named("println")), injectionMethodInterceptor);
        });
        TestGuiceAopSenior application = injector.getInstance(TestGuiceAopSenior.class);
        application.printlnService.println("Hello Guice AOP");
    }
}

咱们运行程序输入

Before method [println]
Hello Guice AOP
After [println]

须要留神的是:
binder.requestInjection(injectionMethodInterceptor); 该段代码用于注入自定义的 AOP 服务
binder.bindInterceptor(Matchers.any(), Matchers.annotatedWith(Names.named("println")), injectionMethodInterceptor); 这里的第二个参数不能应用 Matchers.any() 否则会呈现死循环, 因为容器会一直的进行 aop 操作

源码地址

GitHub