本教程主要详细讲解Guice的一些AOP方式,通过该简单教程让我们可以快速使用Guice进行AOP开发,后续我们会更深入讲解更多Guice中的AOP.
基础环境
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初始化项目
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mvn archetype:generate -DgroupId=io.edurt.lc.guice -DartifactId=guice-aop-senior -DarchetypeArtifactId=maven-archetype-quickstart -Dversion=1.0.0 -DinteractiveMode=false
<?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
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首先我们定义服务Service,这个服务有一个简单的方法println
.
- 在
src/main/java
目录下新建io.edurt.lc.guice.GuiceAopSeniorService类文件,在文件输入以下内容
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,在文件输入以下内容
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
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Guice允许在关联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,在文件输入以下内容
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,在文件输入以下内容
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,在文件输入以下内容
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
目录创建io.edurt.lc.guice.TestGuiceAopSenior
类文件进行定义的服务进行测试,添加以下代码
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");
}
}
我们运行程序输出
Before method [println]
Hello Guice AOP
After [println]
需要注意的是:
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使用Matchers.any()
否则会出现死循环,因为容器会不断的进行aop操作
源码地址
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GitHub