如何在spring bean上强制/验证spring scope注释

Question

此外，如果spring bean中有@autowire注释，那么是否有一种方法可以验证注入的bean是否具有正确的作用域。我的假设是，如果您将原型作用域bean注入到单例作用域bean中，很可能这不是您想要的。虽然在某些用例中，这是开发人员想要的，但在我们的案例中，到目前为止，这主要是开发人员的错误。

Answer 1

您可以使用AspectJ的能力来基于切入点声明错误和/或警告。

免责声明：我从来没有使用过Spring，所以我不是那里的专家，只是编了一个没有太多示范意义的例子。

具有原型作用域的Spring bean：

package de.scrum_master.app;

import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;

@Component
@Scope("prototype")
public class ScopedBean {}

package de.scrum_master.app;

import org.springframework.stereotype.Component;

@Component
public class UnscopedBean {}

package de.scrum_master.app;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;

@Component
@Scope("singleton")
public class BeanWithAutowire {
    //@Autowired
    private ScopedBean scopedBean;

    @Autowired
    public BeanWithAutowire(ScopedBean scopedBean) {
        this.scopedBean = scopedBean;
    }

    @Autowired
    public void setScopedBean(ScopedBean scopedBean) {
        this.scopedBean = scopedBean;
    }
}

静态注释一致性检查的方面：

package de.scrum_master.aspect;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;

public aspect BeanAnnotationChecker {
    declare error :
        @annotation(Component) && !@annotation(Scope) :
        "Spring component without scope declaration found";

    declare error :
        execution(@Autowired *.new(.., @Scope("prototype") *, ..)) && within(@Scope("singleton") *) :
        "singleton bean auto-wired into prototype container via constructor";

    declare error :
        execution(@Autowired * *(.., @Scope("prototype") *, ..)) && within(@Scope("singleton") *) :
        "singleton bean auto-wired into prototype container via setter method";

    declare error :
        set(@Autowired * *) && within(@Scope("singleton") *) :
        "singleton bean auto-wired into prototype container via field assignment";
}

使用AspectJ编译器的Maven POM：

<?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>de.scrum-master.stackoverflow</groupId>
    <artifactId>aspectj-fail-build</artifactId>
    <version>1.0-SNAPSHOT</version>

    <name>AspectJ - fail build for wrong/missing annotations</name>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.source-target.version>1.7</java.source-target.version>
        <aspectj.version>1.8.4</aspectj.version>
        <main-class>de.scrum_master.app.ScopedBean</main-class>
    </properties>

    <build>
        <pluginManagement>
            <plugins>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.1</version>
                    <configuration>
                        <source>${java.source-target.version}</source>
                        <target>${java.source-target.version}</target>
                        <!-- IMPORTANT -->
                        <useIncrementalCompilation>false</useIncrementalCompilation>
                    </configuration>
                </plugin>
                <plugin>
                    <groupId>org.codehaus.mojo</groupId>
                    <artifactId>aspectj-maven-plugin</artifactId>
                    <version>1.7</version>
                    <configuration>
                        <showWeaveInfo>true</showWeaveInfo>
                        <source>${java.source-target.version}</source>
                        <target>${java.source-target.version}</target>
                        <Xlint>ignore</Xlint>
                        <complianceLevel>${java.source-target.version}</complianceLevel>
                        <encoding>UTF-8</encoding>
                        <verbose>true</verbose>
                    </configuration>
                    <executions>
                        <execution>
                            <!-- IMPORTANT -->
                            <phase>process-sources</phase>
                            <goals>
                                <goal>compile</goal>
                                <goal>test-compile</goal>
                            </goals>
                        </execution>
                    </executions>
                    <dependencies>
                        <dependency>
                            <groupId>org.aspectj</groupId>
                            <artifactId>aspectjtools</artifactId>
                            <version>${aspectj.version}</version>
                        </dependency>
                    </dependencies>
                </plugin>
            </plugins>
        </pluginManagement>

        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>aspectj-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.aspectj</groupId>
                <artifactId>aspectjrt</artifactId>
                <version>${aspectj.version}</version>
                <scope>runtime</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjrt</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>4.0.7.RELEASE</version>
        </dependency>
    </dependencies>

</project>

MVN clean包的控制台输出：

(...)
[INFO] ------------------------------------------------------------------------
[INFO] Building AspectJ - fail build for wrong/missing annotations 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
(...)
[ERROR] singleton bean auto-wired into prototype container via constructor
    C:\Users\Alexander\Documents\java-src\SO_AJ_MavenFailBuildOnWrongAnnotation\src\main\java\de\scrum_master\app\BeanWithAutowire.java:14
public BeanWithAutowire(ScopedBean scopedBean) {
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

[ERROR] singleton bean auto-wired into prototype container via setter method
    C:\Users\Alexander\Documents\java-src\SO_AJ_MavenFailBuildOnWrongAnnotation\src\main\java\de\scrum_master\app\BeanWithAutowire.java:19
public void setScopedBean(ScopedBean scopedBean) {
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

[ERROR] Spring component without scope declaration found
    C:\Users\Alexander\Documents\java-src\SO_AJ_MavenFailBuildOnWrongAnnotation\src\main\java\de\scrum_master\app\UnscopedBean.java:6
public class UnscopedBean {}
             ^^^^^^^^^^^

[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
(...)