使用JavaConfig方式-Spring 基础学习

在Spring的使用中，大量采用xml方式配置类之间的关系太过于繁琐(个人这么认为)，而在学习了Spring4后发下使用JavaConfig方式来配置这些关系会更加的简单明了。

测试环境

1. Apache Maven

2. JDK 1.8

3. IDEA 15

先决条件

1. 使用IDEA创建一个Maven项目

2. 在pom.xml 中引用

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>4.1.5.RELEASE</version>
</dependency>

3. 实际代码

很简单的一个Service吧！(这里为了方便省略了interface)

public class FunctionService {
    public String sayHello(String msg) {
        return "Hello " + msg + "!";
    }
}

这里相当于组合上面的类

public class UseFunctionService {
    private FunctionService functionService;
 
    public void setFunctionService(FunctionService functionService) {
        this.functionService = functionService;
    }
 
    public String SayHello(String msg) {
        return functionService.sayHello(msg);
    }
}

然后重头戏

1. 用@Configuration 表示这是一个spring java配置类

2. 定义了 ApplicationContext中的一个Bean等同于<bean id="functionService" class="com.malin.FunctionService"/>

3. 同2一样

package com.malin.javaconfig;
 
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
 
@Configuration　　//1 
public class JavaConfig {
    @Bean　　　　　//2
    public FunctionService functionService() {
        return new FunctionService();
    }
    @Bean　　　　　　//3
    public UseFunctionService useFunctionService() {
        UseFunctionService useFunctionService = new UseFunctionService();
        useFunctionService.setFunctionService(functionService());
        return useFunctionService;
    }
}

在编写一个测试类吧

package com.malin.javaconfig;
 
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 
public class Main {
    public static void main(String[] args) {
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(JavaConfig.class);
        UseFunctionService service = context.getBean(UseFunctionService.class);
        System.out.println(service.SayHello("小马"));
        context.close();
    }
}

　　然后输出了结果

D:\software\java\bin\java -Didea.launcher.port=7534 "-Didea.launcher.bin.path=D:\software\IntelliJ IDEA 2016.1.3\bin" -Dfile.encoding=UTF-8 -classpath "D:\software\java\jre\lib\charsets.jar;D:\software\java\jre\lib\deploy.jar;D:\software\java\jre\lib\ext\access-bridge-64.jar;D:\software\java\jre\lib\ext\cldrdata.jar;D:\software\java\jre\lib\ext\dnsns.jar;D:\software\java\jre\lib\ext\jaccess.jar;D:\software\java\jre\lib\ext\jfxrt.jar;D:\software\java\jre\lib\ext\localedata.jar;D:\software\java\jre\lib\ext\nashorn.jar;D:\software\java\jre\lib\ext\sunec.jar;D:\software\java\jre\lib\ext\sunjce_provider.jar;D:\software\java\jre\lib\ext\sunmscapi.jar;D:\software\java\jre\lib\ext\sunpkcs11.jar;D:\software\java\jre\lib\ext\zipfs.jar;D:\software\java\jre\lib\javaws.jar;D:\software\java\jre\lib\jce.jar;D:\software\java\jre\lib\jfr.jar;D:\software\java\jre\lib\jfxswt.jar;D:\software\java\jre\lib\jsse.jar;D:\software\java\jre\lib\management-agent.jar;D:\software\java\jre\lib\plugin.jar;D:\software\java\jre\lib\resources.jar;D:\software\java\jre\lib\rt.jar;D:\workspace\spring-1\target\classes;C:\Users\Administrator\.m2\repository\org\springframework\spring-webmvc\4.1.5.RELEASE\spring-webmvc-4.1.5.RELEASE.jar;C:\Users\Administrator\.m2\repository\org\springframework\spring-beans\4.1.5.RELEASE\spring-beans-4.1.5.RELEASE.jar;C:\Users\Administrator\.m2\repository\org\springframework\spring-core\4.1.5.RELEASE\spring-core-4.1.5.RELEASE.jar;C:\Users\Administrator\.m2\repository\org\springframework\spring-context\4.1.5.RELEASE\spring-context-4.1.5.RELEASE.jar;C:\Users\Administrator\.m2\repository\org\springframework\spring-aop\4.1.5.RELEASE\spring-aop-4.1.5.RELEASE.jar;C:\Users\Administrator\.m2\repository\aopalliance\aopalliance\1.0\aopalliance-1.0.jar;C:\Users\Administrator\.m2\repository\org\springframework\spring-expression\4.1.5.RELEASE\spring-expression-4.1.5.RELEASE.jar;C:\Users\Administrator\.m2\repository\commons-logging\commons-logging\1.2\commons-logging-1.2.jar;C:\Users\Administrator\.m2\repository\org\springframework\spring-web\4.1.5.RELEASE\spring-web-4.1.5.RELEASE.jar;D:\software\IntelliJ IDEA 2016.1.3\lib\idea_rt.jar" com.intellij.rt.execution.application.AppMain com.malin.javaconfig.Main
六月 26, 2016 4:18:45 上午 org.springframework.context.annotation.AnnotationConfigApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@1a6c5a9e: startup date [Sun Jun 26 04:18:45 CST 2016]; root of context hierarchy
Hello 小马!
六月 26, 2016 4:18:45 上午 org.springframework.context.annotation.AnnotationConfigApplicationContext doClose
信息: Closing org.springframework.context.annotation.AnnotationConfigApplicationContext@1a6c5a9e: startup date [Sun Jun 26 04:18:45 CST 2016]; root of context hierarchy
 
Process finished with exit code 0