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:softwarejavainjava -Didea.launcher.port=7534 "-Didea.launcher.bin.path=D:softwareIntelliJ IDEA 2016.1.3in" -Dfile.encoding=UTF-8 -classpath "D:softwarejavajrelibcharsets.jar;D:softwarejavajrelibdeploy.jar;D:softwarejavajrelibextaccess-bridge-64.jar;D:softwarejavajrelibextcldrdata.jar;D:softwarejavajrelibextdnsns.jar;D:softwarejavajrelibextjaccess.jar;D:softwarejavajrelibextjfxrt.jar;D:softwarejavajrelibextlocaledata.jar;D:softwarejavajrelibext
ashorn.jar;D:softwarejavajrelibextsunec.jar;D:softwarejavajrelibextsunjce_provider.jar;D:softwarejavajrelibextsunmscapi.jar;D:softwarejavajrelibextsunpkcs11.jar;D:softwarejavajrelibextzipfs.jar;D:softwarejavajrelibjavaws.jar;D:softwarejavajrelibjce.jar;D:softwarejavajrelibjfr.jar;D:softwarejavajrelibjfxswt.jar;D:softwarejavajrelibjsse.jar;D:softwarejavajrelibmanagement-agent.jar;D:softwarejavajrelibplugin.jar;D:softwarejavajrelib
esources.jar;D:softwarejavajrelib
t.jar;D:workspacespring-1	argetclasses;C:UsersAdministrator.m2
epositoryorgspringframeworkspring-webmvc4.1.5.RELEASEspring-webmvc-4.1.5.RELEASE.jar;C:UsersAdministrator.m2
epositoryorgspringframeworkspring-beans4.1.5.RELEASEspring-beans-4.1.5.RELEASE.jar;C:UsersAdministrator.m2
epositoryorgspringframeworkspring-core4.1.5.RELEASEspring-core-4.1.5.RELEASE.jar;C:UsersAdministrator.m2
epositoryorgspringframeworkspring-context4.1.5.RELEASEspring-context-4.1.5.RELEASE.jar;C:UsersAdministrator.m2
epositoryorgspringframeworkspring-aop4.1.5.RELEASEspring-aop-4.1.5.RELEASE.jar;C:UsersAdministrator.m2
epositoryaopallianceaopalliance1.0aopalliance-1.0.jar;C:UsersAdministrator.m2
epositoryorgspringframeworkspring-expression4.1.5.RELEASEspring-expression-4.1.5.RELEASE.jar;C:UsersAdministrator.m2
epositorycommons-loggingcommons-logging1.2commons-logging-1.2.jar;C:UsersAdministrator.m2
epositoryorgspringframeworkspring-web4.1.5.RELEASEspring-web-4.1.5.RELEASE.jar;D:softwareIntelliJ IDEA 2016.1.3libidea_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