1. Spring4.x Java配置

Java配置的基本使用

1. 新建一个功能类

package com.xiaohan.javaconfig;

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

2. 新建一个使用功能类的类

package com.xiaohan.javaconfig;

public class UseFunctionService {
    FunctionService functionService;
    public void setFunctionService(FunctionService functionService) {
        this.functionService = functionService;
    }

    public String sayHello(String word) {
        return functionService.sayHello(word);
    }
}

3. 新建一个Java配置类

package com.xiaohan.javaconfig;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

// 声明这是一个Java配置类
@Configuration
public class JavaConfig {

    // 实例化 功能类
    @Bean
    public FunctionService functionService() {
        return new FunctionService();
    }

    // 实例化 使用功能类的类
    @Bean
    public UseFunctionService useFunctionService(FunctionService functionService) {
        UseFunctionService useFunctionService = new UseFunctionService();

        // 注入功能类
        useFunctionService.setFunctionService(functionService);
        return useFunctionService;
    }
}

4. 创建一个Main方法 初始化容器 并测试

package com.xiaohan.javaconfig;

import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

// Java配置
public class Main {

    public static void main(String[] args) {
        // 指定配置类 初始化 Spring容器 可指定多个配置类
        ApplicationContext ac = new AnnotationConfigApplicationContext(JavaConfig.class);
        UseFunctionService useFunctionService = ac.getBean(UseFunctionService.class);
        System.err.println(useFunctionService.sayHello("JavaConfig"));
        //Hello JavaConfig
    }

}