Spring---IOC/DI(四)

spring--bean装配（四）

运行时注入

package com.spring.study.runtime.di;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Employee {
    private String id;
    private String name;

    public void printInfo(){
        System.out.println("Employee: id：" + id + "," + " name:"+name);
    }
}

package com.spring.study.runtime.di;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import org.springframework.context.support.PropertySourcesPlaceholderConfigurer;
import org.springframework.core.env.Environment;

@Configuration
@ComponentScan
@PropertySource("classpath:employee.properties")
public class EmployeeConfig {
    @Autowired
    private Environment environment;

    //外部属性注入避免硬编码
    @Bean
    public Employee employee(){
        return new Employee(environment.getProperty("employee.id"),environment.getProperty("employee.name"));
    }

    //使用占位符
    public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer(){
        return new PropertySourcesPlaceholderConfigurer();
    }
}

package com.spring.study.runtime.di;

import lombok.Data;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Data
@Component
public class Manager {
    /**
     * @Value(${})代替Environment
     */
    @Value("${employee.id}")
    private String id;
    @Value("${employee.name}")
    private String name;
}

package com.spring.study.bean.runtime.di;

import com.spring.study.runtime.di.Employee;
import com.spring.study.runtime.di.EmployeeConfig;
import com.spring.study.runtime.di.Manager;
import lombok.extern.slf4j.Slf4j;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = EmployeeConfig.class)
@Slf4j
public class EmployeeTest {
    @Autowired
    private Employee employee;
    @Autowired
    private Manager manager;
    @Test
    public void testEmp(){
        employee.printInfo();
    }

    @Test
    public void testManager(){
        log.info("manager:{}",manager);
    }

}

SpEL表达式

package com.spring.study.runtime.di.spel;

import lombok.Data;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Data
@Component
public class ElDemo {
    //EL表达式引用其他bean的属性
    //#{systemProperties}引用系统属性
    //#{3.14}.#{'hello'} #{true}
    //?.
    //T()静态方法
    @Value("#{employee.name}")
    private String name;
}

package com.spring.study.runtime.di.spel;

import lombok.Data;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Data
@Component
public class ElDemo {
    //EL表达式引用其他bean的属性
    //#{systemProperties}引用系统属性
    //#{3.14}.#{'hello'} #{true}
    //?.
    //T()静态方法
    @Value("#{employee.name}")
    private String name;
}