spring自动装配

1.自动装配，有用到这个自动装配的时候，就去扫描包，spring把带有@Component和@Bean的自动实例。

package bean;

import org.springframework.stereotype.Component;

/**
 * Created by zipon on 2017/7/15.
 */
@Component
public class Task {
    private String taskId ;
    private String taskName ;

    public String getTaskId() {
        return taskId;
    }

    public void setTaskId(String taskId) {
        this.taskId = taskId;
    }

    public String getTaskName() {
        return taskName;
    }

    public void setTaskName(String taskName) {
        this.taskName = taskName;
    }

    @Override
    public String toString() {
        return "Task{" +
                "taskId='" + taskId + '\'' +
                ", taskName='" + taskName + '\'' +
                '}';
    }

    public void getTask(){
        System.out.println("=============>renwushi=======>"+"renwuId:"+taskId+",renwuname:"+taskName);
    }
}

通过@Configuration创建设置类，通过@ComponentScan(basePackageClasses = {Task.class})扫描Task.class所在的包。

package springTest;

import bean.Task;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.test.context.ContextConfiguration;

/**
 * Created by zipon on 2017/7/15.
 */
@Configuration
@ComponentScan(basePackageClasses = {Task.class})
public class ComponentConfig {
}

 

通过@ContextConfiguration(classes = ComponentConfig.class)导入配置

package springTest;

import bean.Task;
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;
import static org.junit.Assert.*;

/**
 * Created by zipon on 2017/7/15.
 */
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = ComponentConfig.class)
public class AutowiredTest {
    @Autowired
    private Task task;

    @Test
    public void test(){
        System.out.println(task.toString());
        task.getTask();
        assertNotNull(task);
    }
}

 如果不加入自动装配的话，就会报空指针异常