spring prototype怎么注入到singleton 里面

最新推荐文章于 2025-02-14 02:27:19 发布

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本文通过具体示例探讨了Spring框架中如何通过容器而非注解方式来实例化对象，并对比了两种不同方法下实例化结果的差异。

经过测试之后用注解的方式不行所以只能采用容器取的方式。例子代码如下

package com.dragon.service.test;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;

@Component("testBean")
@Scope("singleton")
public class TestBean {
<span style="white-space:pre">	</span>//@Autowired
<span style="white-space:pre">	</span>//private TestBean1 testBean1;
	public TestBean1 getTestBean1() {
		return (TestBean1) SpringBeanUtils.getBean("testBean1");
	}

}

package com.dragon.service.test;

import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;

@Component("testBean1")
@Scope("prototype")
public class TestBean1 {

	private Integer num = 1;

	public Integer getNum() {
		num++;
		return num;
	}

}

package com.dragon.service.test;

import java.util.Map;

import org.slf4j.*;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Service;

@Service
public class SpringBeanUtils implements ApplicationContextAware {

	private static ApplicationContext appContext;
	private Logger logger = LoggerFactory.getLogger(getClass());

	public void setApplicationContext(ApplicationContext applicationContext)
			throws BeansException {
		SpringBeanUtils.appContext = applicationContext;
		logger.debug("初始化Spring上下文成功。");
	}

	/**
	 * 获取 ApplicationContext
	 */
	public static ApplicationContext getApplicationContext() {
		return appContext;
	}

	/**
	 * 获取 TestBean
	 * 
	 * @param beanName
	 *            bean 名称
	 * @return
	 */
	public static Object getBean(String beanName) {
		checkApplicationContext();
		return appContext.getBean(beanName);
	}

	/**
	 * 获取 TestBean
	 * 
	 * @param clazz
	 *            bean 类
	 * @return
	 */
	@SuppressWarnings("unchecked")
	public static <T> T getBean(Class<T> clazz) {
		checkApplicationContext();
		Map<?, ?> map = appContext.getBeansOfType(clazz);
		return map.isEmpty() ? null : (T) map.values().iterator().next();
	}

	/**
	 * 检查 ApplicationContext 是否注入
	 */
	private static void checkApplicationContext() {
		if (null == appContext) {
			throw new IllegalStateException("applicaitonContext未注入");
		}
	}

}

测试类如下

package com.dragon.test;

import org.junit.Test;
import org.springframework.beans.factory.annotation.Autowired;

import com.dragon.service.test.TestBean;

public class TestBeanTest extends BaseTest {
	@Autowired
	private TestBean testBean1;
	@Autowired
	private TestBean testBean2;

	@Test
	public void testAdd() {
		System.out.println(testBean1.getTestBean1().getNum());
		System.out.println(testBean2.getTestBean1().getNum());
	}
}

这样子输出的结果是 2,2 也就说明了每次取到的testbean1对象都是新的对象

如果testbean里面采用注入的方式打印的结果是2,3