有时候,会有这样一个需求,在程序运行时动态生成的对象,需要注入到Spring容器中进行管理。
下面是获取Bean以及注入Bean的工具类
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;
import java.lang.reflect.Field;
import java.util.Map;
@Component
public class SpringUtils implements ApplicationContextAware {
private static ApplicationContext applicationContext;
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
SpringUtils.applicationContext = applicationContext;
}
public static ApplicationContext getApplicationContext() {
return applicationContext;
}
public static Object getBean(String name) throws BeansException {
return applicationContext.getBean(name);
}
public static Object getBean(Class name) throws BeansException {
return applicationContext.getBean(name);
}
/**
* bean注入spring容器
* map[id,className,...]
* id 为 bean的标识
* className 为 类的全限定类名
* ... 为其他属性
* @param map
*/
public static void injectBean(Map<String, String> map) {
String className = map.get("className");
Class<?> aClass;
if (className == null) {
throw new RuntimeException("map参数缺少className");
}
try {
aClass = Class.forName(className);
if (aClass == null) {
throw new RuntimeException("className不存在");
}
} catch (ClassNotFoundException e) {
throw new RuntimeException(e);
}
BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(aClass);
Field[] declaredFields = aClass.getDeclaredFields();
for (int i = 0; i < declaredFields.length; i++) {
String fieldName = declaredFields[i].getName();
if (map.get(fieldName) != null) {
// 必须设置可访问,否则下面的操作做不了
// declaredFields[i].setAccessible(true);
builder.addPropertyValue(fieldName, map.get(fieldName));
}
}
BeanDefinitionRegistry registry = (BeanDefinitionRegistry) applicationContext;
// 注册bean 第一个参数为 name ,第二个为 bean定义类
String id = map.get("id");
if (id == null) {
registry.registerBeanDefinition(className, builder.getBeanDefinition());
return;
}
registry.registerBeanDefinition(id, builder.getBeanDefinition());
}
}
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测试
@Test
public void test2() {
HashMap<String, String> map = new HashMap<>();
map.put("id", "helloTask");
map.put("className", "com.example.demo.Task.HelloTask4");
// 注册bean
SpringUtils.injectBean(map);
// HelloTask4 helloTask =(HelloTask4) SpringUtils.getBean(HelloTask4.class);
HelloTask4 helloTask = (HelloTask4) SpringUtils.getBean("helloTask");
System.out.println(helloTask.getClass());
}
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