Spring注入多例Bean [笔记]

傷城~ 2022-12-25 01:50 76阅读 0赞

在Spring开发体系中很少用到多例的Bean，所以这个知识点很容易被忘记。

Spring注入多例Bean的俩种方式：

import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.context.annotation.Scope;
    
    @Configuration
    public class BeanTest {
    	
    	
    	@Bean
    	@Scope("prototype")
    	public StaffDTO staffDTO() {
    		return new StaffDTO();
    	}
    }

### 1.使用ObjectFactory ###

示例：

import org.springframework.beans.factory.ObjectFactory;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.beans.factory.annotation.Lookup;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import com.test.entity.StaffDTO;
    
    @RestController
    @RequestMapping("/staffs")
    public class StaffController {
    	
    
    	
    	@Autowired
    	private ObjectFactory<StaffDTO> objectFactory;
    	
    	
    	
    	@GetMapping("/dto")
    	public Object getDto() {
    		return objectFactory.getObject();
    	}
    
    }

### 2.使用@Lookup注解 ###

示例：

import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.beans.factory.annotation.Lookup;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import com.test.entity.StaffDTO;
    
    
    @RestController
    @RequestMapping("/staffs")
    public abstract class StaffController {
    	
    
    	
    	@Lookup
        protected abstract StaffDTO getStaffDTO();
    	
    	
    	
    	@GetMapping("/dto")
    	public Object getDto() {
    		return getStaffDTO().toString();
    	}
    	
    	
    }