終於搞懂Spring中Scope為Request和Session的Bean了
阿新 • • 發佈：2020-07-19
之前只是很模糊的知道其意思，在request scope中，每個request建立一個新的bean，在session scope中，同一session中的bean都是一樣的
但是不知道怎麼用程式碼去驗證它
今天可找到驗證它的程式碼了
首先定義一個簡單的類
```java
import lombok.Getter;
import lombok.Setter;
@Getter
@Setter
public class HelloMessageGenerator {
private String message;
@Override
public String toString() {
return getClass().getSimpleName() + "@" + Integer.toHexString(hashCode());
}
}
```
然後定義一個配置類
```java
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.context.annotation.RequestScope;
import org.springframework.web.context.annotation.SessionScope;
@Configuration
public class ScopesConfig {
@Bean
@RequestScope
public HelloMessageGenerator requestScopedBean() {
return new HelloMessageGenerator();
}
@Bean
@SessionScope
public HelloMessageGenerator sessionScopedBean() {
return new HelloMessageGenerator();
}
}
```
最後定義個控制類
```java
import com.google.common.collect.Maps;
import java.util.Map;
import javax.annotation.Resource;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
@RequestMapping("/scopes")
@Slf4j
public class ScopesController {
@Resource(name = "requestScopedBean")
private HelloMessageGenerator requestScopedBean;
@Resource(name = "sessionScopedBean")
private HelloMessageGenerator sessionScopedBean;
@GetMapping("/request")
pu