原文网址：SpringBoot--将组件注入到静态工具类--方法/实例_IT利刃出鞘的博客-CSDN博客
简介说明
本文用示例介绍Spring如何将组件注入到静态工具类。
需求
在Controller层想使用一个静态工具，这个静态工具要使用其他组件。
错误方法：在静态字段上注入Controller
package com.example.controller;
import com.example.component.WelcomeUtil;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class HelloController {
@GetMapping("/test")
public String test() {
WelcomeUtil.welcome();
return "test success";
}
}
工具类
package com.example.component;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
@Component
public class WelcomeUtil {
@Autowired
private static Hello hello;
public static void welcome() {
hello.sayHello();
}
}
引入的组件
package com.example.component;
import org.springframework.stereotype.Component;
@Component
public class Hello {
public void sayHello() {
System.out.println("Hello");
}
}
测试
访问：http://localhost:8080/test
后端结果
方案1：构造器注入其余代码与上边相同
工具类
package com.example.component;
import org.springframework.stereotype.Component;
@Component
public class WelcomeUtil {
private static Hello hello;
public WelcomeUtil(Hello hello) {
WelcomeUtil.hello = hello;
}
public static void welcome() {
hello.sayHello();
}
}
测试
访问：http://localhost:8080/test
后端结果
方案2：setter注入其余代码与上边相同
工具类
package com.example.component;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
@Component
public class WelcomeUtil {
private static Hello hello;
public static void welcome() {
hello.sayHello();
}
@Autowired
public void setHello(Hello hello) {
WelcomeUtil.hello = hello;
}
}
测试
访问：http://localhost:8080/test
结果
后端结果
方案3：ApplicationContext工具类ApplicationContext工具类
package com.example.util;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;
@Component
public class ApplicationContextHolder implements ApplicationContextAware {
private static ApplicationContext context;
@Override
public void setApplicationContext(ApplicationContext context) throws BeansException {
ApplicationContextHolder.context = context;
}
public static ApplicationContext getContext() {
return context;
}
}
工具类
package com.example.component;
import com.example.util.ApplicationContextHolder;
import org.springframework.stereotype.Component;
@Component
public class WelcomeUtil {
public static void welcome() {
ApplicationContextHolder.getContext()
.getBean(Hello.class).sayHello();
}
}
测试
访问：http://localhost:8080/test
结果
后端结果
