选择在运行时注入哪种实现

小编典典

选择在运行时注入哪种实现

spring

我有以下课程：

public interface MyInterface{}

public class MyImpl1 implements MyInterface{}

public class MyImpl2 implements MyInterface{}

public class Runner {
        @Autowired private MyInterface myInterface;
}

我要确定的是，在应用已运行（即未启动时）的情况下，应将哪种实施注入Runner。

所以理想情况是这样的：

ApplicationContext appContext = ...
Integer request = ...

Runner runner = null;
if (request == 1) {
        //here the property 'myInterface' of 'Runner' would be injected with MyImpl1
        runner = appContext.getBean(Runner.class) 
}
else if (request == 2) {
        //here the property 'myInterface' of 'Runner' would be injected with MyImpl2
        runner = appContext.getBean(Runner.class)
}
runner.start();

做到这一点的最佳方法是什么？

阅读 247

2020-04-21

共1个答案

小编典典

用@Component("implForRq1")和声明实现@Component("implForRq2")

然后将它们都注入并使用：

class Runner {

    @Autowired @Qualifier("implForRq1")
    private MyInterface runnerOfRq1;

    @Autowired @Qualifier("implForRq2")
    private MyInterface runnerOfRq2;

    void run(int rq) {
        switch (rq) {
            case 1: runnerOfRq1.run();
            case 2: runnerOfRq2.run();
            ...

        }
    }

}

...

@Autowired
Runner runner;

void run(int rq) {
    runner.run(rq);
}

2020-04-21