if,else太多使用策略模式解决

TestController

@RestController("TestController")
@RequestMapping("/test")
public class TestController {
    @Autowired
    private TestService testService;
    private Map<String, Function<String, String>> resultMap = Maps.newConcurrentMap();

    @PostConstruct
    public void init() {
        resultMap.put("1", type -> testService.handler1(type));
        resultMap.put("2", type -> testService.handler2(type));
        resultMap.put("3", type -> testService.handler3(type));
        resultMap.put("4", type -> testService.handler4(type));
    }

    @RequestMapping(value = "/listByType2", method = RequestMethod.GET)
    public String listByType2(@RequestParam(value = "type") String type) {
        Function<String, String> function = resultMap.get(type);
        if (function == null) {
            return null;
        }
        return function.apply(type);
    }

    //正常写法
    @RequestMapping(value = "/listByType", method = RequestMethod.GET)
    public String listByType(@RequestParam(value = "type") String type) {
        if (type.equals("1")) {
            return testService.handler1(type);
        } else if (type.equals("2")) {
            return testService.handler2(type);
        } else if (type.equals("3")) {
            return testService.handler3(type);
        } else if (type.equals("4")) {
            return testService.handler4(type);
        }
        return "执行其他函数0";
    }

}

TestService

public interface TestService {
    String handler1(String type);
    String handler2(String type);
    String handler3(String type);
    String handler4(String type);
}

TestServiceImpl

@Service("TestService")
public class TestServiceImpl implements TestService{
    @Override
    public String handler1(String type) {
        return "执行逻辑方法1";
    }

    @Override
    public String handler2(String type) {
        return "执行逻辑方法2";
    }

    @Override
    public String handler3(String type) {
        return "执行逻辑方法3";
    }

    @Override
    public String handler4(String type) {
        return "执行逻辑方法4";
    }
}