Spring Bean 注入示例

1. 接口多实现

@RestController
public class ProviderController {
    @Resource
    private Provider queryProvider;
    @Resource
    private Provider subQueryProvider;

    @RequestMapping("/provider")
    public String provider() {
        queryProvider.execute();
        subQueryProvider.execute();
        return "provider";
    }
}

接口

public interface Provider {
    void execute();
}

public interface SubProvider extends Provider {
}

实现类

@Service
public class QueryProvider implements Provider {
    @Override
    public void execute() {
        System.out.println("QueryProvider...");
    }
}

@Service
public class SubQueryProvider implements SubProvider {
    @Override
    public void execute() {
        System.out.println("SubQueryProvider...");
    }
}

2. 接口调用链

2.1 常用写法

@RestController
public class CommonProcessorController {

    @Resource
    private CommonProcessor commonProcessor;
    @Resource
    private CommonProcessor batchCommonProcessor;

    @RequestMapping("/config/common")
    public String commonConfig() {
        BaseContext context = new QueryContext();
        commonProcessor.execute(context);
        return "common processor";
    }

    @RequestMapping("/config/batch")
    public String batchConfig() {
        BaseContext context = new QueryContext();
        batchCommonProcessor.execute(context);
        return "batch common processor";
    }
}

注入 Bean

@Configuration
public class CommonProcessorConfig {

    @Resource
    private IProcessor queryProcessor;
    @Resource
    private IProcessor updateProcessor;
    @Resource
    private IProcessor batchProcessor;

    @Bean
    public CommonProcessor commonProcessor() {
        CommonProcessor commonProcessor = new CommonProcessor();
        List<IProcessor> processorList = new ArrayList<>();
        processorList.add(queryProcessor);
        processorList.add(updateProcessor);
        commonProcessor.setProcessorList(processorList);
        return commonProcessor;
    }

    @Bean
    public CommonProcessor batchCommonProcessor() {
        CommonProcessor commonProcessor = new CommonProcessor();
        List<IProcessor> processorList = Arrays.asList(batchProcessor);
        commonProcessor.setProcessorList(processorList);
        return commonProcessor;
    }
}

public class CommonProcessor {
    
    private List<IProcessor> processorList;
    
    public void execute(BaseContext context) {
        for (IProcessor processor : processorList) {
            processor.execute(context);
        }
    }

    public List<IProcessor> getProcessorList() {
        return processorList;
    }

    public void setProcessorList(List<IProcessor> processorList) {
        this.processorList = processorList;
    }
}

public interface IProcessor<T extends BaseContext> {
    void execute(T context) throws RuntimeException;
}

@Component
public class QueryProcessor implements IProcessor<QueryContext> {
    @Override
    public void execute(QueryContext context) throws RuntimeException {
        context.setTotal(100);
        System.out.println("QueryProcessor: " + JSON.toJSONString(context));
    }
}

@Component
public class UpdateProcessor implements IProcessor<QueryContext> {
    @Override
    public void execute(QueryContext context) throws RuntimeException {
        context.setName("update");
        System.out.println("UpdateProcessor: " + JSON.toJSONString(context));
    }
}

@Component
public class BatchProcessor implements IProcessor<QueryContext> {
    
    @Override
    public void execute(QueryContext context) throws RuntimeException {
        context.setName("batch");
        context.setTotal(200);
        System.out.println("BatchProcessor..." + JSON.toJSONString(context));
    }
}

@Data
public class QueryContext extends BaseContext {
    private static final long serialVersionUID = -3626780096892721560L;

    private Integer total;
    
    private String name;

    public QueryContext() {}

    public QueryContext(BaseContext baseContext) {
        super(baseContext);
    }
}

public class BaseContext implements Serializable {
    private static final long serialVersionUID = -1013819823166401300L;

    private Request request;
    private Response response;
    private BaseContext baseContext;

    public BaseContext() {

    }

    public BaseContext(BaseContext baseContext) {
        this.baseContext = baseContext;
    }

    public Request getRequest() {
        if (baseContext != null) {
            return baseContext.getRequest();
        }
        return request;
    }

    public void setRequest(Request request) {
        if (baseContext != null) {
            baseContext.setRequest(request);
        }
        this.request = request;
    }

    public Response getResponse() {
        if (baseContext != null) {
            return baseContext.getResponse();
        }
        return response;
    }

    public void setResponse(Response response) {
        if (baseContext != null) {
            baseContext.setResponse(response);
        }
        this.response = response;
    }

    @Data
    public static class Request {
        private String baseName;
    }

    @Data
    public static class Response {

    }
}

2.2 在方法参数注入

@Configuration
public class CommonProcessorConfig {

    @Bean
    public CommonProcessor commonProcessor(IProcessor queryProcessor, IProcessor updateProcessor) {
        CommonProcessor commonProcessor = new CommonProcessor();
        List<IProcessor> processorList = new ArrayList<>();
        processorList.add(queryProcessor);
        processorList.add(updateProcessor);
        commonProcessor.setProcessorList(processorList);
        return commonProcessor;
    }

    @Bean
    public CommonProcessor batchCommonProcessor(IProcessor batchProcessor) {
        CommonProcessor commonProcessor = new CommonProcessor();
        List<IProcessor> processorList = Arrays.asList(batchProcessor);
        commonProcessor.setProcessorList(processorList);
        return commonProcessor;
    }
}

2.3 @Bean 方式注入

@Configuration
public class CommonProcessorConfigBack2 {

    @Bean
    public CommonProcessor commonProcessor() {
        CommonProcessor commonProcessor = new CommonProcessor();
        List<IProcessor> processorList = new ArrayList<>();
        processorList.add(queryProcessor());
        processorList.add(updateProcessor());
        commonProcessor.setProcessorList(processorList);
        return commonProcessor;
    }

    @Bean
    public CommonProcessor batchCommonProcessor() {
        CommonProcessor commonProcessor = new CommonProcessor();
        List<IProcessor> processorList = Arrays.asList(batchProcessor());
        commonProcessor.setProcessorList(processorList);
        return commonProcessor;
    }

    @Bean
    public IProcessor queryProcessor() {
        return new QueryProcessor();
    }

    @Bean
    public IProcessor updateProcessor() {
        return new UpdateProcessor();
    }

    @Bean
    public IProcessor batchProcessor() {
        return new BatchProcessor();
    }
}

注意：此方式注入 bean, 需要将 QueryProcessor, 的 @Component 注解去掉

3. 升级

@RestController
public class CommonProcessorController {
    @Resource
    private ProcessorEnumBuild processorEnumBuild;

    @RequestMapping("/config/enum")
    public String enumConfig() {
        CommonProcessor processor = processorEnumBuild.getProcessorByBizType("COMMON_BIZ_PROCESSOR");
        processor.execute(new QueryContext());
        return JSON.toJSONString(processorEnumBuild.getProcessorMap());
    }
}

@Component
public class ProcessorEnumBuild implements ApplicationContextAware, InitializingBean {

    public static ApplicationContext applicationContext;

    private Map<String, CommonProcessor> processorMap = new HashMap<>();

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        ProcessorEnumBuild.applicationContext = applicationContext;
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        for (ProcessTypeEnum value : ProcessTypeEnum.values()) {
            CommonProcessor processor = (CommonProcessor) applicationContext.getBean(value.getProcessName());
            processorMap.put(value.getBizType(), processor);
        }
    }

    public CommonProcessor getProcessorByBizType(String processorName) {
        return processorMap.get(processorName);
    }

    public Map<String, CommonProcessor> getProcessorMap() {
        return processorMap;
    }
}

public enum ProcessTypeEnum {

    COMMON_BIZ_PROCESSOR("COMMON_BIZ_PROCESSOR", "commonProcessor", "普通执行器"),
    BATCH_BIZ_PROCESSOR("BATCH_BIZ_PROCESSOR", "batchCommonProcessor", "批量执行器"),
    ;

    private String bizType;
    private String processName;
    private String desc;

    ProcessTypeEnum(String bizType, String processName, String desc) {
        this.bizType = bizType;
        this.processName = processName;
        this.desc = desc;
    }

    public String getBizType() {
        return bizType;
    }

    public String getProcessName() {
        return processName;
    }

    public String getDesc() {
        return desc;
    }

    public ProcessTypeEnum getProcessor(String bizType) {
        for (ProcessTypeEnum value : values()) {
            if (Objects.equals(bizType, value.getBizType())) {
                return value;
            }
        }
        return null;
    }
}