Java使用@value构造成员字段大小

Question

我正在使用番石榴缓存，我想在其中保持最大大小可配置。我尝试为此使用@value，但问题是私有成员缓存在@value 注入之前创建。如何从配置属性中读取此大小？我目前使用的代码如下

@Component
public class DataProcessor {

@Value("${cacheSize}")
private long cacheSize;
@Value(value = "${rawSensorDataTopic}")
private String rawSensorDataTopic;

private LoadingCache<String, DataPacketGroup> rfPacketsCache = CacheBuilder.newBuilder().maximumSize(cacheSize)
        .concurrencyLevel(1).expireAfterWrite(15, TimeUnit.MINUTES)
        .build(new CacheLoader<String, DataPacketGroup>() {
            @Override
            public DataPacketGroup load(String key) throws Exception {
                return null;
            }
        });

Answer 1

您可以将缓存创建放在一个用 @PostConstruct

注释的方法中

@Component
public class DataProcessor {

@Value("${cacheSize}")
private long cacheSize;
@Value(value = "${rawSensorDataTopic}")
private String rawSensorDataTopic;

private LoadingCache<String, DataPacketGroup> rfPacketsCache;

@PostConstruct
private void createcache() {
     CacheBuilder.newBuilder().maximumSize(1000)
        .concurrencyLevel(1).expireAfterWrite(15, TimeUnit.MINUTES)
        .build(new CacheLoader<String, DataPacketGroup>() {
            @Override
            public DataPacketGroup load(String key) throws Exception {
                return null;
            }
        });
}

如果构造了bean并注入了属性，就会执行这个方法

Java使用@value构造成员字段大小

Java using @value to construct a member field size

java

spring

guava