@Cacheable「註釋類型不適用於這種聲明」

Question

我正在學習Spring和Data JPA。我對Ehcache有問題。我想緩存從數據庫返回一些記錄的方法之一的返回值。這是Ehcache實例預先配置的練習（我假設）。問題是我不能使用註釋@Cacheable將我的方法標記爲應該緩存其返回值的方法。我得到一個不兼容的類型編譯錯誤（必需：boolean，found：String）。這裏是我的服務層的類，我想我應該把@Cacheable這裏的一個（是嗎？）：

package wad.datatables.service; 

import javax.persistence.Cacheable; 
import org.springframework.beans.factory.annotation.Autowired; 
import org.springframework.data.domain.Page; 
import org.springframework.data.domain.PageRequest; 
import org.springframework.data.domain.Pageable; 
import org.springframework.data.domain.Sort; 
import org.springframework.stereotype.Service; 
import org.springframework.transaction.annotation.Transactional; 
import wad.datatables.domain.Book; 
import wad.datatables.repository.BookRepository; 
import wad.datatables.view.DataTablesResponse; 

@Service 
public class JpaDataTablesBookService implements DataTablesBookService { 

    @Autowired 
    private BookRepository bookRepository;  

    @Override 
    @Transactional(readOnly = true) 
    @Cacheable("books") 
    public DataTablesResponse getBooks(String queryString) { 
     Pageable pageable = new PageRequest(0, 10, Sort.Direction.ASC, "title"); 

     Page<Book> page = bookRepository.findByTitleContaining(queryString, pageable); 

     DataTablesResponse response = new DataTablesResponse(); 
     response.setTotalRecords(page.getTotalElements()); 
     response.setTotalDisplayRecords(page.getNumberOfElements()); 
     response.setData(page.getContent()); 

     return response; 
    } 
} 

而且我的倉庫層（只有一個類）：

package wad.datatables.repository; 

import org.springframework.data.domain.Page; 
import org.springframework.data.domain.Pageable; 
import org.springframework.data.jpa.repository.JpaRepository; 
import wad.datatables.domain.Book; 

public interface BookRepository extends JpaRepository<Book, Long> {   
    Page<Book> findByTitleContaining(String title, Pageable pageable); 
} 

這裏是我的配置文件：

cache.xml（位於WEB-INF /春/）：

<?xml version="1.0" encoding="UTF-8"?> 
<beans xmlns="http://www.springframework.org/schema/beans" 
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
     xmlns:cache="http://www.springframework.org/schema/cache" 
     xsi:schemaLocation="http://www.springframework.org/schema/beans 
      http://www.springframework.org/schema/beans/spring-beans.xsd 
      http://www.springframework.org/schema/cache 
      http://www.springframework.org/schema/cache/spring-cache.xsd"> 

    <cache:annotation-driven cache-manager="cacheManager" /> 

    <bean id="cacheManager" class="org.springframework.cache.ehcache.EhCacheCacheManager"> 
     <property name="cacheManager" ref="ehcache"/> 
    </bean> 

    <bean id="ehcache" class="org.springframework.cache.ehcache.EhCacheManagerFactoryBean"> 
     <property name="configLocation" value="classpath:ehcache.xml" /> 
    </bean> 
</beans> 

和的Ehcache。 xml（位於src/main/resources）：

<ehcache xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
     xsi:noNamespaceSchemaLocation="ehcache.xsd" 
     updateCheck="true" 
     monitoring="autodetect" 
     dynamicConfig="true"> 
    <cache name="books" maxEntriesLocalHeap="1000" eternal="true" memoryStoreEvictionPolicy="LRU"/> 
</ehcache> 

Answer 1

錯誤是因爲您使用了錯誤的Cacheable註釋。而不是javax.persistence.Cacheable使用org.springframework.cache.annotation.Cacheable。