通用DAO實現，在控制器級別注入失敗

Question

  import java.lang.reflect.Field;
import java.lang.reflect.ParameterizedType;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Date;
import java.util.List;
import java.util.Map;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.Query;
import javax.persistence.Transient;

import org.apache.log4j.Logger;
import org.springframework.dao.DataAccessException;


/**
 * Generic DAO implementation class that provides basic Data access and
 * manipulation functionality
 * 
 * @author syed.ammar
 * 
 */
public abstract class GenericDAOImpl<T> implements GenericDAO<T> {

    private static Logger logger = Logger.getLogger(GenericDAOImpl.class);

    @SuppressWarnings("unchecked")
    protected Class<T> clazz = (Class<T>) ((ParameterizedType) this.getClass().getGenericSuperclass()).getActualTypeArguments()[0];

    @PersistenceContext
    protected EntityManager entityManager;

    public EntityManager getEntityManager() {
        return entityManager;
    }

    public void setEntityManager(EntityManager entityManager) {
        this.entityManager = entityManager;
    }

    @Override
    public T save(T entity) throws DataAccessException {
        logger.debug("Merging Object of Type: " + entity.getClass().getCanonicalName());
        entity = entityManager.merge(entity);
        return entity;
    }

    @Override
    public void persist(T entity) throws DataAccessException {
        logger.debug("Persisting Object of Type: " + entity.getClass().getCanonicalName());
        entityManager.persist(entity);
    }


    /**
     * This method update record in database
     * 
     * @param updatableObj
     *            - the updated copy to merge
     * @return the updated, registered persistent instance
     * */
    @Override
    public T update(T entity) {
        return save(entity);
    }

    /**
     * Delete the given entity.
     * 
     * @param entityClass
     *            - the entityClass to delete
     * */
    @Override
    public void delete(T entity) {
        logger.debug("Delete entity of Type: " + entity.getClass().getCanonicalName());
        entityManager.remove(entity);
    }

    /**
     * Delete all given entities.
     * 
     * @param entities
     *            - the entities to delete
     * */
    public void deleteAll(List<T> entities) {
        for (T entity : entities) {
            delete(entity);
        }
    }

    /**
     * Delete Entity by Id
     * @param id
     *      - Entity Id 
     */
    @Override
    public int deleteById(Long id) {
        Query deleteQuery = entityManager.createQuery("DELETE FROM " + clazz.getName() + " entity WHERE entity.id=:id");
        deleteQuery.setParameter("id", id);
        return deleteQuery.executeUpdate();     
    }

    /**
     * Delete Entity by Customer
     * @param customer
     *      - Customer Entity 
     */
/*  @Override
    public int deleteByCustomer(Customer customer) {
        Query deleteQuery = entityManager.createQuery("DELETE FROM " + clazz.getName() + " entity WHERE entity.customer=:customer");
        deleteQuery.setParameter("customer", customer);
        return deleteQuery.executeUpdate();
    }
*/  
    /**
     * Delete Entity by Reseller
     * @param reseller
     *      - Reseller Entity 
     */
/*  @Override
    public int deleteByReseller(Reseller reseller) {
        Query deleteQuery = entityManager.createQuery("DELETE FROM " + clazz.getName() + " entity WHERE entity.customer.reseller=:reseller");
        deleteQuery.setParameter("reseller", reseller);
        return deleteQuery.executeUpdate();
    }
*/
    /**
     * Read the entity instance of the given class with the given id, throwing
     * an exception if not found. Retrieves read-write objects from the
     * hibernate UnitOfWork in case of a non-read-only transaction, and
     * read-only objects else.
     * @param id
     *            - Identity key of the desired object
     * @return the entity instance
     * */
    @Override
    public T getById(Long id) {
        logger.debug("getById:" + id + ", T class: " + clazz );
        return entityManager.find(clazz, id);
    }

    @Override
    public List<T> getResultList(String jpql, Map<String, Object> queryParams) {
        logger.debug("Query: " + jpql);
        Query query = entityManager.createQuery(jpql.toString());
        for(Map.Entry<String, Object> entry : queryParams.entrySet()){
            query.setParameter(entry.getKey(), entry.getValue());
        }
        @SuppressWarnings("unchecked")
        List<T> resultList = (List<T>) query.getResultList();
        return resultList;
    }

    /**
     * Generic search method without sort column and direction which searches
     * the record depending upon property values set in the passed model bean. 
     * This method has been deprecated and will be removed soon. Create Query 
     * specific methods in related Entity DAO's instead.
     * 
     * @param entity
     *            Entity with data set for criteria search
     * @return List of searched model beans by applying the passed values of
     *         model bean as criteria
     */
    @Override
    @Deprecated
    public List<T> search(T entity) {
        return search(entity, null, null);
    }

    /**
     * Generic search method which searches the record depending upon property
     * values set in the passed model bean. 
     * This method has been deprecated and will be removed soon. Create Query 
     * specific methods in related Entity DAO's instead.
     * 
     * @param entity
     *            Entity with data set for criteria search
     * @param sortByColumn
     *            Name of column to be used for sorting result
     * @param sortDirection
     *            1: ASC 2:DESC
     * @return List of searched model beans by applying the passed values of
     *         model bean as criteria
     */
    @Override
    @Deprecated
    @SuppressWarnings("unchecked")
    public List<T> search(T entity, String sortByColumn, Long sortDirection) {
        List<Object> params = new ArrayList<Object>();
        String query = "SELECT entity FROM " + clazz.getName() + " entity";

        Field[] publicFields = entity.getClass().getDeclaredFields();
        for (Field field : publicFields) {
            field.setAccessible(true);
            Object value = null;
            try {
                value = field.get(entity);
            } catch (IllegalArgumentException e) {
                logger.error("", e);
            } catch (IllegalAccessException e) {
                logger.error("", e);
            }
            if (value == null
                    || Collection.class.isAssignableFrom(field.getType())
                    || java.lang.reflect.Modifier.isStatic(field.getModifiers())
                    || field.getAnnotation(Transient.class) != null) {
                continue;
            }
            if (field.getType().equals(String.class)) {
                if (query.contains("where")) {
                    query = query + " and " + field.getName() + " like ?"
                            + params.size();
                } else {
                    query = query + " where " + field.getName() + " like ?"
                            + params.size();
                }
                params.add("%" + value.toString() + "%");
            } else if (field.getType().equals(Date.class)) {
                Date startDateTime = null;
                Date endDateTime = null;
                String startTime = DATE_FORMAT.format(value) + " 00:00:00";
                String endTime = DATE_FORMAT.format(value) + " 23:59:59";
                try {
                    startDateTime = DATE_TIME_FORMAT.parse(startTime);
                    endDateTime = DATE_TIME_FORMAT.parse(endTime);
                } catch (ParseException e) {
                    logger.error("", e);
                }
                if (startDateTime == null || endDateTime == null) {
                    continue;
                }
                if (query.contains("where")) {
                    query = query + " and " + field.getName() + " between ?"
                            + params.size() + " and ?" + (params.size() + 1);
                } else {
                    query = query + " where " + field.getName() + " between ?"
                            + params.size() + " and ?" + (params.size() + 1);
                }

                params.add(startDateTime);
                params.add(endDateTime);
            } else {
                if (query.contains("where")) {
                    query = query + " and " + field.getName() + " = "
                            + params.size();
                } else {
                    query = query + " where " + field.getName() + " = ?"
                            + params.size();
                }
                params.add(value);
            }
        }

        Query queryObj = entityManager.createQuery(query);

        // Check is sorting parameters are not not blank or null, apply sorting
        // criteria
        if (sortByColumn != null && sortDirection != null) {
            if (sortDirection == 1L) {
                query = query + " Order By " + sortByColumn + " ASC";
            } else {
                query = query + " Order By " + sortByColumn + " DESC";
            }
            if (params.size() > 0) {
                for (int i = 0; i < params.size(); i++) {
                    queryObj.setParameter(i, params.get(i));
                }
            }
        }

        return queryObj.getResultList();
    }

    @Override
    public List<T> getAll() {
        return getAll(null, null);
    }

    @Override
    public List<T> getAll(String sortByColumn, Long sortDirection) {
        String query = "SELECT entity FROM " + clazz.getName() + " entity";
        if (sortByColumn != null && sortDirection != null) {
            if (sortDirection == 1L) {
                query = query + " Order By " + sortByColumn + " ASC";
            } else {
                query = query + " Order By " + sortByColumn + " DESC";
            }
        }
        @SuppressWarnings("unchecked")
        List<T> resultList = (List<T>) entityManager.createQuery(query).getResultList();
        return resultList;
    }
    /**
     * Generic find method which identify the exact records depending upon
     * property values set in the passed model bean else null will be returned
     * 
     * @param entity
     *            Entity with data set for criteria search
     * @return List of identified model beans by applying the passed values of
     *         model bean as criteria
     */
    @Override
    @SuppressWarnings("unchecked")
    public List<T> find(T entity) {
        List<Object> params = new ArrayList<Object>();
        String query = "SELECT entity FROM " + entity.getClass().getName()
                + " entity";

        Field[] publicFields = entity.getClass().getDeclaredFields();
        for (Field field : publicFields) {
            field.setAccessible(true);
            Object value = null;

            try {
                value = field.get(entity);
            } catch (IllegalArgumentException e) {
                logger.error("", e);
            } catch (IllegalAccessException e) {
                logger.error("", e);
            }
            if (value == null
                    || Collection.class.isAssignableFrom(field.getType())
                    || java.lang.reflect.Modifier.isStatic(field.getModifiers())
                    || field.getAnnotation(Transient.class) != null) {
                continue;
            }

            if (field.getType().equals(Date.class)) {
                Date startDateTime = null;
                Date endDateTime = null;
                String startTime = DATE_FORMAT.format(value) + " 00:00:00";
                String endTime = DATE_FORMAT.format(value) + " 23:59:59";               
                try {
                    startDateTime = DATE_TIME_FORMAT.parse(startTime);
                    endDateTime = DATE_TIME_FORMAT.parse(endTime);
                } catch (ParseException e) {
                    logger.error("", e);
                }
                if (startDateTime == null || endDateTime == null) {
                    continue;
                }
                if (query.contains("where")) {
                    query = query + " and " + field.getName() + " between ?"
                            + params.size() + " and ?" + (params.size() + 1);
                } else {
                    query = query + " where " + field.getName() + " between ?"
                            + params.size() + " and ?" + (params.size() + 1);
                }
                params.add(startDateTime);
                params.add(endDateTime);
            } else {
                if (query.contains("where")) {
                    query = query + " and " + field.getName() + " = ?"
                            + params.size();
                } else {
                    query = query + " where " + field.getName() + " = ?"
                            + params.size();
                }
                params.add(value);
            }
        }
        if (params.size() > 0) {
            Query queryObj = entityManager.createQuery(query);

            for (int i = 0; i < params.size(); i++) {
                queryObj.setParameter(i, params.get(i));
            }
            return queryObj.getResultList();
        } else {
            return null;
        }
    }
}

///自動接線

@Controller
public class CourseController   {

//  @Autowired
//  private SearchService searchService;

    @Autowired
    CourseDAOImp courseDAO;
    //..............
}

嚴重：異常將上下文初始化事件發送到類org.springframework.web.context.ContextLoaderListener org.springframework.beans.factory.BeanCreationException的偵聽器實例：創建名稱為“ courseController”的bean時出錯：自動連接依賴項注入失敗； 嵌套的異常是org.springframework.beans.factory.BeanCreationException：無法自動連線字段：com.softech.ls360.lcms.contentbuilder.dao.impl.CourseDAOImp com.softech.ls360.lcms.contentbuilder.web.controller.CourseController.courseDAO ; 嵌套的異常是org.springframework.beans.factory.NoSuchBeanDefinitionException：沒有找到類型為[com.softech.ls360.lcms.contentbuilder.dao.impl.CourseDAOImp]的匹配bean作為依賴項：至少應有1個可作為自動裝配候選的bean這種依賴性。 依賴項注釋：org.springframework.bean上的org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues（AutowiredAnnotationBeanPostProcessor.java:285）上的{@ org.springframework.beans.factory.annotation.Autowired（required = true）}。 org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean（AbstractAutowireCapableBeanFactory.java:517）的org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean（AbstractAutowireCapableBeanFactory.java:1074） org.springframework.beans.factory.support.AbstractBeanFactory $ 1.getObject（AbstractBeanFactory.java:291）處的org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton（DefaultSingletonBeanRegistry.java:222）處的AbstractAutowireCapableBeanFactory.java:456） org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean（AbstractBeanFactory.java ：288），位於org.springframework.beans.factory.support.AbstractBeanFactory.getBean（AbstractBeanFactory.java:190），位於org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons（DefaultListableBeanFactory.java:580）。在org.springframework.context.support.AbstractApplicationContext.refresh（AbstractApplicationContext.java:425）處的context.support.AbstractApplicationContext.finishBeanFactoryInitialization（AbstractApplicationContext.java:895）在org.springframework.web.context.ContextLoader.createWebApplicationContext（ContextLoader.java： 276）在org.springframework.web.context.ContextLoader.initWebApplicationContext（ContextLoader.java:197）在org.springframework.web.context.ContextLoaderListener.contextInitialized（ContextLoaderListener.java:47）在org.apache.catalina.core.StandardContext org.apache.catalina.core上的.listenerStart（StandardContext.java:4791）org.apache.catalina.util.Lifecy上的.listenerStart（StandardContext.java:4791） org.apache.catalina.core.ContainerBase.addChild（ContainerBase.java:877）的org.apache.catalina.core.ContainerBase.addChildInternal（ContainerBase.java:901）的cleBase.start（LifecycleBase.java:150） org.apache.catalina.startup.HostConfig.deployWAR（HostConfig.java:963）上的.apache.catalina.core.StandardHost.addChild（StandardHost.java:618）在org.apache.catalina.startup.HostConfig $ DeployWar.run （HostConfig.java:1600）在java.util.concurrent.Executors $ RunnableAdapter.call（Executors.java:471）在java.util.concurrent.FutureTask.run（FutureTask.java:262）在java.util.concurrent。 ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1145）at java.util.concurrent.ThreadPoolExecutor $ Worker.run（ThreadPoolExecutor.java:615）at java.lang.Thread.run（Thread.java:744）原因：org.springframework .beans.factory.BeanCreationException：無法自動連線字段：com.softech.ls360.lcms.contentbuilder.dao.impl.CourseDAOImp com.softech.ls360.lcms.contentbuilder.web.controller.CourseController.courseDAO; 嵌套的異常是org.springframework.beans.factory.NoSuchBeanDefinitionException：沒有找到類型為[com.softech.ls360.lcms.contentbuilder.dao.impl.CourseDAOImp]的匹配bean作為依賴項：至少應有1個可作為自動裝配候選的bean這種依賴性。 依賴項注釋：在org.springframework的org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor $ AutowiredFieldElement.inject（AutowiredAnnotationBeanPostProcessor.java:502）的{@ org.springframework.beans.factory.annotation.Autowired（required = true）}。 org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues（AutowiredAnnotationBeanPostProcessor.java:282）上的beans.factory.annotation.InjectionMetadata.inject（InjectionMetadata.java:84）... 26個以上原因：org.springframeworkbean。 .factory.NoSuchBeanDefinitionException：找不到依賴項類型為[com.softech.ls360.lcms.contentbuilder.dao.impl.CourseDAOImp]的匹配bean：期望至少有1個bean符合此依賴項的自動裝配條件。 依賴注釋：org.springframework.beans上的org.springframework.beans.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException（DefaultListableBeanFactory.java:920）上的{@ org.springframework.beans.factory.annotation.Autowired（required = true）}。 org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcess。$ org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency（DefaultListableBeanFactory.java:703）的factory.support.DefaultListableBeanFactory.doResolveDependency（DefaultListableBeanFactory.java:789） inject（AutowiredAnnotationBeanPostProcessor.java:474）...還有28個

Answer 1

您沒有使用名稱“ courseController”注冊bean。首先將該類注冊為bean。您在不注冊courseController的情況下注入了該類。 通過添加@ComponenetScan批注，您可以掃描所有bean，spring會注冊它們。

Answer 2

您應該在xml中定義bean

或entry of <context:component-scan base-package=" " />

Answer 3

我認為問題在於DAO沒有注入到Controller中，我在此DAO類中添加了另一層作為Service和autowired服務，這對我來說很好用。

在我的情況下，我不需要定義bean是因為我正在為此使用Annotation並且正在掃描整個包。

謝謝，