细节详解AnnotationSessionFactoryBean

AnnotationSessionFactoryBean是org.springframework.orm.hibernate3.annotation包下的一个创建session工厂的类，该类继承了LocalSessionFactoryBean类，该类可以可以扫描你的工程中被注解的实体类，也可以通过packagesToScan扫描包的方式批量扫描被注解的实体类。还可以使用它配置hibernate的相关配置，这样就不用再添加hibernate的配置文件。
该类在spring的核心配置文件中配置如下:

<bean id="sessionFactory"
            class="org.springframework.orm.hibernate4.annotation.AnnotationSessionFactoryBean">
            <property name="dataSource" ref="dataSource" />
            <property name="annotatedClasses">
                <list>
                <value>cn.edu.imau.jsj.beans.BaseMessage</value>
                <value>cn.edu.imau.jsj.beans.Family</value>
                <value>cn.edu.imau.jsj.beans.ProductedArea</value>
                <value>cn.edu.imau.jsj.beans.SelectedProductedArea</value>
                <value>cn.edu.imau.jsj.beans.SelectedSoil</value>
                <value>cn.edu.imau.jsj.beans.ShapeFeature</value>
                <value>cn.edu.imau.jsj.beans.Soil</value>
                <value>cn.edu.imau.jsj.beans.User</value>
                <value>cn.edu.imau.jsj.beans.Distribution</value>
                <value>cn.edu.imau.jsj.beans.SelectedDistribution</value>
                <value>cn.edu.imau.jsj.beans.SelectedUseby</value>
                <value>cn.edu.imau.jsj.beans.Useby</value>
                <value>cn.edu.imau.jsj.beans.CultivatedTech</value>
                <value>cn.edu.imau.jsj.beans.ProcessingTech</value>
                </list>
            </property>
            <property name="hibernateProperties">
                <value>
                    hibernate.dialect=org.hibernate.dialect.MySQLDialect
                    hibernate.hbm2ddl.auto=update
                    hibernate.show_sql=true
                    hibernate.format_sql=true
              </value>
            </property>
        </bean>

AnnotationSessionFactoryBean的源码：

/* * Copyright 2002-2014 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */

package org.springframework.orm.hibernate3.annotation;

import java.io.IOException;
import java.util.Set;
import java.util.TreeSet;
import javax.persistence.Embeddable;
import javax.persistence.Entity;
import javax.persistence.MappedSuperclass;

import org.hibernate.HibernateException;
import org.hibernate.MappingException;
import org.hibernate.cfg.Configuration;

import org.springframework.context.ResourceLoaderAware;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternUtils;
import org.springframework.core.type.classreading.CachingMetadataReaderFactory;
import org.springframework.core.type.classreading.MetadataReader;
import org.springframework.core.type.classreading.MetadataReaderFactory;
import org.springframework.core.type.filter.AnnotationTypeFilter;
import org.springframework.core.type.filter.TypeFilter;
import org.springframework.util.ClassUtils;

/** * Subclass of Spring's standard LocalSessionFactoryBean for Hibernate, * supporting annotation metadata for mappings. * * <p>Example for an AnnotationSessionFactoryBean bean definition: * * <pre class="code"> * &lt;bean id="sessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean"&gt; * &lt;property name="dataSource" ref="dataSource"/&gt; * &lt;property name="annotatedClasses"&gt; * &lt;list&gt; * &lt;value&gt;test.package.Foo&lt;/value&gt; * &lt;value&gt;test.package.Bar&lt;/value&gt; * &lt;/list&gt; * &lt;/property&gt; * &lt;/bean&gt;</pre> * * Or when using classpath scanning for autodetection of entity classes: * * <pre class="code"> * &lt;bean id="sessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean"&gt; * &lt;property name="dataSource" ref="dataSource"/&gt; * &lt;property name="packagesToScan" value="test.package"/&gt; * &lt;/bean&gt;</pre> * * <p>Requires Hibernate 3.6.x, as of Spring 4.0. * * @author Juergen Hoeller * @since 1.2.2 * @see #setDataSource * @see #setHibernateProperties * @see #setAnnotatedClasses * @see #setAnnotatedPackages * @deprecated as of Spring 4.3, in favor of Hibernate 4.x/5.x */
@Deprecated
public class AnnotationSessionFactoryBean extends org.springframework.orm.hibernate3.LocalSessionFactoryBean implements ResourceLoaderAware {

    private static final String RESOURCE_PATTERN = "/**/*.class";

    private static final String PACKAGE_INFO_SUFFIX = ".package-info";


    private Class<?>[] annotatedClasses;

    private String[] annotatedPackages;

    private String[] packagesToScan;

    private TypeFilter[] entityTypeFilters = new TypeFilter[] {
            new AnnotationTypeFilter(Entity.class, false),
            new AnnotationTypeFilter(Embeddable.class, false),
            new AnnotationTypeFilter(MappedSuperclass.class, false),
            new AnnotationTypeFilter(org.hibernate.annotations.Entity.class, false)};

    private ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();


    /** * Specify annotated classes, for which mappings will be read from * class-level annotation metadata. * @see org.hibernate.cfg.Configuration#addAnnotatedClass(Class) */
    public void setAnnotatedClasses(Class<?>... annotatedClasses) {
        this.annotatedClasses = annotatedClasses;
    }

    /** * Specify the names of annotated packages, for which package-level * annotation metadata will be read. * @see org.hibernate.cfg.Configuration#addPackage(String) */
    public void setAnnotatedPackages(String... annotatedPackages) {
        this.annotatedPackages = annotatedPackages;
    }

    /** * Specify packages to search using Spring-based scanning for entity classes in * the classpath. This is an alternative to listing annotated classes explicitly. * <p>Default is none. Specify packages to search for autodetection of your entity * classes in the classpath. This is analogous to Spring's component-scan feature * ({@link org.springframework.context.annotation.ClassPathBeanDefinitionScanner}). */
    public void setPackagesToScan(String... packagesToScan) {
        this.packagesToScan = packagesToScan;
    }

    /** * Specify custom type filters for Spring-based scanning for entity classes. * <p>Default is to search all specified packages for classes annotated with * {@code @javax.persistence.Entity}, {@code @javax.persistence.Embeddable} * or {@code @javax.persistence.MappedSuperclass}, as well as for * Hibernate's special {@code @org.hibernate.annotations.Entity}. * @see #setPackagesToScan */
    public void setEntityTypeFilters(TypeFilter... entityTypeFilters) {
        this.entityTypeFilters = entityTypeFilters;
    }

    @Override
    public void setResourceLoader(ResourceLoader resourceLoader) {
        this.resourcePatternResolver = ResourcePatternUtils.getResourcePatternResolver(resourceLoader);
    }


    /** * Reads metadata from annotated classes and packages into the * AnnotationConfiguration instance. */
    @Override
    protected void postProcessMappings(Configuration config) throws HibernateException {
        if (this.annotatedClasses != null) {
            for (Class<?> annotatedClass : this.annotatedClasses) {
                config.addAnnotatedClass(annotatedClass);
            }
        }
        if (this.annotatedPackages != null) {
            for (String annotatedPackage : this.annotatedPackages) {
                config.addPackage(annotatedPackage);
            }
        }
        scanPackages(config);
    }

    /** * Perform Spring-based scanning for entity classes. * @see #setPackagesToScan */
    protected void scanPackages(Configuration config) {
        if (this.packagesToScan != null) {
            Set<String> classNames = new TreeSet<String>();
            Set<String> packageNames = new TreeSet<String>();
            try {
                for (String pkg : this.packagesToScan) {
                    String pattern = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX +
                            ClassUtils.convertClassNameToResourcePath(pkg) + RESOURCE_PATTERN;
                    Resource[] resources = this.resourcePatternResolver.getResources(pattern);
                    MetadataReaderFactory readerFactory = new CachingMetadataReaderFactory(this.resourcePatternResolver);
                    for (Resource resource : resources) {
                        if (resource.isReadable()) {
                            MetadataReader reader = readerFactory.getMetadataReader(resource);
                            String className = reader.getClassMetadata().getClassName();
                            if (matchesEntityTypeFilter(reader, readerFactory)) {
                                classNames.add(className);
                            }
                            else if (className.endsWith(PACKAGE_INFO_SUFFIX)) {
                                packageNames.add(className.substring(0, className.length() - PACKAGE_INFO_SUFFIX.length()));
                            }
                        }
                    }
                }
            }
            catch (IOException ex) {
                throw new MappingException("Failed to scan classpath for unlisted classes", ex);
            }
            try {
                for (String className : classNames) {
                    config.addAnnotatedClass(this.resourcePatternResolver.getClassLoader().loadClass(className));
                }
                for (String packageName : packageNames) {
                    config.addPackage(packageName);
                }
            }
            catch (ClassNotFoundException ex) {
                throw new MappingException("Failed to load annotated classes from classpath", ex);
            }
        }
    }

    /** * Check whether any of the configured entity type filters matches * the current class descriptor contained in the metadata reader. */
    private boolean matchesEntityTypeFilter(MetadataReader reader, MetadataReaderFactory readerFactory) throws IOException {
        if (this.entityTypeFilters != null) {
            for (TypeFilter filter : this.entityTypeFilters) {
                if (filter.match(reader, readerFactory)) {
                    return true;
                }
            }
        }
        return false;
    }

}