告别繁琐的配置文件 ---- 全注解Spring,Hibernate开发 不完全指南

当我最开始接触Spring和hibernate开发的时候，也是从别人（学长）那里拷贝过来一个项目，自己学习研究，在当时，像applicationContext.xml这种配置文件也是他写成什么样，我就跟着照猫画虎的改，甚是觉得别扭，程序是万能的，为何我们不能突破常规，选择一种提高我们开发效率的方式？

说时迟，那时快，我决定全部采用注解来配置我的web应用，当时也不知道是否可行，不过，经过我的实践，最后成功了，在这里与大家分享。

首先看一下我的Spring 配置文件 applicationContext.xml

<?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:aop="http://www.springframework.org/schema/aop"xmlns:context="http://www.springframework.org/schema/context"xmlns:mvc="http://www.springframework.org/schema/context/mvc" xmlns:p="http://www.springframework.org/schema/p"xmlns:tx="http://www.springframework.org/schema/tx" xmlns:util="http://www.springframework.org/schema/util"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsdhttp://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsdhttp://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsdhttp://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsdhttp://www.springframework.org/schema/context/mvc http://www.springframework.org/schema/context/mvc/spring-mvc-3.0.xsd">    <aop:aspectj-autoproxy/><!-- 配置数据源 --><bean id="propertyConfigurer"class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"><property name="location" value="/WEB-INF/datasource-conf.properties"></property></bean><bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"destroy-method="close"><property name="driverClass" value="${driverClass}" /><property name="jdbcUrl" value="${jdbcUrl}" /><property name="user" value="${user}" /><property name="password" value="${password}" /><property name="initialPoolSize" value="${initialPoolSize}"></property><property name="minPoolSize" value="${minPoolSize}"></property><property name="maxPoolSize" value="${maxPoolSize}"></property><property name="maxIdleTime" value="${maxIdleTime}"></property><property name="acquireIncrement" value="${acquireIncrement}"></property><property name="idleConnectionTestPeriod" value="${idleConnectionTestPeriod}"></property><property name="acquireRetryAttempts" value="${acquireRetryAttempts}"></property><property name="breakAfterAcquireFailure" value="${breakAfterAcquireFailure}"></property><property name="maxStatements" value="${maxStatements}"></property><property name="testConnectionOnCheckout" value="${testConnectionOnCheckout}"></property></bean>    <!-- 启动注解自动装配 --><beanclass="org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor" /><!-- 启动基于注解(annotation)驱动 MVC--><context:component-scan base-package="net.woaoo"><context:include-filter type="annotation"expression="org.springframework.stereotype.Controller" /></context:component-scan><!--基于注解映射的hibernateTemplate --><bean id="sessionFactory"class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean"><property name="dataSource" ref="dataSource" /><property name="annotatedClasses"><bean class="net.woaoo.common.config.EntityBeanFinderFactoryBean">        <property name="classNamePattern" value="net.woaoo.**.model.**"/>      </bean></property><property name="hibernateProperties"><props><prop key="hibernate.dialect">${hibernate.dialect}</prop><prop key="hibernate.show_sql">${hibernate.show_sql}</prop></props></property></bean><!-- HibernateTemplate --><bean id="hibernateTemplate" class="org.springframework.orm.hibernate3.HibernateTemplate"><property name="sessionFactory" ref="sessionFactory" /></bean><!-- JDBCTemplate --><bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate"><property name="dataSource" ref="dataSource" /></bean></beans>

我的修改主要有两点：

1.首先，bean不需要再配置文件中配置，在类中使用 @Repository  @Service 注解，spring会基于你的类名生成 首字母小写与之对应的对象，例如

@Service

public class ExampleService implements IExample{

} 
你可以这样调用：

@Autowired

IExample exampleService;

........

2.hibernate与数据库的映射类不通过手动配置，而是通过扫描的方式，这在一个新的项目的开发阶段很有帮助，能大大提高效率，数据库即便改来改去也不用修改配置文件，

传统的数据源dataSource 配置方式：

<property name="dataSource" ref="dataSource" /><property name="annotatedClasses"><list><value>xxx.xxx.xxxModel</value><value>.........</value></list></property>

....

我的配置方式

<property name="dataSource" ref="dataSource" /><property name="annotatedClasses"><bean class="net.woaoo.common.config.EntityBeanFinderFactoryBean">        <property name="classNamePattern" value="net.woaoo.**.model.**"/>      </bean></property>

........

这个方法是我在逛spring论坛上看到的，springsource.org

分享下这个类：

package net.woaoo.common.config;import java.io.BufferedInputStream;import java.io.DataInputStream;import java.io.InputStream;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import org.springframework.beans.factory.FactoryBean;import org.springframework.context.ResourceLoaderAware;import org.springframework.core.io.Resource;import org.springframework.core.io.ResourceLoader;import org.springframework.core.io.support.ResourcePatternResolver;import org.springframework.core.io.support.ResourcePatternUtils;/** * This class finds all @Entity annotated classes defined by an ANT style class name pattern. Default * pattern is **.domain.** *  * @author [e-mail] */public class EntityBeanFinderFactoryBean implements ResourceLoaderAware,        FactoryBean {    private ResourcePatternResolver resolver;    private List<Class> managedClasses = null;    private String classPattern = "classpath*:**/domain/**/*.class";    static final int UTF = 1, INTEGER = 3, FLOAT = 4, LONG = 5, DOUBLE = 6,            CLASS = 7, STRING = 8, FIELD_REF = 9, METHOD_REF = 10,            INTERFACE_METHOD_REF = 11, NAME_AND_TYPE = 12;    public void setResourceLoader(ResourceLoader resourceLoader) {        resolver = ResourcePatternUtils                .getResourcePatternResolver(resourceLoader);    }    /**     * Determines what class files to scan for @Entity annotations. The string      * behaves like ANT paths. Default value is "**.domain.**"     * @param packagePattern     */    public void setClassNamePattern(String packagePattern) {        classPattern = "classpath*:" + packagePattern.replace(".", "/")                + "/*.class";    }    public Object getObject() throws Exception {        if (managedClasses == null) {            loadManagedClasses();        }        return managedClasses;    }    public Class getObjectType() {        return List.class;    }    public boolean isSingleton() {        return true;    }    private void loadManagedClasses() throws Exception {        managedClasses = new ArrayList<Class>();        Resource[] resources = resolver.getResources(classPattern);        if (resources != null) {            for (Resource res : resources) {                Class klass = getClass(res);                if (hasEntityAnnotation(klass)) {                    managedClasses.add(klass);                }            }        }    }        private Class getClass(Resource res) throws Exception{        String className = className(res);        System.out.println(className);        return Class.forName(className);            }    private boolean hasEntityAnnotation(Class klass) {        return (klass.getAnnotation(javax.persistence.Entity.class) != null);    }    // Parses java class files (byte code) to find class name    // Must be a better way to do this...    private String className(Resource res) throws Exception {        InputStream is = res.getInputStream();        Map<Integer, Integer> offsetTable = new HashMap<Integer, Integer>();        Map<Integer, String> classNameTable = new HashMap<Integer, String>();        DataInputStream data = new DataInputStream(new BufferedInputStream(is));        int magic = data.readInt();        int minorVersion = data.readShort();        int majorVersion = data.readShort();        int constant_pool_count = data.readShort();        int[] constant_pool = new int[constant_pool_count];        for (int i = 1; i < constant_pool_count; i++) {            int tag = data.read();            int tableSize;            switch (tag) {            case CLASS:                int offset = data.readShort();                offsetTable.put(i, offset);                break;            case UTF:                int length = data.readShort();                char[] bytes = new char[length];                for (int k = 0; k < bytes.length; k++)                    bytes[k] = (char) data.read();                String className = new String(bytes);                classNameTable.put(i, className);                break;            case LONG:            case DOUBLE:                data.readLong();                i++;                break;            case STRING:                data.readShort();                break;            default:                data.readInt();            }        }        short access_flags = data.readShort();        int this_class = data.readShort();        int super_class = data.readShort();        String thisClassName = classNameTable.get(offsetTable.get(this_class));        is.close();        return thisClassName.replace("/", ".");    }}