1、搭建传统的ssh开发环境,并成功运行(插入、查询)
2、了解c3p0连接池相关配置
3、了解验证hibernate的二级缓存,并验证
4、了解spring事物配置,并验证
5、了解spring的IOC(依赖注入),将struts2的action对象(bean)交给spring管理,自定义bean等...并验证
6、了解spring aop(面向切面编程),并编写自定义切面函数,验证结果
开发环境:eclipse for java ee;mysql5.5.25;jdk1.7.0_79;navicat10.1.7(可选);
创建数据库demo:
/* Navicat MySQL Data Transfer Source Server : localhost_3306 Source Server Version : 50519 Source Host : localhost:3306 Source Database : demo Target Server Type : MYSQL Target Server Version : 50519 File Encoding : 65001 Date: 2016-01-09 23:36:02 */ SET FOREIGN_KEY_CHECKS=0; -- ---------------------------- -- Table structure for `user` -- ---------------------------- DROP TABLE IF EXISTS `user`; CREATE TABLE `user` ( `id` bigint(20) NOT NULL AUTO_INCREMENT, `account` varchar(200) NOT NULL, `name` varchar(200) NOT NULL, `address` varchar(1000) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
新建web工程,目录结构如下:
jar包准备,放到WEB-INF的lib目录下(有兴趣的可以用maven管理过程,但是有时候下载jar包很慢...)
相关jar包都可以在下载下来的struts、spring、hibernate中找到,这里给个参考,有些是可以删除的,比如spring mvc部分的jar包:
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0"> <display-name>SSH</display-name> <filter> <filter-name>struts2</filter-name> <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class> </filter> <filter-mapping> <filter-name>struts2</filter-name> <url-pattern>*.action</url-pattern> </filter-mapping> <context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:applicationContext.xml</param-value> </context-param> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> </web-app>
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:p="http://www.springframework.org/schema/p" xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:jdbc="http://www.springframework.org/schema/jdbc" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.1.xsd http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-4.1.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.1.xsd"> <!-- scans the classpath for annotated components (including @Repostory and @Service that will be auto-registered as Spring beans --> <context:component-scan base-package="ssh" /> <!--配数据源 --> <bean name="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close"> <property name="driverClass" value="com.mysql.jdbc.Driver" /> <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/demo" /> <property name="user" value="root" /> <property name="password" value="root" /> <property name="acquireIncrement" value="1"></property> <property name="initialPoolSize" value="80"></property> <property name="maxIdleTime" value="60"></property> <property name="maxPoolSize" value="80"></property> <property name="minPoolSize" value="30"></property> <property name="acquireRetryDelay" value="1000"></property> <property name="acquireRetryAttempts" value="60"></property> <property name="breakAfterAcquireFailure" value="false"></property> <!-- 如出现Too many connections, 注意修改mysql的配置文件my.ini,增大最多连接数配置项,(查看当前连接命令:show processlist) --> </bean> <bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean"> <property name="dataSource" ref="dataSource" /> <property name="hibernateProperties"> <props> <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop> <prop key="hibernate.show_sql">true</prop> <prop key="hibernate.hbm2ddl.auto">update</prop> <prop key="current_session_context_class">thread</prop> <prop key="hibernate.cache.use_second_level_cache">true</prop> <prop key="hibernate.cache.region.factory_class">org.hibernate.cache.ehcache.EhCacheRegionFactory</prop> <prop key="hibernate.cache.use_query_cache">true</prop> <prop key="hibernate.cache.provider_configuration_file_resource_path">ehcache.xml</prop> </props> </property> <property name="mappingLocations"> <list> <value>classpath:ssh/model/User.hbm.xml</value> </list> </property> <!-- <property name="annotatedClasses"> <list> <value>ssh.model.User</value> </list> </property> --> </bean> <!-- 配置事务管理器 --> <bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager"> <property name="sessionFactory" ref="sessionFactory" /> </bean> <!-- 事务的传播特性 --> <tx:advice id="txadvice" transaction-manager="transactionManager"> <tx:attributes> <tx:method name="add*" propagation="REQUIRED" read-only="false" rollback-for="java.lang.Exception"/> <tx:method name="delete*" propagation="REQUIRED" read-only="false" rollback-for="java.lang.Exception"/> <tx:method name="update*" propagation="REQUIRED" read-only="false" rollback-for="java.lang.Exception"/> <tx:method name="save*" propagation="REQUIRED" read-only="false" rollback-for="java.lang.Exception"/> </tx:attributes> </tx:advice> <aop:config> <aop:pointcut id="pcMethod" expression="execution(* ssh.service..*.*(..))" /> <aop:advisor pointcut-ref="pcMethod" advice-ref="txadvice" /> </aop:config> <!-- 自定义aop处理 测试 --> <bean id="aopTest" class="ssh.aop.AopTest"></bean> <bean id="myAop" class="ssh.aop.MyAop"></bean> <aop:config proxy-target-class="true"> <aop:aspect ref="myAop"> <aop:pointcut id="pcMethodTest" expression="execution(* ssh.aop.AopTest.test*(..))"/> <aop:before pointcut-ref="pcMethodTest" method="before"/> <aop:after pointcut-ref="pcMethodTest" method="after"/> </aop:aspect> </aop:config> </beans>
配置struts.objectFactory常数为spring,表示action由通过spring的bean中获取;
配置result type为"json",也可以配置其它的,这里为了前后端数据交互简便,配置成json格式;
配置两个action,addUser和queryAllUser;
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN" "http://struts.apache.org/dtds/struts-2.3.dtd"> <struts> <constant name="struts.objectFactory" value="spring"/> <constant name="struts.enable.DynamicMethodInvocation" value="false" /> <constant name="struts.devMode" value="false" /> <package name="default" extends="struts-default,json-default"> <global-results> <result type="json"> <param name="root">json</param> <param name="contentType">text/html</param> </result> </global-results> <action name="addUser" class="userAction" method="addUser"> <result>.</result> </action> <action name="queryAllUser" class="userAction" method="queryAllUser"> <result>.</result> </action> </package> <!-- Add packages here --> </struts>
注意事项:
dao继承HibernateDaoSupport类,所有数据库相关操作用hibernateTemplate操作;
给dao层,service层,action添加相应注解,注册为spring的bean;
附代码如下:
UserAction.java
package ssh.action; import java.io.PrintWriter; import java.util.List; import javax.annotation.Resource; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.log4j.Logger; import org.apache.struts2.ServletActionContext; import org.springframework.stereotype.Controller; import ssh.aop.AopTest; import ssh.model.User; import ssh.service.UserService; import com.google.gson.Gson; @Controller public class UserAction { Logger logger = Logger.getLogger(UserAction.class); @Resource private UserService userService; @Resource private AopTest aopTest; public void addUser(){ PrintWriter out = null; try{ HttpServletRequest request = ServletActionContext.getRequest(); HttpServletResponse response = ServletActionContext.getResponse(); response.setContentType("text/html;charset=UTF-8"); String account = request.getParameter("account"); String name = request.getParameter("name"); String address = request.getParameter("address"); User user = new User(); user.setAccount(account); user.setAddress(address); user.setName(name); userService.add(user); out = response.getWriter(); out.write(new Gson().toJson("success")); }catch(Exception e){ e.printStackTrace(); logger.error(e.getMessage()); if(out != null) out.write(new Gson().toJson("fail")); }finally{ out.flush(); out.close(); } } public void queryAllUser(){ PrintWriter out = null; aopTest.test1(); aopTest.test2(); //logger.error("i"); try { HttpServletResponse response = ServletActionContext.getResponse(); response.setContentType("text/html;charset=UTF-8"); Gson gson = new Gson(); List<User> userList= userService.queryAllUser(); String gsonStr = gson.toJson(userList); out = response.getWriter(); out.write(gsonStr); } catch (Exception e) { e.printStackTrace(); logger.error(e.getMessage()); if(out != null) out.write(new Gson().toJson("fail")); }finally{ out.flush(); out.close(); } } }
AopTest.java
package ssh.aop; public class AopTest { public void test1(){ System.out.println("AopTest test1 method is running~"); } public void test2(){ System.out.println("AopTest test2 method is running~"); } }
MyAop.java
package ssh.aop; public class MyAop { public void before(){ System.out.println("befor~"); } public void after(){ System.out.println("after~"); } }
BaseDao.java
package ssh.dao.base; import javax.annotation.Resource; import org.hibernate.SessionFactory; import org.springframework.orm.hibernate4.support.HibernateDaoSupport; public class BaseDao extends HibernateDaoSupport{ @Resource public void setMySessionFactory(SessionFactory sessionFactory){ this.setSessionFactory(sessionFactory); } }
UserDao.java
package ssh.dao; import java.util.ArrayList; import java.util.List; import org.springframework.orm.hibernate4.HibernateTemplate; import org.springframework.stereotype.Repository; import ssh.dao.base.BaseDao; import ssh.model.User; @Repository public class UserDao extends BaseDao{ public void add(User user){ this.getHibernateTemplate().save(user); } @SuppressWarnings("unchecked") public List<User> queryAllUser(){ List<User> users = new ArrayList<User>(); HibernateTemplate hibernateTemplate = this.getHibernateTemplate(); hibernateTemplate.setCacheQueries(true); users = (List<User>) hibernateTemplate.find("from User"); hibernateTemplate.setCacheQueries(false); return users; } }
User.java
package ssh.model; import java.io.Serializable; public class User implements Serializable{ /** * */ private static final long serialVersionUID = -6190571611246371934L; private Long id; private String account; private String name; private String address; public String getAccount() { return account; } public String getName() { return name; } public String getAddress() { return address; } public void setAccount(String account) { this.account = account; } public void setName(String name) { this.name = name; } public void setAddress(String address) { this.address = address; } /** * @return the id */ public Long getId() { return id; } /** * @param id the id to set */ public void setId(Long id) { this.id = id; } }
User.hbm.xml
<?xml version="1.0"?> <!-- ~ Hibernate, Relational Persistence for Idiomatic Java ~ ~ Copyright (c) 2010, Red Hat Inc. or third-party contributors as ~ indicated by the @author tags or express copyright attribution ~ statements applied by the authors. All third-party contributions are ~ distributed under license by Red Hat Inc. ~ ~ This copyrighted material is made available to anyone wishing to use, modify, ~ copy, or redistribute it subject to the terms and conditions of the GNU ~ Lesser General Public License, as published by the Free Software Foundation. ~ ~ This program is distributed in the hope that it will be useful, ~ but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY ~ or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License ~ for more details. ~ ~ You should have received a copy of the GNU Lesser General Public License ~ along with this distribution; if not, write to: ~ Free Software Foundation, Inc. ~ 51 Franklin Street, Fifth Floor ~ Boston, MA 02110-1301 USA --> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> <hibernate-mapping package="ssh.model"> <class name="User" table="user"> <cache usage="read-write"/> <id name="id" column="id"> <generator class="increment"/> </id> <property name="account" type="java.lang.String" column="account"/> <property name="name" type="java.lang.String" column="name"/> <property name="address" type="java.lang.String" column="address"/> </class> </hibernate-mapping>
UserService.java
package ssh.service; import java.util.List; import javax.annotation.Resource; import org.springframework.stereotype.Service; import ssh.dao.UserDao; import ssh.model.User; @Service public class UserService { @Resource private UserDao userDao = new UserDao(); public List<User> queryAllUser(){ return userDao.queryAllUser(); } public void add(User user){ userDao.add(user); } }
index.jsp(记得添加jquery库)
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> <style> .mt20{ margin-top: 20px; } </style> </head> <body> <div style="text-align: center;"> <div class="mt20"><label>账号:</label><input id="account" type="text"/></div> <div class="mt20"><label>姓名:</label><input id="name" type="text"/></div> <div class="mt20"><label>地址:</label><input id="address" type="text"/></div> <div class="mt20"><button id="addUser" >添加</button></div> </div> <h3>用户列表:</h3> <ul id="userList"> </ul> <script type="text/javascript" src="js/jquery-1.11.1.min.js"></script> <script> $(function() { $.ajax({ url : 'queryAllUser.action', type : 'post', dataType : 'json', success : function(data) { try { for(var i = 0; i < data.length; i++){ $("#userList").append("<li><span style='color:red'>id="+data[i].id+"</span>,account="+data[i].account+",name="+data[i].name+",address="+data[i].address+"</li>"); } } catch (e) {}; } , error : function(e) { alert("sys error"); } }); $("#addUser").on("click", function() { var account = $("#account").val(); var name = $("#name").val(); var address = $("#address").val(); $.ajax({ url : 'addUser.action', type : 'post', dataType : 'json', data : { account : account, name : name, address : address }, success : function(data) { try { $("#userList").append("<li>account="+account+",name="+name+",address="+address+"</li>"); alert("添加成功"); } catch (e) { } }, error : function(e) { alert("sys error"); } }); }); }); </script> </body> </html>
回到开头,开始熟悉了解相关技术,并验证结果
1、搭建传统的ssh开发环境,并成功运行(插入、查询)
如下图:查询及添加用户成功;
2、了解c3p0连接池相关配置
数据库连接是一种昂贵的资源,开启及关闭比较消耗性能,因此可以用连接池来管理,初始化若干个连接,重复使用,而不是重复创建关闭,有点类似线程池;
配置如下,要根据实际项目情况合理配置最小最大连接数,详细的各个参数含义可以参考链接
另外要验证连接数相关配置很简单,可以自己写个程序验证,比如当配置最大连接数为10的时候,可以写个程序验证,当打开10个connection后,第11个connection会一直处于等待状态,获取不到;所以要根据情况合理配置连接数,否则有可能会影响应用性能;
<!--配数据源 --> <bean name="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close"> <property name="driverClass" value="com.mysql.jdbc.Driver" /> <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/demo" /> <property name="user" value="root" /> <property name="password" value="root" /> <property name="acquireIncrement" value="1"></property> <property name="initialPoolSize" value="80"></property> <property name="maxIdleTime" value="60"></property> <property name="maxPoolSize" value="80"></property> <property name="minPoolSize" value="30"></property> <property name="acquireRetryDelay" value="1000"></property> <property name="acquireRetryAttempts" value="60"></property> <property name="breakAfterAcquireFailure" value="false"></property> <!-- 如出现Too many connections, 注意修改mysql的配置文件my.ini,增大最多连接数配置项,(查看当前连接命令:show processlist) --> </bean>
3、了解验证hibernate的二级缓存,并验证
hibernate的一级缓存是指session范围的缓存,默认开启,二级缓存是sessionFactory范围缓存,在配置sessionFactory的时候,我们已经配置二级缓存为ehcache,接下来验证效果,查询user操作,发现第一次查询会操作数据库,打印sql语句,刷新页面后,发现查询成功且没打印sql语句,如下图,可见二级缓存工作OK;
4、了解spring事物配置,并验证
所谓事务控制,原理都一样,就是要保证原子性、一致性、隔离性、持久性,jdbc编程的时候,都是自己控制,通过set autocommit=false设置成不自动提交,然后开始写具体的数据库操作,发生异常的时候rollback,否则commit;其实spring对事物的控制原理也差不多,加了一些封装,配置等,更加方便而已,比如可以在service层不同方法进行控制等;
验证的话很简单,在service层某个方法(注意方法名要符合spring配置文件中配置的规则)内写两个插入user的操作,在中间抛出一个异常,然后执行,如果发现第一个user插入成功,说明事务控制失效,否则ok;
5、了解spring的IOC(依赖注入),将struts2的action对象(bean)交给spring管理,自定义bean等...并验证
仔细观察的话,在配置applicationContext.xml文件的过程中,主要工作都是在配置bean相关信息,这些bean都是事先创建好的,其实所谓的bean就是对象;
之所以把对象的创建交给spring容器,目的是为了解耦;
另外在用struts的时候,spring把action注册为bean,默认是单例的,访问的时候并不是每次都new出一个action,在并发访问的时候,会有风险;
不过,可以通过scope="prototype",把action配置成多例;ps:struts2中的action默认是多例;
注意:applicationContext.xml配置的bean和自定义注解的bean都是可以在程序运行的过程中直接获取的,通过@Resource等方式,这个很好验证,写个小程序即可;
6、了解spring aop(面向切面编程),并编写自定义切面函数,验证结果
切面编程这种形式很多地方都用了该思想,什么过滤器,拦截器,事务控制等等...
其原理还是java的反射和动态代理,在方法执行前后加以控制,加入自己要执行的代码;
小例子中加了个切面,在方法执行前后打印before和after字符串,如下图,工作正常,代码参考前面部分:
<!-- 自定义aop处理 测试 --> <bean id="aopTest" class="ssh.aop.AopTest"></bean> <bean id="myAop" class="ssh.aop.MyAop"></bean> <aop:config proxy-target-class="true"> <aop:aspect ref="myAop"> <aop:pointcut id="pcMethodTest" expression="execution(* ssh.aop.AopTest.test*(..))"/> <aop:before pointcut-ref="pcMethodTest" method="before"/> <aop:after pointcut-ref="pcMethodTest" method="after"/> </aop:aspect> </aop:config>