（四）spring+servlet 整合

一、Spring与Servlet的整合

  • 1.1：

　　　　加入Spring的jar包。（要加web.jar包）

 

  • 1.2：

    • 　　java工程中获取Spring的上下文对象。

    ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml")来初始化Spring的上下文环境。

    • 　　WEB工程中初始化Spring的上下文环境。

    在web.xml中添加监听器（ContextLoaderListener继承ContextLoader类，ContextLoader的静态常量CONFIG_LOCATION_PARAM = "contextConfigLocation"
    ContextLoaderListener读取Spring默认文件的位置就是"contextConfigLocation"的值，而这个值可以在web.xml <context-param>标签里设置contextConfigLocation）：　　　　如下：

  <listener>
        <listener-class>
            org.springframework.web.context.ContextLoaderListener
        </listener-class>
    </listener>

    ContextLoaderListener读取Spring默认文件的位置：/WEB-INF/applicationContext.xml
    可以改变读取的位置。配置context-param参数。

  <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:spring.xml</param-value>
    </context-param>
  • 如上配置，ContextLoaderListener类负责初始化spring的上下文环境，其路径为spring.xml。

 

　　1.3　　spring与servlet 的整合

  • sping有三大特性： IOC(控制反转)/DI(依赖注入)/AOP(面向切面编程、代理模式),而servlet是单例模式只实例一次，一般我们使用servlet的时候并不定义成员属性，因为成员属性会被所有用户所共用，而DI是通过属性注入的方式这样就会冲突，所以servlet+spring只能使用spring中的IOC和AOP两种特性进行编程。

　　1.4　　案例

index.jsp

<%@ 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>
<% String path=request.getContextPath(); %>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
    <a href="<%=path%>/servlet/exam"> spring和servlet整合</a>
</body>
</html>

web.xml

<?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_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>spring_servlet</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
   
  <context-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:spring.xml</param-value>
  </context-param>
  
  <listener>
      <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>
  
 <!-- 这个servlet只用于创建ApplicationContext对象，并不被人访问所以无须配置servlet-mapping -->
  <servlet>
      <servlet-name>loderServlet</servlet-name>
      <servlet-class>servlet.LoderServlet</servlet-class>
      <load-on-startup>1</load-on-startup>
  </servlet>
 <!-- end -->

  <servlet>
      <servlet-name>exam</servlet-name>
      <servlet-class>servlet.Example</servlet-class>
  </servlet>
  
  <servlet-mapping>
      <servlet-name>exam</servlet-name>
      <url-pattern>/servlet/exam</url-pattern>
  </servlet-mapping>
  
</web-app>
  • spring.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:p="http://www.springframework.org/schema/p"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
    http://www.springframework.org/schema/context     
        http://www.springframework.org/schema/context/spring-context-3.0.xsd
    http://www.springframework.org/schema/tx 
    http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
    http://www.springframework.org/schema/aop 
    http://www.springframework.org/schema/aop/spring-aop-3.0.xsd">
    
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <constructor-arg index="0"  name="driverClassName" value="com.mysql.jdbc.Driver" ></constructor-arg>
        <constructor-arg index="1" name="url"  value="jdbc:mysql://127.0.0.1:3306/user?useUnicode=true&amp;characterEncoding=UTF-8" ></constructor-arg>
        <constructor-arg index="2" name="username" value="root"></constructor-arg>
        <constructor-arg index="3" name="password" value=""></constructor-arg>
    </bean>

    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"></property>
    </bean>
    
    <tx:advice id="advice_1" transaction-manager="transactionManager">
        <tx:attributes>
            <tx:method name="update*" propagation="REQUIRED"/>
        </tx:attributes>
    </tx:advice>
    <aop:config proxy-target-class="true">
        <aop:pointcut expression="execution(* service..*.*(..))" id="poin_1"/>
        <aop:advisor advice-ref="advice_1" pointcut-ref="poin_1"/>
    </aop:config>
    
    <bean id="testService" class="service.TestService">
        <property name="roledao">
            <bean class="dao.RoleDao">
                <property name="dataSource" ref="dataSource"></property>
            </bean>
        </property>
        <property name="userdao">
            <bean class="dao.UserDao">
                <property name="dataSource" ref="dataSource"></property>
            </bean>
        </property>
    </bean>
    
    
    </beans>
  • Example.java
package servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.context.ApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;

import service.TestService;

public class Example extends HttpServlet{

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        
        TestService testService=(TestService)LoderServlet.getBean("testService");
        
        testService.update();

    }
}
  • LoderServlet.java
package servlet;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;

import org.springframework.context.ApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;
import org.springframework.web.jsf.el.WebApplicationContextFacesELResolver;

public class LoderServlet extends HttpServlet {

    private static ApplicationContext context=null;
    
    @Override
    public void init() throws ServletException {
    
        System.out.println("初始化servlet");
        
        if(context==null){
            context=WebApplicationContextUtils.getWebApplicationContext(this.getServletContext());
            
        }
    }
    
    public static Object getBean(String beanName){
        Object bean=null;
        
        bean=context.getBean(beanName);
        
        return bean;
    }
    
    
    @Override
    public void destroy() {
        // TODO Auto-generated method stub
        super.destroy();
    }
    
}
  • TestService.java
package service;

import dao.RoleDao;
import dao.UserDao;

public class TestService {
    private UserDao userdao;
    private RoleDao roledao;
    public void setUserdao(UserDao userdao) {
        this.userdao = userdao;
    }
    public void setRoledao(RoleDao roledao) {
        this.roledao = roledao;
    }

    public boolean update(){
    
        boolean flag=false;
        try {
            
            this.userdao.update_1();
            this.roledao.update_2();
            flag=true;
        } catch (Exception e) {
            e.printStackTrace();
            flag=false;
            throw new RuntimeException(e);
        }
        
        return flag;    
    }
}
  • RoleDao.java
package dao;

import org.springframework.jdbc.core.support.JdbcDaoSupport;

public class RoleDao extends JdbcDaoSupport {

    public void update_2(){
        
        this.getJdbcTemplate().update("update role set role_name='aa' where role_id=1 ");
        this.getJdbcTemplate().update("update role set role_name='bb' where role_id=2 ");
}
}
  • UserDao.java
package dao;

import org.springframework.jdbc.core.support.JdbcDaoSupport;

public class UserDao extends JdbcDaoSupport{

    public void update_1(){
            
        this.getJdbcTemplate().update("update user set age=111 where userName='张三'");
        this.getJdbcTemplate().update("update user set age=111 where userName='李四'");
}
}

结果：

在Example类中调用TestService的update方法，这个方法又调用了UserDao的update_1方法和RoleDao的update_2方法，如果update_2方法出现异常，则update_1和update_2方法

同时回滚。 本例实现了servlet+spring的事务管理。

 

本题代码在：   链接

 

 

 


 

posted @ 2017-04-19 21:44  shyroke、  阅读(11106)  评论(0)  编辑  收藏  举报
作者：shyroke 博客地址：http://www.cnblogs.com/shyroke/ 转载注明来源~