Java之struts2框架基础知识

struts2

struts2的写法

Action类

public class HelloAction {
    public String hello() {
        System.out.println("Hello Struts!");
        return "success";
    }
}

配置 struts.xml

<struts>
    <package name="hello" namespace="/hello" extends="struts-default">
        <action name="HelloAction" class="com.lanou3g.hello.HelloAction" method="hello">
            <result name="success" type="dispatcher">/hello.jspresult>
        action>
    package>

    
    <include file="com/lanou3g/def/struts.xml">include>
    <include file="com/lanou3g/dynamic/struts.xml">include>
    <include file="com/lanou3g/dynamic/struts.xml">include>
    <include file="com/lanou3g/test/struts.xml">include>
struts>

配置struts2的核心过滤器

在web.xml中配置:
  <filter>
    <filter-name>struts2filter-name>
    <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilterfilter-class>
  filter>
  <filter-mapping>
    <filter-name>struts2filter-name>
    /*
  filter-mapping>

使用快捷键(command + shift + t)搜索StrutsP

struts2执行流程

localhost:8080/sh-struts2-01/hello/HelloAction
1.通过网址请求中的hello
2.找到对应的命名空间(网址)
3.找到后 再通过网址中的HelloAction去匹配Action标签中的name
4.匹配上,用class标签创建其类的对象
5.调用该类中的方法
6.拿到类中的方法的返回值去匹配result标签的name
7.返回值匹配上,就调用标签中的页面

struts架构图

常量配置修改

指定Web应用的默认编码集

<constant name="struts.i18n.encoding" value="UTF-8">constant>

指定需要Struts2处理的请求后缀

    
<constant name="struts.action.extension" value="action,,">constant>

给配置文件提供热加载(更改完了不用重启服务器)

<constant name="struts.devMode" value="true">constant>

这些常量配置都可以去default.properties文件找到你要修改的配置

动态方法调用

Action类

public class Demo02Action {
    public String add() {
        System.out.println("增加");
        return "success";
    }
    public String delete() {
        System.out.println("删除");
        return "success";
    }
    public String update() {
        System.out.println("修改");
        return "success";
    }
    public String find() {
        System.out.println("查询");
        return "success";
    }
}

配置struts.xml

<struts>
    
    
    
    
    <constant name="struts.enable.DynamicMethodInvocation" value="false">constant>

    <package name="dynamic" namespace="/dynamic" extends="struts-default">
        
        <action name="Demo02Action_*" class="com.lanou3g.dynamic.Demo02Action" method="{1}">
            <result name="success">/hello.jspresult>
        action>
    package>
struts>

Action类的创建方式

创建方式一

public class Demo03Action {

}
随便一个普通类都可以作为一个Action类
只需要你去配置struts.xml文件
相比于servlet减少代码的侵入性

创建方式二

public class Demo04Action implements Action {

    @Override
    public String execute() throws Exception {
        return null;
    }

}
实现Action接口
意义在于提醒你Action类中的方法该怎么写

创建方式三(常用方式)

public class Demo05Action extends ActionSupport{

}
因为该类实现了很多接口,一个接口就有一个功能

Action标签的默认值

Action类

public class Demo06Action {
    public String execute() {
        System.out.println("测试 action标签的默认值");
        return "success";
    }
}

struts.xml

<struts>
    
    <package name="test" namespace="/test" extends="struts-default">
        <action name="Demo06Action">
            <result>/hello.jspresult>
        action>
    package>
struts>

使用struts2实现筛选

CustomerAction类

public class CustomerAction extends ActionSupport{
    public String findByName() {
        // 获取参数
        HttpServletRequest request = ServletActionContext.getRequest();
        String string = request.getParameter("cust_name");


        if (StringUtils.isNotBlank(string)) {
            // 创建离线对象
            DetachedCriteria criteria = DetachedCriteria.forClass(Customer.class);
            // 添加查询条件
            criteria.add(Restrictions.like("cust_name", "%"+string+"%"));

            // 调用service方法
            CustomerService service = new CustomerServiceImpl();
            List list = service.find(criteria);
            // 存域
            request.setAttribute("list", list);
        }       
        return "success";
    }
}

配置struts.xml

<struts>
    <package name="web" namespace="/" extends="struts-default">
        <action name="CustomerAction" class="com.lanou3g.web.CustomerAction" method="findByName">
            <result name="success">/jsp/customer/list.jspresult>
        action>
    package>
struts>

web.xml 配置核心过滤器

<filter>
  <filter-name>struts2filter-name>
  <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilterfilter-class>
filter>
<filter-mapping>
  <filter-name>struts2filter-name>
  /CustomerAction
filter-mapping>

service层

    public List find(DetachedCriteria criteria) {
        // 开启事务
        Session session = HibernateUtils.getCurrentSession();
        Transaction transaction = session.beginTransaction();   
        // 调用dao层方法
        CustomerDao dao = new CustomerDaoImpl();
        List list = dao.find(criteria);
        // 提交事务
        transaction.commit();
        return list;
    }

dao层

    public List<Customer> find(DetachedCriteria criteria) {
        
        Session session = HibernateUtils.getCurrentSession();
        
        Criteria c = criteria.getExecutableCriteria(session);
        
        List<Customer> list = c.list();
        return list;
    }