Struts2学习(十一)【拦截器】

来源：互联网发布：java substring的用法编辑：程序博客网时间：2024/05/29 13:25

一、拦截器的三种创建方式

拦截器有三种创建方式：

实现Interceptor接口
继承AbstractInterceptor
继承MethodFilterInterceptor

需要说明的是：

AbstractInterceptor 是 Interceptor 的实现类

MethodFilterInterceptor 是 AbstractInterceptor 的子类

1.1 实现Interceptor接口

1.1.1 Interceptor接口

public interface Interceptor extends Serializable {    /**     * Called to let an interceptor clean up any resources it has allocated.     */    void destroy();    /**     * Called after an interceptor is created, but before any requests are processed using     * {@link #intercept(com.opensymphony.xwork2.ActionInvocation) intercept} , giving     * the Interceptor a chance to initialize any needed resources.     */    void init();    /**     * Allows the Interceptor to do some processing on the request before and/or after the rest of the processing of the     * request by the {@link ActionInvocation} or to short-circuit the processing and just return a String return code.     *     * @param invocation the action invocation     * @return the return code, either returned from {@link ActionInvocation#invoke()}, or from the interceptor itself.     * @throws Exception any system-level error, as defined in {@link com.opensymphony.xwork2.Action#execute()}.     */    String intercept(ActionInvocation invocation) throws Exception;}

1.1.2 代码示例

package com.qwm.s4.a_create;import com.opensymphony.xwork2.ActionInvocation;import com.opensymphony.xwork2.interceptor.Interceptor;/** * @author：qiwenming * @date：2017/9/23 0023   22:59 * @description： * 拦截器的第一种创建方式 实现接口 */public class MyInterceptor1 implements Interceptor{    @Override    public void destroy() {    }    @Override    public void init() {    }    @Override    public String intercept(ActionInvocation actionInvocation) throws Exception {        return null;    }}

1.2 继承AbstractInterceptor

1.2.1 AbstractInterceptor类

public abstract class AbstractInterceptor implements Interceptor {    /**     * Does nothing     */    public void init() {    }    /**     * Does nothing     */    public void destroy() {    }    /**     * Override to handle interception     */    public abstract String intercept(ActionInvocation invocation) throws Exception;}

1.2.2 代码示例

package com.qwm.s4.a_create;import com.opensymphony.xwork2.ActionInvocation;import com.opensymphony.xwork2.interceptor.AbstractInterceptor;/** * @author：qiwenming * @date：2017/9/23 0023   23:00 * @description： * 拦截器的第二种创建方式 继承 AbstractInterceptor */public class MyInterceptor2 extends AbstractInterceptor{    @Override    public String intercept(ActionInvocation actionInvocation) throws Exception {        return null;    }}

1.3 继承MethodFilterInterceptor

1.3.1 MethodFilterInterceptor

public abstract class MethodFilterInterceptor extends AbstractInterceptor {    private static final Logger LOG = LogManager.getLogger(MethodFilterInterceptor.class);    protected Set<String> excludeMethods = Collections.emptySet();    protected Set<String> includeMethods = Collections.emptySet();    public void setExcludeMethods(String excludeMethods) {        this.excludeMethods = TextParseUtil.commaDelimitedStringToSet(excludeMethods);    }    public Set<String> getExcludeMethodsSet() {        return excludeMethods;    }    public void setIncludeMethods(String includeMethods) {        this.includeMethods = TextParseUtil.commaDelimitedStringToSet(includeMethods);    }    public Set<String> getIncludeMethodsSet() {        return includeMethods;    }    @Override    public String intercept(ActionInvocation invocation) throws Exception {        if (applyInterceptor(invocation)) {            return doIntercept(invocation);        }         return invocation.invoke();    }    protected boolean applyInterceptor(ActionInvocation invocation) {        String method = invocation.getProxy().getMethod();        // ValidationInterceptor        boolean applyMethod = MethodFilterInterceptorUtil.applyMethod(excludeMethods, includeMethods, method);        if (!applyMethod) {            LOG.debug("Skipping Interceptor... Method [{}] found in exclude list.", method);        }        return applyMethod;    }    /**     * Subclasses must override to implement the interceptor logic.     *      * @param invocation the action invocation     * @return the result of invocation     * @throws Exception in case of any errors     */    protected abstract String doIntercept(ActionInvocation invocation) throws Exception;}

1.3.2 代码示例

package com.qwm.s4.a_create;import com.opensymphony.xwork2.ActionInvocation;import com.opensymphony.xwork2.interceptor.MethodFilterInterceptor;/** * @author：qiwenming * @date：2017/9/23 0023   22:59 * @description： * 拦截器的第三种创建方式 继承 */public class MyInterceptor3 extends MethodFilterInterceptor{    @Override    protected String doIntercept(ActionInvocation actionInvocation) throws Exception {        return null;    }}

二、准备一个测试的Action

2.1 DemoAction

package com.qwm.s4.b_test;import com.opensymphony.xwork2.ActionContext;import com.opensymphony.xwork2.ActionSupport;/** * @author：qiwenming * @date：2017/9/23 0023   23:29 * @description： * 测试 */public class DemoAction extends ActionSupport{    public String add(){        System.out.println("-----add------");        ActionContext.getContext().put("msg","--add--");        return SUCCESS;    }    public String delete(){        System.out.println("-----delete------");        ActionContext.getContext().put("msg","--delete--");        return SUCCESS;    }    public String update(){        System.out.println("-----update------");        ActionContext.getContext().put("msg","--update--");        return SUCCESS;    }    public String find(){        System.out.println("-----find------");        ActionContext.getContext().put("msg","--find--");        return SUCCESS;    }}

2.2 message.jsp

<%--  Created by IntelliJ IDEA.  User: Administrator  Date: 2017/9/23 0023  Time: 23:39  To change this template use File | Settings | File Templates.--%><%@ page contentType="text/html;charset=UTF-8" language="java" %><html><head>    <title>信息显示</title></head><body><h1>    Hellow,wiming<br>    ${msg}</h1></body></html>

2.3 struts.xml

<!DOCTYPE struts PUBLIC        "-//Apache Software Foundation//DTD Struts Configuration 2.5//EN"        "http://struts.apache.org/dtds/struts-2.5.dtd"><struts>    <package name="intertest" namespace="/" extends="struts-default">        <!--全局允许方法调用-->        <global-allowed-methods>regex:.*</global-allowed-methods>        <!--动态方法调用-->        <action name="demoAction_*" class="com.qwm.s4.b_test.DemoAction" method="{1}">            <result name="success">/message.jsp</result>        </action>    </package></struts>

2.4 图示

三、使用拦截器

创建拦截器的时候，往往使用上面的创建方式3，这里我们使用的也是方式3

3.1 MyInterceptor

package com.qwm.s4.b_test;import com.opensymphony.xwork2.ActionInvocation;import com.opensymphony.xwork2.interceptor.MethodFilterInterceptor;/** * @author：qiwenming * @date：2017/9/23 0023   23:12 * @description： * 拦截器使用 */public class MyInterceptor extends MethodFilterInterceptor{    @Override    protected String doIntercept(ActionInvocation invocation) throws Exception {        //前处理        System.out.println("-----MyInterceptor------前处理");        //放行 ，如果不放行，也可以直接放回结果        String resultCode = invocation.invoke();        System.out.println("-----MyInterceptor------后处理");        return resultCode;    }//    @Override//    protected String doIntercept(ActionInvocation invocation) throws Exception {//        //不放行，也可以直接放回结果//        return "success";//    }}

3.2 配置 struts.xml

配置可以查看默认配置 struts2-core-2.5.13.jar!\struts-default.xml。

配置分为三个步骤：

注册拦截器
注册拦截器栈
指定包中的默认拦截器栈

下面的配置中，我们拦截了 add 和 delete 方法

<!DOCTYPE struts PUBLIC        "-//Apache Software Foundation//DTD Struts Configuration 2.5//EN"        "http://struts.apache.org/dtds/struts-2.5.dtd"><struts>    <package name="intertest" namespace="/" extends="struts-default">        <!--1.注册拦截器-->        <interceptors>            <interceptor name="myinterceptor" class="com.qwm.s4.b_test.MyInterceptor"/>            <!-- 2.注册拦截器栈 -->            <interceptor-stack name="myStack">                <!-- 自定义拦截器引入(建议放在20个拦截器之前) -->                <interceptor-ref name="myinterceptor">                    <!-- 指定哪些方法不拦截                     <param name="excludeMethods">add,delete</param> -->                    <!-- 指定哪些方法需要拦截 -->                    <param name="includeMethods">add,delete</param>                </interceptor-ref>                <!-- 引用默认的拦截器栈(20个) -->                <interceptor-ref name="defaultStack"></interceptor-ref>            </interceptor-stack>        </interceptors>       <!-- 3.指定包中的默认拦截器栈 -->        <default-interceptor-ref name="myStack"></default-interceptor-ref>        <!--全局允许方法调用-->        <global-allowed-methods>regex:.*</global-allowed-methods>        <!--动态方法调用-->        <action name="demoAction_*" class="com.qwm.s4.b_test.DemoAction" method="{1}">            <!-- 为Action单独指定走哪个拦截器(栈) -->            <!--<interceptor-ref name="myStack"/>-->            <result name="success">/message.jsp</result>        </action>    </package></struts>

3.3 图示

这里写图片描述

阅读全文

0 0