利用Struts2拦截器完成文件上传功能

Struts2的图片上传以及页面展示图片

在上次的CRUD基础上加上图片上传功能（https://www.cnblogs.com/liuwenwu9527/p/11108611.html）

文件上传：
三种上传方案
1、上传到tomcat服务器
2、上传到指定文件目录，添加服务器与真实目录的映射关系，从而解耦上传文件与tomcat的关系
文件服务器
3、在数据库表中建立二进制字段，将图片存储到数据库(现在基本不用了)

我们使用第二种方法实现图片上传实现效果如下：

首先是展示页面 clzList.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
    <%@taglib prefix="z" uri="/zking" %>
<!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>
</head>
<body>
<h2>班级</h2><br>
    <form action="${pageContext.request.contextPath }/sy/clz_list.action" method="post">
        班级名：<input type="text" name="cname">
              <input type="submit" value="确定">
    </form>
    <a href="${pageContext.request.contextPath }/sy/clz_preSave.action">新增</a>
    <table border="1" width="100%">
        <tr>
            <td>编号</td>
            <td>班级名</td>
            <td>教员</td>
            <td>图片</td>
            <td>操作</td> 
        </tr>    
        <c:forEach items="${clzList }" var="c">
        <tr>
            <td>${c.cid }</td>
            <td>${c.cname }</td>
            <td>${c.cteacher}</td>
            <td>
                <img alt="" style=" 60px;height: 60px" src="${pageContext.request.contextPath }${c.pic }">
            </td>
            <td>
                <a href="${pageContext.request.contextPath }/sy/clz_preSave.action?cid=${c.cid}">修改</a>&nbsp;&nbsp;
                <a href="${pageContext.request.contextPath }/sy/clz_del.action?cid=${c.cid}">删除</a>&nbsp;&nbsp;
                <a href="${pageContext.request.contextPath }/sy/clz_preUpload.action?cid=${c.cid}">图片上传</a>&nbsp;&nbsp;
            </td>
        </tr>    
        </c:forEach>
    </table>
    <z:page pageBean="${pageBean }"></z:page>
    
</body>
</html>

图片上传界面 upload.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>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="${pageContext.request.contextPath}/sy/clz_upload.action" method="post" enctype="multipart/form-data">
    <input type="hidden" name="cid" value="${clz.cid }"><br>
    <input type="hidden" name="cname" value="${clz.cname }"><br>
    <input type="hidden" name="cteacher" value="${clz.cteacher }"><br>
    <!-- 注意：name对应的值决定了，子控制器action属性的命名  -->
    <input type="file" name="file" >
    <input type="submit" >
</form>
</body>
</html>

ClazzAction类

package com.liuwenwu.crud.web;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.sql.SQLException;
import java.util.List;

import org.apache.commons.io.FileUtils;

import com.liuwenwu.crud.dao.ClazzDao;
import com.liuwenwu.crud.entity.Clazz;
import com.liuwenwu.crud.util.PageBean;
import com.opensymphony.xwork2.ModelDriven;

public class ClazzAction extends BaseAction implements ModelDriven<Clazz>{
    
    private ClazzDao clzDao=new ClazzDao();
    private Clazz clz=new Clazz();
//    img/img/imgContentType/imgFileName
    private File file;
    private String fileContentType;
    private String fileFileName;
    
    public String list() {
        PageBean pageBean=new PageBean();
        pageBean.setRequest(request);
        try {
            List<Clazz> list= this.clzDao.list(clz, pageBean);
//            this.result=this.clzDao.list(clz, pageBean);
            request.setAttribute("clzList", list);
            request.setAttribute("pageBean", pageBean);
        } catch (Exception e) {
            e.printStackTrace();
        } 
        return "list";
    }

    /**
     * 直接上传图片
     * @return
     */
    public String upload() {
        try {
//            注意：在linux下是没有F盘的，linux下只有一个盘符，那么意味着，当打包到linux服务器的时候需要改动代码
//            这个时候通常是这么解决的，将targetPath对应的目录串，配置到资源文件中，通过Properties类进行动态读取
//            那么当需要将项目发布到linux服务器的时候，只需要改变xxx.properties文件中的targetPath=/zking/T224/img
//            实际图片存储的位置
            String targetDir="F:/zz";
//            存储到数据库中的地址
            String serverPath="/upload";
            FileUtils.copyFile(file, new File(targetDir+"/"+fileFileName));    
//            注意：数据库存放的是网络请求地址 ，而不是本地图片存放地址
            clz.setPic(serverPath+"/"+fileFileName);
            this.clzDao.edit(clz);
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
        } 
        return "toList";
    }

    /**
     * 跳转文件上传页面
     * @return
     */
    public String preUpload() {
        try {
            Clazz c = this.clzDao.list(clz, null).get(0);
            request.setAttribute("clz", c);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return "toUpload";
    }
    
    /**
     * 跳转新增修改页面的公用方法
     * @return
     */
    public String preSave() {
        if(clz.getCid()!=0) {
            try {
                Clazz c = this.clzDao.list(clz, null).get(0);
                request.setAttribute("clz", c);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return "preSave";
    }
    /**
     * 新增
     * @return
     */
    public String add() {
        try {
            result=this.clzDao.add(clz);
        } catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException
                | SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return "toList";
    }
    /**
     * 修改
     * @return
     */
    public String edit() {
        try {
            this.clzDao.edit(clz);
        } catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException
                | SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return "toList";
    }
    /**
     * 删除
     * @return
     */
    public String del() {
        try {
            this.clzDao.del(clz);
        } catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException
                | SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return "toList";
    }
    
    @Override
    public Clazz getModel() {
        // TODO Auto-generated method stub
        return clz;
    }

    public File getFile() {
        return file;
    }

    public void setFile(File file) {
        this.file = file;
    }

    public String getFileContentType() {
        return fileContentType;
    }

    public void setFileContentType(String fileContentType) {
        this.fileContentType = fileContentType;
    }

    public String getFileFileName() {
        return fileFileName;
    }

    public void setFileFileName(String fileFileName) {
        this.fileFileName = fileFileName;
    }
}

struts-sy.xml的配置

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.5//EN"
    "http://struts.apache.org/dtds/struts-2.5.dtd">
<struts>
    <!-- /user/bookAction?methodName=list 
        /sy/bookAction?methodName=list
    -->
    <package name="sy" extends="base" namespace="/sy">
        <action name="/demo_*" class="com.liuwenwu.web.HelloAction" method="{1}">
            <result name="rs">/rs.jsp</result>
        </action>
        
        <action name="/stack_*" class="com.liuwenwu.test.DemoAction" method="{1}">
            <result name="rs">/rs.jsp</result>
        </action>

        <action name="/clz_*" class="com.liuwenwu.crud.web.ClazzAction" method="{1}">
            <result name="list">/clzList.jsp</result>
            <result name="preSave">/clzEdit.jsp</result>
            <result name="toList" type="redirectAction">/clz_list</result>
            <result name="toUpload">/upload.jsp</result>
        </action>
    </package>
</struts>

eclipse中修改Tomcat服务器配置文件添加服务器与真实目录映射关系

添加

<Context path="/T224_struts/upload" docBase="F:/zz/"/>

path是指服务器路径 docBase是指服务器本地映射地址

理解图片上传的原理自己写一个通过缓冲区增强的图片上传方法

    /**
     * FileUtils.copyFile的底层，并且通过缓冲区进行了增强
     * @param source
     * @param target
     * @throws Exception
     */
    public void conpyBufFile(File source,File target) throws Exception{
        //读取
        BufferedInputStream in=new BufferedInputStream(new FileInputStream(source));
        //写入
        BufferedOutputStream out=new BufferedOutputStream(new FileOutputStream(target));
        byte[] bbuf=new byte[1024];
        int len=0;
        while((len=in.read(bbuf))!=-1){
            out.write(bbuf, 0, len);
        }
        in.close();
        out.close();
    }

　拦截器 Interceptor：

实现的2种方法：
implements Interceptor
extends AbstractInterceptor

先定义两个拦截器

package com.liuwenwu.crud.interceptor;

import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.Interceptor;

public class OneInterceptor implements Interceptor{

    @Override
    public void destroy() {
        // TODO Auto-generated method stub
        
    }

    @Override
    public void init() {
        // TODO Auto-generated method stub
        
    }

    @Override
    public String intercept(ActionInvocation invocation) throws Exception {
        // TODO Auto-generated method stub
        System.out.println("=======OneInterceptor==========1");
        String invoke = invocation.invoke();
        System.out.println("=======OneInterceptor==========2");
        return invoke;
    }
}

package com.liuwenwu.crud.interceptor;

import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.Interceptor;

public class TwoInterceptor implements Interceptor{

    @Override
    public void destroy() {
        // TODO Auto-generated method stub
        
    }

    @Override
    public void init() {
        // TODO Auto-generated method stub
        
    }

    @Override
    public String intercept(ActionInvocation invocation) throws Exception {
        // TODO Auto-generated method stub
        System.out.println("=======TwoInterceptor==========1");
        String invoke = invocation.invoke();
        System.out.println("=======TwoInterceptor==========2");
        return invoke;
    }
}

拦截器的工作原理：

在struts-sy.xml中配置拦截器

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.5//EN"
    "http://struts.apache.org/dtds/struts-2.5.dtd">
<struts>
    <package name="sy" extends="base" namespace="/sy">
     <interceptors>
        <interceptor name="one" class="com.liuwenwu.crud.interceptor.OneInterceptor"></interceptor>
        <interceptor name="two" class="com.liuwenwu.crud.interceptor.TwoInterceptor"></interceptor>
    </interceptors> 
        <action name="/demo_*" class="com.liuwenwu.web.HelloAction" method="{1}">
            <result name="rs">/rs.jsp</result>
        </action>
        
        <action name="/stack_*" class="com.liuwenwu.test.DemoAction" method="{1}">
            <result name="rs">/rs.jsp</result>
        </action>
        
        <action name="/clz_*" class="com.liuwenwu.crud.web.ClazzAction" method="{1}">
            <interceptor-ref name="one"></interceptor-ref>
            <interceptor-ref name="two"></interceptor-ref>
            <result name="list">/clzList.jsp</result>
            <result name="preSave">/clzEdit.jsp</result>
            <result name="toList" type="redirectAction">/clz_list</result>
            <result name="toUpload">/upload.jsp</result>
        </action>
    </package>
</struts>

当拦截器起作用：