今天来分享一个图片上传
现在很多小项目里面基本上都有要显示图片的功能，所以呢图片上传是基本要掌握的啦
一般的图片上传原理就是从本地选择一张图片然后通过io流发布到服务器上去
上传方案基本有三种：
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
一：创建数据库表并且连接数据库
struts_class表
config.properties配置文件
二：dao层
ClassDao类
package com.crud.dao; import java.sql.SQLException; import java.util.List; import com.crud.entity.Class; import com.crud.util.BaseDao; import com.crud.util.EntityBaseDao; import com.crud.util.PageBean; import com.crud.util.StringUtils; /** * 班级dao方法类 * @author Administrator */ public class ClassDao extends EntityBaseDao<Class>{ /** * 查询分页方法，查询数据公用方法 * @param c * @param paBean * @return * @throws InstantiationException * @throws IllegalAccessException * @throws SQLException */ public List<Class> list(Class c,PageBean paBean) throws InstantiationException, IllegalAccessException, SQLException{ String sql="select * from struts_class where true "; String classname=c.getClassname(); int cid=c.getCid(); if (cid!=0) { sql +=" and cid = "+cid; } if (StringUtils.isNotBlank(classname)) { sql+=" and classname like '%"+classname+"%'"; } return super.executeQuery(sql,paBean,Class.class); } /** * 新增方法 * @param c * @return * @throws NoSuchFieldException * @throws SecurityException * @throws IllegalArgumentException * @throws IllegalAccessException * @throws SQLException */ public int add(Class c) throws NoSuchFieldException, SecurityException, IllegalArgumentException, IllegalAccessException, SQLException { String sql="insert into struts_class values(?,?,?)"; return super.executeUpdate(sql, new String[] {"classname","cname","upload"},c); } /** * 删除方法 * @param c * @return * @throws NoSuchFieldException * @throws SecurityException * @throws IllegalArgumentException * @throws IllegalAccessException * @throws SQLException */ public int del(Class c) throws NoSuchFieldException, SecurityException, IllegalArgumentException, IllegalAccessException, SQLException { String sql="delete from struts_class where cid=?"; return super.executeUpdate(sql, new String[] {"cid"},c); } /** * 修改方法 * @param c * @return * @throws NoSuchFieldException * @throws SecurityException * @throws IllegalArgumentException * @throws IllegalAccessException * @throws SQLException */ public int edit(Class c) throws NoSuchFieldException, SecurityException, IllegalArgumentException, IllegalAccessException, SQLException { String sql="update struts_class set classname=?,cname=?,upload=? where cid=?"; return super.executeUpdate(sql, new String[] {"cid","classname","cname","upload"},c); } }
三：web层
BaseAction类
package com.crud.web; import javax.servlet.ServletContext; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import org.apache.struts2.interceptor.ServletRequestAware; import org.apache.struts2.interceptor.ServletResponseAware; /** * 每一个开发的子控制器要用的属性都定义在通用的action中。 * @author Administrator * */ public class BaseAction implements ServletRequestAware, ServletResponseAware{ /** * 为了传值使用 */ protected HttpServletResponse response; protected HttpServletRequest request; protected HttpSession session; protected ServletContext application; /** * 为了配置跳转页面所用 */ protected final static String SUCCESS = "success"; protected final static String FAIL = "fail"; protected final static String LIST = "list"; protected final static String ADD = "add"; protected final static String EDIT = "edit"; protected final static String DETAIL = "detail"; /** * 具体传值字段 后端向jsp页面传值所用字段 */ protected Object result; protected Object msg; protected int code; public Object getResult() { return result; } public Object getMsg() { return msg; } public int getCode() { return code; } @Override public void setServletResponse(HttpServletResponse arg0) { this.response = arg0; } @Override public void setServletRequest(HttpServletRequest arg0) { this.request = arg0; this.session = arg0.getSession(); this.application = arg0.getServletContext(); } }
ClassAction类
package com.crud.web; import java.io.File; import java.io.IOException; import java.sql.SQLException; import java.util.List; import org.apache.commons.io.FileUtils; import com.crud.dao.ClassDao; import com.crud.entity.Class; import com.crud.util.PageBean; import com.opensymphony.xwork2.ActionSupport; import com.opensymphony.xwork2.ModelDriven; /** * 班级web层 * @author Administrator */ public class ClassAction extends BaseAction implements ModelDriven<Class>{ private ClassDao cldao=new ClassDao(); private Class cls=new Class(); // private File file; private String fileContentType; private String fileFileName; //文件名称 public String list() { PageBean pageBean=new PageBean(); pageBean.setRequest(request); try { List<Class> list = this.cldao.list(cls, pageBean); request.setAttribute("mylist", list); request.setAttribute("pageBean", pageBean); } catch (InstantiationException | IllegalAccessException | SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return "list"; } /** * 直接上传图片 * @return * @throws SQLException * @throws IllegalAccessException * @throws IllegalArgumentException * @throws SecurityException * @throws NoSuchFieldException */ public String upload() throws NoSuchFieldException, SecurityException, IllegalArgumentException, IllegalAccessException, SQLException { try { //注意：在linux下是没有E盘的，linux下只有一个盘服，那么意味着当打包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对应目录串，配置到资源文件中，通过properties类进行读取 // 那么需要将项目发布到linux服务器的时候，只需要改变xxx.properties文件中targetPath=E:/黄婷 T221/Y2/struts2/04、拦截器与文件上传 // 实际图片的储存位置 String targetPath="E:/黄婷 T221/Y2/struts2/04、拦截器与文件上传"; // 存到数据库中的地址 String serverPath ="/uploads"; FileUtils.copyFile(file, new File(targetPath+"/"+fileFileName)); // 注意：数据库存放是网络请求地址，而不是本地图片存放地址 cls.setUpload(serverPath+"/"+fileFileName); this.cldao.edit(cls); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } return "toList"; } /** * 跳转文件上传页面 * @return * @throws SQLException * @throws IllegalAccessException * @throws InstantiationException */ public String preupload() throws InstantiationException, IllegalAccessException, SQLException { Class cl = this.cldao.list(cls, null).get(0); request.setAttribute("cls",cl); return "toUpload"; } /** * 跳转新增修改页面的公用方法 * @return * @throws SQLException * @throws IllegalAccessException * @throws InstantiationException */ public String preSave() throws InstantiationException, IllegalAccessException, SQLException { if (cls.getCid()!=0) { Class cl = this.cldao.list(cls, null).get(0); request.setAttribute("cls",cl); } return "preSave"; } /** * 新增 * @return */ public String add() { try { result = this.cldao.add(cls); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } return "toList"; } /** * 删除 * @return */ public String del() { try { this.cldao.del(cls); } catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException | SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return "toList"; } /** * 修改 * @return */ public String edit() { try { this.cldao.edit(cls); } catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException | SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return "toList"; } @Override public Class getModel() { // TODO Auto-generated method stub return null; } //上传图片属性的getset方法 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; } }
前端界面
clsList.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="${pageContext.request.contextPath }/sy/cls_list.action" method="post"> 班级名：<input type="text" name="classname"> <input type="submit" value="确定"> </form> <a href="${pageContext.request.contextPath }/sy/cls_preSave.action">新增</a> <table border="1" width="100%"> <tr> <td>编号</td> <td>班级名</td> <td>学生名</td> <td>图片</td> <td>操作</td> </tr> <c:forEach items="${mylist }" var="c"> <tr> <td>${c.cid }</td> <td>${c.classname }</td> <td>${c.cname}</td> <td> <img style=" 60px;height:60px;" src="${pageContext.request.contextPath }/${c.cid }"> </td> <td> <a href="${pageContext.request.contextPath }/sy/cls_preSave.action?cid=${c.cid}">修改</a> <a href="${pageContext.request.contextPath }/sy/cls_del.action?cid=${c.cid}">删除</a> <a href="${pageContext.request.contextPath }/sy/cls_upload.action?cid=${c.cid}">图片上传</a> </td> </tr> </c:forEach> </table> <z:page pageBean="${pageBean}"></z:page> </body> </html>
效果图：
上传图片的前端页面：
upload.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="${pageContext.request.contextPath}/sy/cls_upload.action" method="post" enctype="multipart/form-data">
<input type="hidden" name="cid" value="${cls.cid}"><br>
<input type="hidden" name="classname" value="${cls.classname }"><br>
<input type="hidden" name="cname" value="${cls.cname }"><br>
<!-- name对应的值决定了action属性的命名 -->
<input type="file" name="file" ><br>
<input type="submit">
</form>
</body>
</html>
效果图：
修改server.xml配置文件
<Context path="/T224_struts/upload" docBase="E:/黄婷 T221/Y2/struts2/04、拦截器与文件上传/"/>
四：拦截器Interceptor
拦截器有两种方式
1.implements Interceptor
2.extends AbstractInterceptor
OneInterceptor 类
package com.crud.web; 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 arg0) throws Exception { // TODO Auto-generated method stub System.out.println("========OneInterceptor=====1"); String invoke = arg0.invoke(); System.out.println("============OneInterceptor============2"); return invoke; } }
TwoInterceptor类
package com.crud.web; 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 arg0) throws Exception { // TODO Auto-generated method stub System.out.println("========TwoInterceptor=====1"); String invoke = arg0.invoke(); System.out.println("============TwoInterceptor============2"); return invoke; } }
效果图：
图解运行原理：
今天的分享到此结束！