struts2文件上传

使用struts2进行文件上传操作，struts2自身封装了一个文件上传jar包，并且设计实现了一个文件上传的拦截器FileUpload，该拦截器会将浏览器提交的File对象进行拦截，保存在临时目录中。用户通过设置拦截器参数，实现从临时目录到指定目录的文件迁移，且该拦截器是默认启动的。

实现

• 前端jsp页面的表单属性设置
  enctype="multipart/form-data"。
• 配置文件struts.xml拦截器设置

    <interceptor-ref name="defaultStack">
         <param name="fileUpload.allowedExtensions">jpg, jpeg, png</param>
    </interceptor-ref>

  有多种类型只需要加逗号分隔即可

• 定义接收的变量

    private File upload;//前端上传框的name值
    private String uploadContentType;//上传文件的mimeType类型
    private String uploadFileName;//上传文件的名称    

• 将文件复制到自定义目录

    FileUtils.copyFile(upload, new File(ServletActionContext.getServletContext().getRealPath("/upload"), uploadFileName));
    ServletActionContext.getServletContext().getRealPath("/upload")得到的是tomcat下该项目的发布路径，即E:\tomcat服务器\apache-tomcat-9.0.30\strut2demo\upload路径
    可直接使用链接访问到该文件，如"http://localhost:8080/strut2demo(项目名)/upload(自定义接收文件的目录)/"+uploadFileName

代码示例

• 前端jsp

   <s:form action="upfile" method="POST" enctype="multipart/form-data">
        <s:textfield name="name" label="用户名"/>
        <s:textfield name="password" label="密码"/>
        <s:file name="upload" label="头像"/>
        <s:submit value="提交"/>
    </s:form>

• 创建文件到达目录存放默认文件
  

• Java代码

code

public class UpLoadFile extends ActionSupport {
    private String name;
    private String password;
    private File upload;
    private String uploadContentType;//上传文件的mimeType类型
    private String uploadFileName;//上传文件的名称
public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getPassword() {
    return password;
}

public void setPassword(String password) {
    this.password = password;
}

public File getUpload() {
    return upload;
}

public void setUpload(File upload) {
    this.upload = upload;
}

public String getUploadContentType() {
    return uploadContentType;
}

public void setUploadContentType(String uploadContentType) {
    this.uploadContentType = uploadContentType;
}

public String getUploadFileName() {
    return uploadFileName;
}

public void setUploadFileName(String uploadFileName) {
    this.uploadFileName = uploadFileName;
}

public String uploadFile() throws IOException {
    String path = "E:/JetBrainJava/strut2demo/target/strut2demo/upload";

    System.out.println("path："+path);
    if(name == null || name.equals("")){
        this.addFieldError("nameError", "用户名不能为空");
        return "fail";
    }
    if(password == null || password.equals("")){
        this.addFieldError("passwordError", "密码不能为空");
        return "fail";
    }
    ServletActionContext.getContext().getSession().put("name", name);
    //将访问图片的链接存放在session中
    if(upload == null){//如果没有上传图像，则使用默认图片
        ServletActionContext.getContext().getSession().put("image", "http://localhost:8080/strut2demo/upload/default.png");
        System.out.println("保存成功");
        return "success";
    }
    else{//如果上传图片成功，则将上传图片设置为其头像
        String pre = uploadFileName.split("\\.")[0];
        String tail = uploadFileName.split("\\.")[1];
        pre = pre + System.currentTimeMillis();
        uploadFileName = pre + "." + tail;//对名字加上时间戳，防止重名导致文件被覆盖

//            File dest = new File(path, uploadFileName);

//            System.out.println("dest: "+dest);

//            FileUtils.copyFile(upload, dest);

//复制到tomcat目录下

FileUtils.copyFile(upload, new File(ServletActionContext.getServletContext().getRealPath("/upload"), uploadFileName));

ServletActionContext.getContext().getSession().put("image", "http://localhost:8080/strut2demo/upload/"+uploadFileName);

System.out.println("保存成功");

return "success";

}

}

• 配置文件

<action name="upfile" class="com.mystruts2.struts2demo.action.UpLoadFile" method="uploadFile">
        <result name="success">uploadSuccess.jsp</result>
        <result name="fail">uploadFail.jsp</result>
        <interceptor-ref name="defaultStack">
            <param name="fileUpload.allowedExtensions">jpg, jpeg, png</param>
        </interceptor-ref>
</action>

• 跳转成功显示页面
  
  将从seesion将连接取出直接访问图片