struts2基于注解的文件下载

参数说明：

type = "stream"，这里的type一定要等于stream；

对params的几个参数的解释：

"contentType", "application/octet-stream" : 文件格式；

"inputName", "attachstream" ：获取文件的方法名；这里的attachstream需要和action里的attachstream对应，类型就是InputStream;

"contentDisposition", "attachment;filename="${attachname}""：文件内容（显示的）属性,

这里的filename="${attachname}" ：下载之后的文件名；这里需要在action里定义一个变量，去获取下载文件的文件名，包括后缀，例如：下载的文件为**/**/upload/test.jpg,那么需要定义一个变量attachname，变量名一定要对应，然后,attachname = test.jsp;

"bufferSize", "4096" ：限定下载文件 缓冲区的值；

通过上述属性的解释，我们可以知道，在action里需要定义的变量有以下几个：

private InputStream attachstream;//文件读取流对象

private String attachname;//下载文件的名字

然后需要对应的getter/setter方法，

action实现代码如下：

@Action(value = "/admin/toDownload",
            results = {@Result(name = "download", type = "stream", 
                        params = {
                        "contentType", "application/octet-stream",
                        "inputName", "attachstream",
                        "contentDisposition", "attachment;filename="${attachname}"",
                        "bufferSize", "4096"
            })})
    public String toDownload(){
        String path = ServletActionContext.getServletContext().getRealPath("/" + fileName);//fileName是页面传过来的参数
        try {
            attachstream = new FileInputStream(path);
            String []attachnames = fileName.split("/");
            attachname = attachnames[attachnames.length - 1];
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        return "download";
    }

我自己写的：

@ParentPackage("managerPackage")
@Namespace("/districtTest")
@Action("districtTest")
@Results({
    @Result(name="districtTest_list",location="/manage/districtTest/districtTest_list.jsp"),
    @Result(name="districtTest_add",location="/manage/districtTest/districtTest_add.jsp"),
    @Result(name="districtTest_edit",location="/manage/districtTest/districtTest_edit.jsp"),
    @Result(name="districtTest_show",location="/manage/districtTest/districtTest_show.jsp"),
    @Result(name="districtTest_show0",location="/manage/districtTest/districtTest_show0.jsp"),
    @Result(name = "download", type = "stream", 
    params = {
    "contentType", "application/octet-stream",
    "inputName", "inputStream",
    "contentDisposition", "attachment;filename="${attachname}"",
    "bufferSize", "4096"
})
    
})



//下载
    public String download(){
        try {
            
            if(upload!=null&&!"".equals(upload)){
                String path = ServletActionContext.getServletContext().getRealPath("/" + upload);
                inputStream = new FileInputStream(path);
                String []attachnames = upload.split("/");
                attachname = attachnames[attachnames.length - 1];
            }
            return "download";
        } catch (Exception e) {
            // TODO: handle exception
            Loggers.error("----DistrictTestAction的download方法错误"+e.getMessage());
            e.printStackTrace();
        }
        return ERROR;
    }