struts文件上传和下载

文件上传

jsp中

<a href="/file/new.action">文件上传案例</a>

fileaction中

@Override
public String execute() throws Exception {
　　return SUCCESS;
}

配置xml,记得在struts.xml中导入这个xml,
<constant name="struts.multipart.maxSize" value="10485760"/>是修改默认文件上传大小限制

<struts>

    <package name="filePackage" extends="basePackage" namespace="/file">
        <!--没有method默认调用execute-->
        <action name="new" class="com.kaishengit.action.FileAction">
            <result>/WEB-INF/views/file/upload.jsp</result>
        </action>
        
        <action name="upload" class="com.kaishengit.action.FileAction" method="upload">
            <result type="redirectAction">
                <param name="actionName">new</param>
                <param name="namespace">/file</param>
            </result>
        </action>
        
        <action name="download" class="com.kaishengit.action.FileAction" method="download">
            <result type="stream">
                <param name="contentType">${downloadType}</param>
                <!-- 
                <param name="contentLength"></param>
                 -->
                <param name="contentDisposition">attachment;filename="${downloadName}"</param>
                <param name="inputName">downloadFile</param>
                <param name="bufferSize">2048</param>
                <param name="allowCaching">true</param>
                <param name="contentCharSet">UTF-8</param>
            </result>
        </action>
    </package>
</struts>

跳转到/WEB-INF/views/file/upload.jsp这个jsp中的form表单 

action中即使没有doget和dopost方式也要写post提交,但在搜索的时候的form表单中是用get提交
文件上传的时候必须要写enctype="multipart/form-data" 否则用strut2会报错说没有什么input视图
要切记

<form action="/file/upload.action" method="post" enctype="multipart/form-data">
        
        <input type="text" name="title">
        <input type="file" name="pic">
        <input type="file" name="pic">
        <input type="file" name="pic">
        <button>保存</button>
</form>

通过配置项来到upload方法中

public String upload() {
        /*private File pic;等
            记得生成get和set
            */
        //System.out.println("Title:" + title);
        //这个时候获得的是上传缓存的名字,看不懂
        //System.out.println("file:" + pic.getName());
        /*这里才是获得文件名字,是使用了约定
            private String picFileName
            表单file名字+FileName;生成get set*/
        //System.out.println("file:" + picFileName);
        /*这里才是获得文件类型,是使用了约定
            private String picContentType
            表单file名字+ContentType;生成get set*/
        //System.out.println("type:" + picContentType);
        
        
        
        try {
            //单文件上传
            IOUtils.copy(new FileInputStream(pic), new FileOutputStream(new File("C:/upload",fileName)));
            
            /*多文件上传时
            
                <input type="file" name="pic">
                <input type="file" name="pic">
                <input type="file" name="pic">
                用数组或者集合的形式接收
                private List<File> pic;
                private List<String> picFileName;
                private List<String> picContentType;*/
            for(int i = 0;i < pic.size();i++) {
                File file = pic.get(i);
                String fileName = picFileName.get(i);
                IOUtils.copy(new FileInputStream(file), new FileOutputStream(new File("C:/upload",fileName)));
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        
        return SUCCESS;
    }

文件下载

方法一:

jsp中

<a href="/file/download.action">下载文件</a>

Fileaction中  获取response

public String download(){
     HttpServletResponse response = ServletActionContext.getResponse();
     response.setContentType("application/pdf");
     OutputStream out = response.getOutputStream();
     InputStream in = new FileInputStream(new File("c:/xx.pdf"));
     IOUtils.copy(in,out);
     out.flush();
     out.close();
     in.close();
     
     return NONE;
}

可以写在basicAction中,不用每次都写一遍,然后在Fileaction中传入路径即可

public void downloadFile(String filePath) throws Exception{
     HttpServletResponse response = ServletActionContext.getResponse();
     response.setContentType("application/pdf");
     OutputStream out = response.getOutputStream();
     InputStream in = new FileInputStream(new File(filePath));
     IOUtils.copy(in,out);
     out.flush();
     out.close();
     in.close();
    }

但是我们下载的格式不是固定的,可以定义一个map集合,根据后缀名判断
在basicAction中

public static Map<String,String> mimeType = new HashMap<String, String>();
    static {
        mimeType.put(".pdf", "application/pdf");
        mimeType.put(".json", "application/json");
        mimeType.put(".doc","application/msword");
        mimeType.put(".jpg","image/jpeg");
        mimeType.put(".jpeg","image/jpeg");
        mimeType.put(".jpe","image/jpeg");
        mimeType.put(".xls","application/vnd.ms-excel");
        mimeType.put(".zip","application/zip");
        mimeType.put(".wps","application/vnd.ms-works");
        mimeType.put(".gif","image/gif");
        mimeType.put(".mp3","audio/mpeg");
        //application/octet-stream
    }

    public void downloadFile(String filePath,String downloadFileName) throws Exception{
        HttpServletResponse response = getResponse();
        
        
        downloadFileName = new String(downloadFileName.getBytes("UTF-8"),"ISO8859-1");
        // 设置下载文件的名字
        response.addHeader("contentDisposition", "attachment;filename=""+downloadFileName+""");
        
        String fileType = filePath.substring(filePath.lastIndexOf("."));
        if(mimeType.containsKey(fileType)) {
            response.setContentType(mimeType.get(fileType));
        } else {
        //没有的话就认为是2进制
            response.setContentType("application/octet-stream");
        }
        
        OutputStream out = response.getOutputStream();
        InputStream in = new FileInputStream(new File(filePath));
        
        IOUtils.copy(in, out);
        out.flush();
        out.close();
        in.close();
    }

方法二

Fileaction中

public String download() throws Exception {
        downloadType = "application/pdf";
        downloadName = new String("缓存.pdf".getBytes("UTF-8"),"ISO8859-1");
        //return了一个success.需要在xml中配置一个返回值是stream
        return SUCCESS;
    }
    
    public InputStream getDownloadFile() throws Exception {
        return new FileInputStream("C:/upload/065-cache.pdf");
    }

struts-file.xml中

<action name="download" class="com.kaishengit.action.FileAction" method="download">
            <result type="stream">
                <param name="contentType">${downloadType}</param>
                <!-- 进度条
                <param name="contentLength"></param>
                 -->
                <!--下载框--><param name="contentDisposition">attachment;filename="${downloadName}"</param>
                <!--给一个输入流,需要在FileAction中配置一个方法获取输入流,返回值是InputStream
                方法名为get开头,param里面的参数为去掉get后首字母小写的结果-->
                <param name="inputName">downloadFile</param>
                <param name="bufferSize">2048</param>
                <param name="allowCaching">true</param>
                <param name="contentCharSet">UTF-8</param>
            </result>
        </action>

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这里再讲一个struts中常用的返回形式json

方法1:使用常用的返回方式返回json,首先在pom里添加对gson的导入

public class JSONAction extends BasicAction{

    private static final long serialVersionUID = 1L;
    @Override
    public String execute() throws Exception {
        
        /*在basic中提供renderJSON
    public void renderJSON(Object obj) throws Exception {
        HttpServletResponse response = getResponse();
        response.setContentType("application/json;charset=UTF-8");
        
        Gson gson = new Gson();
        String json = gson.toJson(obj);
        
        PrintWriter out = response.getWriter();
        out.print(json);
        out.flush();
        out.close();
    }
    
        */
        
        Map<String, Object> map = new HashMap<String, Object>();
        map.put("state", "success");
        map.put("result", "OK");
        
        renderJSON(map);
        return NONE;
    }


    
} 

struts-json中  要继承json-default

<package name="jsonPackage" extends="basePackage,json-default" namespace="/json">
        <action name="product" class="com.kaishengit.action.JSONAction">
            
        </action>
    </package>

方法2:使用插件返回
导入struts-json-plugin,必须和struts-core的版本一致

public class JSONAction extends BasicAction{

    private static final long serialVersionUID = 1L;

    private Map<String, Object> map;
    
    @Override
    public String execute() throws Exception {
        
    
        map = new HashMap<String, Object>();
        map.put("id", 1001);
        map.put("name", "Jerry");
        map.put("address", "中国河南省");
        
        return SUCCESS;
    }

    //get set

    public Map<String, Object> getMap() {
        return map;
    }
    public void setMap(Map<String, Object> map) {
        this.map = map;
    }
    
} 

struts-json中
extends="basePackage,json-default"多继承

<package name="jsonPackage" extends="basePackage,json-default" namespace="/json">
        <action name="product" class="com.kaishengit.action.JSONAction">
        <!--插件中定义了新的返回值json-->
            <result name="success" type="json">
            <!--root默认是一个action,会把里面所有的属性都转换成json--
            修改成map后只转化里面的map-->
                <param name="root">map</param>
                <param name="enableGZIP">true</param>压缩,传输快
                <param name="noCache">true</param>不缓存
                <param name="excludeNullProperties">true</param>排除没有值的属性,不生成json
                <param name="contentType">application/JSON</param>
                <param name="encoding">UTF-8</param>
            </result>
        </action>
    </package>