javajson上傳文件
A. 關於 java在後台傳一個json數據到前台的問題
從你傳的json來看，你傳回的sessionModel僅僅是一個字元串，並不是包含對象的結構體，所以你取不到類成員的，如果sessionModel是一個對象，那麼相應的字元串應該類似如下結構
{「model」:{"sessionModel":{"id":"1","name","lz"}}}
B. java如何實現文件上傳和下載的功能
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.jspsmart.upload.*;
import net.sf.json.JSONObject;
import action.StudentAction;
public class UploadServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
boolean result=true;
SmartUpload mySmartUpload=new SmartUpload();
mySmartUpload.initialize(this.getServletConfig(), request,response);
mySmartUpload.setTotalMaxFileSize(50*1024*1024);//大小限制
mySmartUpload.setAllowedFilesList("doc,docx");//後綴名限制
try {
mySmartUpload.upload();
com.jspsmart.upload.File myFile = mySmartUpload.getFiles().getFile(0);
myFile.saveAs("/file/"+1+".doc");//保存目錄
} catch (SmartUploadException e) {
e.printStackTrace();result=false;
}
//*****************************//
response.setContentType("text/html;charset=UTF-8");
response.setHeader("Cache-Control","no-cache");
PrintWriter out = response.getWriter();
out.print(result);
out.flush();
out.close();
}
}
//我這是ajax方式的，不想這樣,把//**********************//以下部分修改就行了
//需要SmartUpload組件，去網上下個就行了，也有介紹的
C. java後台post方法上傳文件
/** * 執行post請求並將返回內容轉為json格式返回 */public static JsonObject doPost(String url, JsonObject message)throws WeiXinException {JsonObject jo = null;PrintWriter out = null;InputStream in = null;try {if (url.startsWith("https")){//https方式提交需要SSLContext sc = SSLContext.getInstance("SSL");sc.init(null, new TrustManager[] { new TrustAnyTrustManager() },new java.security.SecureRandom());URL console = new URL(url);HttpsURLConnection conn = (HttpsURLConnection) console.openConnection();conn.setSSLSocketFactory(sc.getSocketFactory());conn.setHostnameVerifier(new TrustAnyHostnameVerifier());conn.connect();in = conn.getInputStream();}else{in = new URL(url).openStream();}// 打開和URL之間的連接URLConnection conn = new URL(url).openConnection();// 設置通用的請求屬性conn.setRequestProperty("accept", "*/*");conn.setRequestProperty("connection", "Keep-Alive");conn.setRequestProperty("user-agent","Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");// 發送POST請求必須設置如下兩行conn.setDoOutput(true);conn.setDoInput(true);// 獲取URLConnection對象對應的輸出流out = new PrintWriter(conn.getOutputStream());// 發送請求參數out.print(message.toString());// flush輸出流的緩沖out.flush();// POST請求out.flush();out.close();in = conn.getInputStream();jo = JSON.parse(getContext(in));doExeption(jo);} catch (MalformedURLException e) {e.printStackTrace();} catch (ProtocolException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} catch (KeyManagementException e) {e.printStackTrace();} catch (NoSuchAlgorithmException e) {e.printStackTrace();} finally {if (out != null) {out.flush();out.close();}if (in != null ){try {in.close();} catch (IOException e) {e.printStackTrace();}}}return jo;}
D. 使用ajaxFileUpload這個控制項上傳文件，返回json數據出錯
用這個東西返回的data其實與一般ajax返回的不同，因為它本身就是一個模擬ajax的操作，所以只不過是對用iframe的onload事件對返回的response進行截取......
E. 能用json傳遞文件嗎
Java裡面可以用BASE64Encoder，BASE64Decoder，這是sun.misc包裡面的，一般是不公開的Android 裡面沒有用過，不過有個android.util.Base64，你可以使試一試encodeToString（）decode（）方法
F. java後台怎樣傳json格式的數據
通過 JSONObject類就可以了
首先 你把這幾個包 下下來 放到你項目。如果有就不要下了：
1.commons-lang.jar
2.commons-beanutils.jar
3.commons-collections.jar
4.commons-logging.jar
5.ezmorph.jar
6.json-lib-2.2.2-jdk15.jar
像你這種是數據形式 就通過 JSONArray 如：
JSONArray datasJson = JSONArray.fromObject(datas);最好把datas toString 一下