Ajax使用jQuery與後臺交互

Ajax使用jQuery與後臺交互 文件上傳

前言:

Ajax就是異步JavaScript and XML縮寫。

Ajax的優點:

  1. 通過異步模式,提高用戶體驗
  2. 優化瀏覽器與服務器之間傳輸,按需索取
  3. Ajax引擎是在客戶端運行的,承擔了一部分本來由服務器承擔的工作

XmlHttpRequest對象

數據交互:

jquery-form的方式提交數據:
1. 前端數據

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Ajax提交表單</title>
</head>
<body>
    <form action="form_submit" method="post" id="myform" name="myform">
        <input type="text" id="mytext" name="mytext" value="text"/>
        <button type="button" id="mybutton" name="mybutton">提交</button>
    </form>

<!-- 導入必須的文件 -->
<script type="text/javascript" src="/MyAjax/resource/js/jquery-1.9.1.js"></script>
<script type="text/javascript" src="/MyAjax/resource/js/jquery-form.js"></script>
<script type="text/javascript">
    <!--向後臺發送post請求-->
    $(document).ready(function() {
        $("#mybutton").click(function () {
            $.ajax({
                type:"POST",//提交請求的方式
                cache:true,//是否有緩存
                url:"form_submit",//訪問servlet的路徑
                dataType:"json",//沒有這個,將把後臺放會的json解析成字符串
                data:$('#myform').serialize(),//把內容序列化
                async:true,//是否異步
                error:function(request) {//請求出錯
                    alert("出錯");
                },
                success:function(data) {//獲得返回值
                    alert(data["mytext"]);
                }
            })

        });
    });
</script>
</body>
</html>
  1. 後臺代碼
package com.chen.servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import net.sf.json.JSONObject;
/**
 * 
 * @author CHEN
 * @description 提交表單 
 * @導包:json-lib-2.2.2-jdk15.jar\ezmorph-1.0.4.jar
 */
@WebServlet("/form_submit")
public class FormSubmit extends HttpServlet{

    /**
     * 
     */
    private static final long serialVersionUID = -8615452472287083708L;

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");
        resp.setCharacterEncoding("utf-8");
        System.out.println(req.getParameter("myid"));
        String mytext=req.getParameter("mytext");
        JSONObject jObject=new JSONObject();
        jObject.put("mytext", mytext);
        PrintWriter out=resp.getWriter();
        out.print(jObject);
        out.close();
    }
}

自定義數據交互

自定義上傳的數據:

有時候,我們所需的內容並不總是在一個表單中,這時候,我們就需要進行拼接,以下提供了兩種拼接的方法。

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Ajax提交表單</title>
</head>
<body>
    <!-- 共有的某行數據 -->
    <input type="hidden" id="myid" name="myid" value="123456">
    <form action="form_submit" method="post" id="myform" name="myform">
        <input type="text" id="mytext" name="mytext" value="text"/>
        <button type="button" id="mybutton" name="mybutton">提交</button>
    </form>

<!-- 導入必須的文件 -->
<script type="text/javascript" src="/MyAjax/resource/js/jquery-1.9.1.js"></script>
<script type="text/javascript" src="/MyAjax/resource/js/jquery-form.js"></script>
<script type="text/javascript">
    <!--向後臺發送post請求-->
    $(document).ready(function() {
        $("#mybutton").click(function () {
            //準備數據
            var myform=$('#myform').serialize();//表單序列化
            //myform += "&myid="+encodeURIComponent($('#myid').val());//方法1:按格式拼接
            myform+= "&"+$('#myid').serialize();//方法2:拼接上需要的字符串            
            $.ajax({
                type:"POST",//提交請求的方式
                cache:true,//是否有緩存
                url:"form_submit",//訪問servlet的路徑
                dataType:"json",//沒有這個,將把後臺放會的json解析成字符串
                data:myform,//把內容序列化
                async:true,//是否異步
                error:function(request) {//請求出錯
                    alert("出錯");
                },
                success:function(data) {//獲得返回值
                    alert(data["mytext"]);
                }
            })

        });
    });
</script>
</body>
</html>

方法1:按格式拼接 :
myform +=“&myid=”+encodeURIComponent($(‘#myid’).val());

方法2:拼接上需要的字符串
myform+= “&”+$(‘#myid’).serialize();

後臺的接收還是一樣的。

上傳文件

前臺使用ajaxupload.js對文件進行上傳

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Ajax提交表單</title>
</head>
<body>
    <!-- 共有的某行數據 -->
    <input type="hidden" id="myid" name="myid" value="123456"/>
    <form action="form_submit" method="post" id="myform" name="myform" >
        <input type="text" id="mytext" name="mytext" value="text"/>

        <button type="button" id="mybutton" name="mybutton">提交</button>
    </form>

    <br/>
    <form action="#" enctype="multipart/form-data">
        <input type="file" id="myfile" name="myfile"/>
        <button type="button" id="myfilebutton" name="myfilebutton">上傳</button>
    </form>

    <div id="mydiv"></div>
<!-- 導入必須的文件 -->
<script type="text/javascript" src="/MyAjax/resource/js/jquery-1.9.1.js"></script>
<script type="text/javascript" src="/MyAjax/resource/js/jquery-form.js"></script>
<script type="text/javascript" src="/MyAjax/resource/js/ajaxupload.js"></script>
<script type="text/javascript">
    /**
    向後臺發送post請求
    **/
    $(document).ready(function() {
        $("#mybutton").click(function () {
            //準備數據
            var myform=$('#myform').serialize();//表單序列化
            //myform += "&myid="+encodeURIComponent($('#myid').val());//方法1:按格式拼接
            myform+= "&"+$('#myid').serialize();//方法2:拼接上需要的字符串            
            $.ajax({
                type:"POST",//提交請求的方式
                cache:true,//是否有緩存
                url:"form_submit",//訪問servlet的路徑
                dataType:"json",//沒有這個,將把後臺放會的json解析成字符串
                data:myform,//把內容序列化
                async:true,//是否異步
                error:function(request) {//請求出錯
                    alert("出錯");
                },
                success:function(data) {//獲得返回值
                    alert(data["mytext"]);
                }
            })

        });
    });


    /**
    向後臺發送文件
    **/
    $(document).ready(function() {
        $('#myfilebutton').click(function() {
            $.ajaxFileUpload({
                url:"file_submit",//後他處理的路徑
                secureuri:false,//是否需要安全協議,一般置爲false
                fileElementId:'myfile',//文件id
                dataType:"json",//返回類型,默認string
                success:function(data,status) {
                    alert(data["message"]);//返回信息
                    //拼接
                    var a=document.createElement("a");
                    a.href=data['allUrl'];
                    a.innerHTML=data['fileName'];
                    var mydiv=document.getElementById('mydiv');
                    mydiv.appendChild(a);
                },
                error:function(data,status,e) {//返回信息
                    alert('出錯了');
                }
            });
            return false;
        });
    });

</script>
</body>
</html>

後臺使用commons-fileupload.jar上傳文件

package com.chen.servlet;

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.InetAddress;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.FileUploadException;

import net.sf.json.JSONObject;

import com.chen.model.MyFile;
import com.chen.util.UploadUtil;

/**
 * 
 * @author CHEN
 * @description 上傳文件
 */
@WebServlet("/file_submit")
public class FileSumbit extends HttpServlet{

    /**
     * 
     */
    private static final long serialVersionUID = -1868776810282017505L;

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");
        resp.setCharacterEncoding("utf-8");
        System.out.println("上傳文件");
        MyFile file=new MyFile(req.getServletContext().getRealPath("/resource/uploadTemp"),req.getServletContext().getRealPath("/resource/upload"));
        UploadUtil uUtil=new UploadUtil();
        String message="上傳失敗";
        try {
            message=uUtil.uploadfiFactoryle(file, req);
        } catch (FileUploadException e) {

            e.printStackTrace();
        }

        //返回的內容
        PrintWriter out=resp.getWriter();
        JSONObject jsonObject=new JSONObject();
        jsonObject.put("message", message);

        jsonObject.put("allUrl","http://"+InetAddress.getLocalHost().getHostAddress()+":"
        +req.getLocalPort()+File.separator+req.getContextPath()+"/resource/upload/"+file.getFileName());
        jsonObject.put("fileName", file.getFileName());
        out.print(jsonObject);
        out.close();
    }
}

MyFile.java文件

package com.chen.model;


import java.io.File;
/**
 * 
 * @author CHEN
 *
 */
public class MyFile {
    private File file;
    private String fileName;//文件名
    private String tempUrl;//緩存路徑
    private String saveUrl;//保存路徑

    private String allUrl;//文件全路徑



    public String getFileName() {
        return fileName;
    }
    public void setFileName(String fileName) {
        this.fileName = fileName;
    }
    public MyFile() {
        super();
    }
    public File getFile() {
        return file;
    }
    public void setFile(File file) {
        this.file = file;
    }
    public String getSaveUrl() {
        return saveUrl;
    }
    public void setSaveUrl(String saveUrl) {
        this.saveUrl = saveUrl;
    }
    public String getTempUrl() {
        return tempUrl;
    }
    public void setTempUrl(String tempUrl) {
        this.tempUrl = tempUrl;
    }



    public String getAllUrl() {
        return allUrl;
    }
    public void setAllUrl(String allUrl) {
        this.allUrl = allUrl;
    }
    public MyFile(String tempUrl, String saveUrl) {
        super();
        this.tempUrl = tempUrl;
        this.saveUrl = saveUrl;
    }
    public MyFile(String saveUrl) {
        super();
        this.saveUrl = saveUrl;
    }
}

UploadUtil.java工具

package com.chen.util;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.servlet.http.HttpServletRequest;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.fileupload.servlet.ServletRequestContext;

import com.chen.model.MyFile;

import java.util.List;
/**
 * 
 * @author CHEN
 * @description 上傳文件的工具
 */
public class UploadUtil {

    public String uploadfiFactoryle(MyFile file, HttpServletRequest request)
            throws FileUploadException, IOException {

        // 配置上傳的屬性
        DiskFileItemFactory dfiFactory = new DiskFileItemFactory();
        dfiFactory.setSizeThreshold(10 * 1024);
        dfiFactory.setRepository(new File(file.getTempUrl()));

        // 配置解析器
        ServletFileUpload sfupLoad = new ServletFileUpload(dfiFactory);
        sfupLoad.setHeaderEncoding("utf-8");

        // 對請求進行解析
        List<FileItem> filList = sfupLoad
                .parseRequest(new ServletRequestContext(request));
        // 文件名
        String fileName = null;
        String allUrl=null;

        //for (FileItem item : filList) {
        FileItem item = getUploadFileItem(filList);
            if (item.isFormField()) {// 普通表單
                return "文件錯誤";
            } else {// file表單
                fileName = item.getName();
                System.out.println(fileName);
                allUrl=file.getSaveUrl()+ File.separator + fileName;
                FileOutputStream out = new FileOutputStream(allUrl);
                InputStream in = item.getInputStream();
                // 開始存入服務器端
                byte[] buf = new byte[1024];
                int len = 0;
                while ((len = in.read(buf)) > 0)
                    out.write(buf, 0, len);
                in.close();
                out.close();
                item.delete();// 刪除臨時文件
            }
        //}
        file.setFileName(fileName);
        file.setAllUrl(allUrl);
        return "上傳成功";
    }

    private FileItem getUploadFileItem(List<FileItem> list) {
        for (FileItem fileItem : list) {
            if(!fileItem.isFormField()) {
                return fileItem;
            }
        }
        return null;
    }
}

JAR包
這裏寫圖片描述

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