毕业设计《项目管理》总结06之ajax的初步使用经验

1、ajax页面时不能实现下载功能，因为后台下载功能返回的是一个流，而ajax得到后台的数据只能是字符串或字符，所以实现的方法可以：

例如：用js生成一个form，用这个form提交参数，并返回“流”类型的数据。在实现过程中，页面也没有进行刷新。

var form=$("<form>");//定义一个form表单
form.attr("style","display:none");
form.attr("target","");
form.attr("method","post");
form.attr("action","exportData");
var input1=$("<input>");
input1.attr("type","hidden");
input1.attr("name","exportData");
input1.attr("value",(new Date()).getMilliseconds());
$("body").append(form);//将表单放置在web中
form.append(input1);
 
form.submit();//表单提交

2、在页面内有多文件上传时，存在一个链接来进行文件下载时，可以使用第1个方法实现。

3、在页面内有多文件上传时，存在一个链接来进行文件删除时，使用ajax向后台传递参数，参数封装在data中，同时将contentType设置为application/x-www-form-urlencoded;charset=utf-8，这样后台便可以得到参数。

4、ajax传递参数方法有：

①使用默认contentType，参数追加到url后传递

$.ajax({
    url: "http://localhost:8082/boot/request/parameter?name=aaa&paraB=bbb",
    contentType: "application/x-www-form-urlencoded;charset=utf-8",
    success: function(json){
        console.log(json);
    }
});

//请求中包含的参数的名称
Enumeration<String> parameterNames = request.getParameterNames();
while (parameterNames.hasMoreElements()) {
    String s = parameterNames.nextElement();
    System.out.println("getParameterNames:" + s);
    String paraA = request.getParameter(s);
    System.out.println("getParameter:" + paraA);
}
 
// 返回包含在路径后的请求 URL 中的查询字符串
String queryString = request.getQueryString();
System.out.println("getQueryString:" + queryString);

②使用默认contentType，参数放到data中传递

$.ajax({
    url: "http://localhost:8082/boot/request/parameter",
    contentType: "application/x-www-form-urlencoded;charset=utf-8",
    data: {name: "aaa", paraB:"bbb"},
    success: function(json){
        console.log(json);
    }
});

//请求中包含的参数的名称
Enumeration<String> parameterNames = request.getParameterNames();
while (parameterNames.hasMoreElements()) {
    String s = parameterNames.nextElement();
    System.out.println("getParameterNames:" + s);
    String paraA = request.getParameter(s);
    System.out.println("getParameter:" + paraA);
}

③用默认contentType，data中传递数组

$.ajax({
    url: "http://localhost:8082/boot/request/parameter",
    type: "post",
    contentType: "application/x-www-form-urlencoded;charset=utf-8",
    data: {foo: ["bar1", "bar2"]},
    success: function (json) {
        console.log(json);
    }
});

// 返回一个字符串对象的数组
String[] parameterValues = request.getParameterValues("foo[]");
if (parameterValues != null) {
    for (String parameterValue : parameterValues) {
        System.out.println("getParameterValues:" + parameterValue);
    }
}

④使用contentType为application/json，在data中传递复杂参数

$.ajax({
    url: "http://localhost:8082/boot/request/parameter",
    type: "post",
    contentType: "application/json;charset=utf-8",
    data: JSON.stringify({name: "aaa", foo: ["bar1", "bar2"]}),
    success: function (json) {
        console.log(json);
    }
});

// 以二进制数据形式检索请求的主体
ServletInputStream inputStream = request.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(inputStream));
String line = "";
StringBuilder sb = new StringBuilder();
while ((line = br.readLine()) != null) {
    sb.append(line);
}
System.out.println("getInputStream:" + sb);

⑤使用contentType为application/json，在data中传递复杂参数，并使用springmvc接收

$.ajax({
    url: "http://localhost:8082/boot/request2/requestBody",
    type: "post",
    contentType: "application/json;charset=utf-8",
    data: JSON.stringify({id: 111, name: "aaa", foo: ["bar1", "bar2"]}),
    success: function (json) {
        console.log(json);
    }
});

@RequestMapping(value = "/requestBody")
public void RequestBody(@RequestBody User user) throws IOException {
    System.out.println(user.toString());
}

⑥url追加参数与data中放json同时使用

$.ajax({
    // url: "http://localhost:8082/boot/request/parameter?userName=aaa",
    url: "http://localhost:8082/boot/request2/parm?userName=aaa",
    type: "post",
    contentType: "application/json;charset=utf-8",
    data: JSON.stringify({id: 111, name: "aaa", foo: ["bar1", "bar2"]}),
    async:false,
    success: function (json) {
        console.log(json);
    }
});

//请求中包含的参数的名称
Enumeration<String> parameterNames = request.getParameterNames();
while (parameterNames.hasMoreElements()) {
    String s = parameterNames.nextElement();
    System.out.println("getParameterNames:" + s);
    String paraA = request.getParameter(s);
    System.out.println("getParameter:" + paraA);
}
// 以二进制数据形式检索请求的主体
ServletInputStream inputStream = request.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(inputStream));
String line = "";
StringBuilder sb = new StringBuilder();
while ((line = br.readLine()) != null) {
    sb.append(line);
}
System.out.println("getInputStream:" + sb);

RequestMapping(value = "/parm")
public void parm(@RequestParam String userName, @RequestBody User user) throws IOException {
    System.out.println("userName:" + userName);
    System.out.println(user.toString());
}

参考文章：https://www.cnblogs.com/ooo0/p/10535278.html