在maven项目的servlet使用fastjson无法传送数据给前端

  • Z时代
  • 2024-01-10
  • 分类：IT

package com.mvc.servlet;
import com.mvc.bean.Goods;
import com.mvc.bean.GoodsItem;
import com.mvc.dao.GoodsDao;
import com.mvc.impl.GoodsDaoImpl;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Map;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.serializer.JSONLibDataFormatSerializer;
import com.alibaba.fastjson.serializer.JSONSerializerMap;
import com.alibaba.fastjson.serializer.SerializerFeature;
import java.io.PrintWriter;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpSession;
import com.mvc.bean.Student;
public class GetGoodsServlet  extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        doPost(request, response);
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        //得到编号
        String goodsName = request.getParameter("goodsName");
        System.out.println(goodsName);
        String output = "后台返回的结果加上前台的结果";
        Student student = new Student(0, "Aaron", 24);
        System.out.println(JSON.toJSONString(student));
        response.getWriter().write(JSON.toJSONString(student));
    }
}

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    function ajax(){
        var ajaxData = {
            type:arguments[0].type || "GET",
            url:arguments[0].url || "",
            async:arguments[0].async || "true",
            data:arguments[0].data || null,
            dataType:arguments[0].dataType || "text",
            contentType:arguments[0].contentType || "application/x-www-form-urlencoded",
            beforeSend:arguments[0].beforeSend || function(){},
            success:arguments[0].success || function(){},
            error:arguments[0].error || function(){}
        }
        ajaxData.beforeSend()
        var xhr = createxmlHttpRequest();
        xhr.responseType=ajaxData.dataType;
        xhr.open(ajaxData.type,ajaxData.url,ajaxData.async);
        xhr.setRequestHeader("Content-Type",ajaxData.contentType);
        //xhr.send(convertData(ajaxData.data));
        xhr.send("goodsName="+"youda");
        xhr.onreadystatechange = function() {
            console.log(xhr.readyState)
            if (xhr.readyState == 4) {
                console.log(xhr.status)
                if(xhr.status == 200){
                    console.log(XMLHttpRequest);
                    ajaxData.success(xhr.response)
                }else{
                    ajaxData.error()
                }
            }
        }
    }
    function createxmlHttpRequest() {
        if (window.ActiveXObject) {
            return new ActiveXObject("Microsoft.XMLHTTP");
        } else if (window.XMLHttpRequest) {
            return new XMLHttpRequest();
        }
    }
    function convertData(data){
        if( typeof data === 'object' ){
            var convertResult = "" ;
            for(var c in data){
                convertResult+= c + "=" + data[c] + "&";
            }
            convertResult=convertResult.substring(0,convertResult.length-1)
            return convertResult;
        }else{
            return data;
        }
    }
    ajax({
        type:"POST",
        url:"getGoods",
        dataType:"json",
        data:{"val1":"abc","val2":123,"val3":"456"},
        beforeSend:function(){
            //some js code
        },
        success:function(msg){
            console.log(msg)
        },
        error:function(){
            console.log("error")
        }
    })
</script>
<div><button id="getGoods" value="显示全部商品" onclick="getInfoByName()">点击商品全部</button></div>
</body>
</html>

package com.mvc.bean;
public class Student {
    private int id;
    private String name;
    private int age;
    /**
     * 默认的构造方法必须不能省，不然不能解析
     */
    public Student(){
    }
    public Student(int id,String name,int age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    @Override
    public String toString() {
        return "Student [id=" + id + ", name=" + name + ", age=" + age + "]";
    }
}

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回答：

你这个问题和fastjson没太大关系
1.你需要现保证后台的数据能传到前台，比如console.info(xxx)能打印出来
2.第一步搞定后，再把你的对象搞成你的业务数据，就是那个json形式的字符串，剩下的就是前段的json数据处理了

加油，你行滴！

回答：

根据发出来异常

1.首先要解决的是，你没有成功引入fastJson包。rootCase提示NoClassDefFoundError， 可能是部署的时候没打包成功。试下更新下你的依赖？

回答：

异常信息显示找不到FastJSON相关的类,检查一下相关jar包是否已经引入...

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