echarts在java中与后台交互

完整流程：

    python爬取股票信息-------将信息保存到数据库----------通过ajax发送post请求到java后台-----java后台连接数据库获取到数据库信息-------通过echarts进行展示（柱状图、折线图）

python爬取股票信息就不贴代码了，主要是后面的。

jsp

1、通过ajax发送post请求到后台获取数据进行展示

<%@ page language="java" contentType="text/html; charset=UTF-8"  
    pageEncoding="UTF-8"%>  
<%  
    String path = request.getContextPath();  
    String basePath = request.getScheme() + "://" + request.getServerName()  
            + ":" + request.getServerPort() + path + "/";  
%>  
 
 
     
     
     
     
     
 
 
     
   

 
     
 

2、barCandBean.java

package com.helloBar;
public class barCandBean {
private String day;
private String shoupan;
private String kaipan;
private String heightmax;
//private String slowmin;
public String getDay() {
return day;
}
public String getHeightmax() {
return heightmax;
}
public void setHeightmax(String heightmax) {
this.heightmax = heightmax;
}
public String getShoupan() {
return shoupan;
}
public void setShoupan(String shoupan) {
this.shoupan = shoupan;
}
public void setDay(String day) {
this.day = day;
}
public String getKaipan() {
return kaipan;
}
public void setKaipan(String kaipan) {
this.kaipan = kaipan;
}
}

3、BarCandDao.java

package com.helloBar;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

public class barCandDao {
Connection connection;
public Connection getConnection() {
try {
String name = "xxx";//用户名
String password = "xxx";//密码
String url = "jdbc:mysql://127.0.0.1:3306/stockdatabase";//连接stockdatabase数据库
Class.forName("com.mysql.jdbc.Driver");
connection = DriverManager.getConnection(url, name, password);
} catch (Exception e) {
e.printStackTrace();
}
return connection;
}
public void setConnection(Connection connection) {
this.connection = connection;
}
public ArrayList listAll() {
ArrayList list = new ArrayList();
PreparedStatement pstmt = null;
ResultSet rs = null;

try {

pstmt = this.getConnection().prepareStatement("SELECT * FROM stock_600000");
rs = pstmt.executeQuery();
while (rs.next()) {
barCandBean bar = new barCandBean();
bar.setKaipan(rs.getString("kaipan"));
bar.setDay(rs.getString("day"));
bar.setHeightmax(rs.getString("heightmax"));
bar.setShoupan(rs.getString("shoupan"));
//bar.setSlowmin(rs.getString("slowmin"));
list.add(bar);
System.out.println("连接数据库成功");
}
} catch (Exception e) {
e.printStackTrace();
//System.out.println("连接失败");
} finally {
try {
connection.close();
} catch (Exception e) {
e.printStackTrace();
}
}
return list;
}
}

4、HelloBarCand.java

public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//创建了一个barcanddao的对象，barcanddao主要是对数据库的连接和对数据库的操作
        barCandDao barcanddao=new barCandDao();
        //调用barcanddao的select_all()方法把从数据库中读取所有的数据返回的是一个ArrayList，ArrayList里面放的是一个barBean
        ArrayList array = (ArrayList) barcanddao.listAll();
        System.out.println("s"+array);
        //设置返回时的编码格式
        response.setContentType("text/html; charset=utf-8");
      //调用JSONArray.fromObject方法把array中的对象转化为JSON格式的数组
        JSONArray json=JSONArray.fromObject(array);
        System.out.println(json.toString());
        //返回给前段页面
        PrintWriter out = response.getWriter();  
        out.println(json);  
        out.flush();  
        out.close();   
}

4.web.xml

    helloBarCand
    com.helloBar.helloBarCand
 
 
    helloBarCand
    /bar.do

 

5、数据库表就不进行贴了

//其中Java代码参考其它博客代码，十分感谢~