MongoDB数据库（JSON）和Echarts-gl映射实例2-CFANZ编程社区

接着上篇导入数据

此篇内容为，用JAVA连接MongoDB，接着在浏览器里通过地址栏提取出数据。

结果

浏览器地址栏输入：http://localhost/test/lbsA
返回如下结果，“data”，“machineIdentifier”,“counter”,“processIdentifier”,“time”,“timeSecond”,“timestamp”这些文档并不是数据里的。我认为是Http里respon的头。没影响我暂时不管它
MongoDB数据库（JSON）和Echarts-gl映射实例2_mongodb

电脑环境
  Java-Jdk：jdk1.8.0_131/jre1.8.0_131
  Java-IDE：Eclipse IDE for Enterprise Java Developers - 2019-12
  Servlet：apache-tomcat-9.0.19

新建两个Java包，com.fossil.dao和com.fossil.servlet，还有在WebContent/WEB-INF目录下创建web.xml文件

com.fossil.dao包内容如下

MongoDao.java

package com.fossil.dao;

import org.bson.Document;

import com.mongodb.MongoClient;
import com.mongodb.client.FindIterable;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;

public class MongoDao {
  
  public FindIterable<Document> find(){
    //创建MongoDB连接
    MongoClient mc = new MongoClient("localhost",27017);
    
    //创建MongoDB数据库
    MongoDatabase db = mc.getDatabase("dbo");
    
    //创建数据库服务连接对象MongoCollection
    MongoCollection<Document> collection =db.getCollection("data");
    
    //
    FindIterable<Document> find = collection.find();
    return find;
  }
}

com.fossil.servlet包内容如下

LbsAction.java
新建servlet。纯手打可能会报错

package com.fossil.servlet;

import java.io.IOException;

import javax.servlet.ServletContext;
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.bson.Document;

import com.alibaba.fastjson.JSON;
import com.fossil.dao.MongoDao;
import com.mongodb.client.FindIterable;
import com.mongodb.client.MongoCursor;

/**
 * Servlet implementation class LbsAcition
 */
@WebServlet("/LbsAcition")
public class LbsAcition extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public LbsAcition() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        //实例化MongoDao
        response.setCharacterEncoding("utf-8");
        MongoDao md =new MongoDao();
        FindIterable<Document> find= md.find();
        MongoCursor<Document> cursor=find.iterator();
        
        String json = JSON.toJSON(cursor).toString();
        response.getWriter().println(json);
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(request, response);
    }

}

web.xml内容如下

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <display-name>demo</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  <servlet>
    <servlet-name>LbsAcition</servlet-name>
    <servlet-class>com.fossil.servlet.LbsAcition</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>LbsAcition</servlet-name>
    <url-pattern>/lbsA</url-pattern>
  </servlet-mapping>
</web-app>