在线读取Mongodb数据库下载EXCEL文件
版本:Mongodb2.4.8
通过页面下载Excel文件
jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<form method="post">
<a href="/Demo/DownDemo"><h2>下载</h2></a>
</form>
</body>
</html>
Mongodb配置文件dbconfig.properties：
url=localhost port=27017 db=movie table=mv
连接Mongodb工具类:
package util;
import java.io.IOException;
import java.io.InputStream;
import java.net.UnknownHostException;
import java.util.Properties;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.Mongo;
import com.mongodb.MongoException;
public class DBConn {
private static String url;
private static int port;
private static String db;
private static String table;
// 初始化加载
static{
//加载
Properties p = new Properties();
InputStream input = DBConn.class.getClassLoader().getResourceAsStream("dbconfig.properties");
try {
p.load(input);
url = p.getProperty("url");
port = Integer.valueOf(p.getProperty("port"));
db = p.getProperty("db");
table = p.getProperty("table");
} catch (IOException e) {
e.printStackTrace();
}finally{
if (input != null) {
try {
input.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
/**
* 获取连接mongodb
* @Description:
* @param @return
* @return DBCollection 返回类型
*/
public static DBCollection getConn(){
DBCollection conn = null;
try {
Mongo m = new Mongo(url,port);
DB d = m.getDB(db);
conn = d.getCollection(table);
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (MongoException e) {
e.printStackTrace();
}
return conn;
}
/**
* 关闭连接
* @Description:
* @param @param m
* @return void 返回类型
*/
public static void getClose(Mongo m){
m.close();
}
}
读取Mongodb数据写入到excel中:
public class WriteExcelUtils {
/**
* @Description:mongdb中读取数据写入到Excel
* @param title
* @param filename
* @param rownum
* @param cursor
* @return void 返回类型
*/
public static void Excel(DBCursor cursor,OutputStream out) {
Workbook book = new HSSFWorkbook();
// 获取标题
DBObject ob = cursor.toArray().get(0);
ArrayList<String> title = new ArrayList<>();
for(String key:ob.keySet()){
if (key.equals("_id")) {
continue;
}
title.add(key);
}
// 创建sheet
Sheet sheet = book.createSheet();
try {
// 写入标题栏
Row row = null;
// 标题栏的行数
Cell cell = null;
for(int i = 0;i< (cursor.count() + 1);i++){
// 标题栏
if (i == 0) {
row = sheet.createRow(i);
for (int j = 0; j < title.size(); j++) {
cell = row.createCell(j);
// 设置标题栏
cell.setCellValue(title.get(j));
}
continue;
}
// 写入数据
row = sheet.createRow(i);
DBObject obj = null;
for (int j = 0; j < title.size(); j++) {
cell = row.createCell(j);
obj = cursor.toArray().get(j);
for(String key :obj.keySet()){
if (key.equals("_id")) {
continue;
}
if (key.equals(title.get(j))) {
cell.setCellValue((String)(obj.get(key)));
}
}
}
}
// 写入到excel
book.write(out);
} catch (IOException e1) {
e1.printStackTrace();
} finally {
try {
out.flush();
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
Servlet：
package servlet;
import java.io.BufferedOutputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
import util.DBConn;
import util.WriteExcelUtils;
/**
* Servlet implementation class DownDemo
*/
@WebServlet("/DownDemo")
public class DownDemo extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public DownDemo() {
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
doPost(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
getMongodbExcle(request, response);
}
/**
* 从mongdb中读取数据下载到客户端
* @Description:
* @param request
* @param response
* @return void 返回类型
*/
private void getMongodbExcle(HttpServletRequest request, HttpServletResponse response){
// 设置请求
response.setContentType("application/vnd.ms-excel;charset=UTF-8");
response.setHeader("Content-Disposition", "attachment;filename=data.xls");
// 从mongodb中读取数据
DBCollection conn = DBConn.getConn();
DBCursor cursor = conn.find();
OutputStream out = null;
try {
out = new BufferedOutputStream(response.getOutputStream());
} catch (IOException e) {
e.printStackTrace();
}
WriteExcelUtils.Excel(cursor,out);
}
}
