JAVA--将MongoDB数据写出到CSV

package com.ReadMongodbToCsv;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.net.UnknownHostException;
import java.util.ArrayList;

import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.Mongo;

public class WriteCsv {
private static Mongo mg;
private static DB db;
private static BufferedWriter bw ;
public static void main(String args[]){
initToMongoDB();
try {
bw = new BufferedWriter(new FileWriter(new File("F:/vv.csv")));
DBCollection dd = db.getCollection("zq2");
DBCursor dc = dd.find();
int num = 0;
while(dc.hasNext()){
num++;
BasicDBObject basi = (BasicDBObject)dc.next();
ArrayList<BasicDBObject> list = (ArrayList<BasicDBObject>)basi.get("l");
String ss = "";
StringBuffer sb = new StringBuffer();
sb.append(basi.get("z") + ",");
sb.append(basi.get("n") + ",");
for(BasicDBObject b : list){
sb.append(b.get("n") + ",");
sb.append(b.get("t") + ",");
}
sb = sb.deleteCharAt(sb.length() - 1);
bw.write(sb.toString() + "\r\n");
if(num % 10000 == 0){
bw.flush();
}
}
System.out.println("写入完成");
} catch (IOException e) {
e.printStackTrace();
}finally{
if(bw != null){
try {
bw.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

}

public static void initToMongoDB(){
try {
mg = new Mongo("localhost",27017);
db = mg.getDB("admin");
boolean auth = db.authenticate("root", "root".toCharArray());
if(auth){
db = mg.getDB("test");
}else{
System.err.println("mongodb链接失败");
}
} catch (UnknownHostException e) {
e.printStackTrace();
}
}
}