Develop Reference

Java status 400 for URL

Hello - I'm trying to download a file using Apache commons fileUtils but it always ends up getting a 400 error. The file's URL is valid because I successfully downloaded it many times using the browser. Any ideas?
java.io.IOException: Server returned HTTP response code: 400 for URL:
http://www.nikaia-hosp.gr/img/ΤΕΛΙΚΕΣ ΠΡΟΔΙΑΓΡΑΦΕΣ ΓΙΑ ΥΠΕΡΗΧΟ
ΓΥΝΑΙΚΟΛΟΓΙΚΟ ΜΑΙΕΥΤΙΚΟ ΠΡΟΓΕΝΝΗΤΙΚΟΥ ΕΛΕΓΧΟΥ.pdf at
sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1894)
at
sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1492)
at java.net.URL.openStream(URL.java:1045) at
org.apache.commons.io.FileUtils.copyURLToFile(FileUtils.java:1478) at
com.nikaia.main.NikaiaReader.Downloader.download(Downloader.java:17)
at com.nikaia.main.NikaiaReader.Downloader.main(Downloader.java:32)
import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import org.apache.commons.io.FileUtils;
public class Downloader {
public static void download(String url,String filename){
//System.out.println("filename is : "+filename);
try {
// FileUtils.copyURLToFile(new URL(url), new File("C:/downloads/"+filename));
FileUtils.copyURLToFile(new URL(url), new File(PropertyReader.readProperty("ExtractedFilesPath")+"/"+filename));
try {
Thread.sleep(Integer.parseInt(PropertyReader.readProperty("downloadTimeout"))*1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String ar[]){
download("http://www.nikaia-hosp.gr/img/ΤΕΛΙΚΕΣ ΠΡΟΔΙΑΓΡΑΦΕΣ ΓΙΑ ΥΠΕΡΗΧΟ ΓΥΝΑΙΚΟΛΟΓΙΚΟ ΜΑΙΕΥΤΙΚΟ ΠΡΟΓΕΝΝΗΤΙΚΟΥ ΕΛΕΓΧΟΥ.pdf","stupid.pdf");
}
}

OK answer found , I checked the encoded browser url and the url that UTF-8 java returns and the difference was that browser had %20 in the url but java had + .
I replaced all + with %20 in java and its working.
import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;
import org.apache.commons.io.FileUtils;
public class Downloader {
public static void download(String url, String filename) {
try {
String base = "http://www.nikaia-hosp.gr/img/";
if (url.contains("http://www.nikaia-hosp.gr/img/")) {
FileUtils.copyURLToFile(
new URL(base + URLEncoder.encode(url.replace(base, ""), "UTF-8").replaceAll("\\+", "%20")),
new File(PropertyReader.readProperty("ExtractedFilesPath") + "/" + filename));
} else {
FileUtils.copyURLToFile(new URL(url),
new File(PropertyReader.readProperty("ExtractedFilesPath") + "/" + filename));
}
try {
Thread.sleep(Integer.parseInt(PropertyReader.readProperty("downloadTimeout")) * 1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String ar[]) {
download(
"http://www.nikaia-hosp.gr/img/ΤΕΛΙΚΕΣ ΠΡΟΔΙΑΓΡΑΦΕΣ ΓΙΑ ΥΠΕΡΗΧΟ ΓΥΝΑΙΚΟΛΟΓΙΚΟ ΜΑΙΕΥΤΙΚΟ ΠΡΟΓΕΝΝΗΤΙΚΟΥ ΕΛΕΓΧΟΥ.pdf",
"stupid.pdf");
}
}

this work for me, the problem was the encoding, you need encode only the path of the url
InputStream in = new URL(url).openStream();
FileUtils.copyToFile(in,new File(filename));
first open a Stream with the url and then copy this stream data in a file. using copyToFile method
your code will be
public static void download(String url,String filename){
try {
//changed this 2 lines
URL encodeUrl = new URL(UriUtils.encodePath(url, "UTF-8"));
InputStream in = encodeUrl.openStream();
FileUtils.copyToFile(in, new File(PropertyReader.readProperty("ExtractedFilesPath")+"/"+filename));
try {
Thread.sleep(Integer.parseInt(PropertyReader.readProperty("downloadTimeout"))*1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String ar[]){
download("http://www.nikaia-hosp.gr/img/ΤΕΛΙΚΕΣ ΠΡΟΔΙΑΓΡΑΦΕΣ ΓΙΑ ΥΠΕΡΗΧΟ ΓΥΝΑΙΚΟΛΟΓΙΚΟ ΜΑΙΕΥΤΙΚΟ ΠΡΟΓΕΝΝΗΤΙΚΟΥ ΕΛΕΓΧΟΥ.pdf","stupid.pdf");
}
and add this dependency to your pom.xml
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>3.0.4.RELEASE</version>
</dependency>
this does the magic.
UriUtils.encodePath(host+path, "UTF-8");

Error: java.io.IOException: Type mismatch in key from map: expected org.apache.hadoop.io.Text, received org.apache.hadoop.io.LongWritable

I am new to hadoop and trying to run a sample program from book. I am facing error
Error: java.io.IOException: Type mismatch in key from map: expected org.apache.hadoop.io.Text, received org.apache.hadoop.io.LongWritable
Below is my code
package com.hadoop.employee.salary;
import java.io.IOException;
import org.apache.hadoop.io.FloatWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
public class AvgMapper extends Mapper<LongWritable,Text,Text,FloatWritable>{
public void Map(LongWritable key,Text empRec,Context con) throws IOException,InterruptedException{
String[] word = empRec.toString().split("\\t");
String sex = word[3];
Float salary = Float.parseFloat(word[8]);
try {
con.write(new Text(sex), new FloatWritable(salary));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
package com.hadoop.employee.salary;
import java.io.IOException;
import org.apache.hadoop.io.FloatWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;
public class AvgSalReducer extends Reducer<Text,FloatWritable,Text,Text> {
public void reduce(Text key,Iterable<FloatWritable> valuelist,Context con)
throws IOException,
InterruptedException
{
float total =(float)0;
int count =0;
for(FloatWritable var:valuelist)
{
total += var.get();
System.out.println("reducer"+var.get());
count++;
}
float avg =(float) total/count;
String out = "Total: " + total + " :: " + "Average: " + avg;
try {
con.write(key,new Text(out));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
package com.hadoop.employee.salary;
import java.io.IOException;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
public class AvgSalary {
public static void main(String[] args) throws IOException {
// TODO Auto-generated method stub
if(args.length!=2)
{
System.out.println("Please provide twp parameters");
}
Job job = new Job();
job.setJarByClass(AvgSalary.class);//helps hadoop in finding the relevant jar if there are multiple jars
job.setJobName("Avg Salary");
job.setMapperClass(AvgMapper.class);
job.setReducerClass(AvgSalReducer.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(Text.class);
//job.setMapOutputKeyClass(Text.class);
//job.setMapOutputValueClass(FloatWritable.class);
FileInputFormat.addInputPath(job, new Path(args[0]));
FileOutputFormat.setOutputPath(job,new Path(args[1]));
try {
System.exit(job.waitForCompletion(true)?0:1);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

In your mapper you've called the map method Map, it should be map. Because of this it will be calling the default implementation, since you aren't overriding the map method. Which results in the same input key/value types coming in being emitted, thus they key is a LongWritable.
Changing the name to map should fix this error.

Unknown host RMI java

I get an unknown host error when I try to start an RMI server
here. The error is unknown host. Actually, I'm just a beginner in RMI and sockets programming in JAVA. Can you please provide me with some tutorials
concerning my problem.
My interface code:
package ApplicationServer;
import java.io.File;
import java.rmi.RemoteException;
import java.sql.ResultSet;
public interface Méthodes {
public String authentification(String login, String mdp) throws RemoteException;
public ResultSet selection(String requete) throws RemoteException;
public int miseAjour(String requete) throws RemoteException;
public String envoyerFichier(File fichier) throws RemoteException;
}
In this class I have all the methods that I need in my program:
package ApplicationServer;
import java.io.File;
import java.rmi.RemoteException;
import java.rmi.server.UnicastRemoteObject;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class Traitements extends UnicastRemoteObject implements Méthodes {
private Connection cnx;
private Statement stm;
private ResultSet rst;
private int rs;
public void setCnx(Connection cnx) {
this.cnx = cnx;
}
public void setStm(Statement stm) {
this.stm = stm;
}
public void setRst(ResultSet rst) {
this.rst = rst;
}
public void setRs(int rs) {
this.rs = rs;
}
protected Traitements() throws RemoteException {
super();
// TODO Auto-generated constructor stub
}
#Override
public String authentification(String login, String mdp) throws RemoteException {
// TODO Auto-generated method stub
try {
setCnx(null);
setStm(null);
setRst(null);
Class.forName("com.mysql.jdbc.Driver");
cnx=DriverManager.getConnection("jdbc:mysql://localhost:3306/banque","root","");
stm=cnx.createStatement();
rst=stm.executeQuery("select md5('"+mdp+"');");
while(rst.next()){
mdp=rst.getString(1);
}
stm.clearBatch();
stm=cnx.createStatement();
setRst(null);
String Query = "select * from utilisateurs where login like '"+login+"' and motdepasse like '"+mdp+"';";
rst=stm.executeQuery(Query);
int id = 0;
String nm = null;
String prm = null;
while(rst.next()){
id = rst.getInt("id");
nm = rst.getString("nom");
prm = rst.getString("prenom");
}
if(id>0 && nm!=null && prm!=null){
return id+" "+nm+" "+prm;
}
}catch (SQLException | ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
#Override
public ResultSet selection(String requete) throws RemoteException {
try{
setCnx(null);
setStm(null);
setRst(null);
Class.forName("com.mysql.jdbc.Driver");
cnx=DriverManager.getConnection("jdbc:mysql://localhost:3306/banque","root","");
stm=cnx.createStatement();
rst=stm.executeQuery(requete);
}catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return rst;
}
#Override
public int miseAjour(String requete) throws RemoteException {
try{
setCnx(null);
setStm(null);
setRs(0);
Class.forName("com.mysql.jdbc.Driver");
cnx=DriverManager.getConnection("jdbc:mysql://localhost:3306/banque","root","");
stm=cnx.createStatement();
rs=stm.executeUpdate(requete);
}catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return rs;
}
#Override
public String envoyerFichier(File fichier) throws RemoteException {
// TODO Auto-generated method stub
return null;
}
}
This is the main class that runs the server:
package ApplicationServer;
import java.net.MalformedURLException;
import java.rmi.Naming;
import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import javax.swing.JOptionPane;
public class Main {
public static void main(String[] args) {
// TODO Auto-generated method stub
try {
int port=12345;
String url="rmi://serveur:"+port+"/reference";
LocateRegistry.createRegistry(port);
Traitements srv = new Traitements();
Naming.rebind(url, srv);
JOptionPane.showMessageDialog(null, "Serveur Lance :");
} catch (RemoteException | MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

You are supposed to replace serveur with a real hostname in that code.
However it's far better to use localhost in the RMI URL when binding. The Registry has to be local to the host anyway so there's no point in using anything else.

How to write into the USB (External storage)

I am trying to copy a file from my computer to USB in java. The problem is, the code creates a file on the Usb but the content of the file is not copied from source to destination(computer to usb). How can i do that?
I want the filename R.java to be copied into the usb as system.txt.
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.channels.FileChannel;
public class R {
private static File to;
public static void main(String[] args) {
// current working dir where there is file u want to replicate
File f = new File("." + "/R.java");
// destination location
File so = new File("/media");
for (File s : so.listFiles()) {
String r = s.getName();
to = new File("/media/" + r + "/system.txt");
if (!to.exists()) {
try {
to.createNewFile();
} catch (IOException e) {
// TODO Auto-generated catch block
System.out
.print(to.getName() + " " + e.getMessage() + "\n");
}
}
if (f.exists()) {
FileChannel is = null;
FileChannel os = null;
try {
is = new FileInputStream(f).getChannel();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
os = new FileOutputStream(to).getChannel();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
os.transferFrom(is, 0, is.size());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
I am on LINUX machine

Java program terminating after ObjectMapper.writeValue(System.out, responseData) - Jackson Library

I'm using the Jackson library to create JSON objects, but when I use the mapper.writeValue(System.out, responseData) function, the program terminates. Here is my code:
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import org.codehaus.jackson.JsonGenerationException;
import org.codehaus.jackson.map.JsonMappingException;
import org.codehaus.jackson.map.ObjectMapper;
public class Test {
public static void main(String[] args){
new Test().test();
}
public void test() {
ObjectMapper mapper = new ObjectMapper();
Map<String, Object> responseData = new HashMap<String, Object>();
responseData.put("id", 1);
try {
mapper.writeValue(System.out, responseData);
System.out.println("done");
} catch (JsonGenerationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (JsonMappingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}.
}
After this executes, the console shows {"id":1}, but does not show "done".

The problem is with the Jackson implementation, as ObjectMapper._configAndWriteValue calls UtfGenerator.close(), which calls PrintStream.close().
I'd log an issue at https://jira.codehaus.org/browse/JACKSON
To change the default behavior of target being closed you can do the following:
mapper.configure(JsonGenerator.Feature.AUTO_CLOSE_TARGET, false);

While declaring variable names in your data files/getter files, the first letter should be small.