bufferedwriter

问题 Please have a look at the following code import java.io.*; public class CSVConverter { private File csvFile; private BufferedReader reader; private StringBuffer strBuffer; private BufferedWriter writer; int startNumber = 0; private String strString[]; public CSVConverter(String location, int startNumber) { csvFile = new File(location); strBuffer = new StringBuffer(""); this.startNumber = startNumber; //Read try { reader = new BufferedReader(new FileReader(csvFile)); String line = ""; while(

问题 I have a program that add persons to an arraylist. What I'm trying to do is add these persons to a text file as well but the program overwrites the first line so the persons get erased. How do I tell the compiler to write at the next free line? import java.io.*; import java.util.*; import javax.swing.JTextArea; public class Logic { File file; FileWriter fw; FileReader fr; BufferedWriter bw; ArrayList<Person> person; public Logic() { try { file = new File("register.txt"); if (!file.exists()) {

问题 I have a program that add persons to an arraylist. What I'm trying to do is add these persons to a text file as well but the program overwrites the first line so the persons get erased. How do I tell the compiler to write at the next free line? import java.io.*; import java.util.*; import javax.swing.JTextArea; public class Logic { File file; FileWriter fw; FileReader fr; BufferedWriter bw; ArrayList<Person> person; public Logic() { try { file = new File("register.txt"); if (!file.exists()) {

问题 I'm trying to write sample file from applet but is not working. Below is the code. Applet public class PasteImageApplet extends JApplet { Clipboard clipboard; Toolkit toolkit; JLabel lbl; public String getClipboardImageURL(String server) { lbl.setText("pasting image"); String url = ""; try { DataFlavor dataFlavor = DataFlavor.imageFlavor; System.out.println(dataFlavor.getDefaultRepresentationClass()); Object object = null; try { object = clipboard.getContents(null) .getTransferData(dataFlavor

问题 So I'm using a BufferedWriter and would like to write some text to a text file. try { BufferedWriter b = new BufferedWriter(new FileWriter ("/home/usr/Desktop/logger/logs.txt")); b.write("hello"); } catch (Exception e1) { e1.printStackTrace(); } For some reason the text document is being created but nothing is being written to it, why is this? 回答1: You need to close BufferedWriter , or use try-with-resource BufferedWriter b = new BufferedWriter( new FileWriter ("/home/usr/Desktop/logger/logs

问题 I was trying some stuff in Swing (Java), but getting very strange results. I am getting a String from JTextArea.getText() method and adding "\n" to it. This resultant string I am writing into a file, using BufferedWriter which is chaining through FileOutputStream to a file. But the new line character "\n" is not creating new line in the .txt file. How can I fix this issue? My Code is here: package quizCardGame; import java.awt.*; import java.awt.event.*; import java.io.*; import java.util

问题 Here is the code snippet. read = new FileReader("trainfiles/"+filenames[i]); br = new BufferedReader(read); while((lines = br.readLine())!=null){ st = new StringTokenizer(lines); while(st.hasMoreTokens()){ bw = new BufferedWriter(new FileWriter("files/file.txt")); bw.write(st.nextToken()); bw.newLine(); } } Edit: I am reading files from a directory. So, I need to open the reader in every loop. I have made some modification, but then also it is not writing to that file. Here is the code: for(i

问题 Here is the code snippet. read = new FileReader("trainfiles/"+filenames[i]); br = new BufferedReader(read); while((lines = br.readLine())!=null){ st = new StringTokenizer(lines); while(st.hasMoreTokens()){ bw = new BufferedWriter(new FileWriter("files/file.txt")); bw.write(st.nextToken()); bw.newLine(); } } Edit: I am reading files from a directory. So, I need to open the reader in every loop. I have made some modification, but then also it is not writing to that file. Here is the code: for(i

问题 This question already has answers here : Correct way to close nested streams and writers in Java [duplicate] (10 answers) Closed 4 years ago . Consider a BufferedReader as below: writer = new BufferedWriter(new FileWriter(new File("File.txt"), true)); In this case at the end of the application, I am closing the writer with writer.close() Will this be enough? Won't that FileWriter created with new FileWriter(new File("File.txt"), true) need to be closed? 回答1: It is not necessary to close it,

问题 I am trying to write a single huge file in Java using multiple threads. I have tried both FileWriter and bufferedWriter classes in Java. The content being written is actually an entire table (Postgres) being read using CopyManager and written. Each line in the file is a single tuple from the table and I am writing 100s of lines at a time. Approach to write: The single to-be-written file is opened by multiple threads in append mode. Each thread thereafter tries writing to the file file.