printwriter

PrintWriter add text to file

由 两盒软妹~` 提交于 2020-01-21 08:51:06
问题 In my online computer science class I have to write a program to determine the surface gravity on each planet in the solar system. I have gotten almost every aspect of it to work save one. I need to write the surface gravity to a file using a separate method. This is my current method: public static void writeResultsToFile(double g) throws IOException{ PrintWriter outFile = new PrintWriter(new File("planetaryData.txt")); outFile.printf("%.2f%n", g); outFile.close(); } My problem is that when

深入理解通讯协议学习

由 江枫思渺然 提交于 2020-01-19 23:02:19
目录： 知识架构： 网络模型： Tcp/IP系列协议 tcp的3次握手协议 Tcp的三次握手的漏洞： Tcp的4次挥手协议 抓包工具： 三次握手： TCP的通讯原理： http协议： http协议的报文组成 UDP协议： Tcp通讯代码实战： package io.renren.modules.tcp; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.IOException; import java.io.InputStreamReader; import java.io.OutputStreamWriter; import java.net.ServerSocket; import java.net.Socket; public class IcpServer { public static void main(String[] args ) { //创建一个serverSocker监听一个端口：8888 try { ServerSocket serverSocket = new ServerSocket(8888); System. out .println( "Tcp服务器已经启动，端口8888" ); //无限循环 while ( true ) { //等待客户端的请求

FileWrite BufferedWriter and PrintWriter combined

由 与世无争的帅哥 提交于 2020-01-19 04:59:15
问题 Ok so I am learning about I/O, and I found the following code in one of the slides. can someone please explain why there is a need to have a FileWrite, BufferedWriter and PrintWriter? I know BufferedWriter is to buffer the output and put it all at once but why would they use FileWriter and PrintWriter ? dont they pretty much do the same with a bit of difference in error handling etc? And also why do they pass bw to PrintWriter ? FileWriter fw = new FileWriter (file); BufferedWriter bw = new

FileWrite BufferedWriter and PrintWriter combined

由 时光怂恿深爱的人放手 提交于 2020-01-19 04:59:05
问题 Ok so I am learning about I/O, and I found the following code in one of the slides. can someone please explain why there is a need to have a FileWrite, BufferedWriter and PrintWriter? I know BufferedWriter is to buffer the output and put it all at once but why would they use FileWriter and PrintWriter ? dont they pretty much do the same with a bit of difference in error handling etc? And also why do they pass bw to PrintWriter ? FileWriter fw = new FileWriter (file); BufferedWriter bw = new

Android 全局捕获异常信息-工具类

由 纵饮孤独 提交于 2020-01-18 01:25:59
只是代码的搬运工， import java.io.File; import java.io.FileOutputStream; import java.io.PrintWriter; import java.io.StringWriter; import java.io.Writer; import java.lang.reflect.Field; import java.text.DateFormat; import java.text.SimpleDateFormat; import java.util.Date; import java.util.HashMap; import java.util.Map; public class CrashHandler implements Thread.UncaughtExceptionHandler { public static final String TAG = "CrashHandler"; //系统默认的UncaughtException处理类 private Thread.UncaughtExceptionHandler mDefaultHandler; //CrashHandler实例 private static CrashHandler INSTANCE = new CrashHandler(); /

PrintWriter or any other output stream in Java do not know “\r\n”

由 一世执手 提交于 2020-01-14 09:44:10
问题 I have trouble using PrintWriter or any other output stream to send message between server and client program. It works properly if I use println("abc") to communicate, but it does not work if I use print("abc\r\n"), print("abc\n") or print("abc\r"). What I mean by "it does not work" is that the readLine() will not end because it seems not to see "newline" character and it is still waiting for "\r" or "\n" To make it more clear, I will simply put some codes in the following: The client:

一文看懂HttpServletResponse

由 馋奶兔 提交于 2020-01-10 02:47:35
https://www.jianshu.com/p/8bc6b82403c5 Web服务器收到客户端的http请求，会针对每一次请求，分别创建一个用于代表请求的request对象、和代表响应的response对象。获取网页提交过来的数据，只需要找request对象就行了。要向网页输出数据，只需要找response对象。 一，HttpServletResponse对象介绍 1.jpg HttpServletResponse对象代表服务器的响应。这个对象中封装了向客户端发送数据、发送响应头，发送响应状态码的方法。 二，HttpServletResponse对象常用方法 **1，负责向客户端(浏览器)发送数据的相关方法 ** getOutputStream() 该方法用于返回Servlet引擎创建的字节输出流对象，Servlet程序可以按字节形式输出响应正文。 getWriter() 该方法用于返回Servlet引擎创建的字符输出流对象，Servlet程序可以按字符形式输出响应正文。 注意： 1，getOutputStream()和getWriter()这两个方法 互相排斥 ，调用了其中的任何一个方法后，就不能再调用另一方法。 2，getOutputStream()返回的字节输出流对象，类型为：ServletOutputStream，直接输出字节数组中的 二进制数据 。 3

Passing FileWriter as a parameter to a method

由 微笑、不失礼 提交于 2020-01-04 08:23:44
问题 I'm sure there is a fairly simple answer to this question, so here we go. I'm trying to use a FileWriter to write text to a file. My program reads text in from an already existing file, specified by the user and then asks whether to print the text to the console or to a new file, also to be named by the user. I believe my problem is with passing the FileWriter to the "FileOrConsole" method. Am I not passing or declaring the FileWriter in the "FileOrConsole" method correctly? The file is

Printwriter destination issue

由 不想你离开。 提交于 2020-01-04 01:29:07
问题 I am successfully writing strings to a text file with the PrintWriter, and by default the output text file is written to the directory of the Eclipse project I'm working on. But my Eclipse project has a specific folder called Resources that I want the text file to be written to: My code is: protected void saveCommandsToFile() throws FileNotFoundException, IOException { PrintWriter out = new PrintWriter("commands.txt"); int listsize = list.getModel().getSize(); for (int i=0; i<listsize; i++){

Java PrintWriter FileNotFound

由 谁说胖子不能爱 提交于 2020-01-01 10:27:51
问题 I'm having trouble with writing to a txt file. I am getting a FileNotFound Exception, but I don't know why because the file most definitely is there. Here is the code. import java.io.FileNotFoundException; import java.io.PrintWriter; import java.io.File; public class Save { public static void main(String[] args) { File file = new File("C:/Users/Daniel/Desktop/Programs/Save Data Test/save.txt"); PrintWriter pw = new PrintWriter(file); pw.println("Hello World"); pw.close(); } } 回答1: You must
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