Java FileOutputStream字符串写入 [英] Java FileOutputStream String Writing

问题描述

我一直有一个Java文件的问题。它被设计成在测试文件中作为日志逐行写入。不幸的是，每次我打电话时都会覆盖同一行。

如果有人能帮忙，我会永远感激的，因为这已经把我推上了墙！

$ b

代码如下。

  public abstract class Log {
 
保护静态字符串DefaultLogFileLocation =c：\\LOG.txt; 
 
 public static void ToFile（String pInputString）{
 FileOutputStream pOUTPUT; 
 PrintStream pPRINT; 
尝试
 {
 pOUTPUT = new FileOutputStream（DefaultLogFileLocation）; 
 pPRINT = new PrintStream（pOUTPUT）; 
 pPRINT.println（pInputString +\\\
）; 
 pPRINT.close（）; 
 
 catch（Exception e）
 {
 System.err.println（写入文件时出错）; 
 
 
 
 
 $ div class =h2_lin>解决方案 
 pre pre $ pOUTPUT = new FileOutputStream（DefaultLogFileLocation ，真）; 
  

另外，为什么不使用一些Java记录框架？例如。 java.util.logging 或< a href =http://logging.apache.org/log4j/1.2/index.html =noreferrer> log4j

log4j配置写入文件：

 < log4j：configuration xmlns：log4j =http ：//jakarta.apache.org/log4j/> 
< appender name =consoleclass =org.apache.log4j.ConsoleAppender> 
< param name =Targetvalue =System.out/> 
< layout class =org.apache.log4j.PatternLayout> 
< param name =ConversionPatternvalue =％ -  5p％c {1}  - ％m％n/> 
< / layout> 
< / appender> 
 
< appender name =FILEclass =org.apache.log4j.DailyRollingFileAppender> 
< param name =filevalue =C：\\LOG.TXT/> 
< param name =datePatternvalue ='。yyyy -MM/> 
< param name =appendvalue =true/> 
< layout class =org.apache.log4j.PatternLayout> 
< param name =ConversionPatternvalue =％d [％t]％-5p％C {6}（％F：％L） - ％m％n/> 
< / layout> 
< / appender> 
< root> 
< priority value =debug/> 
< appender-ref ref =FILE/> 
< appender-ref ref =console/> 
< / root> 
  

I’ve been having issues with a Java File. It's designed to write line after line in a test file as a log. Unfortunately it overwrites the same line every time I call it.

If anyone can help I would be eternally grateful as this has been driving me up the wall!

Code Below.

public abstract class Log {

    protected static String DefaultLogFileLocation = "c:\\LOG.txt";

    public static void ToFile(String pInputString) {
        FileOutputStream pOUTPUT;
        PrintStream pPRINT;
        try
        {
            pOUTPUT = new FileOutputStream(DefaultLogFileLocation);
            pPRINT = new PrintStream(pOUTPUT);
            pPRINT.println (pInputString + "\n");
            pPRINT.close();
        }
        catch (Exception e)
        {
            System.err.println ("Error writing to file");
        }
    }
}

解决方案

You forgot to pass constructor parameter to specify you need to append data to file.

pOUTPUT = new FileOutputStream(DefaultLogFileLocation, true);

Also, why you don't use some Java Logging Framework? E.g. java.util.logging or log4j

Example of log4j configuration to write to file:

<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
  <appender name="console" class="org.apache.log4j.ConsoleAppender"> 
    <param name="Target" value="System.out"/> 
    <layout class="org.apache.log4j.PatternLayout"> 
      <param name="ConversionPattern" value="%-5p %c{1} - %m%n"/> 
    </layout> 
  </appender> 

  <appender name="FILE" class="org.apache.log4j.DailyRollingFileAppender">
    <param name="file" value="C:\\LOG.TXT" />
    <param name="datePattern" value="'.'yyyy-MM" />
    <param name="append" value="true" />
    <layout class="org.apache.log4j.PatternLayout">
      <param name="ConversionPattern" value="%d [%t] %-5p %C{6} (%F:%L) - %m%n"/> 
    </layout>
  </appender> 
  <root> 
    <priority value ="debug" /> 
    <appender-ref ref="FILE" /> 
    <appender-ref ref="console" /> 
  </root>

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