load file within a jar
String examplejsPrefix = "example";
String examplejsSuffix = "js";
String examplejs = examplejsPrefix + "." + examplejsSuffix;
try {
// save it as a temporary file so the JVM will handle creating it and deleting
File file = File.createTempFile(examplejsPrefix, examplejsSuffix);
file.deleteOnExit();
OutputStream out = new FileOutputStream(file);
InputStream in = getClass().getResourceAsStream("/com/" + examplejs);
int len = 0;
byte[] buffer = new byte[1024];
while ((len = in.read(buffer)) != -1) {
out.write(buffer, 0, len);
}
out.close();
in.close();
} catch (Exception e) {
e.printStackTrace();
}
===============
https://alvinalexander.com/blog/post/java/read-text-file-from-jar-file
Java jar file reading FAQ: Can you show me how a Java application can read a text file from own of its own Jar files?
Here's an example of some Java code I'm using to read a file (a text file) from a Java Jar file. This is useful any time you pack files and other resources into Jar files to distribute your Java application.
How to read a Java Jar file, example #1
The source code to read a file from a Java Jar file uses the getClass
and getResourceAsStream
methods:
public void test3Columns()
throws IOException
{
InputStream is = getClass().getResourceAsStream("3Columns.csv");
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
String line;
while ((line = br.readLine()) != null)
{
CSVLineTokenizer tok = new CSVLineTokenizer(line);
assertEquals("Should be three columns in each row",3,tok.countTokens());
}
br.close();
isr.close();
is.close();
}
The trick to reading text files from JAR files are these lines of code, especially the first line:
InputStream is = getClass().getResourceAsStream("3Columns.csv");
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
In my example I have a plain text file named "3Columns.csv
" in the same directory as the class that contains this method. Without a path stated before the filename (like "/foo/bar/3Columns.csv
") the getResourceAsStream
method looks for this text file in its current directory.
Note that I'm doing all of this within the context of a JUnit test method. Also note that I'm throwing any exceptions that occur rather than handling them. I don't recommend this for real world programming, but it works okay for my unit testing needs today.
I haven't read through the Javadocs yet to know if all of those close
statements at the end are necessary. I'll try to get back to that later.
Java: How to read a Jar file, example #2
Here is a slightly more simple version of that method:
public String readFromJARFile(String filename)
throws IOException
{
InputStream is = getClass().getResourceAsStream(filename);
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
StringBuffer sb = new StringBuffer();
String line;
while ((line = br.readLine()) != null)
{
sb.append(line);
}
br.close();
isr.close();
is.close();
return sb.toString();
}
In this sample I've eliminated the CSVLineTokenizer and replaced it with a simple StringBuffer
, and I return a plain old String
at the end of the method.
Also, if I didn't stress it properly earlier, with this approach the resource file that you're trying to read from must be in the same directory in the jar file as this class. This is inferred by the getClass().getResourceAsStream()
method call, but I don't think I really stressed that enough earlier.
Also, I haven't looked at it in a while, but I think you can just call the is.close()
method to close all your resources, you don't have to make all the close
calls I make here, but I'm not 100% positive.
Reading a file from a jar file as a File
Here's one more example of how to do this, this time using some code from a current Scala project:
val file = new File(getClass.getResource("zipcode_data.csv").toURI)
Although the code shown is Scala, I think you can see that you can use this approach to read the file as a java.io.File instead of reading it as a stream.
One more Java "read from Jar file" example
While I'm working on another Java project, I just ran across another example of how to read a file from a Java jar file in this method:
private void playSound(String soundfileName)
{
try
{
ClassLoader CLDR = this.getClass().getClassLoader();
InputStream inputStream = CLDR.getResourceAsStream("com/devdaily/desktopcurtain/sounds/" + soundfileName);
AudioStream audioStream = new AudioStream(inputStream);
AudioPlayer.player.start(audioStream);
}
catch (Exception e)
{
// log this
}
}
As you can guess from looking at this code, this example shows how to read a resource file from a jar file in a java application, and in this approach, the resource file that I'm reading doesn't have to be in the same directory as the Java class file. As you can imagine, this is a much more flexible approach.
load file within a jar的更多相关文章
- configuration error-could not load file or assembly crystaldecisions.reportappserver.clientdoc
IIS启动网站后报错: configuration error Could not load file or assembly 'crystaldecisions.reportappserver.cl ...
- Could not load file or assembly 'Microsoft.ReportViewer.WebForms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its de
页面加载时出现这个错误: Could not load file or assembly 'Microsoft.ReportViewer.WebForms, Version=10.0.0.0, Cul ...
- Could not load file or assembly 'System.ServiceModel.DomainServices.Hosting'.系统找不到指定文件
项目部署到服务器后出现如下错误信息: Parser Error Message: Could not load file or assembly 'System.ServiceModel.Domain ...
- ASP.NET corrupt assembly “Could not load file or assembly App_Web_*
以下是从overFlow 复制过来的问题 I've read through many of the other questions posted on the same issue, but I s ...
- Could not load file or assembly 'Microsoft.SqlServer.Management.Sdk.Sfc, Version=11.0.0.0 系统找不到指定的文件。
环境: web服务器: ip:192.168.1.32 ,安装有 Visual Studio Premium 2013 操作系统: Microsoft Server 2008 r2+sp1 数据库服 ...
- NopCommerce 发布时 Could not load file or assembly 'file:///...\Autofac.3.5.2\lib\net40\Autofac.dll' or one of its dependencies
本文转自:http://www.nopcommerce.com/boards/t/33637/4-errors.aspx 问题: The 3.5 solution compiles fine, and ...
- Could not load file or assembly 'MySql.Data.CF,
Could not load file or assembly 'MySql.Data.CF, Version=6.4.4.0, Culture=neutral, PublicKeyToken=c56 ...
- Could not load file or assembly 'System.Data.SQLite' or one of its dependencies
试图加载格式不正确的程 异常类型 异常消息Could not load file or assembly 'System.Data.SQLite' or one of its dependencies ...
- System.BadImageFormatException: Could not load file or assembly
C:\Windows\Microsoft.NET\Framework64\v4.0.30319>InstallUtil.exe C:\_PRODUKCIJA\Debug\DynamicHtmlT ...
随机推荐
- Redis开发与运维
常用命令 redis-server启动redis redis-server /opt/redis/redis.conf 配置启动 redis-server --port 6379 --dir / ...
- 《Netty权威指南》目录
一.基础篇 走进Java NIO 1. Java 的 I/O 演进之路:https://www.cnblogs.com/zengzhihua/p/9930652.html 2. NIO 入门:http ...
- Solidity字符串和函数
字符串:需要使用双引号""或者单引号''括起来,例如:定义一个字符串变量:string name="jake":string字符串不能通过length方法获得长 ...
- ASP.NET MVC View中的标签(tag)
在编辑View的时候会用到各种HTML标签,如<a>,<input>,<p>等待,这些标签在ASP.NET MVC中都有对应的编程语法,它叫Razor,它是帮助我们 ...
- BIO与NIO、AIO的区别(这个容易理解)
转自:http://blog.csdn.net/skiof007/article/details/52873421 BIO与NIO.AIO的区别(这个容易理解) IO的方式通常分为几种,同步阻塞的BI ...
- mac 入门操作
1. 打开制定目录 在finder里使用command+shift+g 快捷键可以完成到达某路径的操作选中文件/目录,显示简介可以查看路径 2. home end pageUp pageDown 在苹 ...
- 【Vue】v-if与v-show的区别
相同点:v-if与v-show都可以动态控制dom元素显示隐藏 不同点:v-if显示隐藏是将dom元素整个添加或删除,而v-show隐藏则是为该元素添加css--display:none,dom元素还 ...
- iphone safari浏览器CSS兼容性的解决方案集合
1.iphone safari不兼容CSS的active的解决方案如下: <body ontouchstart="" onmouseover=""> ...
- C# serialPort的DataReceived事件无法触发 ,用的霍尼韦尔的扫码枪并且装了相应的USB转串口驱动。
昨天想试试霍尼韦尔的扫码枪,扫码枪有两种模式,键盘模式和串口模式, 1.键盘模式直接插上就行了,就像一个键盘一样不需要任何驱动,扫出来的数据直接落到PC的输入焦点上.就像一个键盘一样,只能输入字符. ...
- python基础训练题1-列表操作
1,在列表末尾添加一个值 >>> l = [ 10, 20 ] >>> l [10, 20] >>> l.append( 'ghostwu' ) ...