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工程：GetResourceAsStreamDemo
磁盘路径：E:\hotyeWorkspace\webterminal\GetResourceAsStreamDemo
工程目录如下：
1.利用FIle定位：
File txtFile = new File("bin/demo/demo1/1.txt");//这里相当于File txtFile = new File("src/demo/demo1/1.txt"); 因为src的文件会build到bin中
System.out.println("txtFile = " + txtFile);
System.out.println("path = " + txtFile.getCanonicalPath());
System.out.println("file = " + txtFile.isFile());
输出：
txtFile = bin\demo\demo1\1.txt
path = E:\hotyeWorkspace\webterminal\GetResourceAsStreamDemo\bin\demo\demo1\1.txt
file = true
这里，File里面的路径，假如不从"/"开始，就表示相对于当前用户目录（即System.getProperty("user.dir")）
System.out.println("dir = " + System.getProperty("user.dir"));
输出：dir = E:\hotyeWorkspace\webterminal\GetResourceAsStreamDemo
File dotFile = new File(".");//表示当前工程目录，和当前用户目录相同
System.out.println("dotFile = " + dotFile.getCanonicalPath());
File file1 = new File("..");//表示当前工程目录的上一级目录
System.out.println("file1 = " + file1.getCanonicalPath());
File file2 = new File("/");//表示当前工程目录的最顶层目录
System.out.println("file2 = " + file2.getCanonicalPath());
输出：
dotFile = E:\hotyeWorkspace\webterminal\GetResourceAsStreamDemo
file1 = E:\hotyeWorkspace\webterminal
file2 = E:\
因此，
File txtFile = new File("/bin/demo/demo1/1.txt");
System.out.println("txtFile = " + txtFile);
System.out.println("path = " + txtFile.getCanonicalPath());
System.out.println("file = " + txtFile.isFile());
输出：
txtFile = \bin\demo\demo1\1.txt
path = E:\bin\demo\demo1\1.txt
file = false
总感觉用File的路径定位不靠谱而且难用，而且结合网上的资料，还是用classloader，即类路径来定位好些。
System.out.println(Main.class.getResource(""));//相对于当前文件的路径，不包含自身(即Main类)
System.out.println(Main.class.getResource("/"));//得到的是当前的classpath的绝对URI路径。
System.out.println(Main.class.getClassLoader().getResource(""));//得到的是当前的classpath的绝对URI路径。相当于 System.out.println(Main.class.getResource("/"));
System.out.println(Main.class.getClassLoader().getResource("/"));//ClassLoader路径不允许以/开头
输出：
file:/E:/hotyeWorkspace/webterminal/GetResourceAsStreamDemo/bin/demo/
file:/E:/hotyeWorkspace/webterminal/GetResourceAsStreamDemo/bin/
file:/E:/hotyeWorkspace/webterminal/GetResourceAsStreamDemo/bin/
null
用classpath来定位1.txt
方法1： File txtFile = new File(Main.class.getClassLoader().getResource("demo/demo1/1.txt").getFile());
System.out.println("txtFile = " + txtFile);
System.out.println("path = " + txtFile.getCanonicalPath());
System.out.println("file = " + txtFile.isFile());
输出：
txtFile = E:\hotyeWorkspace\webterminal\GetResourceAsStreamDemo\bin\demo\demo1\1.txt
path = E:\hotyeWorkspace\webterminal\GetResourceAsStreamDemo\bin\demo\demo1\1.txt
file = true
方法2： File txtFile = new File(Main.class.getResource("/demo/demo1/1.txt").getFile());
System.out.println("txtFile = " + txtFile);
System.out.println("path = " + txtFile.getCanonicalPath());
System.out.println("file = " + txtFile.isFile());
输出：
txtFile = E:\hotyeWorkspace\webterminal\GetResourceAsStreamDemo\bin\demo\demo1\1.txt
path = E:\hotyeWorkspace\webterminal\GetResourceAsStreamDemo\bin\demo\demo1\1.txt
file = true
方法3： File txtFile = new File(Main.class.getResource("demo1/1.txt").getFile());
System.out.println("txtFile = " + txtFile);
System.out.println("path = " + txtFile.getCanonicalPath());
System.out.println("file = " + txtFile.isFile());
输出：
txtFile = E:\hotyeWorkspace\webterminal\GetResourceAsStreamDemo\bin\demo\demo1\1.txt
path = E:\hotyeWorkspace\webterminal\GetResourceAsStreamDemo\bin\demo\demo1\1.txt
file = true
getResourceAsStream 和 getResource类似
InputStream in = Main.class.getResourceAsStream("demo1/1.txt");
InputStream in1 = Main.class.getResourceAsStream("/demo/demo1/1.txt");
InputStream in2 = Main.class.getClassLoader().getResourceAsStream("demo/demo1/1.txt");
System.out.println("in = " + in);
System.out.println("in1 = " + in1);
System.out.println("in2 = " + in2);
输出：
in = Java.io.BufferedInputStream@de6ced
in1 = java.io.BufferedInputStream@c17164
in2 = java.io.BufferedInputStream@1fb8ee3
这些代码是写在Main类中，IDE是eclipse，只在windows下测试过。
最近在学习classloader，也顺便总结了下资源文件的定位，至于里面更深刻的原理还有待进一步学习。
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