java资源定位（非web项目）


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