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工程：GetResourceAsStreamDemo
磁盤(pán)路徑：E:\hotyeWorkspace\webterminal\GetResourceAsStreamDemo
工程目錄如下：
1.利用FIle定位：
File txtFile = new File("bin/demo/demo1/1.txt");//這里相當(dāng)于File txtFile = new File("src/demo/demo1/1.txt"); 因?yàn)閟rc的文件會(huì)build到bin中
System.out.println("txtFile = " + txtFile);
System.out.println("path = " + txtFile.getCanonicalPath());
System.out.println("file = " + txtFile.isFile());
輸出：
txtFile = bin\demo\demo1\1.txt
path = E:\hotyeWorkspace\webterminal\GetResourceAsStreamDemo\bin\demo\demo1\1.txt
file = true
這里，F(xiàn)ile里面的路徑，假如不從"/"開(kāi)始，就表示相對(duì)于當(dāng)前用戶(hù)目錄（即System.getProperty("user.dir")）
System.out.println("dir = " + System.getProperty("user.dir"));
輸出：dir = E:\hotyeWorkspace\webterminal\GetResourceAsStreamDemo
File dotFile = new File(".");//表示當(dāng)前工程目錄，和當(dāng)前用戶(hù)目錄相同
System.out.println("dotFile = " + dotFile.getCanonicalPath());
File file1 = new File("..");//表示當(dāng)前工程目錄的上一級(jí)目錄
System.out.println("file1 = " + file1.getCanonicalPath());
File file2 = new File("/");//表示當(dāng)前工程目錄的最頂層目錄
System.out.println("file2 = " + file2.getCanonicalPath());
輸出：
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());
輸出：
txtFile = \bin\demo\demo1\1.txt
path = E:\bin\demo\demo1\1.txt
file = false
總感覺(jué)用File的路徑定位不靠譜而且難用，而且結(jié)合網(wǎng)上的資料，還是用classloader，即類(lèi)路徑來(lái)定位好些。
System.out.println(Main.class.getResource(""));//相對(duì)于當(dāng)前文件的路徑，不包含自身(即Main類(lèi))
System.out.println(Main.class.getResource("/"));//得到的是當(dāng)前的classpath的絕對(duì)URI路徑。
System.out.println(Main.class.getClassLoader().getResource(""));//得到的是當(dāng)前的classpath的絕對(duì)URI路徑。相當(dāng)于 System.out.println(Main.class.getResource("/"));
System.out.println(Main.class.getClassLoader().getResource("/"));//ClassLoader路徑不允許以/開(kāi)頭
輸出：
file:/E:/hotyeWorkspace/webterminal/GetResourceAsStreamDemo/bin/demo/
file:/E:/hotyeWorkspace/webterminal/GetResourceAsStreamDemo/bin/
file:/E:/hotyeWorkspace/webterminal/GetResourceAsStreamDemo/bin/
null
用classpath來(lái)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());
輸出：
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());
輸出：
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());
輸出：
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類(lèi)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);
輸出：
in = Java.io.BufferedInputStream@de6ced
in1 = java.io.BufferedInputStream@c17164
in2 = java.io.BufferedInputStream@1fb8ee3
這些代碼是寫(xiě)在Main類(lèi)中，IDE是eclipse，只在windows下測(cè)試過(guò)。
最近在學(xué)習(xí)classloader，也順便總結(jié)了下資源文件的定位，至于里面更深刻的原理還有待進(jìn)一步學(xué)習(xí)。
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