Java实现读取resources目录下的文件路径的九种方式

    
    public static void getFileContent(Object fileInPath) throws ioException {
        BufferedReader br = null;
        if (fileInPath == null) {
            return;
        }
        if (fileInPath instanceof String) {
            br = new BufferedReader(new FileReader(new File((String) fileInPath)));
        } else if (fileInPath instanceof InputStream) {
            br = new BufferedReader(new InputStreamReader((InputStream) fileInPath));
        }
        String line;
        while ((line = br.readLine()) != null) {
            System.out.println(line);
        }
        br.close();
    }

    public void function1(String fileName) throws IOException {
        String path = this.getClass().getClassLoader().getResource("").getPath();//注意getResource("")里面是空字符串
        System.out.println(path);
        String filePath = path + fileName;
        System.out.println(filePath);
        getFileContent(filePath);
    }

    
    public void function2(String fileName) throws IOException {
        String path = this.getClass().getClassLoader().getResource(fileName).getPath();//注意getResource("")里面是空字符串
        System.out.println(path);
        String filePath = URLDecoder.decode(path, "UTF-8");//如果路径中带有中文会被URLEncoder,因此这里需要解码
        System.out.println(filePath);
        getFileContent(filePath);
    }

url.getFile()=/pub/files/foobar.txt?id=123456
url.getPath()=/pub/files/foobar.txt

    
    public void function3(String fileName) throws IOException {
        String path = this.getClass().getClassLoader().getResource(fileName).getFile();//注意getResource("")里面是空字符串
        System.out.println(path);
        String filePath = URLDecoder.decode(path, "UTF-8");//如果路径中带有中文会被URLEncoder,因此这里需要解码
        System.out.println(filePath);
        getFileContent(filePath);
    }

    
    public void function4(String fileName) throws IOException {
        InputStream in = this.getClass().getClassLoader().getResourceAsStream(fileName);
        getFileContent(in);
    }

    
    public void function5(String fileName) throws IOException {
        InputStream in = this.getClass().getResourceAsStream("/" + fileName);
        getFileContent(in);
    }

    
    public void function6(String fileName) throws IOException {
        ClassPathResource classPathResource = new ClassPathResource(fileName);
        InputStream inputStream = classPathResource.getInputStream();
        getFileContent(inputStream);
    }

    
    public void function7(String fileName) throws IOException {
        String rootPath = System.getProperty("user.dir");//E:\WorkSpace\git\spring-framework-learning-example
        String filePath = rootPath + "\\chapter-2-springMVC-quickstart\\src\\main\\resources\\"+fileName;
        getFileContent(filePath);
    }

    
    public void function8(String fileName) throws IOException {
        //参数为空
        File directory = new File("");
        //规范路径：getCanonicalPath() 方法返回绝对路径，会把 ..\ 、.\ 这样的符号解析掉
        String rootCanonicalPath = directory.getCanonicalPath();
        //绝对路径：getAbsolutePath() 方法返回文件的绝对路径，如果构造的时候是全路径就直接返回全路径，如果构造时是相对路径，就返回当前目录的路径 + 构造 File 对象时的路径
        String rootAbsolutePath =directory.getAbsolutePath();
        System.out.println(rootCanonicalPath);
        System.out.println(rootAbsolutePath);
        String filePath = rootCanonicalPath + "\\chapter-2-springmvc-quickstart\\src\\main\\resources\\"+fileName;
        getFileContent(filePath);
    }

 System.getenv("TEST_ROOT");
 System.getProperty("TEST_ROOT")

    
    public void function9(String fileName) throws IOException {
        System.setProperty("TEST_ROOT","E:\\WorkSpace\\Git\\spring-framework-learning-example");
        //参数为空
        String rootPath = System.getProperty("TEST_ROOT");
        System.out.println(rootPath);
        String filePath = rootPath + "\\chapter-2-springmvc-quickstart\\src\\main\\resources\\"+fileName;
        getFileContent(filePath);
    }