maven项目加载文件资源

加载路径问题

public class PathProblem {
          
   
    public static void main(String[] args) {
          
   
        // 编译后，项目根路径，写法1
        String url1 = PathProblem.class.getClassLoader().getResource("").toString();
        System.out.println("url1 = " + url1);
        //url1 = file:/D:/IdeaSpace/plus/target/classes/
        
        // 编译后，项目根路径，写法2
        String url2 = PathProblem.class.getResource("/").toString();
        System.out.println("url2 = " + url2);
        //url2 = file:/D:/IdeaSpace/plus/target/classes/

        // 编译后，文件根路径
        String url3 = PathProblem.class.getResource("").toString();
        System.out.println("url3 = " + url3);
		//url3 = file:/D:/IdeaSpace/plus/target/classes/com/boot/post/reflect/

        // 编译后，文件根路径
        String url4 = Thread.currentThread().getContextClassLoader().getResource("").toString();
        System.out.println("url4 = " + url4);
		//url4 = file:/D:/IdeaSpace/plus/target/classes/

    }
}

知道加载路径，就可以将资源放在具体的加载路径目录下面。

6种加载文件方法

public class LoadTxt {
          
   
    public static void main(String[] args) throws Exception {
          
   
        //1.通过spring提供的ResourceLoader工具类加载
        DefaultResourceLoader resourceLoader = new DefaultResourceLoader();
        Resource resource = resourceLoader.getResource("classpath:aa.txt");
        InputStream inputStream = resource.getInputStream();

        //2.通过ClassPathResource加载
        ClassPathResource resource2 = new ClassPathResource("aa.txt");
        InputStream inputStream1 = resource2.getInputStream();

        //3.通过Class类加载
        URL resource3 = LoadTxt.class.getResource("/aa.txt");
        InputStream inputStream3 = resource3.openStream();

        //4通过类加载器加载
        InputStream inputStream4 = Thread.currentThread().getContextClassLoader().getResourceAsStream("aa.txt");

        //5.通过流加载
        FileInputStream inputStream5 = new FileInputStream("src/main/resources/aa.txt");

        //6.通过文件转换流加载
        File file = new File("src/main/resources/aa.txt");
        InputStream inputStream6 = new FileInputStream(file);
        
        StringBuffer out = new StringBuffer();
        byte[] b = new byte[4096];
        for (int n; (n = inputStream6.read(b)) != -1; ) {
          
   
            out.append(new String(b, 0, n));
        }
        System.out.println(out);
    }
}

aa.txt文件放在resources目录下面。 注意：文件命名不能使用关键字，例如load.txt，会异常！！！