Java中的substring()方法使用举例详解

String substring(int beginIndex)
String substring(int beginIndex, int endIndex)

public class SubstringExample {
    public static void main(String[] args) {
        String str = "Hello, Java!";
        
        // 提取从索引 7 开始的子字符串
        String result = str.substring(7);
        
        System.out.println("结果: " + result);  // 输出: "Java!"
    }
}

public class SubstringExample {
    public static void main(String[] args) {
        String str = "Hello, Java!";
        
        // 提取从索引 7 到 11 之间的子字符串
        String result = str.substring(7, 11);
        
        System.out.println("结果: " + result);  // 输出: "Java"
    }
}

String str = "Hello, Java!";
String result = str.substring(15);  // 这会抛出异常，因为索引超出范围

String str = "Hello, Java!";
String result = str.substring(12, 12);  // 返回空字符串

String fileName = "example.txt";
String extension = fileName.substring(fileName.lastIndexOf(".") + 1);
System.out.println("文件扩展名是: " + extension);  // 输出: "txt"

String url = "https://www.example.com/index.html";
String domain = url.substring(url.indexOf("://") + 3, url.indexOf("/", url.indexOf("://") + 3));
System.out.println("域名是: " + domain);  // 输出: "www.example.com"

String text = "(Java)";
String result = text.substring(1, text.length() - 1);
System.out.println("去除括号后的文本: " + result);  // 输出: "Java"