JAVA中try-catch结构之异常处理的使用方法

try {
    // 有可能抛出异常的代码块
    // 这里可以调用方法、执行操作等
    riskyOperation();
} catch (SpecificExceptionType1 e) {
    // 处理 SpecificExceptionType1 类型异常的代码块
    // 可以访问到异常对象 e，通过 e.getMessage(), e.printStackTrace() 等方法获取异常信息
    System.out.println("Caught Exception Type 1: " + e.getMessage());
} catch (SpecificExceptionType2 e) {
    // 处理 SpecificExceptionType2 类型异常的代码块
    System.out.println("Caught Exception Type 2: " + e.getMessage());
} finally {
    // 无论是否发生异常，都会执行的代码块
    // 通常用于资源清理，如关闭文件、数据库连接等
    cleanupResources();
}

try {
    int denominator = 0;
    int result = 10 / denominator; // 这将抛出 ArithmeticException
} catch (ArithmeticException e) {
    System.out.println("Divide by zero error occurred: " + e.getMessage());
} finally {
    System.out.println("Finally block executed.");
}

try {
    // 可能抛出多种类型异常的代码
    File file = new File("non_existent_file.txt");
    FileReader fr = new FileReader(file);
    BufferedReader br = new BufferedReader(fr);
    String line = br.readLine();
} catch (FileNotFoundException e) {
    // 处理找不到文件异常
    System.out.println("File not found: " + e.getMessage());
} catch (IOException e) {
    // 处理读取文件时发生的其他IO异常，如读取错误、缓冲区溢出等
    System.out.println("An IO error occurred: " + e.getMessage());
} finally {
    // 清理资源，如关闭文件流
    try {
        if (br != null) {
            br.close();
        }
    } catch (IOException ex) {
        System.out.println("Error closing the reader: " + ex.getMessage());
    }
}

catch (FileNotFoundException | IOException e) {
    System.out.println("An error occurred: " + e.getMessage());
}

//自定义异常类
class MyException extends Exception {
    static final long serialVersionUID = 23423423435L;
    private int idnumber;
    public MyException(String message, int id) {
        super(message);
        this.idnumber = id;
    }
    public int getId() {
        return idnumber;
    }
}

public class MyExpTest {
    public void regist(int num) throws MyException {
        if (num < 0)
            throw new MyException("人数为负值，不合理", 3);//手动抛出异常对象
        else
            System.out.println("登记人数" + num);
    }
    public void manager() {
        try {
            regist(100);//执行会产生异常对象的代码，就需要进行异常处理
        } catch (MyException e) {
            System.out.print("登记失败，出错种类" + e.getId());
        }
        System.out.print("本次登记操作结束");
    }
    public static void main(String args[]) {
        MyExpTest t = new MyExpTest();
        t.manager();
    }
}