Read Code(Chap.05)

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package chap05;
 
public class ClassCastExceptionClass {
    public static void main(String[] args) {
        ClassCastSubClass cs;
        ClassCastSuperClass css;
        ClassCastSuperClass css1;
        try {
            cs = new ClassCastSubClass();
            css = cs;
            css.print();
            cs.print();
            // css1=(ClassCastSuperClass1)cs;//IS A의 관계 아님
            // cs=(ClassCastSuperClass)css;//ClassCastSuperClass 상위 클래스
            Object ob = css;
            // css=(Object)ob;//Object 상위 클래스 임
            css = (ClassCastSuperClass) ob;
            css.print();
            // if(css instanceof ClassCastSuperClass1){
            // css1=css;
            // }
            Object ob1 = new Object();
            String st = new String("test");
            // String str=(String)ob1;
            if (st instanceof Object) {
                ob1 = st;
            }
            if (ob1 instanceof String) {
                String str = (String) ob1;
            }
        } catch (Exception e) {
            System.out.println(e.toString());
        }
        System.out.println("프로그램 종료");
    }
}
 
class ClassCastSuperClass {
    int a = 5;
 
    public void print() {
        System.out.println(a);
    }
}
 
class ClassCastSubClass extends ClassCastSuperClass {
    int a = 10;
 
    public void print() {
        System.out.println(a);
    }
}
 
class ClassCastSuperClass1 {
    int a = 5;
 
    public void print() {
        System.out.println(a);
    }
}
 
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package chap05;
 
public class CreateInvoke extends SuperExceptionClass {
    public static void main(String[] args) {
        CreateInvoke i = null;
        try {
            i = new CreateInvoke();
        } catch (Exception e) {
            System.out.println(e.getMessage());
        } finally {
            System.out.println("프로그램 종료");
        }
    }
 
    CreateInvoke() throws ArithmeticException, Exception {
 
    }
}
 
class SuperExceptionClass extends Exception {
    public SuperExceptionClass() throws Exception {
        throw new Exception("Super Exception");
    }
}
 
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package chap05;
 
import java.io.*;
import java.io.FileNotFoundException;
 
public class FileFindException {
    public static void main(String[] args) {
        FileFindRead fr = null;
        String str = "";
        try {
            File f = new File("D:/test.txt");
            // File이라는 클래스를 통해서 파일존재 여부를 팡악할 수 있음.
            if (f.exists() && f.isFile()) {
                // f.exeist는 파일이 있는냐라고 물어본다.
                // f.isFile은 해당파일이 파일인지 폴더인지 확인해준다.
                // 맞으면 True값을 return
                System.out.println("파일존재");
                fr = new FileFindRead(new FileInputStream("D:/test.txt"));
                // FileInputStram을 호출해서 FileFindRead라는 생성자를 호출한다.
            } else {
                System.out.println("파일 존재 하지 않음");
            }
        } catch (FileNotFoundException e) {
            System.err.println(e.toString());
        }
        try {
            str = fr.readLine();
        } catch (IOException e) {
            System.err.println(e.toString());
        } finally {
            try {
                fr.fis.close();
            } catch (Exception e) {
                System.err.println(e.toString());
            }
        }
        System.out.println(str);
    }
}
 
class FileFindRead {
    FileInputStream fis;
 
    FileFindRead(FileInputStream fis) {
    // FileFindRead 생성자의 매개변수인 FileInputStream 변수명 fis를 멤버변수 fis에 넣어줌
        this.fis = fis;
    }
 
    public String readLine() throws IOException {
        String str = "", st;
        BufferedReader br = null;
        if (fis != null) {
            br = new BufferedReader(new InputStreamReader(fis));
            // InputStreamReader가 없으면 한글이 깨진다.
            while ((st = br.readLine()) != null) {
                System.out.println(str);
                str += st;
            }
            throw new IOException();
        }
        return str;
    }
}
 
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package chap05;
 
import java.io.*;
 
public class GuGuDan {
    int num;
 
    public static void main(String[] args) {
        GuGuDan ml = new GuGuDan();
        try {
            System.out.println("2~9사이의 숫자만 입력합니다.");
            boolean f = true;
            do {
                try {
                    if (ml.readNumber()) {
                        f = false;
                        ml.print(ml.num);
                    } else {
                        throw new NumberFormatException("2~9사이 숫자");
                    }
                } catch (NumberFormatException e) {
                    System.out.println(e.getMessage());
                }
            } while (f);
        } catch (Exception e) {
            System.out.println(e.getMessage());
        }
    }
 
    public void print(int dan) {
        System.out.printf("-----%d단-----%n", dan);
        for (int i = 1; i <= 9; i++) {
            System.out.printf("%d * %d = %d %n", dan, i, dan * i);
        }
        System.out.println("-------------");
    }
 
    public boolean readNumber() throws IOException, NumberFormatException {
        boolean f = false;
        BufferedReader br = null;
        String st = null;
        br = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("원하는 단수를 입력하시오: ");
        st = br.readLine();
        int num = Integer.parseInt(st);
        if (num >= 1 && num <= 9) {
            f = true;
            this.num = num;
        }
        br.close();
        return f;
    }
}
 
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package chap05;
 
import java.io.*;
 
public class InputNumberLoopException {
    int num;
 
    public static void main(String[] args) {
        InputNumberLoopException il = new InputNumberLoopException();
        try {
            System.out.println("1~10사이의 숫자만 입력합니다.");
            boolean f = true;
            do {
                try {
                    if (il.readNumber()) {
                        f = false;
                        System.out.println(il.num * 10);
                    }
                } catch (NumberFormatException e) {
 
                }
            } while (f);
        } catch (Exception e) {
            System.out.println(e.getMessage());
        }
    }
 
    public boolean readNumber() throws IOException, NumberFormatException {
        boolean f = false;
        BufferedReader br = null;
        String st = null;
        br = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("숫자를 입력해주세요:");
        st = br.readLine();
        int num = Integer.parseInt(st);
        if (num >= 1 && num <= 10) {
            f = true;
            this.num = num;
        }
        br.close();
        return f;
    }
}
 
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package chap05;
 
public class MethodInvoke {
    public static void main(String[] args) {
        String result = "undone";
        try {
            MethodInvoke invoke = new MethodInvoke();
            result = invoke.method();
        } catch (UserException2 ue) {
            System.err.println(ue.getReason());
        } finally {
            System.err.println("finally =" + result);
        }
    }
 
    public String method() throws UserException2 {
        if (true)
            throw new UserException2("User Reason");
        return ("method done.");
    }
}
 
class UserException2 extends Exception {
    private String reason;
 
    public UserException2(String cause) {
        reason = cause;
    }
 
    public String getReason() {
        return reason;
    }
}
 
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package chap05;
 
public class MethodOverridingException extends MethodOverringSuperClass {
    public static void main(String[] args) {
        MethodOverridingException m;
        m = new MethodOverridingException();
        try {
            System.out.println("-----1-----");
            m.method();
            System.out.println("-----2-----");
        } catch (ArithmeticException e) {
            System.out.println(e.getMessage());
        } catch (Exception e) {
            System.out.println(e.getMessage());
        } finally {
            System.out.println("프로그램 종료");
        }
    }
 
    protected String method() throws ArithmeticException {
        if (true)
            new ArithmeticException("하위클래스 method");
        return "하위클래스";
    }
}
 
class MethodOverringSuperClass {
    protected String method(String ar) throws Exception {
        if (true)
            new Exception("상위 클래스 Method");
        return "상위클래스";
    }
}
 
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package chap05;
 
public class NotYet {
    public static void main(String[] args) {
        AssertTest at = new AssertTest();
        at.method();// false이면 오류 발생
    }
}
 
class AssertTest {
    boolean value = false;
 
    void method() {
        assert value;
        System.out.println("AssertTest.method()");
    }
}
 
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package chap05;
 
import java.io.*;
 
public class NumberFormatExceptionClass {
    public static void main(String[] args) throws IOException {
        BufferedReader br;
        br = new BufferedReader(new InputStreamReader(System.in
        // 표준입력 : 키보드 입력
        ));
        String st = "";
        System.out.println("숫자를 입력하세요");
        st = br.readLine();
        System.out.println(st);
        new Atype(new Btype());
        int num = 0;
        try {
            num = Integer.parseInt(st);
        } catch (NumberFormatException e) {
            System.out.println("숫자를 다시 입력하세요:");
            st = br.readLine();
        } finally {
            System.out.println(num * 10);
        }
    }
}
 
class Atype {
    Atype(Btype b) {
 
    }
}
 
class Btype {
 
}
 
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package chap05;
 
public class StackTrace {
    public static void main(String[] args) {
        try {
            StackTrace trace = new StackTrace();
            trace.method();
        } catch (ArrayIndexOutOfBoundsException e) {
            System.out.println("exception: " + e.getMessage());
            e.printStackTrace();
        }
    }
 
    public void method() {
        int[] array = new int[2];
        System.out.println(array[2]);
    }
}
 
// throw 예외상황을 던져주는 것
// throws는 예외상황을
 
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package chap05;
 
public class ThrowException {
    public static void main(String[] args) {
        new ThrowExceptionClass().print();
    }
}
 
class ThrowExceptionClass {
    public void print() {
        System.out.println("예외상황발생시키기");
        int a = 5, b = 0, c = 0;
        try {
            c = a / b;
            throw new Exception("예외상황 발생 :예외객체 생성");
        } catch (ArithmeticException e) {
            System.out.println("ArithmeticException:" + e.toString());
            // throw new Exception("예외상황 발생: 예외객체 생성")
        } catch (NullPointerException e) {
            System.out.println("NullPounterException:" + e.toString());
        } catch (ArrayIndexOutOfBoundsException e) {
            System.out.println("ArrayIndexOutOfBoundsException:" + e.toString());
        } catch (Exception e) {
            System.out.println("Exception:" + e.toString());
        } finally {
            System.out.println("exception 처리 종료");
        }
    }
}
 
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package chap05;
 
public class ThrowsException {
    public static void main(String[] args) {
        ThrowsExceptionClass te = new ThrowsExceptionClass();
        try {
            te.print();
        } catch (Exception e) {
            e.printStackTrace();
        } // printStackTrace란? 에러를 출력하는 역할.
        try {
            int a = te.print(3);
            System.out.println(a);
        } catch (Exception e) {
            e.printStackTrace();
        }
        try {
            String st = te.print("예외처리");
            System.out.println(st);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
 
class ThrowsExceptionClass {
    public void print() throws Exception {
        System.out.println("예외상황 Throws 하기");
        throw new Exception("예외상황 객체생성");
    }
 
    public int print(int a) throws Exception {
        try {
            System.out.println("예외상황 Throws 하기1");
            throw new Exception("예외상황 객체생성");
        } catch (Exception e) {
            System.out.println("예외상황 Throw Exception 처리");
        } finally {
            System.out.println("예외상황 Throws finally 블록 수행");
        }
        return a * 10;
    }
 
    public String print(String str) throws Exception {
        String reStr = "테스트:" + str;
        int a = 5, b = 0, c = 0;
        System.out.println("예외상황 Throws 하기2");
        c = a / b;
        return reStr;
    }
}
 
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package chap05;
 
public class ThrowsSample {
    public static void main(String[] args) {
        ThrowsSampleClass t = new ThrowsSampleClass();
        System.out.println("print 메소드 수행 전");
        try {
            t.print();
        } catch (Exception e) {
            System.out.println(e.toString());
        }
        System.out.println("print 메소드 수행 후");
        System.out.println("print1 메소드 수행 전");
        // try{
        // t.print1();
        // }catch(Exception e){}
        System.out.println("프로그램 정상종료");
    }
}
 
class ThrowsSampleClass {
    public void print() throws ArithmeticException, NullPointerException {
        int c = 0;
        c = 5 / 0;
    }
 
    public void print1() {
        int c = 0;
        c = 5 / 0;
    }
}
 
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package chap05;
 
public class UserException extends Exception {
    // Exception 클래스를 상속 받아야만 Exception이 된다.
    private String exceptionName;
 
    public static void main(String[] args) {
        UserException ue;
        try {
            throw new UserException("내가만든 예외처리");
            // throw new TestException("내가만든 예외처리")
            // 실행할 수 없는 이유는 TestException은
            // Exception 상속을 받지 않았기 때문에 Exception이 아니다.
            // System.out.println(ue.getName());
        } catch (UserException e) {// 하위클래스에서 예외처리르 받는다.
            System.out.println(e.getName());
            // getName()은 이름을 호출하는 것이며,
            // 여기서는 String 타입인 "내가만든 예외처리"를 실행한다.
        } catch (Exception e) {// 하위클래스에서 예외처리를 받을 수 없을 경우,
                                // 상위클래스에서 예외처리를 받는다.
            System.out.println(e.toString());
            // Exception의 경우 상위클래스가 Object이기 때문에 toString을 쓴 것이다.
        } finally {
            System.out.println("예외처리 종료");
        }
        System.out.println("프로그램 정상종료");
    }
 
    public UserException(String exceptionName) {
        this.exceptionName = exceptionName;
    }
 
    public String getName() {
        return exceptionName;
    }
}
 
class TestException {
    private String exceptionName;
 
    public TestException(String exceptionName) {
        this.exceptionName = exceptionName;
    }
 
    public String getName() {
        return exceptionName;
    }
}
 
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