From 173c311577d97be46bc989d0a29581065a33f27d Mon Sep 17 00:00:00 2001
From: HansBug <hansbug@questionor.cn>
Date: Fri, 24 Dec 2021 17:12:11 +0800
Subject: [PATCH] dev(hansbug): add problems in exception part

---
 .../checked_exception.json"                   |   7 +
 .../checked_exception.md"                     | 247 ++++++++++++++++++
 .../config.json"                              |   4 +-
 .../runtime_exception.json"                   |   7 +
 .../runtime_exception.md"                     | 179 +++++++++++++
 5 files changed, 443 insertions(+), 1 deletion(-)
 create mode 100644 "data/1.Java\345\210\235\351\230\266/9.\346\216\247\345\210\266\346\211\247\350\241\214\346\265\201\347\250\213/4.\351\200\232\350\277\207\345\274\202\345\270\270\345\244\204\347\220\206\351\224\231\350\257\257/checked_exception.json"
 create mode 100644 "data/1.Java\345\210\235\351\230\266/9.\346\216\247\345\210\266\346\211\247\350\241\214\346\265\201\347\250\213/4.\351\200\232\350\277\207\345\274\202\345\270\270\345\244\204\347\220\206\351\224\231\350\257\257/checked_exception.md"
 create mode 100644 "data/1.Java\345\210\235\351\230\266/9.\346\216\247\345\210\266\346\211\247\350\241\214\346\265\201\347\250\213/4.\351\200\232\350\277\207\345\274\202\345\270\270\345\244\204\347\220\206\351\224\231\350\257\257/runtime_exception.json"
 create mode 100644 "data/1.Java\345\210\235\351\230\266/9.\346\216\247\345\210\266\346\211\247\350\241\214\346\265\201\347\250\213/4.\351\200\232\350\277\207\345\274\202\345\270\270\345\244\204\347\220\206\351\224\231\350\257\257/runtime_exception.md"

diff --git "a/data/1.Java\345\210\235\351\230\266/9.\346\216\247\345\210\266\346\211\247\350\241\214\346\265\201\347\250\213/4.\351\200\232\350\277\207\345\274\202\345\270\270\345\244\204\347\220\206\351\224\231\350\257\257/checked_exception.json" "b/data/1.Java\345\210\235\351\230\266/9.\346\216\247\345\210\266\346\211\247\350\241\214\346\265\201\347\250\213/4.\351\200\232\350\277\207\345\274\202\345\270\270\345\244\204\347\220\206\351\224\231\350\257\257/checked_exception.json"
new file mode 100644
index 0000000..c4d2103
--- /dev/null
+++ "b/data/1.Java\345\210\235\351\230\266/9.\346\216\247\345\210\266\346\211\247\350\241\214\346\265\201\347\250\213/4.\351\200\232\350\277\207\345\274\202\345\270\270\345\244\204\347\220\206\351\224\231\350\257\257/checked_exception.json"
@@ -0,0 +1,7 @@
+{
+  "type": "code_options",
+  "author": "HansBug",
+  "source": "checked_exception.md",
+  "notebook_enable": false,
+  "exercise_id": "302ed00decc24b4ba435aab028582ac4"
+}
\ No newline at end of file
diff --git "a/data/1.Java\345\210\235\351\230\266/9.\346\216\247\345\210\266\346\211\247\350\241\214\346\265\201\347\250\213/4.\351\200\232\350\277\207\345\274\202\345\270\270\345\244\204\347\220\206\351\224\231\350\257\257/checked_exception.md" "b/data/1.Java\345\210\235\351\230\266/9.\346\216\247\345\210\266\346\211\247\350\241\214\346\265\201\347\250\213/4.\351\200\232\350\277\207\345\274\202\345\270\270\345\244\204\347\220\206\351\224\231\350\257\257/checked_exception.md"
new file mode 100644
index 0000000..e4f1911
--- /dev/null
+++ "b/data/1.Java\345\210\235\351\230\266/9.\346\216\247\345\210\266\346\211\247\350\241\214\346\265\201\347\250\213/4.\351\200\232\350\277\207\345\274\202\345\270\270\345\244\204\347\220\206\351\224\231\350\257\257/checked_exception.md"
@@ -0,0 +1,247 @@
+# 自定义可查异常（Checked Exception）
+
+现有如下的学生考试成绩查询程序，会根据给定的字符串格式`studentID`进行学生分数查询，如果该学生存在，则返回其分数（确保为非负整数）；如果该学生不存在，则返回`-1`，如下所示
+
+```java
+public class TestMain {
+    private static boolean containsStudent(String studentID) {
+        // Return true when the given `studentID` represents an existing student.
+    }
+
+    private static int queryScore(String studentID) {
+        // Get and then return score of the student
+        // whose ID is `StudentID` from the database.
+    }
+
+    private static int getScoreByStudentID(String studentID) {
+        if (containsStudent(studentID)) {
+            return queryScore(studentID);
+        } else {
+            return -1;
+        }
+    }
+
+    public static void main(String[] args) {
+        String studentID = "ID20211224";
+
+        int score = getScoreByStudentID(studentID);
+        if (score >= 0) {
+            System.out.printf("Student ID : %s%n", studentID);
+            System.out.printf("Score : %d%n", score);
+        } else {
+            System.out.printf("Student ID %s not found!%n", studentID);
+        }
+    }
+}
+
+```
+
+请改写上述代码，对于学生不存在的情况，**使用可查异常（Checked Exception）对潜在的异常情况进行妥善处理**而不是返回`-1`。
+
+> 可查异常（Checked Exception）是编译器在编译时会进行检查，也称为编译时异常（Compile Time Exception）。 这些异常往往具备可预见性，且不能简单地被忽略，编程者应当对其进行妥善处理。
+
+因此，下列修改方式正确的是：
+
+## 答案
+
+```java
+public class TestMain {
+    private static boolean containsStudent(String studentID) {
+        // Return true when the given `studentID` represents an existing student.
+    }
+
+    private static int queryScore(String studentID) {
+        // Get and then return score of the student
+        // whose ID is `StudentID` from the database.
+    }
+
+    public static class StudentNotExistException extends Exception {
+        public StudentNotExistException(String studentID) {
+            super(String.format("Student ID %s not found.", studentID));
+        }
+    }
+
+    private static int getScoreByStudentID(String studentID) throws StudentNotExistException {
+        if (containsStudent(studentID)) {
+            return queryScore(studentID);
+        } else {
+            throw new StudentNotExistException(studentID);
+        }
+    }
+
+    public static void main(String[] args) {
+        String studentID = "ID20211224";
+
+        try {
+            int score = getScoreByStudentID(studentID);
+            System.out.printf("Student ID : %s%n", studentID);
+            System.out.printf("Score : %d%n", score);
+        } catch (StudentNotExistException err) {
+            System.out.printf("Student ID %s not found!%n", studentID);
+        }
+    }
+}
+```
+
+## 选项
+
+### A
+
+```java
+public class TestMain {
+    private static boolean containsStudent(String studentID) {
+        // Return true when the given `studentID` represents an existing student.
+    }
+
+    private static int queryScore(String studentID) {
+        // Get and then return score of the student
+        // whose ID is `StudentID` from the database.
+    }
+
+    public static class StudentNotExistException extends RuntimeException {
+        public StudentNotExistException(String studentID) {
+            super(String.format("Student ID %s not found.", studentID));
+        }
+    }
+
+    private static int getScoreByStudentID(String studentID) throws StudentNotExistException {
+        if (containsStudent(studentID)) {
+            return queryScore(studentID);
+        } else {
+            throw new StudentNotExistException(studentID);
+        }
+    }
+
+    public static void main(String[] args) {
+        String studentID = "ID20211224";
+
+        try {
+            int score = getScoreByStudentID(studentID);
+            System.out.printf("Student ID : %s%n", studentID);
+            System.out.printf("Score : %d%n", score);
+        } catch (StudentNotExistException err) {
+            System.out.printf("Student ID %s not found!%n", studentID);
+        }
+    }
+}
+```
+
+### B
+
+```java
+public class TestMain {
+    private static boolean containsStudent(String studentID) {
+        // Return true when the given `studentID` represents an existing student.
+    }
+
+    private static int queryScore(String studentID) {
+        // Get and then return score of the student
+        // whose ID is `StudentID` from the database.
+    }
+
+    public static class StudentNotExistException extends RuntimeException {
+        public StudentNotExistException(String studentID) {
+            super(String.format("Student ID %s not found.", studentID));
+        }
+    }
+
+    private static int getScoreByStudentID(String studentID) {
+        if (containsStudent(studentID)) {
+            return queryScore(studentID);
+        } else {
+            throw new StudentNotExistException(studentID);
+        }
+    }
+
+    public static void main(String[] args) {
+        String studentID = "ID20211224";
+
+        int score = getScoreByStudentID(studentID);
+        System.out.printf("Student ID : %s%n", studentID);
+        System.out.printf("Score : %d%n", score);
+    }
+}
+```
+
+### C
+
+```java
+public class TestMain {
+    private static boolean containsStudent(String studentID) {
+        // Return true when the given `studentID` represents an existing student.
+    }
+
+    private static int queryScore(String studentID) {
+        // Get and then return score of the student
+        // whose ID is `StudentID` from the database.
+    }
+
+    public static class StudentNotExistException extends Error {
+        public StudentNotExistException(String studentID) {
+            super(String.format("Student ID %s not found.", studentID));
+        }
+    }
+
+    private static int getScoreByStudentID(String studentID) throws StudentNotExistException {
+        if (containsStudent(studentID)) {
+            return queryScore(studentID);
+        } else {
+            throw new StudentNotExistException(studentID);
+        }
+    }
+
+    public static void main(String[] args) {
+        String studentID = "ID20211224";
+
+        try {
+            int score = getScoreByStudentID(studentID);
+            System.out.printf("Student ID : %s%n", studentID);
+            System.out.printf("Score : %d%n", score);
+        } catch (StudentNotExistException err) {
+            System.out.printf("Student ID %s not found!%n", studentID);
+        }
+    }
+}
+```
+
+### D
+
+```java
+public class TestMain {
+    private static boolean containsStudent(String studentID) {
+        // Return true when the given `studentID` represents an existing student.
+    }
+
+    private static int queryScore(String studentID) {
+        // Get and then return score of the student
+        // whose ID is `StudentID` from the database.
+    }
+
+    public static class StudentNotExistException extends Exception {
+        public StudentNotExistException(String studentID) {
+            super(String.format("Student ID %s not found.", studentID));
+        }
+    }
+
+    private static int getScoreByStudentID(String studentID) throws StudentNotExistException {
+        if (containsStudent(studentID)) {
+            return queryScore(studentID);
+        } else {
+            throw new StudentNotExistException(studentID);
+        }
+    }
+
+    public static void main(String[] args) {
+        String studentID = "ID20211224";
+
+        try {
+            int score = getScoreByStudentID(studentID);
+            System.out.printf("Student ID : %s%n", studentID);
+            System.out.printf("Score : %d%n", score);
+        } except (StudentNotExistException err) {
+            System.out.printf("Student ID %s not found!%n", studentID);
+        }
+    }
+}
+```
+
diff --git "a/data/1.Java\345\210\235\351\230\266/9.\346\216\247\345\210\266\346\211\247\350\241\214\346\265\201\347\250\213/4.\351\200\232\350\277\207\345\274\202\345\270\270\345\244\204\347\220\206\351\224\231\350\257\257/config.json" "b/data/1.Java\345\210\235\351\230\266/9.\346\216\247\345\210\266\346\211\247\350\241\214\346\265\201\347\250\213/4.\351\200\232\350\277\207\345\274\202\345\270\270\345\244\204\347\220\206\351\224\231\350\257\257/config.json"
index 2db98dc..53a7e14 100644
--- "a/data/1.Java\345\210\235\351\230\266/9.\346\216\247\345\210\266\346\211\247\350\241\214\346\265\201\347\250\213/4.\351\200\232\350\277\207\345\274\202\345\270\270\345\244\204\347\220\206\351\224\231\350\257\257/config.json"
+++ "b/data/1.Java\345\210\235\351\230\266/9.\346\216\247\345\210\266\346\211\247\350\241\214\346\265\201\347\250\213/4.\351\200\232\350\277\207\345\274\202\345\270\270\345\244\204\347\220\206\351\224\231\350\257\257/config.json"
@@ -223,7 +223,9 @@
   ],
   "export": [
     "exception.json",
-    "using.json"
+    "using.json",
+    "runtime_exception.json",
+    "checked_exception.json"
   ],
   "title": "通过异常处理错误"
 }
\ No newline at end of file
diff --git "a/data/1.Java\345\210\235\351\230\266/9.\346\216\247\345\210\266\346\211\247\350\241\214\346\265\201\347\250\213/4.\351\200\232\350\277\207\345\274\202\345\270\270\345\244\204\347\220\206\351\224\231\350\257\257/runtime_exception.json" "b/data/1.Java\345\210\235\351\230\266/9.\346\216\247\345\210\266\346\211\247\350\241\214\346\265\201\347\250\213/4.\351\200\232\350\277\207\345\274\202\345\270\270\345\244\204\347\220\206\351\224\231\350\257\257/runtime_exception.json"
new file mode 100644
index 0000000..4e50742
--- /dev/null
+++ "b/data/1.Java\345\210\235\351\230\266/9.\346\216\247\345\210\266\346\211\247\350\241\214\346\265\201\347\250\213/4.\351\200\232\350\277\207\345\274\202\345\270\270\345\244\204\347\220\206\351\224\231\350\257\257/runtime_exception.json"
@@ -0,0 +1,7 @@
+{
+  "type": "code_options",
+  "author": "HansBug",
+  "source": "runtime_exception.md",
+  "notebook_enable": false,
+  "exercise_id": "61a61ce93dca4b2e9049f5318e4d2a21"
+}
\ No newline at end of file
diff --git "a/data/1.Java\345\210\235\351\230\266/9.\346\216\247\345\210\266\346\211\247\350\241\214\346\265\201\347\250\213/4.\351\200\232\350\277\207\345\274\202\345\270\270\345\244\204\347\220\206\351\224\231\350\257\257/runtime_exception.md" "b/data/1.Java\345\210\235\351\230\266/9.\346\216\247\345\210\266\346\211\247\350\241\214\346\265\201\347\250\213/4.\351\200\232\350\277\207\345\274\202\345\270\270\345\244\204\347\220\206\351\224\231\350\257\257/runtime_exception.md"
new file mode 100644
index 0000000..c489160
--- /dev/null
+++ "b/data/1.Java\345\210\235\351\230\266/9.\346\216\247\345\210\266\346\211\247\350\241\214\346\265\201\347\250\213/4.\351\200\232\350\277\207\345\274\202\345\270\270\345\244\204\347\220\206\351\224\231\350\257\257/runtime_exception.md"
@@ -0,0 +1,179 @@
+# 自定义运行时异常（RuntimeException）
+
+现有如下的海伦公式计算函数，根据三角形的三条边长`a`、`b`和`c`（均确保大于0）计算三角形的面积。当三角形本身非法时返回负数，否则返回面积，如下所示
+
+```java
+public class TestMain {
+    private static float getArea(float a, float b, float c) {
+        if ((a + b < c) || (a + c < b) || (b + c < a)) {
+            return -1;  // 非法三角形
+        } else {
+            float p = (a + b + c) / 2;
+            return (float) Math.sqrt((p - a) * (p - b) * (p - c) * p);  // 海伦公式
+        }
+    }
+
+    public static void main(String[] args) {
+        System.out.println(TestMain.getArea(3, 4, 5));
+    }
+}
+```
+
+请改写上述代码，对于三角形非法的情况，**仅在运行抛出不可查异常（Unchecked Exception）**而不是返回`-1`。
+
+> 不可查异常（Unchecked Exception）指在运行时发生的异常。这些也被称为运行时异常（Runtime Exception）。其中包括程序逻辑错误或API使用不当等，例如ArrayIndexOutOfBoundsException、IllegalStateException与NullPointerException等，此类异常将在编译时忽略，仅在运行时处理。
+
+因此，下列修改方式正确的是：
+
+## 答案
+
+```java
+public class TestMain {
+    public static class InvalidTriangleException extends RuntimeException {
+        public InvalidTriangleException(float a, float b, float c) {
+            super(String.format("Invalid triangle - (%.3f, %.3f, %.3f).", a, b, c));
+        }
+    }
+
+    private static float getArea(float a, float b, float c) {
+        if ((a + b < c) || (a + c < b) || (b + c < a)) {
+            throw new InvalidTriangleException(a, b, c);
+        } else {
+            float p = (a + b + c) / 2;
+            return (float) Math.sqrt((p - a) * (p - b) * (p - c) * p);
+        }
+    }
+
+    public static void main(String[] args) {
+        System.out.println(TestMain.getArea(3, 4, 5));
+    }
+}
+```
+
+## 选项
+
+### A
+
+```java
+public class TestMain {
+    public class InvalidTriangleException extends RuntimeException {
+        public InvalidTriangleException(float a, float b, float c) {
+            super(String.format("Invalid triangle - (%.3f, %.3f, %.3f).", a, b, c));
+        }
+    }
+
+    private float getArea(float a, float b, float c) {
+        if ((a + b < c) || (a + c < b) || (b + c < a)) {
+            throw new InvalidTriangleException(a, b, c);
+        } else {
+            float p = (a + b + c) / 2;
+            return (float) Math.sqrt((p - a) * (p - b) * (p - c) * p);
+        }
+    }
+
+    public static void main(String[] args) {
+        System.out.println(TestMain.getArea(3, 4, 5));
+    }
+}
+```
+
+### B
+
+```java
+public class TestMain {
+    public static class InvalidTriangleException extends Exception {
+        public InvalidTriangleException(float a, float b, float c) {
+            super(String.format("Invalid triangle - (%.3f, %.3f, %.3f).", a, b, c));
+        }
+    }
+
+    private static float getArea(float a, float b, float c) {
+        if ((a + b < c) || (a + c < b) || (b + c < a)) {
+            throw new InvalidTriangleException(a, b, c);
+        } else {
+            float p = (a + b + c) / 2;
+            return (float) Math.sqrt((p - a) * (p - b) * (p - c) * p);
+        }
+    }
+
+    public static void main(String[] args) {
+        System.out.println(TestMain.getArea(3, 4, 5));
+    }
+}
+```
+
+### C
+
+```java
+public class TestMain {
+    public static class InvalidTriangleException extends Exception {
+        public InvalidTriangleException(float a, float b, float c) {
+            super(String.format("Invalid triangle - (%.3f, %.3f, %.3f).", a, b, c));
+        }
+    }
+
+    private static float getArea(float a, float b, float c) throws InvalidTriangleException {
+        if ((a + b < c) || (a + c < b) || (b + c < a)) {
+            throw new InvalidTriangleException(a, b, c);
+        } else {
+            float p = (a + b + c) / 2;
+            return (float) Math.sqrt((p - a) * (p - b) * (p - c) * p);
+        }
+    }
+
+    public static void main(String[] args) throws InvalidTriangleException {
+        System.out.println(TestMain.getArea(3, 4, 5));
+    }
+}
+```
+
+### D
+
+```java
+public class TestMain {
+    public static class InvalidTriangleException extends Error {
+        public InvalidTriangleException(float a, float b, float c) {
+            super(String.format("Invalid triangle - (%.3f, %.3f, %.3f).", a, b, c));
+        }
+    }
+
+    private static float getArea(float a, float b, float c) {
+        if ((a + b < c) || (a + c < b) || (b + c < a)) {
+            throw new InvalidTriangleException(a, b, c);
+        } else {
+            float p = (a + b + c) / 2;
+            return (float) Math.sqrt((p - a) * (p - b) * (p - c) * p);
+        }
+    }
+
+    public static void main(String[] args) {
+        System.out.println(TestMain.getArea(3, 4, 5));
+    }
+}
+```
+
+### E
+
+```java
+public class TestMain {
+    public static class InvalidTriangleException extends RuntimeException {
+        public InvalidTriangleException(float a, float b, float c) {
+            super(String.format("Invalid triangle - (%.3f, %.3f, %.3f).", a, b, c));
+        }
+    }
+
+    private static float getArea(float a, float b, float c) throws InvalidTriangleException {
+        if ((a + b < c) || (a + c < b) || (b + c < a)) {
+            throw new InvalidTriangleException(a, b, c);
+        } else {
+            float p = (a + b + c) / 2;
+            return (float) Math.sqrt((p - a) * (p - b) * (p - c) * p);
+        }
+    }
+
+    public static void main(String[] args) throws InvalidTriangleException {
+        System.out.println(TestMain.getArea(3, 4, 5));
+    }
+}
+```
+
-- 
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