(1) 请用java写一个代码批量生成产生习题并用文件存储； (2) 请用java写一个代码生成100以内加法/减法的算式基； (3) 请用java写一个代码批改练习并存储。

好的，我会分别为您提供Java代码。首先是批量生成习题并用文件存储的代码：

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Random;

public class MathExercisesGenerator {
    public static void main(String[] args) {
        int numOfExercises = 50; // 题目数量
        int maxNum = 100; // 最大数值
        String fileName = "math_exercises.txt"; // 存储文件名

        try {
            BufferedWriter writer = new BufferedWriter(new FileWriter(fileName));
            Random random = new Random();
            for (int i = 0; i < numOfExercises; i++) {
                int num1 = random.nextInt(maxNum) + 1;
                int num2 = random.nextInt(maxNum) + 1;
                int operator = random.nextInt(2); // 0代表加法，1代表减法
                String operatorStr = operator == 0 ? "+" : "-";
                int result = operator == 0 ? num1 + num2 : num1 - num2;
                String exercise = num1 + " " + operatorStr + " " + num2 + " = ";
                writer.write(exercise + "\n");
            }
            writer.close();
            System.out.println("Math exercises generated successfully!");
        } catch (IOException e) {
            System.out.println("Error occurred while generating math exercises.");
            e.printStackTrace();
        }
    }
}

代码中通过设置`numOfExercises`和`maxNum`变量来控制生成的习题数量和数值的范围，可以根据需要进行修改。生成的习题会存储在一个名为`math_exercises.txt`的文件中。

接下来是生成100以内加法/减法的算式基的代码：

import java.util.ArrayList;
import java.util.List;

public class MathProblemsGenerator {
    public static void main(String[] args) {
        int maxNum = 100; // 最大数值
        List<String> problems = new ArrayList<>();
        // 生成加法算式基
        for (int i = 1; i <= maxNum; i++) {
            for (int j = 1; j <= maxNum; j++) {
                int result = i + j;
                String problem = i + "+" + j + "=" + result;
                problems.add(problem);
            }
        }
        // 生成减法算式基
        for (int i = 1; i <= maxNum; i++) {
            for (int j = 1; j <= i; j++) {
                int result = i - j;
                String problem = i + "-" + j + "=" + result;
                problems.add(problem);
            }
        }
        System.out.println("Math problems generated successfully!");
        // 打印生成的算式
        for (String problem : problems) {
            System.out.println(problem);
        }
    }
}

代码中通过设置`maxNum`变量来控制数值的范围，可以根据需要进行修改。生成的算式会存储在一个字符串列表中，并打印输出到控制台。

最后是批改练习并存储的代码：

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class MathExercisesChecker {
    public static void main(String[] args) {
        String exercisesFile = "math_exercises.txt"; // 习题文件名
        String answersFile = "math_answers.txt"; // 答案文件名
        String resultFile = "math_result.txt"; // 批改结果文件名

        try {
            BufferedReader exercisesReader = new BufferedReader(new FileReader(exercisesFile));
            BufferedReader answersReader = new BufferedReader(new FileReader(answersFile));
            BufferedWriter resultWriter = new BufferedWriter(new FileWriter(resultFile));
            List<String> exercises = new ArrayList<>();
            List<String> answers = new ArrayList<>();
            String line;
            // 读取习题和答案
            while ((line = exercisesReader.readLine()) != null) {
                exercises.add(line.trim());
            }
            while ((line = answersReader.readLine()) != null) {
                answers.add(line.trim());
            }
            exercisesReader.close();
            answersReader.close();
            // 批改习题
            for (int i = 0; i < exercises.size(); i++) {
                String exercise = exercises.get(i);
                String answer = answers.get(i);
                String result;
                if (exercise.endsWith("+ ")) { // 加法
                    int num1 = Integer.parseInt(exercise.substring(0, exercise.indexOf("+")).trim());
                    int num2 = Integer.parseInt(answer.trim());
                    int correctResult = num1 + num2;
                    result = correctResult == Integer.parseInt(exercise.substring(exercise.indexOf("=") + 1, exercise.length() - 1).trim()) ? "Correct" : "Incorrect";
                } else { // 减法
                    int num1 = Integer.parseInt(exercise.substring(0, exercise.indexOf("-")).trim());
                    int num2 = Integer.parseInt(answer.trim());
                    int correctResult = num1 - num2;
                    result = correctResult == Integer.parseInt(exercise.substring(exercise.indexOf("=") + 1, exercise.length() - 1).trim()) ? "Correct" : "Incorrect";
                }
                // 写入批改结果文件
                resultWriter.write(exercise + answer + result + "\n");
            }
            resultWriter.close();
            System.out.println("Math exercises checked successfully!");
        } catch (IOException e) {
            System.out.println("Error occurred while checking math exercises.");
            e.printStackTrace();
        }
    }
}

代码中通过设置`exercisesFile`、`answersFile`和`resultFile`变量来指定习题文件、答案文件和批改结果文件的文件名，可以根据需要进行修改。批改结果会存储在名为`math_result.txt`的文件中。