泛型的上下限

创建了一个 Info 的泛型类，用来存储数据。

请您在 Solution 类中实现方法 upperLimit() 和 lowerLimit() 的功能。

符合要求通过时显示：

Verification passed.

验证失败，返回结果：

Verification failure.

 info.java

public class Info<T> {

    private T t;

    public void set(T t){
        this.t = t;
    }

    public T get(){
        return t;
    }
}

Main.java

import java.io.FileReader;
import java.io.PrintStream;
import java.lang.reflect.Method;
import java.lang.reflect.Type;
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {
    public static void main(String[] args) {
        PrintStream ps = null;
        try {
            String inputPath = args[0];
            String outputPath = args[1];
            Scanner in = new Scanner(new FileReader(inputPath));
            ps = new PrintStream(outputPath);

            // get data
            Solution solution = new Solution();
            Class<? extends Solution> aClass = solution.getClass();
            Method[] declaredMethods = aClass.getDeclaredMethods();
            int index = 0;
            for (Method md : declaredMethods) {
                if("upperLimit".equals(md.getName())) {
                    Type[] genericParameterTypes = md.getGenericParameterTypes();
                    for (Type type : genericParameterTypes) {
                        if (type.getTypeName().contains("Number")) {
                            index++;
                        }
                    }
                    if (md.getReturnType().getName().contains("Number")) {
                        index++;
                    }
                }
                if("lowerLimit".equals(md.getName())) {
                    Type[] genericParameterTypes = md.getGenericParameterTypes();
                    for (Type type : genericParameterTypes) {
                        if (type.getTypeName().contains("String")) {
                            index++;
                        }
                    }
                    if (md.getReturnType().getName().contains("Object")) {
                        index++;
                    }
                }
            }
            if (index < 4) {
                ps.println("Verification failure.");
                return;
            }

            Info<Integer> info = new Info<>();
            info.set(200);
            Number number = solution.upperLimit(info);
            if(!number.equals(200)) {
                ps.println("Verification failure.");
                return;
            }

            Info<String> infos = new Info<>();
            infos.set("Xx");
            Object oj = solution.lowerLimit(infos);
            if(!oj.equals("Xx")) {
                ps.println("Verification failure.");
                return;
            }
            ps.println("Verification passed.");
            ps.close();
            in.close();
        } catch (Exception e) {
            ps.println("Verification failure.");
        }
    }
}

 例解

Solution.java

import java.lang.reflect.Method;
import java.lang.reflect.Type;
import java.util.Arrays;

public class Solution {
    public Number upperLimit(Info<? extends Number>s){
        return s.get();
    }

    public Object lowerLimit(Info<? super String>s){
        return s.get();
    }
}