在 Java 中更新 MultiKeyMap 中特定键的值

Question

我试图在 Java 中更新 MultiKeyMap 中特定键集的值，但不知道如何操作。

假设我想更新 (key1, key2, value1) 具有不同值 (key1, key2, value2) 的同一组键。

如果我简单地执行 put in MultiKeyMap 然后它会创建新行并且不会更新值。 replace() 也不起作用。

package com.example.demo;

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

import org.apache.commons.collections4.map.LinkedMap;
import org.apache.commons.collections4.map.MultiKeyMap;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;


@SpringBootApplication
public class DemoApplication {

    public static void main(String[] args) {
        //SpringApplication.run(DemoApplication.class, args);

        List<Double> list11 = new ArrayList<Double>();
        list11.add((double) 3);
        list11.add((double) 5000);
        
        List<Double> list22 = new ArrayList<Double>();
        list22.add((double) 7);
        list22.add((double) 2000);
        
        MultiKeyMap<String, List<Double>> multiKeyMap = new MultiKeyMap<String, List<Double>>();
        multiKeyMap.put("sourcecode11", "basecode11", "productcode11", list11);
        multiKeyMap.put("sourcecode22", "basecode22", "productcode22", list22);
        
        String source = "sourcecode11";
        String base = "basecode11";
        String product = "productcode11";
        
        if (multiKeyMap.containsKey(source, base, product)) {
            List<Double> fees = multiKeyMap.get(source, base, product);
            Double count = fees.get(0);
            Double amount = fees.get(1);
            
            count +=1;
            amount+=500;
            List<Double> list33 = new ArrayList<Double>();
            list33.add(count);
            list33.add(amount);
            multiKeyMap.
            multiKeyMap.replace(source, base, product, list33);
        }
        

    }

}

替换函数出错

not applicable for the arguments (String, String, String, List<Double>)

请提供更新 MultiKeyMap 值的解决方案。

maven 依赖：

<!-- https://mvnrepository.com/artifact/org.apache.commons/commons-collections4 -->
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-collections4</artifactId>
    <version>4.4</version>
</dependency>

Answer 1

这令人困惑。您正在通过获取 'count' 和 'amount'、递增它们然后附加递增的值作为两个 来处理列表 'fees'将新 值添加到列表中。请告诉我们那里发生了什么。

同样令人担忧的是，您似乎将 List 视为某种数据封装 class。

Answer 2

您可以使用 put 来用新值列表替换 (key1,key2,key3)。您的代码运行与此示例相符

    List<Double> list11 = new ArrayList<>();
    List<Double> list22 = new ArrayList<>();
    list22.add((double) 7);
    list22.add((double) 2000);

    MultiKeyMap<String, List<Double>> multiKeyMap = new MultiKeyMap<>();
    multiKeyMap.put("sourcecode11", "basecode11", "productcode11", list11);
    multiKeyMap.put("sourcecode22", "basecode22", "productcode22", list22);

    String source = "sourcecode22";
    String base = "basecode22";
    String product = "productcode22";

    if (multiKeyMap.containsKey(source, base, product)) {
        List<Double> fees = multiKeyMap.get(source, base, product);
        System.out.println("before :" + multiKeyMap);
        Double count = fees.get(0);
        Double amount = fees.get(1);
        count += 1;
        amount += 500;
        List<Double> list33 = new ArrayList<>();
        list33.add(count);
        list33.add(amount);
        multiKeyMap.put(source, base, product, list33);
        System.out.println("after :" + multiKeyMap);
    }

在 Java 中更新 MultiKeyMap 中特定键的值

Updating value of particular keys in MultiKeyMap in Java

java

collections

hashmap

multikey