通过引用更新HashMap值将用上次更新的值替换所有值

import java.util.HashMap;
import java.util.Map;

public class HashMapExample {
    public static void main(String[] args) {
        Map<String, MyObject> map = new HashMap<>();
        
        MyObject obj1 = new MyObject("value1");
        map.put("key1", obj1);
        
        MyObject obj2 = new MyObject("value2");
        map.put("key2", obj2);
        
        // 错误的引用更新方式
        MyObject temp = map.get("key1");
        temp.setValue("newValue");
        
        System.out.println(map);
    }
}

class MyObject {
    private String value;
    
    public MyObject(String value) {
        this.value = value;
    }
    
    public void setValue(String value) {
        this.value = value;
    }
    
    @Override
    public String toString() {
        return "MyObject{" +
                "value='" + value + '\'' +
                '}';
    }
}

import java.util.HashMap;
import java.util.Map;

public class HashMapExample {
    public static void main(String[] args) {
        Map<String, MyObject> map = new HashMap<>();
        
        MyObject obj1 = new MyObject("value1");
        map.put("key1", obj1);
        
        MyObject obj2 = new MyObject("value2");
        map.put("key2", obj2);
        
        // 正确的更新方式
        MyObject temp = map.get("key1");
        map.put("key1", new MyObject(temp.getValue() + "_updated"));
        
        System.out.println(map);
    }
}

class MyObject {
    private String value;
    
    public MyObject(String value) {
        this.value = value;
    }
    
    public String getValue() {
        return value;
    }
    
    public void setValue(String value) {
        this.value = value;
    }
    
    @Override
    public String toString() {
        return "MyObject{" +
                "value='" + value + '\'' +
                '}';
    }
}