java - 这个 final 变量将如何被赋值而不被初始化？

Question

我有一个最终变量，save，它是一些信息的可序列化类。我试图做的是将最终变量设置为可序列化类，但是我收到了一些相互矛盾的警告。我试图做到这一点，以便如果文件不可加载/不存在，它只会创建一个新实例，否则它将使用旧实例。

我目前的问题在构造函数打开、关闭和从 ObjectInputStream 读取对象时的代码中进行了注释

private final CannonSet save;


public CannonManager(ManCannon plugin) { // Warning that save is not initialized
    if (/* some conditional statement */) {
        //lot of code removed, unnecessary to problem
        //essentially, save was set conditionally here (loaded from file)
        this.save = new CannonSet();
    }
    if (this.save == null) {
        this.save = new CannonSet(); // Warning that save may have already been set
    }
}

Answer 1

看起来您只需要在整个方法范围内声明您的临时对象，在您正在检查 this.save 的底部测试它是否为 null，然后进行赋值。基本上，只有一行用于分配实例字段。缩写自您的代码:

public CannonManager(ManCannon plugin) {
    CannonSet temp = null;
    try{
       // stuff happens
       temp = (CannonSet) in.readObject();
    }catch( ... ){
       // exception handling
    }
    if(temp == null){
       this.save = new CannonSet();
    }else{
       this.save = temp;
     }
 }