blocks|key|1771902|text|当您调用该方法时，您将把名称作为参数传递给您的参数name和surname。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1771903|Example+test+=+new+Example("Derrick",+"Hamilton");|code-block|syntax|javascript|1771904|然后，这些名称将存储在从该类创建的对象中。参数name和surname只是数据的临时持有者。在构造函数完成之后，这些变量将不复存在。|1771905|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

When you call the method you will pass the names as arguments to your parameters name and surname.

<pre><code>Example test = new Example("Derrick", "Hamilton");
</code></pre>

The names then will be stored in the object created from the class. The parameters name and surname are just temporary holders for the data. After the constructor is complete these variables will cease to exist.

blocks|key|1483157|text|在这种情况下，firstName和secondName+(作为函数参数)只有方法级别的作用域，因此一旦此方法返回控制，数据就会丢失。另一方面，name和surname将被存储，并可用于对此构造函数创建的对象的其他调用。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1483158|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

In this case, firstName and secondName (as function parameters) only have method level scope, therefore as soon as control returns from this method, the data will be lost. On the other hand, name and surname will be stored and available for other calls into the object created by this constructor.

blocks|key|1483170|text|这些不是相同类型的变量：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1483171|1483172|firstName和secondName是方法参数。一旦方法结束，这些变量就会从scope|unordered-list-item|offset|length|style|CODE|1483173|name中消失，而surname则是类中的字段。只要该类的实例存在，它们就会一直“附加”到该类的实例上。|1483174|1483175|下面是一个例子，说明了这意味着什么：|1483176|String+a+=+"Hello";
String+b+=+"World";
//+For+the+duration+of+the+constructor,+a+becomes+firstName,
//+and+b+becomes+secondName
Example+e+=+new+Example(a,+b);
//+Once+the+constructor+exists,+firstName+and+secondName+disappear.
//+Resetting+a+and+b+after+the+call+is+no+longer+relevant
a+=+"Quick+brown+fox+jumps";
b+=+"over+the+lazy+dog";
System.out.println(e.getName()%2B"+"%2Be.getSurname());|code-block|syntax|javascript|1483177|a和b的值已经改变，但存储在Example中的值仍然设置为您传递给构造函数的值。|1483178|entityMap^0|0|0|0|9|A|A|0|0|4|9|7|0|0|0|0|0|1|2|1|E|7|0^^$0|@$1|2|3|4|5|6|7|X|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|Z|8|@$F|10|G|11|H|I]|$F|12|G|13|H|I]]|9|@]|A|$]]|$1|J|3|K|5|E|7|14|8|@$F|15|G|16|H|I]|$F|17|G|18|H|I]]|9|@]|A|$]]|$1|L|3|-4|5|6|7|19|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|1A|8|@]|9|@]|A|$]]|$1|O|3|P|5|Q|7|1B|8|@]|9|@]|A|$R|S]]|$1|T|3|U|5|6|7|1C|8|@$F|1D|G|1E|H|I]|$F|1F|G|1G|H|I]|$F|1H|G|1I|H|I]]|9|@]|A|$]]|$1|V|3|-4|5|6|7|1J|8|@]|9|@]|A|$]]]|W|$]]

These are not the same kinds of variables:

<ul>
<li><code>firstName</code> and <code>secondName</code> are method parameters. As soon as the method is over, these variables go out of scope</li>
<li><code>name</code> and <code>surname</code>, on the other hand, are fields in a class. They remain "attached" to the instance of that class for as long as the instance exists.</li>
</ul>

Here is an illustration of what that means:

<pre><code>String a = "Hello";
String b = "World";
// For the duration of the constructor, a becomes firstName,
// and b becomes secondName
Example e = new Example(a, b);
// Once the constructor exists, firstName and secondName disappear.
// Resetting a and b after the call is no longer relevant
a = "Quick brown fox jumps";
b = "over the lazy dog";
System.out.println(e.getName()+" "+e.getSurname());
</code></pre>

The valuesof <code>a</code> and <code>b</code> have changed, but the values stored in <code>Example</code> remain set to what you passed to the constructor.

blocks|key|1771980|text|你最好写成这样(好的实践)：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1771981|Example(String+firstName,+String+secondName)+{
++++this.name+=+firstName;
++++this.surname+=+secondName;
}|code-block|syntax|javascript|1771982|这指的是这个对象。firstname和secondname都是您稍后要传递的参数。因此，您为示例对象的字段分配了两个值|1771983|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

<h3>You should best write it like this (good practice):</h3>
<pre><code>Example(String firstName, String secondName) {
 this.name = firstName;
 this.surname = secondName;
}
</code></pre>
This refers to this object. firstname and secondname are both parameters you will pass in later. So you are assigning two values to the fields of your Example object

blocks|key|1771998|text|name和surname是在一个名为Example的类中定义的实例(成员)变量。当您创建Example类的对象时，内存将分配给这两个变量，并按默认值进行初始化。这些变量的作用域将一直保留到对象存在。你可以通过object的引用来访问这些变量。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1771999|firstName和secondName是局部变量(方法参数)，一旦方法出来，这些变量的作用域就不存在了。您不能在方法之外访问这些变量。|1772000|在示例方法中，这不是通用方法，它是一个示例类构造器。当您通过传递fistName和secondName的值来创建示例对象时，它将调用参数构造函数，并将值从firstname设置为name，将secondName设置为surname。|1772001|作为最佳实践，请始终使用参数构造函数定义默认构造函数。|1772002|Example()
{
}|code-block|syntax|javascript|1772003|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|Q|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|R|8|@]|9|@]|A|$]]|$1|H|3|I|5|J|7|S|8|@]|9|@]|A|$K|L]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

name and surname are the instance(member) variable defined in a class called Example. When you create the object of Example class, memory get allocated to these two variable and initialized by default value. Scope of these variable remain till the object exists. You can access these variable with the reference of object.

firstName and secondName are the local variable(method parameter), once you come out the method,scope of these variable not exists. You can't access these variable outside the method.

in the Example method this is not the general method its a Example class contructor. When you create the Example object by passing the value for fistName and secondName it will call the parameter constructor and set the value from firstname to name and secondName to surname.

For best practice always define default constructor with parameter constructor.

<pre><code>Example()
{
}
</code></pre>

I don't understand why this is done:

<pre><code>public class Example {
 private String name;
 private String surname;

 Example(String firstName, String secondName) {
 name = firstName;
 surname = secondName;
 }
 // whatever other code goes here
}
</code></pre>

I don't see why I'd need to set <code>name = firstName</code> and <code>surname = secondName</code>. Why can't I just set <code>name</code> and <code>surname</code> directly?

Why assign a variable to another variable?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我不明白为什么要这样做：public class Example {    private String name;    private String surname;    Example(String firstName, String secondName) {        name = firstName;...

问为什么要将一个变量赋给另一个变量呢？
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问为什么要将一个变量赋给另一个变量呢？EN