blocks|key|2671866|text|this关键字引用类的实例。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2671867|2671868|this(512)引用以int作为Argument|unordered-list-item|2671869|this.field的类的构造函数，引用class|2671870|this.method()的字段引用|2671871|类的方法|2671872|toString()方法继承自Object，但可以在子类中重写以获得更有意义的输出。|2671873|entityMap^0|0|4|0|0|0|9|0|0|A|0|0|D|0|0|0|A|0^^$0|@$1|2|3|4|5|6|7|T|8|@$9|U|A|V|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|W|8|@]|D|@]|E|$]]|$1|G|3|H|5|I|7|X|8|@$9|Y|A|Z|B|C]]|D|@]|E|$]]|$1|J|3|K|5|I|7|10|8|@$9|11|A|12|B|C]]|D|@]|E|$]]|$1|L|3|M|5|I|7|13|8|@$9|14|A|15|B|C]]|D|@]|E|$]]|$1|N|3|O|5|6|7|16|8|@]|D|@]|E|$]]|$1|P|3|Q|5|6|7|17|8|@$9|18|A|19|B|C]]|D|@]|E|$]]|$1|R|3|-4|5|6|7|1A|8|@]|D|@]|E|$]]]|S|$]]

The <code>this</code> keyword refers to the instance of the class.

<ul>
<li><code>this(512)</code> refers to a constructor of the class that takes an int as Argument</li>
<li><code>this.field</code> refers to a field of the class</li>
<li><code>this.method()</code> refers to a method of the class</li>
</ul>

The <code>toString()</code> method is inherited from Object but can be overridden in a subclass to get more meaningful output.

blocks|key|547873|text|this关键字引用类的当前实例(请参见http://docs.oracle.com/javase/tutorial/java/javaOO/thiskey.html)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|547874|toString()关键字不是一个关键字:它是一个方法名。它是在Object类中定义的，可以被重写。它所做的是创建类的文本表示形式(参见http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Object.html#toString()。|547875|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.oracle.com/javase/tutorial/java/javaOO/thiskey.html|1|http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Object.html#toString(%2529)^0|0|4|J|1R|0|0|0|A|W|6|1W|25|1|0^^$0|@$1|2|3|4|5|6|7|R|8|@$9|S|A|T|B|C]]|D|@$9|U|A|V|1|W]]|E|$]]|$1|F|3|G|5|6|7|X|8|@$9|Y|A|Z|B|C]|$9|10|A|11|B|C]]|D|@$9|12|A|13|1|14]]|E|$]]|$1|H|3|-4|5|6|7|15|8|@]|D|@]|E|$]]]|I|$J|$5|K|L|M|E|$N|O]]|P|$5|K|L|M|E|$N|Q]]]]

The <code>this</code> keyword refers to the current instance of the class (see <a href="http://docs.oracle.com/javase/tutorial/java/javaOO/thiskey.html" rel="nofollow">http://docs.oracle.com/javase/tutorial/java/javaOO/thiskey.html</a>).

The <code>toString()</code> keyword isn't a keyword: it is a method name. It is defined in the <code>Object</code> class and can be overridden. What it does is creates the text representation of the class (see <a href="http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Object.html#toString()" rel="nofollow">http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Object.html#toString()</a>).

blocks|key|547914|text|this.something引用当前类中的object+something。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|BOLD|entityRanges|data|547915|this.method()引用当前类的方法|547916|this()引用当前类的构造函数|547917|toString()是一种用于创建对象的String表示的方法。因为Java中的每个类都是Object的子类，并且Object有toString()方法，所以每个类都有一个默认的toString()方法。通常，您需要覆盖默认的toString()才能获得有意义的结果。|547918|entityMap^0|0|E|S|9|L|6|0|0|D|J|2|0|0|6|C|4|0|0|A|K|6|19|6|1L|6|1S|A|2H|A|35|A|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]|$9|T|A|U|B|D]]|E|@]|F|$]]|$1|G|3|H|5|6|7|V|8|@$9|W|A|X|B|C]|$9|Y|A|Z|B|D]]|E|@]|F|$]]|$1|I|3|J|5|6|7|10|8|@$9|11|A|12|B|C]|$9|13|A|14|B|D]]|E|@]|F|$]]|$1|K|3|L|5|6|7|15|8|@$9|16|A|17|B|C]|$9|18|A|19|B|C]|$9|1A|A|1B|B|C]|$9|1C|A|1D|B|C]|$9|1E|A|1F|B|C]|$9|1G|A|1H|B|C]|$9|1I|A|1J|B|C]]|E|@]|F|$]]|$1|M|3|-4|5|6|7|1K|8|@]|E|@]|F|$]]]|N|$]]

<code>this.something</code> refers to object <code>something</code> in the current class. 

<code>this.method()</code> refers to a method of the current class

<code>this()</code> refers to constructor of the current class 

<code>toString()</code> is a method used to create <code>String</code> representation of an object. Since every class in Java is a sub-class of <code>Object</code> and <code>Object</code> has <code>toString()</code> method, every class has a default <code>toString()</code> method. Often you will need to override the default <code>toString()</code> in order to get meaningful results.

blocks|key|1100713|text|例如，如果您的类如下所示:+public+class+Database+{+public+Database+(int+port){+}}|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1100714|然后引用这个类的对象，你可以这样使用:+this(3306)；因此这个关键字被用来引用这个类|1100715|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

For example if your class is like the following:
public class Database {
 public Database (int port){
 }
}

Then to refer this class' object, you can use like so: this(3306); 
As a result this keyword is used for referring to the class

I am currently in the process of learning Java, and I have done what I could to try and understand what these two things mean and do, but I simply don't get it. I have done a lot of googling, and also checked around for past questions on the site, but I still don't get it. So far I know that "this" somehow refers to some kind of method/variable/object, but I just don't get how it can refer to any of these, without (in the examples I have seen) actually specifing what to refer to, they just use the keyword "this.something or this(532);", it does not make sense. Same story with toString, they is no logic in these two that I get. Anyways, can anyone explain these two keywords in a simple way to me, and tell me how they can be even remotely useful in any program. Thanks in advance.

What exactly do the keywoards "this" and "toString" mean and do?

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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我目前正处于学习Java的过程中，我已经尽我所能地尝试理解这两件事的含义和作用，但我就是不明白。我做了很多谷歌搜索，也在网站上查看了过去的问题，但我仍然不明白。到目前为止，我知道"this“以某种方式指的是某种方法/变量/对象，但我就是不明白它怎么能指这些方法/变量/对象，如果(在我见过的例子中)没有具体说明要指的是什...

问键盘上的"this“和"toString”到底是什么意思？
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问键盘上的"this“和"toString”到底是什么意思？EN