blocks|key|83333|text|我看到的解释如下：“加号”运算符定义如下：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|83334|83335|int+%2B+int+->+int+|unordered-list-item|83336|int%2B+String+->+String|83337|String+%2Bint+->+String|83338|83339|然后有以下行：(int%2B+int)+%2B+String)+%2B+int)+%2B+int)依次解析该操作，以以下操作结束：|83340|int(20)|83341|int(20)+%2B+|83342|int(10)+%2B+int(10)+->+->字符串(20+Hello)|83343|String+(20+Hello)+%2B+int+(20+)+->+String+(+20+Hello20)|83344|+String+(20+Hello20)%2B+int(10)+->+String+(20+Hello2010)|83345|)|83346|83347|entityMap^0|0|0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|11|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|12|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|13|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|14|8|@]|9|@]|A|$]]|$1|H|3|I|5|E|7|15|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|16|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|17|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|18|8|@]|9|@]|A|$]]|$1|O|3|P|5|E|7|19|8|@]|9|@]|A|$]]|$1|Q|3|R|5|E|7|1A|8|@]|9|@]|A|$]]|$1|S|3|T|5|E|7|1B|8|@]|9|@]|A|$]]|$1|U|3|V|5|E|7|1C|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|1D|8|@]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|1E|8|@]|9|@]|A|$]]|$1|Z|3|-4|5|6|7|1F|8|@]|9|@]|A|$]]]|10|$]]

The explanation I see is the following: the "plus" operator is defined as follows:

<ul>
<li>int + int -> int</li>
<li>int + String -> String</li>
<li>String + int -> String</li>
</ul>

You then have the following line: ((((int + int) + String) + int) + int)
Resolving the operation one after the other, you end with the following operations to resolve:

<ul>
<li>int(10) + int(10) -> int(20)</li>
<li>int(20) + String( Hello ) -> String (20 Hello)</li>
<li>String (20 Hello) + int(20) -> String (20 Hello 20)</li>
<li>String (20 Hello 20) + int(10) -> String (20 Hello 2010)</li>
</ul>

blocks|key|2709677|text|这是字符串连接。一旦添加了字符串，接下来的所有元素都将被添加到字符串中，而不是作为int。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2709678|String+a+=+10+%2B+5+%2B+"+result";|code-block|syntax|javascript|2709679|这是：|2709680|10+%2B+5+%2B+"+result";
15+%2B+"+result";
"15+result";

String+a+=+10+%2B+"+result+"+%2B+5+%2B+2;|2709681|变成：|2709682|"10+result+"+%2B+5+%2B+2;
"10+result+5"+%2B+2;
"10+result+52";+|2709683|确保在连接之前添加了ints：|2709684|String+a+=+10+%2B+"+result+"+%2B+(5+%2B+2);|2709685|编辑:至于|2709686|String+val+=+5+%2B+5;|2709687|这将导致问题，因为这两个元素都是ints。您在这里所做的不是连接，而是添加两个int，这将导致另一个int。|2709688|entityMap^0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|11|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|12|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|13|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|14|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|15|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|16|8|@]|9|@]|A|$]]|$1|Q|3|R|5|D|7|17|8|@]|9|@]|A|$E|F]]|$1|S|3|T|5|6|7|18|8|@]|9|@]|A|$]]|$1|U|3|V|5|D|7|19|8|@]|9|@]|A|$E|F]]|$1|W|3|X|5|6|7|1A|8|@]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]]|Z|$]]

It's String concatenation. As soon as there is a String added, all the next elements will be added to the String, not as an int.

<pre><code>String a = 10 + 5 + " result";
</code></pre>

Does this:

<pre><code>10 + 5 + " result";
15 + " result";
"15 result";

String a = 10 + " result " + 5 + 2;
</code></pre>

becomes:

<pre><code>"10 result " + 5 + 2;
"10 result 5" + 2;
"10 result 52"; 
</code></pre>

Make sure the ints are added before concatenation:

<pre><code>String a = 10 + " result " + (5 + 2);
</code></pre>

EDIT:
As for the

<pre><code>String val = 5 + 5;
</code></pre>

this will cause problems because both elements are ints. What you are doing here is not concatenating, but adding two ints, which results in another int.

blocks|key|2709738|text|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2709739|您不能这样做，因为5%2B5将返回一个整数，因此不能将其赋值为字符串数据类型|ordered-list-item|2709740|，如果您将10%2B10追加到string，那么它将返回一个字符串，因此您可以将其赋值给string+|2709741|--第一个10%2B10仍为整数，然后将其附加到string+=>+--它将返回到string|2709742|2709743|然后，使用整数20+=>将其添加为字符串，如果使用越来越多的整数添加该字符串，则该字符串将返回字符串。|2709744|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|-4|4|5|6|M|7|@]|8|@]|9|$]]|$1|A|3|B|4|C|6|N|7|@]|8|@]|9|$]]|$1|D|3|E|4|C|6|O|7|@]|8|@]|9|$]]|$1|F|3|G|4|C|6|P|7|@]|8|@]|9|$]]|$1|H|3|-4|4|5|6|Q|7|@]|8|@]|9|$]]|$1|I|3|J|4|5|6|R|7|@]|8|@]|9|$]]|$1|K|3|-4|4|5|6|S|7|@]|8|@]|9|$]]]|L|$]]

<ol>
<li>You can't do it like that because 5+5 will return an integer, therefore you can't assign it into string data type</li>
<li>If you append 10+10 then append it with string, it'll return a string, so you can assign it to string</li>
<li>The first 10+10 still count as integer then you append it with string => it'll return to string</li>
</ol>

then you add it with integer 20 => return as string that string will return string if you add it with more and more integer

blocks|key|1137100|text|你可以这样做|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1137101|public+class+Display+{++++
++++public+static+void+main(String[]+args)+{
++++++++String+val+=+10+%2B+10+%2B+"+Hello+"+%2B+(20+%2B+10);
++++++++System.out.println(val);
++++}++++
}|code-block|syntax|javascript|1137102|输出|1137103|20你好30|1137104|因为在字符串之后，所有下一个元素都将连接起来。|1137105|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

you can try like this

<pre><code>public class Display { 
 public static void main(String[] args) {
 String val = 10 + 10 + " Hello " + (20 + 10);
 System.out.println(val);
 } 
}
</code></pre>

output

20 Hello 30

because after string all next element will be concatenation

blocks|key|2709784|text|如果在附加字符串之前插入括号，则它将有效。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2709785|+public+static+void+main(String[]+args)+{
++++String+val+=+10+%2B+10+%2B+"+Hello+"+%2B(+20+%2B+10);
++++System.out.println(val);
}++|code-block|syntax|javascript|2709786|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

If you put parenthesis before appending to string it will work. 

<pre><code> public static void main(String[] args) {
 String val = 10 + 10 + " Hello " +( 20 + 10);
 System.out.println(val);
} 
</code></pre>

blocks|key|1139752|text|操作顺序很重要，也知道如何在屏幕后面计算这样的语句。查看下面关于如何评估您的代码的粗略描述。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1139753|加法和减法之前的乘法和除法。|1139754|在此代码中：|1139755|String+val+=+10+%2B+10+%2B+"+Hello+"+%2B+20+%2B+10;|code-block|syntax|javascript|1139756|评估结果如下：|1139757|Check+operations+for+multiplications+and+division
Nothing+found
Check+for+additions.
Integer+found.
Addition+found
Integer+found
Add+integer+to+integer.+
Remember+integer.
Addition+found
String+found.
Create+string+builder.
Add+remembered+integer+to+string+builder
Add+string+to+stringbuilder
Addition+found
integer+found
add+integer+to+string+builder
Addition+found
integer+found
add+integer+to+string+builder
return+string+from+string+builder.|1139758|如果您有一个附加项，那么首先执行：|1139759|https://ideone.com/aPlaPv|offset|length|1139760|String+val+=+10+%2B+10+%2B+"+Hello+"+%2B+20+*+10;|1139761|1139762|Check+operations+for+multiplication+and+division
Multiplication+found
Integer+found
Multiplication+found
Integer+found
Remember+multiplication
no+more+multiplications+found
Return+to+start
Check+for+additions.
Integer+found.
Addition+found
Integer+found
Add+integer+to+integer.+
Remember+integer.
Addition+found
String+found.
Create+string+builder.
Add+remembered+integer+to+string+builder
Add+string+to+stringbuilder
add+remembered+multiplication+result+to+string+builder
return+string+from+string+builder|1139763|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|0|0|0|0|0|0|P|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|16|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|17|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|18|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|19|8|@]|9|@]|A|$I|J]]|$1|K|3|L|5|6|7|1A|8|@]|9|@]|A|$]]|$1|M|3|N|5|H|7|1B|8|@]|9|@]|A|$I|J]]|$1|O|3|P|5|6|7|1C|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|1D|8|@]|9|@$S|1E|T|1F|1|1G]]|A|$]]|$1|U|3|V|5|H|7|1H|8|@]|9|@]|A|$I|J]]|$1|W|3|L|5|6|7|1I|8|@]|9|@]|A|$]]|$1|X|3|Y|5|H|7|1J|8|@]|9|@]|A|$I|J]]|$1|Z|3|-4|5|6|7|1K|8|@]|9|@]|A|$]]]|10|$11|$5|12|13|14|A|$15|R]]]]

Order of operations matters, also knowing how such a statement is evaluated behind the screen.
Check out the below rough description of how your code is evaluated.

multiplying and division before addition and substraction.

in this code:

<pre><code>String val = 10 + 10 + " Hello " + 20 + 10;
</code></pre>

it's evaluated like:

<pre><code>Check operations for multiplications and division
Nothing found
Check for additions.
Integer found.
Addition found
Integer found
Add integer to integer. 
Remember integer.
Addition found
String found.
Create string builder.
Add remembered integer to string builder
Add string to stringbuilder
Addition found
integer found
add integer to string builder
Addition found
integer found
add integer to string builder
return string from string builder.
</code></pre>

If you'd have an addition, that would be executed first:

<a href="https://ideone.com/aPlaPv" rel="nofollow noreferrer">https://ideone.com/aPlaPv</a>

<pre><code>String val = 10 + 10 + " Hello " + 20 * 10;
</code></pre>

It's evaluated like:

<pre><code>Check operations for multiplication and division
Multiplication found
Integer found
Multiplication found
Integer found
Remember multiplication
no more multiplications found
Return to start
Check for additions.
Integer found.
Addition found
Integer found
Add integer to integer. 
Remember integer.
Addition found
String found.
Create string builder.
Add remembered integer to string builder
Add string to stringbuilder
add remembered multiplication result to string builder
return string from string builder
</code></pre>

blocks|key|2709835|text|这些简单的问题把我弄糊涂了。这是简单的数学优先。当我们尝试连接数字与数字，它将是数字，如果其中一个提供是字符串，然后它将被转换为字符串。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2709836|字符串val+=+10+%2B+10+%2B“Hello”%2B+20+%2B+10；|2709837|+++number++=>+++string++=>+string+=>+string+++->+result+String|code-block|syntax|javascript|2709838|(数%2B数)%2B字符串)%2B数)%2B数)|2709839|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|O|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

These simple questions are confusing me. It's simple math with priority.
when we try to concatenate number with number it will be number if one of provided is string then it will be transformed to string.

String val = 10 + 10 + " Hello " + 20 + 10;

<pre><code> number =&gt; string =&gt; string =&gt; string -&gt; result String
</code></pre>

((((number + number) + string) + number) + number)

blocks|key|2709901|text|问题是java中操作数的相联性。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2709902|java中的"%2B“操作数具有从左到右的结合性，因此这意味着表达式10%2B10是第一个求值的表达式，因为它们是整数(10,10)，所以结果是整数(20)。|2709903|然后计算20+%2B“hello+"，因为它们是整数，java编译器将20转换为字符串。现在，string+%2B+string表达式生成一个字符串"20+hello“。|2709904|现在是问题所在|2709905|此时，由于"20+hello“是字符串，表达式"20+hello”%2B+20将20转换为字符串，结果是"20+hello+20".When添加了最后一个术语(10)，它被转换为字符串，并将连接到字符串"20+hello+20“中，生成"20+hello+2010”。|offset|length|style|BOLD|2709906|为了避免这种不方便，您可以在表达式中放置圆括号，|2709907|20+%2B+"+hello+"%2B+(+20+%2B+10+)|CODE|2709908|entityMap^0|0|0|0|0|2F|3|2L|13|0|0|O|0|0|R|0|R|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|W|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|X|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|Y|8|@$J|Z|K|10|L|M]|$J|11|K|12|L|M]]|9|@]|A|$]]|$1|N|3|O|5|6|7|13|8|@$J|14|K|15|L|M]]|9|@]|A|$]]|$1|P|3|Q|5|6|7|16|8|@$J|17|K|18|L|M]|$J|19|K|1A|L|R]]|9|@]|A|$]]|$1|S|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]]|T|$]]

The problem is the associativity of operand in java

The "+" operand in java have an associativity from left to right , so this means that the expression 10+10 is the first to evalutate and because these are integers (10,10) the result is integer (20). 
Then it evalutate 20 + " hello ", because they are an integer and a string the java compiler transform the 20 into a string. Now string + string expression produces a string "20 hello ". 

Now is the problem

at this point,because "20 hello " is a string, the expression "20 hello" + 20 transform 20 into a string and the result is "20 hello 20".When is added the last term (10) it is converted into a string and it is concatenated to the string "20 hello 20" making "20 hello 2010".

to avoid this inconvenient you can place round brackets in the expression, 
<code>20 + " hello "+ ( 20 + 10 )</code>

blocks|key|1137177|text|问题是您要在连接中传递给字符串的值。您需要指定具体查找的位置。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1137178|最好的方法是将加法值保留在括号内。|1137179|String+val+=+(10+%2B+10)+%2B+"+Hello"+%2B+(20+%2B+10);|code-block|syntax|javascript|1137180|或|1137181|String+val+=+10+%2B+10+%2B+"+Hello"+%2B+(20+%2B+10);|1137182|我建议在编译器编译代码时尽可能使用括号来避免这些小错误。|1137183|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|T|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|U|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|V|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

The problem is that the value you are passing to the string in concatenating. You need to specify where to look specifically. 

The best approach will be to leave the addition values in brackets.

<pre><code>String val = (10 + 10) + " Hello" + (20 + 10);
</code></pre>

or

<pre><code>String val = 10 + 10 + " Hello" + (20 + 10);
</code></pre>

I would suggest using brackets where possible to avoid getting these small errors when the compiler compiles the code.

<ol>
<li>We can't add the numbers in to string data type with out the string value,it will not compile</li>
</ol>

<pre><code>String val = 5+5;
</code></pre>

<ol start="2">
<li>We can add two or more numbers before appending the string.</li>
</ol>

<pre><code>String val = 10 + 10 + " Hello "
System.out.println(val);
</code></pre>

Output

<pre><code>20 Hello
</code></pre>

<ol start="3">
<li>Adding two numbers,append the value to the number but After appending the string value we can't add two or more numbers</li>
</ol>

<pre><code>public class Display { 
 public static void main(String[] args) {
 String val = 10 + 10 + " Hello " + 20 + 10;
 System.out.println(val);
 } 
}
</code></pre>

Output :

<pre><code>20 Hello 2010
</code></pre>

can anyone explain this?

How to add the two or more numbers in to string in java?

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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我们不能在没有字符串值的情况下将数字添加到字符串数据类型中，它不会编译String val = 5+5;我们可以在添加字符串之前添加两个或多个数字.String val = 10 + 10 + " Hello "System.out.println(val);输出20 Hello添加两个数字，将值追加到数字，但在追加字...

问如何在java中将两个或多个数字添加到字符串中？
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问如何在java中将两个或多个数字添加到字符串中？EN