blocks|key|590936|text|学习使用else。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|590937|由于value永远不会同时等于两个不相等的字符串，因此只有5种可能的结果--一个对应于您关心的每个值，另一个对应于“以上任何一个都不是”。但是，因为您的代码不会消除无法通过的测试，所以它有16个“可能”路径(2+%5E测试数量)，其中大多数永远不会被遵循。|590938|对于else，唯一存在的路径是实际可能发生的5个路径。|590939|String+value+=+some+methodx;
if+("apple".equals(value+))+{
++++method1;
}
else+if+("carrot".equals(value+))+{
++++method2;
}
else+if+("mango".equals(value+))+{
++++method3;
}
else+if+("orance".equals(value+))+{
++++method4;
}|code-block|syntax|javascript|590940|或者开始使用JDK7，它包括在switch语句中使用字符串的能力。当然，Java会将switch编译成类似if/else的结构……|590941|entityMap^0|4|4|0|2|5|0|2|4|0|0|F|6|16|6|1H|2|1K|4|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|V|8|@$9|W|A|X|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|Y|8|@$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|J|3|K|5|L|7|11|8|@]|D|@]|E|$M|N]]|$1|O|3|P|5|6|7|12|8|@$9|13|A|14|B|C]|$9|15|A|16|B|C]|$9|17|A|18|B|C]|$9|19|A|1A|B|C]]|D|@]|E|$]]|$1|Q|3|-4|5|6|7|1B|8|@]|D|@]|E|$]]]|R|$]]

Learn to use <code>else</code>.

Since <code>value</code> will never be equal to two unequal strings at once, there are only 5 possible outcomes -- one for each value you care about, plus one for "none of the above". But because your code doesn't eliminate the tests that can't pass, it has 16 "possible" paths (2 ^ the number of tests), of which most will never be followed.

With <code>else</code>, the only paths that exist are the 5 that can actually happen.

<pre><code>String value = some methodx;
if ("apple".equals(value )) {
 method1;
}
else if ("carrot".equals(value )) {
 method2;
}
else if ("mango".equals(value )) {
 method3;
}
else if ("orance".equals(value )) {
 method4;
}
</code></pre>

Or start using JDK 7, which includes the ability to use strings in a <code>switch</code> statement. Course, Java will just compile the <code>switch</code> into an <code>if</code>/<code>else</code> like construct anyway...

blocks|key|375218|text|Java+(版本7之前)不支持switch/case中的字符串。但是您可以通过使用枚举来实现所需的结果。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|375219|private+enum+Fruit+{
++++apple,+carrot,+mango,+orange;
}

String+value;+//+assume+input
Fruit+fruit+=+Fruit.valueOf(value);+//+surround+with+try/catch

switch(fruit)+{
++++case+apple:
++++++++method1;
++++++++break;
++++case+carrot:
++++++++method2;
++++++++break;
++++//+etc...
}|code-block|syntax|javascript|375220|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|$]]

Java (before version 7) does not support String in switch/case. But you can achieve the desired result by using an enum.

<pre><code>private enum Fruit {
 apple, carrot, mango, orange;
}

String value; // assume input
Fruit fruit = Fruit.valueOf(value); // surround with try/catch

switch(fruit) {
 case apple:
 method1;
 break;
 case carrot:
 method2;
 break;
 // etc...
}
</code></pre>

blocks|key|375265|text|Java不支持Switch-case+with+String。我想this+link可以帮到你。:)|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|375266|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/338206/switch-statement-with-strings-in-java^0|X|4|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

Java does not support Switch-case with String. I guess <a href="https://stackoverflow.com/questions/338206/switch-statement-with-strings-in-java">this</a> link can help you. :)

blocks|key|375308|text|要降低圈复杂度，请使用map：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|375309|Map<String,Callable<Object>>+map+=+new+HashMap+<+>+(+)+;
map+.+put+(+"apple"+,+new+Callable<Object>+()+{+public+Object+call+(+method1+(+)+;+return+null+;+}+)+;
...
map+.+get+(+x+)+.+call+(+)+;|code-block|syntax|javascript|375310|或多态|375311|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|$]]

To reduce cyclomatic complexity use a map:

<pre><code>Map&lt;String,Callable&lt;Object&gt;&gt; map = new HashMap &lt; &gt; ( ) ;
map . put ( "apple" , new Callable&lt;Object&gt; () { public Object call ( method1 ( ) ; return null ; } ) ;
...
map . get ( x ) . call ( ) ;
</code></pre>

or polymorphism

blocks|key|591168|text|这是一种可能的1.7之前版本的方式，我不推荐：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|591169|public+class+PoorSwitch
{
++++final+static+public+int+poorHash+(String+s)+{
++++++++long+l+=+0L;
++++++++for+(char+c:+s.toCharArray+())+{
++++++++++++l+=+97*l+%2B+c;
++++++++}
++++++++return+(int)+l;
++++}

++++public+static+void+main+(String+args[])
++++{
++++++++String+param+=+"foo";
++++++++if+(args.length+==+1)
++++++++{
++++++++++++param+=+args[0];
++++++++}
++++++++//+uncomment+these+lines,+to+evaluate+your+hash
++++++++//+test+("foo");
++++++++//+test+("bar");
++++++++switch+(poorHash+(param))+{
++++++++++++//+this+doesn't+work,+since+you+need+a+literal+constant
++++++++++++//+so+we+have+to+evaluate+our+hash+beforehand:
++++++++++++//+case+poorHash+("foo"):+{
++++++++++++case+970596:+{
++++++++++++++++System.out.println+("Foo!");
++++++++++++++++break;
++++++++++++}
++++++++++++//+case+poorHash+("bar"):+{
++++++++++++case+931605:+{
++++++++++++++++System.out.println+("Bar!");
++++++++++++++++break;
++++++++++++}
++++++++++++default:+{
++++++++++++++++System.out.println+("unknown\t"+%2B+param);
++++++++++++++++break;
++++++++++++}
++++++++}
++++}

++++public+static+void+test+(String+s)
++++{
++++++++System.out.println+("Hash:\t+"+%2B+s+%2B+"+=\t"+%2B+poorHash+(s));
++++}
}|code-block|syntax|javascript|591170|也许你可以在生成的代码中使用这样的技巧。否则我就不推荐它了。哈希冲突的可能性并不会让我担心，但是如果把某些东西弄混了(剪切和粘贴)，就很难找到错误。931605不是一个好的文档。|591171|把它当作概念的证明，当作好奇心。|591172|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Here is a possible pre-1.7 way, which I can't recommend: 

<pre><code>public class PoorSwitch
{
 final static public int poorHash (String s) {
 long l = 0L;
 for (char c: s.toCharArray ()) {
 l = 97*l + c;
 }
 return (int) l;
 }

 public static void main (String args[])
 {
 String param = "foo";
 if (args.length == 1)
 {
 param = args[0];
 }
 // uncomment these lines, to evaluate your hash
 // test ("foo");
 // test ("bar");
 switch (poorHash (param)) {
 // this doesn't work, since you need a literal constant
 // so we have to evaluate our hash beforehand:
 // case poorHash ("foo"): {
 case 970596: {
 System.out.println ("Foo!");
 break;
 }
 // case poorHash ("bar"): {
 case 931605: {
 System.out.println ("Bar!");
 break;
 }
 default: {
 System.out.println ("unknown\t" + param);
 break;
 }
 }
 }

 public static void test (String s)
 {
 System.out.println ("Hash:\t " + s + " =\t" + poorHash (s));
 }
}
</code></pre>

Maybe you could work with such a trick in a generated code. Else I can't recommend it. Not so much that the possibility of a hash collision makes me worry, but if something is mixed up (cut and paste), it is hard to find the error. 931605 is not a good documentation. 

Take it just as proof of concept, as curiosity.

blocks|key|591219|text|我们可以只在数据类型兼容的int上应用Switch+:short、Shor、byte、Byte、int、Integer、char、Character或enum类型。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|591220|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|$]]

We can apply Switch just on data type compatible int :short,Shor,byte,Byte,int,Integer,char,Character or enum type.

blocks|key|591284|text|使用Switch语句计算String变量已经在Java+SE+7中实现了，因此它只适用于Java7。您还可以看看这个新的feature是如何在JDK7中实现的。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|591285|entityMap|0|LINK|mutability|MUTABLE|url|http://openjdk.java.net/projects/jdk7/features/|1|http://docs.oracle.com/javase/tutorial/displayCode.html?code=http://docs.oracle.com/javase/tutorial/java/nutsandbolts/examples/StringSwitchDemo.java^0|C|6|N|9|0|1O|7|1|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]]|D|@$9|S|A|T|1|U]|$9|V|A|W|1|X]]|E|$]]|$1|F|3|-4|5|6|7|Y|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]|N|$5|I|J|K|E|$L|O]]]]

Evaluating <code>String</code> variables with a switch statement have been implemented in <a href="http://openjdk.java.net/projects/jdk7/features/" rel="nofollow">Java SE 7</a>, and hence it only works in java 7. You can also have a look at how this new <a href="http://docs.oracle.com/javase/tutorial/displayCode.html?code=http://docs.oracle.com/javase/tutorial/java/nutsandbolts/examples/StringSwitchDemo.java" rel="nofollow">feature</a> is implemented in JDK 7.

blocks|key|591289|text|String+value+=+someMethod();
switch(0)+{
default:
++++if+("apple".equals(value))+{
++++++++method1();
++++++++break;
++++}
++++if+("carrot".equals(value))+{
++++++++method2();
++++++++break;
++++}
++++if+("mango".equals(value))+{
++++++++method3();
++++++++break;
++++}
++++if+("orance".equals(value))+{
++++++++method4();
++++++++break;
++++}
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|591290|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>String value = someMethod();
switch(0) {
default:
 if ("apple".equals(value)) {
 method1();
 break;
 }
 if ("carrot".equals(value)) {
 method2();
 break;
 }
 if ("mango".equals(value)) {
 method3();
 break;
 }
 if ("orance".equals(value)) {
 method4();
 break;
 }
}
</code></pre>

blocks|key|375546|text|不是很漂亮，但这是另一种方式：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|375547|String+runFct+=+
++++++++queryType.equals("eq")+?+"method1":
++++++++queryType.equals("L_L")?+"method2":
++++++++queryType.equals("L_R")?+"method3":
++++++++queryType.equals("L_LR")?+"method4":
++++++++++++"method5";
Method+m+=+this.getClass().getMethod(runFct);
m.invoke(this);|code-block|syntax|javascript|375548|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|$]]

Not very pretty but here is another way: 

<pre><code>String runFct = 
 queryType.equals("eq") ? "method1":
 queryType.equals("L_L")? "method2":
 queryType.equals("L_R")? "method3":
 queryType.equals("L_LR")? "method4":
 "method5";
Method m = this.getClass().getMethod(runFct);
m.invoke(this);
</code></pre>

blocks|key|591377|text|Java+8支持字符串切换大小写。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|591378|String+type+=+"apple";

switch(type){
++++case+"apple":
+++++++//statements
++++break;
++++default:
+++++++//statements
++++break;+}|code-block|syntax|javascript|591379|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|$]]

Java 8 supports string switchcase.

<pre><code>String type = "apple";

switch(type){
 case "apple":
 //statements
 break;
 default:
 //statements
 break; }
</code></pre>

blocks|key|591397|text|++++String+name,lname;
+name=+JOptionPane.showInputDialog(null,"Enter+your+name");
+++lname=+JOptionPane.showInputDialog(null,"Enter+your+father+name");
++++if(name.equals("Ahmad")){
+++++++JOptionPane.showMessageDialog(null,"welcome+"%2Bname);
++++}
++++if(lname.equals("Khan"))
+++JOptionPane.showMessageDialog(null,"Name+:+"%2Bname+%2B"\nLast+name+:"%2Blname+);+

++++else+{
+++++++JOptionPane.showMessageDialog(null,"try+again+"+);
++++}+
++}}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|591398|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code> String name,lname;
 name= JOptionPane.showInputDialog(null,"Enter your name");
 lname= JOptionPane.showInputDialog(null,"Enter your father name");
 if(name.equals("Ahmad")){
 JOptionPane.showMessageDialog(null,"welcome "+name);
 }
 if(lname.equals("Khan"))
 JOptionPane.showMessageDialog(null,"Name : "+name +"\nLast name :"+lname ); 

 else {
 JOptionPane.showMessageDialog(null,"try again " );
 } 
 }}
</code></pre>

I need to change the following <code>if</code>'s to a <code>switch</code>-<code>case</code> while checking for a <code>String</code>, to improve the cyclomatic complexity.

<pre><code>String value = some methodx;
if ("apple".equals(value)) {
 method1;
}

if ("carrot".equals(value)) {
 method2;
}

if ("mango".equals(value)) {
 method3;
}

if ("orange".equals(value)) {
 method4;
}
</code></pre>

But I am not sure what value I'm going to get.

Use string in switch case in java

Java

在检查if时，我需要将以下switch-case更改为String，以提高圈复杂度。String value = some methodx;if ("apple".equals(value)) {    method1;}if ("carrot".equals(value)) {    method2;}if ("ma...

问在java中以大小写形式使用字符串
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