将多个字符串合并为一个 JAVA
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Combine multiple strings into one JAVA
提问by user2762881
I have a set of stringswhich want to combine into one Stringwith all sentences separated with coma like (*.csv)
我有一组strings想要合并成一个String所有句子都用昏迷分隔的句子(*.csv)
here is how it goes with me:
这是我的情况：
String dataContainer;
for(String tempString:setInput){
String finalString = "," + tempString + "," ;
}
This doesn't work with me :(
But it should do for Set ex:
这对我不起作用:(
但它应该适用于 Set ex：
Set<String> setInput = new TreeSet();
setInput.add("Dog");
setInput.add("Cat");
setInput.add("Mouse");
to produce the string:
产生字符串：
,Dog,,Cat,,Mouse,
回答by Suresh Atta
What You are doing is intializingyour result string each time.
您所做的是 intializing每次的结果字符串。
Actually ,you want to do
其实你想做
String finalString ="";
for(String tempString:setInput){
finalString += "," + tempString + "," ;
}
But the above approach causes multiple Stringcreations.
但是上述方法会导致多次String创建。
But I suggest to go for StringBuilder.
但我建议去StringBuilder。
StringBuilder finalStringb =new StringBuilder();
for(String tempString:setInput){
finalStringb.append(",").append(tempString).append(",") ;
}
String finalS = finalStringb.toString();
回答by Ruchira Gayan Ranaweera
It is better to use StringBuilder
最好使用 StringBuilder
StringBuilder sb= new StringBuilder();
for(String tempString:setInput){
sb.append(",").append(tempString).append(",");
}
回答by Josh M
Alternatively, if you are using Java 8, you could try something like this:
或者，如果您使用的是 Java 8，则可以尝试以下操作：
public static String join(final Set<String> set){
return new StringBuilder(",").append(set.stream().collect(Collectors.joining(",,"))).append(",").toString();
}
public static void main(String args[]){
Set<String> setInput = new TreeSet<>();
setInput.add("Dog");
setInput.add("Cat");
setInput.add("Mouse");
System.out.println(join(setInput));
}
The output is:
输出是：
,Cat,,Dog,,Mouse,
,Cat,,Dog,,Mouse,
Although, I'm a little unsure to why you would want 2 commas in between each element and a comma at the start and end. If you just want one comma separating each element (and no comma at the start or end), modify the join(Set<String>)to look like this:
虽然，我有点不确定为什么要在每个元素之间使用 2 个逗号，并在开头和结尾使用逗号。如果您只想用一个逗号分隔每个元素（并且在开头或结尾处没有逗号），请将 修改join(Set<String>)为如下所示：
public static String join(final Set<String> set){
return set.stream().collect(Collectors.joining(",")); //change "," to ", " for spacing
}
After doing so, the new output would be:
这样做之后，新的输出将是：
Cat,Dog,Mouse
Cat,Dog,Mouse
回答by Bukhtawar
org.apache.commons.lang.StringUtils.join() can come in handy
org.apache.commons.lang.StringUtils.join() 可以派上用场
回答by Rituraj
Or we can use Java 8 Stream
或者我们可以使用 Java 8 Stream
String joined = Stream.of("A", "B", "C").collect(Collectors.joining("delimiter", "prefix", "suffix"));
Or
或者
Directly Use StringJoiner class
Or
或者
new StringBuilder().add("A").add("B").toString()
etc
等等
