将多个字符串组合成一个JAVA

Question

我有一组strings想要组合成一个String所有用昏迷分隔的句子(*.csv)

以下是它与我的关系:

String dataContainer;

for(String tempString:setInput){
     String finalString = "," + tempString + "," ;   
}

这不适合我:(
但它应该为Set ex做:

Set<String> setInput = new TreeSet();
setInput.add("Dog");
setInput.add("Cat");
setInput.add("Mouse");

生成字符串:

,Dog,,Cat,,Mouse,

Answer 1

最好使用 StringBuilder

 StringBuilder sb= new StringBuilder();

for(String tempString:setInput){
   sb.append(",").append(tempString).append(",");   
 }

Answer 2

你intializing每次都在做 结果字符串.

实际上,你想做

String finalString ="";
for(String tempString:setInput){
      finalString += "," + tempString + "," ;   
}

但上述方法会导致多次String创作.

但我建议去StringBuilder.

 StringBuilder finalStringb =new StringBuilder();
    for(String tempString:setInput){
          finalStringb.append(",").append(tempString).append(",") ;   
    }

String finalS = finalStringb.toString();

Answer 3

或者我们可以使用Java 8 Stream

String joined = Stream.of("A", "B", "C").collect(Collectors.joining("delimiter", "prefix", "suffix"));

要么

Directly Use StringJoiner class

要么

new StringBuilder().add("A").add("B").toString()

等等