List to comma separated String of Java7 and Java8 implemented respectively

  • 2021-09-24 22:24:22
  • OfStack

Requirements: Arrays. asList ("AA", "BB")-- > "AA,BB"

In Java 8

Adopt stream mode


List<String> strList = Arrays.asList("AA", "BB", "CC");
String newStr = strList.stream().collect(Collectors.joining(","));
System.out.println("Output:" + newStr); // Output:AA,BB,CC

Using the String. join () function, passing a separator to the function to conform to an iterator, the StringJoiner object will help us do everything


String newStr = String.join(",", strList);
System.out.println("Output:" + newStr); // Output:AA,BB,CC

In Java 7

Implementation of Java 7


List<String> strList = Arrays.asList("AA", "BB", "CC");
StringBuilder sb = new StringBuilder();
for (int i = 0; i < strList.size(); i++) {
    if (i != 0) {
        sb.append(",");
    }
    sb.append(strList.get(i));
}
System.out.println("Output:" + sb.toString()); // Output:AA,BB,CC

list and comma-split String interconversion (guava)


import com.alibaba.fastjson.JSON;
import com.google.common.base.Joiner;
import com.google.common.collect.Lists;
import com.google.common.base.Splitter;
        List<String> list = Lists.newArrayList("a","b","c"," ");
        String s = Joiner.on(",").join(list); //  Divided by commas 
        System.out.println(s); // a,b,c, 
        Splitter split = Splitter.on(',').trimResults().omitEmptyStrings(); //  Remove the front and back spaces && Emptying string
        List<String> list1 = split.splitToList(s);
        System.out.println(JSON.toJSONString(list1)); // ["a","b","c"]

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