Java字符串拼接常用方法总结

下边是我使用过的几种方式

1. 使用流
2. StringBuilder
3. StringJoiner
4. Guava
   当然，肯定要看业务场景来选择适当的方法，这里小编为大家做过性能测试。

废话不多说，直接上代码

初始数据

List<String> list = Arrays.asList("Luffy", "Zoro", "Nami", "Usopp", "Sanji", "Chopper", "Robin", "FRANKY", "BROOK");

1.使用流

String result = list.stream().collect(Collectors.joining(","));

2.StringBuilder

StringBuilder strBur = new StringBuilder();
list.forEach(val -> {strBur.append(val).append(",");
});
strBur.toString();

3.StringJoiner （详情请点击，看的大佬的）

StringJoiner strJor = new StringJoiner(",");
for(String str : list) {strJor.add(str);
}
strJor.toString();

4. Guava

String result = Joiner.on(",").join(list);

做一个性能测试

package com.cck;                                                                                                                                                                                                                                                                                                      
import java.util.Arrays;                                                                                                                                
import java.util.List;                                                                                                                                  
import java.util.StringJoiner;                                                                                                                          
import java.util.function.Consumer;                                                                                                                     
import java.util.stream.Collectors;                                                                                                                     import com.google.common.base.Joiner;                                                                                                                   public class Test {                                                                                                                                     // 1.使用流                                                                                                                                            public static Consumer<List<String>> testStream() {                                                                                                 return (list) -> {                                                                                                                              String result = list.stream().collect(Collectors.joining(","));                                                                             };                                                                                                                                              }                                                                                                                                                   // 2.StringBuilder                                                                                                                                  public static Consumer<List<String>> testStringBuilder() {                                                                                          return (list) -> {                                                                                                                              StringBuilder strBur = new StringBuilder();                                                                                                 list.forEach(val -> {                                                                                                                       strBur.append(val).append(",");                                                                                                         });                                                                                                                                         strBur.toString();                                                                                                                          };                                                                                                                                              }                                                                                                                                                   // 3.StringJoiner                                                                                                                                   public static Consumer<List<String>> testStringJoiner() {                                                                                           return (list) -> {                                                                                                                              StringJoiner strjor = new StringJoiner(",");                                                                                                for(String str : list) {                                                                                                                    strjor.add(str);                                                                                                                        }                                                                                                                                           strjor.toString();                                                                                                                          };                                                                                                                                              }                                                                                                                                                   // 4.Guava                                                                                                                                          public static Consumer<List<String>> testGuava() {                                                                                                  return (list) -> {                                                                                                                              String result = Joiner.on(",").join(list);                                                                                                  };                                                                                                                                              }                                                                                                                                                   public static void test(Consumer<List<String>> consumer, List<String> list, String msg) {                                                           long start = System.currentTimeMillis();                                                                                                        for (int i = 0; i < 1000000; i++) {                                                                                                             consumer.accept(list);                                                                                                                      }                                                                                                                                               long end = System.currentTimeMillis();                                                                                                          System.out.println(msg + " need time : " + (end - start));                                                                                      }                                                                                                                                                   public static void main(String[] args) {                                                                                                            List<String> list = Arrays.asList("Luffy", "Zoro", "Nami", "Usopp", "Sanji", "Chopper", "Robin", "FRANKY", "BROOK");   test(testStream(),        list, "1.使用流");                                                                                                              test(testStringBuilder(), list, "2.StringBuilder");                                                                                             test(testStringJoiner(),  list, "3.StringJoiner");                                                                                               test(testGuava(),         list, "4.Guava");                                                                                                             }                                                                                                                                                   }                         

执行10w次用时比较如下：

执行100w次用时比较如下：

感觉需要根据运算量去决定用哪种方法。
在没特别要求的情况下，自己还是使用Guava的多一些，因为看起来好看些。