Java字符串拼接常用方法总结

使用场景:用某个分隔符拼接字符串

  • 下边是我使用过的几种方式
    • 废话不多说,直接上代码
      • 初始数据
    • 1.使用流
    • 2.StringBuilder
    • 3.[StringJoiner](https://blog.csdn.net/qq_43417581/article/details/126076152?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522170478446616800186556680%2522%252C%2522scm%2522%253A%252220140713.130102334..%2522%257D&request_id=170478446616800186556680&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2~all~sobaiduend~default-2-126076152-null-null.142^v99^pc_search_result_base6&utm_term=StringJoiner&spm=1018.2226.3001.4187) (详情请点击,看的大佬的)
    • 4. Guava
    • 做一个性能测试
      • 执行10w次用时比较如下:
      • 执行100w次用时比较如下:

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:

在这里插入图片描述

执行100w次用时比较如下:

在这里插入图片描述
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。

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