当我们仅仅需要a+b 的时候，两个字符串链接任何方法的效率基本一样，都在0.0001毫秒内就可以完成。不过如果需要1万次，10000万次，就会发现string自身的join速度显著下降
package com.java.lang;
public class StringTest {
int MAX = 10000; //1万次累加
public String Buffer(){
StringBuffer sb = new StringBuffer();
for(int i = 0; i < MAX;i++){
sb.append("abc");
}
return sb.toString();
}
public String Build(){
StringBuilder sb = new StringBuilder();
for(int i = 0; i < MAX;i++){
sb.append("abc");
}
return sb.toString();
}
public String StringJoin(){
String a = "";
for(int i = 0; i < MAX;i++){
a += "abc";
}
return a;
}
public static void main(String[] args) {
StringTest st = new StringTest();
long t1,t2,t;
t1 = System.currentTimeMillis();
st.Buffer();
t2 = System.currentTimeMillis();
t = t2 - t1;
System.out.println("StringBuffer 时间"+t);
t1 = System.currentTimeMillis();
st.Build();
t2 = System.currentTimeMillis();
t = t2 - t1;
System.out.println("StringBuild 时间"+t);
t1 = System.currentTimeMillis();
st.StringJoin();
t2 = System.currentTimeMillis();
t = t2 - t1;
System.out.println("String 自身链接 时间"+t);
}
}java StringBuffer,StringBuilder,String自身连接效率对比,布布扣,bubuko.com
java StringBuffer,StringBuilder,String自身连接效率对比
原文：http://blog.csdn.net/ghjhot/article/details/26268751