java中截取string字符串和以逗号分割，StringBuffer的运用

「爱情、让人受尽委屈。」 2022-06-02 09:58 488阅读 0赞

package com.yanshu.test;  
  
  
import com.yanshu.utils.ConnSql;  
  
  
public class StringBu \{  
  
/\*\*  
\* 传入参数即存储名称预编译处理  
\* @param storageName 存储过程的名称  
\* @param size 参数的数量  
\* @return 返回存储过程的参数集  
\*/  
public static String storageNameHandle(String storageName, Integer size) \{  
  
  
// 参数没有，直接返回存储名  
if (size <= 0) \{  
return storageName;  
\}  
// 预处理参数  
String params = "?";  
// 参数拼接  
for (int i = 1; i < size; i++) \{  
params += ",?";  
\}  
String newstorageName = storageName + "(" + params + ")";  
  
  
return newstorageName;  
  
  
\}  
/\*\*  
\*   
\*/  
public static void getString()  
\{  
String string="abc,dde,rrrd,sdmj,rete,ssdfd,";  
String substring = string.substring(0, string.length()-1);//截取最后一个  
System.out.println(substring);  
String\[\] split = substring.split(",");//以逗号分割  
System.out.println(split.length);  
for (String string2 : split) \{  
System.out.println("string2-->>>"+string2);  
\}  
  
  
\}  
  
/\* String str = "";   
StringBuffer sb = new StringBuffer();   
long start = 0L;   
long end = 0L;   
start = System.currentTimeMillis();   
for (int i = 0; i < 9999; i++) \{   
str = str + "a";   
  
\}   
System.out.println("str-->>"+str);  
end = System.currentTimeMillis();   
System.out.println("使用string的时间是:" + (end - start) + "毫秒!");   
  
  
start = System.currentTimeMillis();   
for (int i = 0; i < 9999; i++) \{   
sb.append("a");   
\}   
end = System.currentTimeMillis();   
System.out.println("使用StringBuffer的时间是:" + (end - start) + "毫秒!"); \*/  
public static void getStringBuffer()  
\{  
Long start=0L;  
Long end=0L;  
  
String string="";  
StringBuffer stringBuffer=new StringBuffer();  
start=System.currentTimeMillis();  
for(int i=0;i<9999;i++)  
\{  
string+=i+"a";  
\}  
System.out.println(string);  
end=System.currentTimeMillis();  
System.out.println("使用string用了多少秒:"+(end-start)+"mm");  
  
start=System.currentTimeMillis();  
for(int j=0;j<9999;j++)  
\{  
stringBuffer.append("a");  
  
\}  
System.out.println(stringBuffer.length());  
end=System.currentTimeMillis();  
System.out.println("使用StringBuffer的时间是:" + (end - start) + "毫秒!");  
  
  
/\* for (String string : ids) \{  
idd.append("'"+string+"',");  
\}   
if(idd.length()>0)\{  
idd.deleteCharAt(idd.length()-1);  
\}\*/  
String string2="a,b,c,d,e,f,g,j,k,m,n,";  
String substring = string2.substring(0, string2.length()-1);  
System.out.println(string2);  
String\[\] split = substring.split(",");  
System.out.println(split.length);  
StringBuffer buffer=new StringBuffer();  
buffer.append("\[");  
for(String string3:split)  
\{  
buffer.append(string3+",");  
\}  
//相当于-->>>>String substring = string2.substring(0, string2.length()-1);   
if(buffer.length()>0)  
\{  
buffer.deleteCharAt(buffer.length()-1);  
\}  
buffer.append("\]");  
System.out.println(buffer);  
  
  
  
\}  
  
 static String useStringBuilder()\{  
       StringBuilder builder = new StringBuilder();  
       for (int i=0; i<9999; ++i)\{  
           builder.append("as");  
       \}  
  
  
       return builder.toString();  
   \}  
   
 public static  void getSbf()  
 \{  
 StringBuffer sb = new StringBuffer("TestString");  
          sb.insert(4,false);  
          System.out.println(sb.toString());  
          StringBuffer sbs = new StringBuffer();  
            
            
          String user ="test";  
          String pwd = "123";  
          sbs.append("select \* from userInfo where username=")  
           .append(user)  
           .append("and pwd=")  
           .append(pwd);  
          System.out.println(sbs.toString());  
            
          StringBuffer sbss = new StringBuffer("Test");  
          sbss. deleteCharAt(1);  
          System.out.println(sbss);  
            
 \}  
  
public static void main(String\[\] args) \{  
/\*getString();  
String newstorageName = ConnSql.storageNameHandle("call op\_search\_flow\_port\_analysis\_trend ", 4);  
System.out.println("newstorageName=" + newstorageName);  
\*/  
  
//getStringBuffer();  
//useStringBuilder();  
getSbf();  
  
\}  
  
  
\}