StringBuilder的常用方法:
1、append(String str):字符串连接,在原有的字符串之后连接str,也可以是append(int str),即把整形转换为string再连接;
2、toString():返回一个与构建起或缓冲器内容相同的字符串;
3、length():返回字符串的长度;
4、charAt(int index):返回在下表为index的字符
5、toLowerCase():大写字母格式化为小写
6、subString(int begin,int end):截取begin~end的字符,不包括end。
还有好多方法,这里不列举出来了,代码如下:
MyStringBuilder类:
package num;
public class MyStringBuilder {
private char[] value;
private int count;
public MyStringBuilder(String s) {
count = s.length();
value = new char[1000];
value = s.toCharArray();
}
public MyStringBuilder append(MyStringBuilder s){
count += s.count;
value = String.valueOf(value).concat(String.valueOf(s.value)).toCharArray();
return this;
}
public MyStringBuilder append(int i) {
value = String.valueOf(value).concat(String.valueOf(i)).toCharArray();
count += String.valueOf(i).length();
return this;
}
public int length(){
return count;
}
public char charAt(int index) {
char x = value[index];
return x;
}
public MyStringBuilder toLowerCase() {
value=String.valueOf(value).toLowerCase().toCharArray();
return this;
}
public MyStringBuilder subString(int begin,int end) {
char x[] = new char[end-begin+2];
for(int i=0;i<end-begin;i++)
{
x[i]=value[i+begin];
}
MyStringBuilder ans = new MyStringBuilder(String.valueOf(x));
return ans;
}
public String toString() {
String x = String.valueOf(value);
return x;
}
}
主类:
package num;
import java.util.Scanner;
public class mystringmain {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner scan = new Scanner(System.in);
MyStringBuilder ans = new MyStringBuilder(scan.next());
MyStringBuilder ex = new MyStringBuilder(scan.next());
int x=-100;
System.out.println("长度:"+ans.length());
System.out.println("输出第4个字符:"+ans.toString().toCharArray()[3]);
System.out.println("连接ans和ex:"+String.valueOf(ans.append(ex).toString().toCharArray()));
System.out.println("连接ans和x:"+String.valueOf(ans.append(x).toString().toCharArray()));
System.out.println("截取第2~6的字段:"+String.valueOf(ans.subString(2,6).toString().toCharArray()));
System.out.println("大写变小写:"+String.valueOf(ans.toLowerCase().toString().toCharArray()));
}
}
预览如下:
写在后面
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