java 用StringBuffer类写一个例子

public class Test
{
public static void main(String[] args)
{
StringBuffer a = new StringBuffer("One");
StringBuffer b = new StringBuffer("Two");
System.out.println ("begin a is :" + a);
System.out.println ("begin b is :" + b);
System.out.println ("swap start");
Test.swap(a,b);
System.out.println ("swap end\n");
System.out.println("now a is " + a +"\nnow b is " + b);
}

static void swap(StringBuffer a1, StringBuffer b1)
{
System.out.println ("a1 = " + a1);
System.out.println ("b1 = " + b1);
System.out.println ("append( \" more\")");
a1.append(" more");
System.out.println ("a1 = " + a1);
b1 = a1;
b1.append(" more");
System.out.println ("b1 = " + b1);
}
}

简单点的，最基本的各种数据类型的连接

public class StringBufferTest {
	public static void main(String[] args) {
		char[] charString={'A','B','C','D','E','F','G','H'};
		String string="this is a test message!";
		StringBuffer stringBuffer=new StringBuffer();
		stringBuffer.append("----").append(charString).append(string);
		stringBuffer.toString();
		System.out.println(stringBuffer);
	}
}

稍稍难一点的，可以利用StringBuffer打印一个字符组成的小矩形，例子如下

public class StringBufferDemo {
	public static void main(String[] args) {
		System.out.println(drawRectangle(6, 4));
	}
	
	public static String drawRectangle(int row,int coloum) {
		StringBuffer stringBuffer=new StringBuffer();
		for (int i = 0; i < row; i++) {
			for (int j = 0; j < coloum; j++) {
				stringBuffer.append("*");
			}
			stringBuffer.append("\n");
		}
		return stringBuffer.toString();
	}
}

public class Test{
publci static void main(String []args){
StringBuffer sb = new StringBuffer();
sb.append("hello");
System.out.println(sb); //这里只会输出hello
sb.append(" world!");
System.out.println(sb); //这里就将会输出hello world!

}

}

StringBuffer 一般用到append追加的一个方法;
然后就是一个toString()