_6_5_字符串生成器

package _6_5_字符串生成器;

public class _6_5_Example_1 {

	public static void main(String[] args) {
		// TODO 自动生成的方法存根
		
		//StringBuilder类
		String str="";
		long startTime=System.currentTimeMillis();//定义执行操作的起始时间
		for(long i=0;i<100000;i++){
			str=str+i;//循环增加字符 
		}
		long endTime=System.currentTimeMillis();//定义对字符串操作后的时间
		long time=System.currentTimeMillis();//计算执行操作的时间
		System.out.println("String 消耗时间："+time);
		
		StringBuilder builder=new StringBuilder("");
		startTime=System.currentTimeMillis();
		for(long j=0;j<100000;j++)
			builder.append(j);//循环增加字符
		endTime=System.currentTimeMillis();
		time=endTime-startTime;
		System.out.println("StringBuilder 消耗时间："+time);
	}

}

 

package _6_5_字符串生成器;

//StringBuilder类的常用方法

public class _6_5_Example_2 {

	public static void main(String[] args) {
		// TODO 自动生成的方法存根
		
		String s1="Hello World !";
		StringBuilder builder1=new StringBuilder("I love China!");
		System.out.println("追加前builder1的值是："+builder1);
		builder1.append(s1);
		System.out.println("追加后builder1的值是："+builder1);
		
		StringBuffer s2=new StringBuffer("World");
		StringBuilder builder2=new StringBuilder("Hello");
		System.out.println("追加前builder2的值是："+builder2);
		builder2.append(s2);
		System.out.println("追加后builder2的值是："+builder2);
		
		String s3="int";
		String s4="ser";
		StringBuilder builder3=new StringBuilder(s3);
		System.out.println("追加前builder3的值是："+builder3);
		builder3.insert(2, s4);
		System.out.println("追加后builder3的值是："+builder3);
		
		StringBuilder builder4=new StringBuilder("StringBuilderd");
		System.out.println("删除指定字符串前builder4是："+builder4);
		StringBuilder s5=builder4.delete(5, 5);
		System.out.println("删除指定字符串后是："+s5);
		StringBuilder s6=builder4.delete(5, 10);
		System.out.println("删除指定字符串后是："+s6);
		
		StringBuilder builder5=new StringBuilder("Hello World");
		String s7=builder5.toString();
		System.out.println("String="+s7);
		System.out.println("StringBuilder="+builder5);
		
	}

}

 

package _6_5_字符串生成器;

//将汉字和字母转换成Unicode码
//将字符串添加到字符数组，再将字符数组中的字符转换成Unicode码添加到字符串生成器中
public class _6_5_Example_3 {

	public static void main(String[] args) {
		// TODO 自动生成的方法存根
		String text="我喜欢那个 XXX";
		char charArray[]=text.toCharArray();//获取字符串的字符数组
		StringBuilder builder=new StringBuilder();//创建字符串生成器
		for(int i=0;i<charArray.length;i++){//遍历字符数组
			builder.append((int)charArray[i]+" ");//将每个字符转换成Unicode码
			                                  //并添加到字符串生成器中
		}
		System.out.println(text+"的Unicode码为：\n"+builder.toString());
	}

}

 

package _6_5_字符串生成器;

//去掉字符串中的重复字符

public class _6_5_Example_4 {

	public static void main(String[] args) {
		// TODO 自动生成的方法存根
		
		String s="命运如同海风--吹着青春的舟，飘摇的，曲折的，渡过了时间的海！";
		StringBuilder builder=new StringBuilder(s);
		System.out.println("原来的字符串是："+builder.toString());
		System.out.println("原来字符串的长度为："+builder.toString().length());
		
		for(int i=0;i<builder.length();i++){
			for(int j=i+1;j<builder.length();j++){
				if(builder.charAt(i)==builder.charAt(j))
					builder.deleteCharAt(j);
			}
		}
		System.out.println("现在的字符串是："+builder.toString());
		System.out.println("现在的字符串的长度为："+builder.toString().length());
		
	}

}