字符集及判断字符所在字符串位置

//查找字符或字符串
		int in = str2.indexOf("d");
		
		System.out.println("ab =" + in);
		
		int la = str2.lastIndexOf("d");//课后
		
		System.out.println("d =" + la);
		
		String newStr = str2.substring(5);
		
		newStr = str2.substring(5,6);
		
		System.out.println("substring(） =" + newStr);
		
		str2 = " ab cdd s ";
		
		//去除前后空格
		System.out.println("去空格 =" + str2.trim() + "后面");
		
		//查找替换
		System.out.println("查找替换空格 =" + str2.replace(" ", "") + "后面");
		
		str2 = "abc,你好，abcd";
		
		System.out.println("查找替换 =" + str2.replace("abc", "李四") + "");
		
		System.out.println("查找替换 =" + str2.replaceFirst("abc", "张三") + "");
		
		str2 = "abcdef";
		
		//判断字符串开始和结束
		System.out.println("判断起始1 =" + str2.startsWith("abc"));
		
		System.out.println("判断起始2 =" + (str2.indexOf("abc") == 0));
		
		System.out.println("判断结束  =" + str2.endsWith("ef") + "\t");