string的一些方法

package test;

import java.awt.List;
import java.awt.image.AreaAveragingScaleFilter;
import java.lang.reflect.Array;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.*;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.io.BufferedInputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.Reader;
import java.io.Writer;
import javax.security.auth.callback.LanguageCallback;
import javax.swing.text.StyledEditorKit.BoldAction;

public class Main {

	public static void main(String[] args) throws Exception {

		Scanner scanner = new Scanner(new BufferedInputStream(System.in));
		PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
		
		char [] a = {'a','b','c','d','e'};
		String s = new String(a,2,2);//前面是下标，后边是长度
		System.out.println(s);
		byte [] c = {97,98,99,100};
		String ssString = new String(c);
		System.out.println(ssString);

		String string = "aaaasdsfsffgfgdhg";
		//返回想找的字母第一个出现的位置的函数参数可以传int或者引号里面一个字母
		System.out.println(string.indexOf('f'));
		//从指定位置开始查找
		System.out.println(string.indexOf('a', 2));
		//从指定位置开始查找字符串，没找到返回-1
		System.out.println(string.indexOf("aa", 4));
		//查找最后出现的位置
		System.out.println(string.lastIndexOf('a'));
		//相对应的也有字符串查找
		
		//截取字符串前闭后开
		System.out.println(string.substring(1, 4));
		
		//根据正则表达式的规则我们截取字符串
		String s = "张三,李四,王五";
		
		String [] a = s.split(",");
		for(int i = 0; i < a.length; i ++)
		{
			System.out.println(a[i]);
		}
	
		//将字符串转换成字符数组
		char []chs = s.toCharArray();
		for (int i = 0; i < chs.length; i++) {
			System.out.println(chs[i]);
		}
		System.out.println(s.length());
		
		//将字符串转换成字节
		byte [] by = s.getBytes();
		for (int i = 0; i < by.length; i++) {
			System.out.println(by[i]);
		}
		
		//转换大小写
		System.out.println("abc".toUpperCase());
		System.out.println("AAA".toLowerCase());
		
		//替换字符或者字符串
		System.out.println("abc".replace('a', 'c'));
		System.out.println("abc".replace("ab", "cc"));
		
		//去掉字符串两边空格中间的保留
		System.out.println("   aaaaafd    sfsd  ".trim());
		
		//string.valueOf直接转换字符串类型
		
		//判断字符串的内容是否一致可以忽略大小写
		System.out.println("abc".equalsIgnoreCase("ABc"));
		//判断字符串是否包含另外一个字符串我们可以用indexof
		//也可以用下面的方法
		System.out.println(s.contains("aa"));
		//找开头包含字符串
		//找结尾包含字符串
		System.out.println(s.startsWith("ds"));
		System.out.println(s.endsWith("王五"));
		
		//比较对象大小
		System.out.println(s.compareTo("aa"));

	}
}