Java 工具類String、Strings

package com.neusoft.constant;
/**
 *Java中定義了String與StringBuffer兩個類來封裝對字元串的各種操作
String類與StringBuffer類都被放到了java.lang包中
兩者的主要差別在于
String類對象中的内容初始化不可以改變
StringBuffer類對象中的内容可以改變
 */
import java.util.Date;

public class TestStringBuffer {
	public static void main(String[] args) {
		StringBuffer sb = new StringBuffer("abc");
		sb.append("defg");
		System.out.println(sb);//字元串的追加   abcdefg
		sb.insert(3, "---");
		System.out.println(sb);//abc---defg
		sb.reverse();
		System.out.println(sb);//gfed---cba
		sb.append(new Date());
		System.out.println(sb);//gfed---cbaTue Apr 03 09:43:12 CST 2018
		
		String sql = "select * from EMP";//連接配接where用append
	}

}
           

package com.neusoft.constant;

public class StringDemo {
	public static void main(String[] args) {
		String school = "neusoft";
		String ss = "          asdfghjkl       ";
		String newString = school.concat("ads");
		System.out.println(newString.length());//10
		System.out.println(newString.toUpperCase());//NEUSOFTADS
		System.out.println(newString.substring(2));//usoftads
		System.out.println(ss.valueOf(1));//1
		System.out.println(ss.trim());//asdfghjkl


		String ss1 = "boo<and<foo";
		String[] array = ss1.split("o");
		for(int i = 0;i<array.length;i++){
			System.out.println(array[i]);
		}
		
		String str1 = new String("asd");
		String str2 = new String("asd");
		System.out.println(str1);
		System.out.println(str2);
		
		System.out.println(str1==str2);//false
		System.out.println(str1.equals(str2));//true
		//String 重寫 equals 方法 比較結果為true
		
		Integer integer1 = new Integer(10);		
		Integer integer2 = new Integer(10);
		System.out.println(integer1 == integer2);//false
		System.out.println(integer1.equals(integer2));//true
		//封裝類 重寫equals方法
	}
}