String ???? ??? ???? ???? ?? ?? ? ?????. ? ??? ?? Java ??? ???? ?? ???? ??? ?? ?? ?? ??? ??? ? ????.

1. ??? "??" ??? ??

??? ???? ??? ??? ?????? Java??? "length()"?? ???? ?????. ???? ??? ??? ? ? ?????.

public?class?Str_Sample?{
	public?static?void?main(String[]?args){
		//測試String長度的方法
		String?name="hello?work";
		//length方法返回的是整數(shù)
		int?num=name.length();
		System.out.println("字符串的長度："+num);
	}
}

? ??? ???? ??? ?? ?????.

字符串長度：10

2.String "indexOf()" method

?? ??? ?? ??? ??? ??? ? ? ????

"indexOf"? ?? ??? ?? ???? ??? ???? ? ??? ???. ??? ??? -1? ?????.

public?class?Str_Sample{
????public?static?void?main(String[]?args){
???????String?name="I?like?java.?How?do?you?like?java?";
	???int?num=name.indexOf("java");
	???System.out.println("java第一次出現(xiàn)的位置："+num);
????}
}

? ??? ???? ?? ??? ??? ????.

java第一次出現(xiàn)的位置：7

3. lastindexOf()" ???

??? ?? ??? ??? ??? ??? ??? ?? ????

"lastindexOf"? ??? ???? ??? ??? ???? ????? ??? ?? ??? ???? ??? ??? ? ????. ?? ? ??? -1? ?????.

public?class?Str_Sample{
????public?static?void?main(String[]?args){
????????String?name="I?like?java.?How?do?you?like?java?";
????????//name的長度
????????int?num=name.length();
	????????//lastindexOf(指定特殊字符，指定位置)
??????????????int?index=name.lastindexOf("java",num);
????????????????System.out.println("java最后一次出現(xiàn)的位置："+index);
	?????
????}
]

?? ?? ???? ?? ??? ??? ????.

java最后一次出現(xiàn)的位置：29

4. ??? "substring()" ???

???? ??? ??? ?? ??? ?? ????

"subString"? ??? ???? ???? ???? ???? ???? ??? ? ????. ??: Java? ???? ???? ??? ???? ??? ???? ????.

public?class?Str_Sample{
????public?static?void?main(String[]?args){
????????String?name="I?like?java.?How?do?you?like?java?";
????????//截取How這個(gè)字母，首先你要知道H的下標(biāo),可使用之前的indexOf方法
????????int?num=name.indexOf("H");
????????//由于java中示范圍都是含頭不含尾，所以要多加一位
????????String?str=name.substring(num,num+3);
????????System.out.println(str);
????????//也可從指定位置直接截取到字符串尾部
????????String?str2=name.substring(num);
????????System.out.println(str2);
????}
]

?? ?? ???? ?? ??? ??? ????.

How
How?do?you?like?java?

5.String "charAt()" method

??? ?? ??? ??? ?? ? ????

"chatAt"? ??? ??? ??? ???? ? ?????

public?class?Str_Sample{
????public?static?void?main(String[]?args){
????????String?name="I?like?java.?How?do?you?like?java?";
????????//創(chuàng)建循環(huán)遍歷name的下標(biāo)
????????for(int?i=0;i<name.length();i++){
????????????//將下標(biāo)放入charAt方法中
????????????char?ch=name.charAt(i);
????????????System.out.print(ch);
????????}
????}
]

?? ?? ???? ?? ??? ??? ????.

I?like?java.?How?do?you?like?java?

6. ??? "startsWith(), endWith()" method

?? ?? ?? ???? ???? ????? ?????

"startsWith()", ???? ??? ???? ????? ?????. "endsWith()"? ???? ??? ???? ???? ?????.

public?class?Str_Sample{
????public?static?void?main(String[]?args){
????????String?name="I?like?java.?How?do?you?like?java?";
????????//是否以“I”開頭，正確返回true，否則返回false
????????boolean?s1=name.startsWith("I");
????????//startsWith()第二種用法，可判斷指定位置是否是指定字符串
????????boolean?s2=name.startsWith("java",7);
????????//判斷字符串是否以“?”結(jié)尾
????????boolean?e1=name.endsWith("?");
????????System.out.println("是否以“I”開頭："+s1);????
????????System.out.println("位置7是否是“java”開頭："+s2);
????????System.out.println("是否以“?”結(jié)尾："+e1);
??????}
}

? ??? ???? ?? ??? ??? ????.

否以“I”開頭：true
位置7是否是“java”開頭：true
是否以“?”結(jié)尾：true

7. String "compareTo()"method

"compareTO " it from ??? ? ?? ???? ?????. ?? ??? ???? ? ??? ASCII ? ??? ?? ?????. ?? ?? int ?????.

public?class?Str_Sample{
????public?static?void?main(String[]?args){
????????//A的ascli值為65，a的ascli值為97
????????String?a="A";
????????String?b="a";
????????String?c="aa";
????????String?d="abc";
????????String?e="ad";
????????int?num=a.compareTo(b);
????????//還有一種方法忽略大小寫進(jìn)行比較
????????int?num2=a.compareToIgnoreCase(b);
????????//長度不一樣且前幾個(gè)字符也不一樣,從第一位開始找，當(dāng)找到不一樣的字符時(shí)，則返回的值是這兩個(gè)字符比較的值
????????int?num3=c.compareTo(d);
????????//如多個(gè)字符,第一個(gè)字符相同則直接比較第二個(gè)字符,以此類推
????????int?num4=e.compareTo(c);
????????System.out.println("a與b比較："+num);
????????System.out.println("a與b比較（忽略大小寫）："+num2);
????????System.out.println("c與d比較："+num3);
????????System.out.println("e與d比較："+num4);
?????}
}

? ??? ???? ?? ??? ??? ????.

a與b比較：-32
a與b比較（忽略大小寫）：0
c與d比較：-1
e與d比較：3

8. String "contains()"method

???? ??? ???? ???? ??? ?? ????

??? "contanins"? ??? ???? ???? ??? ???? ?? ??? ??? ? ????.

public?class?Str_Sample{
????public?static?void?main(String[]?args){
????????String?name="I?like?java.?How?do?you?like?java?";
????????//判斷是否包含“you”這個(gè)字符串
????????boolean?bl=name.contains("you");
????????System.out.println("name字符串中是否包含“you”:"+bl);
????}
]

? ??? ???? ?? ??? ??? ????.

name字符串中是否包含“you”:true

9.字符串“replace()”方法

您可以指定要替換的字符串部分以及參數(shù)中的替換字符串。

public?class?Str_Sample{
????public?static?void?main(String[]?args){
????????String?name="I?like?java.?How?do?you?like?java?";
????????String?str=name.replace("java",?"php");
????????System.out.println("替換前："+name);
????????System.out.println("替換后："+str);
????}
]

運(yùn)行以上實(shí)例，輸出結(jié)果如下：

替換前：I?like?java.?How?do?you?like?java?
替換后：I?like?php.?How?do?you?like?php?

10.字符串“toLowerCase()”和“toUpperCase()”方法

“toLowerCase()”將字符串以小寫形式顯示，toUpperCase()”將字符串以大寫形式顯示。

public?class?Str_Sample{
????public?static?void?main(String[]?args){
????????String?name="I?like?java.?How?do?you?like?Java?";
????????String?low=name.toLowerCase();
	????String?upp=name.toUpperCase();
????????System.out.println("小寫顯示："+low);
????????System.out.println("大寫顯示："+upp);
????}
]

運(yùn)行以上實(shí)例，輸出結(jié)果如下：

小寫顯示：i?like?java.?how?do?you?like?java?
大寫顯示：I?LIKE?JAVA.?HOW?DO?YOU?LIKE?JAVA?

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? ??? Java ???? ??? ??? ?? ?? ?? ?????. ??? ??? PHP ??? ????? ?? ?? ??? ?????!