|NO.Z.00023|——————————|BigDataEnd|——|Java&核心类库.V08|——|Java.v08|string类.v08|实现各种方法使用|

一、string类型实现各种方法的使用

### --- 案例题目

~~~     ——>        编程实现上述方法的使用。

方法声明	功能介绍
String concat(String str)	用于实现字符串的拼接
boolean contains(CharSequence s)	用于判断当前字符串是否包含参数指定的内容
String toLowerCase()	返回字符串的小写形式
String toUpperCase()	返回字符串的大写形式
String trim()	返回去掉前导和后继空白的字符串
boolean startsWith(String prefix)	判断字符串是否以参数字符串开头
boolean startsWith(String prefix, int toffset)	从指定位置开始是否以参数字符串开头
boolean endsWith(String suffix)	判断字符串是否以参数字符串结尾

二、编程代码

package com.yanqi.task12;

public class StringManyMethodTest {

    public static void main(String[] args) {

        // 1.构造String类型的对象并打印
        String str1 = new String("     Let Me Give You Some Color To See See!");
        System.out.println("str1 = " + str1); //      Let Me Give You Some Color To See See!

        // 2.实现各种成员方法的调用和测试
        boolean b1 = str1.contains("some");
        System.out.println("b1 = " + b1); // false  区分大小写
        b1 = str1.contains("Some");
        System.out.println("b1 = " + b1); // true

        System.out.println("----------------------------------------------");
        // 将所有字符串转换为大写  小写  以及去除两边的空白字符
        String str2 = str1.toUpperCase();
        System.out.println("str2 = " + str2); //    LET ME GIVE YOU SOME COLOR TO SEE SEE!
        System.out.println("str1 = " + str1); //    Let Me Give You Some Color To See See!   常量

        String str3 = str1.toLowerCase();
        System.out.println("str3 = " + str3); //    let me give you some color to see see!
        System.out.println("str1 = " + str1); //    Let Me Give You Some Color To See See!

        String str4 = str1.trim();
        System.out.println("str4 = " + str4); //Let Me Give You Some Color To See See!     奇点

        System.out.println("----------------------------------------------");
        // 判断字符串是否以...开头  以...结尾
        b1 = str1.startsWith("Let");
        System.out.println("b1 = " + b1); // false
        b1 = str1.startsWith(" ");
        System.out.println("b1 = " + b1); // true
        // 从下标5开始是否以"Let"开头
        b1 = str1.startsWith("Let", 5);
        System.out.println("b1 = " + b1); // true

        b1 = str1.endsWith("See");
        System.out.println("b1 = " + b1); // false
        b1 = str1.endsWith("See!");
        System.out.println("b1 = " + b1); // true
    }
}

三、编译打印

D:\JAVA\jdk-11.0.2\bin\java.exe "-javaagent:D:\IntelliJIDEA\IntelliJ IDEA 2019.3.3\lib\idea_rt.jar=52142:D:\IntelliJIDEA\IntelliJ IDEA 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath E:\NO.Z.10000——javaproject\NO.H.00001.javase\javase\out\production\javase com.yanqi.task12.StringManyMethodTest
str1 =      Let Me Give You Some Color To See See!
b1 = false
b1 = true
----------------------------------------------
str2 =      LET ME GIVE YOU SOME COLOR TO SEE SEE!
str1 =      Let Me Give You Some Color To See See!
str3 =      let me give you some color to see see!
str1 =      Let Me Give You Some Color To See See!
str4 = Let Me Give You Some Color To See See!
----------------------------------------------
b1 = false
b1 = true
b1 = true
b1 = false
b1 = true

Process finished with exit code 0

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Walter Savage Landor:strove with none,for none was worth my strife.Nature I loved and, next to Nature, Art:I warm'd both hands before the fire of life.It sinks, and I am ready to depart

                                                                                                                                                   ——W.S.Landor

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