将给定的一字符串倒序输出,用 JAVA

将给定的一字符串倒序输出,用 JAVA

一、利用String类的toCharArray()，再倒序输出数组。

示例代码：

import javax.swing.JOptionPane;

public class ReverseString {

public static void main (String args[]){

String originalString;

String resultString = ;

originalString = JOptionPane.showInputDialog(Please input a String: );

char[] charArray = originalString.toCharArray();

for (int i=charArray.length-1; i>=0; i--){

resultString += charArray[i];

}

JOptionPane.showMessageDialog(null, resultString, Reverse String, JOptionPane.INFORMATION_MESSAGE);

}

}

二、利用String类提供的subString()方法，利用递归的办法输出倒序字符串。

示例代码：

import javax.swing.JOptionPane;

public class ReverseString {

public static void reverseString (String str){

if (str.length() == 1){

System.out.print(str);

}else{

String subString1 = str.substring(0, str.length()-1);

String subString2 = str.substring(str.length()-1);

System.out.print(subString2);

reverseString (subString1);

}

}

public static void main (String args[]){

String originalString;

originalString = JOptionPane.showInputDialog(Please input a String: );

reverseString (originalString);

}

}

三、把字符串定义成StringBuffer类，用StringBuffer类中的reverse()方法直接倒序字符串。

示例代码：

import javax.swing.JOptionPane;

public class ReverseString {

public static void reverseString (String str){

StringBuffer stringBuffer = new StringBuffer (str);

System.out.print(stringBuffer.reverse());

}

public static void main (String args[]){

String originalString;

originalString = JOptionPane.showInputDialog(Please input a String: );

reverseString (originalString);

}

}

用java代码实现责任链模式的骨干代码

//----------------先写了个，功能是实现了，有待改进-----------

import java.util.ArrayList;

import java.util.List;

/**

* 现有List<SourceBean>类型的List对象，

* 现在需要将该List对象中a是奇数或者b>100的对象过滤掉，

* 请用责任链模式实现此段代码。

* @author Administrator

*

*/

public class Chain_test1 {

public static void main(String[] args) {

List<SourceBean> list = new ArrayList<SourceBean>();

SourceBean bean1 = new SourceBean(1, 100);

SourceBean bean2 = new SourceBean(2, 200);

SourceBean bean3 = new SourceBean(3, 100);

SourceBean bean4 = new SourceBean(4, 100);

SourceBean bean5 = new SourceBean(5, 20);

SourceBean bean6 = new SourceBean(6, 200);

list.add(bean1);

list.add(bean2);

list.add(bean3);

list.add(bean4);

list.add(bean5);

list.add(bean6);

System.out.println(过滤前List中的内容);

printList(list);

// 装配 链条

Filter oddFilter = new OddFilter();

//为了保持Filter里面的逻辑不混乱，OddFilter仅过滤奇数，CompareFilter仅仅过滤b>100

//这里对奇数过滤两次，

//即，过滤掉b>100和a是奇数 共存的情形

Filter oddFilter2 = new OddFilter();

Filter compareFilter = new CompareFilter();

oddFilter.setFilter(null);

compareFilter.setFilter(oddFilter);

oddFilter2.setFilter(compareFilter);

// 进行过滤

oddFilter2.doFilter(list);

System.out.println(\n过滤后List中的内容);

printList(list);

}

public static void printList(List<SourceBean> list){

for(SourceBean s: list){

System.out.print(s.toString());

}

}

}

class Filter{

private Filter filter;

public void doFilter(List<SourceBean> list){

if (filter != null){

filter.doFilter(list);

}else{

System.out.println(处理结束);

}

}

public void setFilter(Filter filter){

this.filter = filter;

}

}

/**

* 仅仅过滤b>100

*/

class CompareFilter extends Filter{

public void doFilter(List<SourceBean> list){

for(int i= 0; i< list.size(); i++){

if(list.get(i).getB() > 100 ){//b>100

list.remove(i);//移除该对象

}else{//交给其他Filter处理

super.doFilter(list);

}

}

}

}

/**

* 仅过滤a为奇数

*/

class OddFilter extends Filter{

public void doFilter(List<SourceBean> list){

for(int i= 0; i< list.size(); i++){

if(list.get(i).getA() % 2 != 0){//非偶数

list.remove(i);//移除该对象

}else{//交给其他Filter处理

super.doFilter(list);

}

}

}

}

class SourceBean {

private int a;

private int b;

public SourceBean(int a, int b){

this.a = a;

this.b = b;

}

public SourceBean(){

}

public String toString(){

return [a=+a+, b=+b+] ;

}

public int getA() {

return a;

}

public void setA(int a) {

this.a = a;

}

public void setB(int b) {

this.b = b;

}

public int getB() {

return b;

}

}

//------------------------执行结果----------------------------

过滤前List中的内容

[a=1, b=100] [a=2, b=200] [a=3, b=100] [a=4, b=100] [a=5, b=20] [a=6, b=200]

过滤后List中的内容

[a=4, b=100]