java古诗代码从右到左 java从左到右取数字

谁能给我解释下java中三目运算符从右向左运算到底是什么意思？

是说有多个三目运算符在一个表达式里的时候，从右向左执行

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a b ? b c ? 1 : 0 : 2会先执行b c ? 1 : 0

写一个java程序 将一首古诗竖着排序从右往左读

import java.awt.Color;

import java.awt.Font;

import java.awt.GradientPaint;

import java.awt.Graphics;

import java.awt.Graphics2D;

import java.awt.Image;

import java.awt.event.MouseAdapter;

import java.awt.event.MouseEvent;

import java.awt.geom.AffineTransform;

import java.awt.image.AffineTransformOp;

import java.awt.image.BufferedImage;

import java.io.BufferedReader;

import java.io.StringReader;

import java.util.ArrayList;

import javax.swing.JFrame;

import javax.swing.JLabel;

public class PoetryTest {

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

final JFrame f = new JFrame();

final ArrayListPoetry ps = PContents.load();

final PoetryLabel plabel = new PoetryLabel();

f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

f.add(plabel);

f.setSize(320,268);

f.setLocationRelativeTo(null);

f.setVisible(true);

plabel.setPoetry(ps.get(0));

f.setTitle(plabel.getTitle()+"-"+plabel.getAuthor());

plabel.addMouseListener(new MouseAdapter(){

int index;

public void mouseClicked(MouseEvent e){

++index;

index=index%ps.size();

Poetry p = ps.get(index);

plabel.setPoetry(p);

f.setTitle(plabel.getTitle()+"-"+plabel.getAuthor());

}

});

}

}

//呈现诗歌的标签类

class PoetryLabel extends JLabel{

private static final Color tColor = Color.white;//标题颜色

private static final Color aColor = Color.yellow;//作者颜色

private static final Color cColor = Color.LIGHT_GRAY;//内容颜色

private static final int fontSize=16;//字体大小

private static final int tType = Font.BOLD;//标题字体样式为粗体

private static final int aType = Font.ITALIC;//作者字体样式为斜体

private static final int cType = Font.PLAIN;//内容字体样式为普通样式

private static final float scaleFactor = 1.2f;//标题字体大小比其它字体大

private static final String fontName="SimSun";//字体名称

private static final int offset=5,space=5;

private Font font;

private AffineTransform at;

private Poetry poem;

public PoetryLabel(){

this.poem=new Poetry();

this.font=new Font(fontName,cType,fontSize);

this.setHorizontalAlignment(JLabel.CENTER);

this.setVerticalAlignment(JLabel.CENTER);

at = new AffineTransform();

at.setToRotation(Math.toRadians(-90));

font = font.deriveFont(at);//将字体逆时针旋转90°

}

public Poetry getPoetry() {

return poem;

}

//设置诗歌,来初始化标签内容

public void setPoetry(Poetry s){

this.poem=s;

this.repaint();

}

public String getTitle(){return poem.title;}

public String getAuthor(){return poem.author;}

//创建图像,先将逆时针旋转了90°的文件画上,然后将整幅图像顺时针旋转90°

private Image createImage(){

int x;

int y=offset;

int w = getTWidth(poem);

int h = getTHeight(poem);

BufferedImage img = new BufferedImage(w,h,BufferedImage.TYPE_INT_ARGB);

Graphics2D g = img.createGraphics();

//draw title

g.setColor(tColor);

Font tfont = font.deriveFont(font.getSize()*scaleFactor).deriveFont(tType);

g.setFont(tfont);

y+=tfont.getSize();

char[] cs = poem.title.toCharArray();

for(int i=0; ics.length; i++){

x=(i+1)*(tfont.getSize()+space)+offset;

g.drawChars(cs, i, 1, x, y);

}

//draw author

y+=space*2+tfont.getSize();

cs = poem.author.toCharArray();

tfont = font.deriveFont(aType);

g.setColor(aColor);

g.setFont(tfont);

for(int i=0; ics.length; i++){

x=(i+1)*(tfont.getSize()+space)+offset;

g.drawChars(cs, i, 1, x, y);

}

//draw contents

y+=space*3;

g.setColor(cColor);

g.setFont(font);

for(int i=0; ipoem.contents.size(); i++){

y+=fontSize+space;

cs = poem.contents.get(i).toCharArray();

for(int j=0; jcs.length; j++){

x=(j+1)*(tfont.getSize()+space)+offset;

g.drawChars(cs, j, 1, x, y);

}

}

g.dispose();

return this.getRotateImage(img);

}

//将图像顺时针旋转90°

private Image getRotateImage(final BufferedImage img) {

int w = img.getWidth();

int h = img.getHeight();

BufferedImage newImg = new BufferedImage(h,w,2);

AffineTransformOp op = new AffineTransformOp(AffineTransform.

getRotateInstance(Math.toRadians(90),h/2,h/2),null);

return op.filter(img,newImg);

}

//绘图

public void paint(Graphics gg){

BufferedImage img = (BufferedImage)this.createImage();

int iw = img.getWidth();

int ih = img.getHeight();

Graphics2D g = (Graphics2D)gg;

int w = this.getWidth();

int h = this.getHeight();

g.setPaint(new GradientPaint(0,0,Color.DARK_GRAY,0,h,Color.black));

g.fillRect(0,0,w,h);

int x = (w-iw)/2;

int y = (h-ih)/2;

g.drawImage(img, x, y, this);

g.dispose();

}

//计算图片的高度

private int getTHeight(Poetry s) {

int h = offset*2+space*5;

h+=(int)(fontSize*(scaleFactor+1));

h+=(fontSize+space*2)*s.contents.size();

return h;

}

//计算图片的宽度

private int getTWidth(Poetry s) {

int tl = (int)(s.title.length()*(fontSize*scaleFactor+space)+offset*2);

int al = s.author.length()*(fontSize+space)+offset*2;

int t;

int max = tlal?tl:al;

for(int i=0; is.contents.size(); i++){

t = s.contents.get(i).length()*(fontSize+space)+offset*2;

max=maxt?max:t;

}

return max;

}

}

//诗歌类

class Poetry{

public String title;//标题

public String author;//作者

public ArrayListString contents=new ArrayListString();//内容

public void addLine(String s){this.contents.add(s);}//加入一行内容

}

//

class PContents{

public static String s=

"苏武庙\r\n"+

"温庭筠\r\n"+

"苏武魂销汉使前，\r\n"+

"古祠高树两茫然。\r\n"+

"云边雁断胡天月，\r\n"+

"陇上羊归塞草烟。\r\n"+

"回日楼台非甲帐，\r\n"+

"去时冠剑是丁年。\r\n"+

"茂陵不见封侯印，\r\n"+

"空向秋波哭逝川。\r\n"+

"\r\n"+

"贫女\r\n"+

"秦韬玉\r\n"+

"蓬门未识绮罗香，\r\n"+

"拟托良媒益自伤。\r\n"+

"谁爱风流高格调？\r\n"+

"共怜时世俭梳妆。\r\n"+

"敢将十指夸针巧，\r\n"+

"不把双眉斗画长。\r\n"+

"苦恨年年压金线，\r\n"+

"为他人作嫁衣裳。\r\n"+

"\r\n"+

"宫词\r\n"+

"薛逢\r\n"+

"十二楼中尽晓妆，\r\n"+

"望仙楼上望君王。\r\n"+

"锁衔金兽连环冷，\r\n"+

"水滴铜龙昼漏长。\r\n"+

"云髻罢梳还对镜，\r\n"+

"罗衣欲换更添香。\r\n"+

"遥窥正殿帘开处，\r\n"+

"袍裤宫人扫御床。\r\n"+

"\r\n"+

"利洲南渡\r\n"+

"温庭筠\r\n"+

"澹然空水对斜晖，\r\n"+

"曲岛苍茫接翠微。\r\n"+

"波上马嘶看棹去，\r\n"+

"柳边人歇待船归。\r\n"+

"数丛沙草群鸥散，\r\n"+

"万顷江田一鹭飞。\r\n"+

"谁解乘舟寻范蠡，\r\n"+

"五湖烟水独忘机？\r\n"+

"\r\n"+

"无题二首之一\r\n"+

"李商隐\r\n"+

"凤尾香罗薄几重，\r\n"+

"碧文圆顶夜深缝。\r\n"+

"扇裁月魄羞难掩，\r\n"+

"车走雷声语未通。\r\n"+

"曾是寂寥金烬暗，\r\n"+

"断无消息石榴红。\r\n"+

"斑骓只系垂杨岸，\r\n"+

"何处西南任好风？\r\n"+

"\r\n"+

"无题二首之二\r\n"+

"李商隐\r\n"+

"重帷深下莫愁堂，\r\n"+

"卧后清宵细细长。\r\n"+

"神女生涯原是梦，\r\n"+

"小姑居处本无郎。\r\n"+

"风波不信菱枝弱，\r\n"+

"月露谁教桂叶香？\r\n"+

"直道相思了无益，\r\n"+

"未妨惆怅是清狂。\r\n"+

"\r\n"+

"金陵图\r\n"+

"韦庄\r\n"+

"江雨霏霏江草齐，\r\n"+

"六朝如梦鸟空啼。\r\n"+

"无情最是台城柳，\r\n"+

"依旧烟笼十里堤。\r\n" +

"\r\n"

;

public static ArrayListPoetry load() throws Exception{

ArrayListPoetry list = new ArrayListPoetry();

BufferedReader br = new BufferedReader(new StringReader(s));

Poetry p = null;

String t = null;

while((t = br.readLine()) != null){

if(p==null)

p=new Poetry();

if(t.isEmpty()){

list.add(p);

p=null;

}

else if(p.title==null)

p.title=t;

else if(p.author==null)

p.author=t;

else

p.addLine(t);

}

return list;

}

}

java 从右往左截取如何截取。

/* 字符串串从右往左截取 

* 思路：

*  让字符串倒序，然后再截取

* */

public static String spiltRtoL(String s){

StringBuffer sb = new StringBuffer();

int length = s.length();

char[] c = new char[length];

for (int i = 0; i  length; i++) {

c[i] = s.charAt(i);

}

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

sb.append(c[i]);

}

return sb.toString();

}

Java中正则表达式如何实现从右往左匹配？

你的左右没分清楚

如果不用正则表达式，就用int i = str.lastIndexOf("/n");能找出位置来

如果用正则表达式，就用"(/n)(?=(^/n)*)"意思就是匹配后面再没有/n的/n