一個是文件的讀寫，一個是文件的復(fù)制，讀寫用io輸入流，復(fù)制用io的輸出流來操作。代碼寫得很明白的。
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package IO;
import java.io.*;
public class FileDirectoryDemo {
public static void main(String[] args) {
// 如果沒有指定參數(shù)，則缺省為當前目錄。
if (args.length == 0) {
args = new String[] { "." };
}
try {
// 新建指定目錄的File對象。
File currentPath = new File(args[0]);
// 在指定目錄新建temp目錄的File對象。
File tempPath = new File(currentPath, "temp");
// 用“tempPath”對象在指定目錄下創(chuàng)建temp目錄。
tempPath.mkdir();
// 在temp目錄下創(chuàng)建兩個文件。
File temp1 = new File(tempPath, "temp1.txt");
temp1.createNewFile();
File temp2 = new File(tempPath, "temp2.txt");
temp2.createNewFile();
// 遞歸顯示指定目錄的內(nèi)容。
System.out.println("顯示指定目錄的內(nèi)容");
listSubDir(currentPath);
// 更改文件名“temp1.txt”為“temp.txt”。
File temp1new = new File(tempPath, "temp.txt");
temp1.renameTo(temp1new);
// 遞歸顯示temp子目錄的內(nèi)容。
System.out.println("更改文件名后，顯示temp子目錄的內(nèi)容");
listSubDir(tempPath);
// 刪除文件“temp2.txt”。
temp2.delete();
// 遞歸顯示temp子目錄的內(nèi)容。
System.out.println("刪除文件后，顯示temp子目錄的內(nèi)容");
listSubDir(tempPath);
} catch (IOException e) {
System.err.println("IOException");
}
}
// 遞歸顯示指定目錄的內(nèi)容。
static void listSubDir(File currentPath) {
// 取得指定目錄的內(nèi)容列表。
String[] fileNames = currentPath.list();
try {
for (int i = 0; i fileNames.length; i++) {
File f = new File(currentPath.getPath(), fileNames[i]);
// 如果是目錄，則顯示目錄名后，遞歸調(diào)用，顯示子目錄的內(nèi)容。
if (f.isDirectory()) {
// 以規(guī)范的路徑格式顯示目錄。
System.out.println(f.getCanonicalPath());
// 遞歸調(diào)用，顯示子目錄。
listSubDir(f);
}
// 如果是文件，則顯示文件名，不包含路徑信息。
else {
System.out.println(f.getName());
}
}
} catch (IOException e) {
System.err.println("IOException");
}
}
}
package IO;
import java.io.*;
public class FileExample {
public FileExample() {
super();// 調(diào)用父類的構(gòu)造函數(shù)
}
public static void main(String[] args) {
try {
String outfile = "demoout.xml";
// 定義了一個變量, 用于標識輸出文件
String infile = "demoin.xml";
// 定義了一個變量, 用于標識輸入文件
DataOutputStream dt = new DataOutputStream(
new BufferedOutputStream(new FileOutputStream(outfile)));
/**
* 用FileOutputStream定義一個輸入流文件，
* 然后用BuferedOutputStream調(diào)用FileOutputStream對象生成一個緩沖輸出流
* 然后用DataOutputStream調(diào)用BuferedOutputStream對象生成數(shù)據(jù)格式化輸出流
*/
BufferedWriter NewFile = new BufferedWriter(new OutputStreamWriter(
dt, "gbk"));// 對中文的處理
DataInputStream rafFile1 = new DataInputStream(
new BufferedInputStream(new FileInputStream(infile)));
/**
*用FileInputStream定義一個輸入流文件，
* 然后用BuferedInputStream調(diào)用FileInputStream對象生成一個緩沖輸出流
* ，其后用DataInputStream中調(diào)用BuferedInputStream對象生成數(shù)據(jù)格式化輸出流
*/
BufferedReader rafFile = new BufferedReader(new InputStreamReader(
rafFile1, "gbk"));// 對中文的處理
String xmlcontent = "";
char tag = 0;// 文件用字符零結(jié)束
while (tag != (char) (-1)) {
xmlcontent = xmlcontent + tag + rafFile.readLine() + '\n';
}
NewFile.write(xmlcontent);
NewFile.flush();// 清空緩沖區(qū)
NewFile.close();
rafFile.close();
System.gc();// 強制立即回收垃圾，即釋放內(nèi)存。
} catch (NullPointerException exc) {
exc.printStackTrace();
} catch (java.lang.IndexOutOfBoundsException outb) {
System.out.println(outb.getMessage());
outb.printStackTrace();
} catch (FileNotFoundException fex) {
System.out.println("fex" + fex.getMessage());
} catch (IOException iex) {
System.out.println("iex" + iex.getMessage());
}
}
}
package IO;
import java.io.*;
public class FileRandomRW {
// 需要輸入的person數(shù)目。
public static int NUMBER = 3;
public static void main(String[] args) {
Persons[] people = new Persons[NUMBER];
people[0] = new Persons("張峰", 26, 2000, "N");
people[1] = new Persons("艷娜", 25, 50000, "Y");
people[2] = new Persons("李朋", 50, 7000, "F");
try {
DataOutputStream out = new DataOutputStream(new FileOutputStream(
"peoplerandom.dat"));
// 將人員數(shù)據(jù)保存至“peoplerandom.dat”二進制文件中。
writeData(people, out);
// 關(guān)閉流。
out.close();
// 從二進制文件“peoplerandom.dat”中逆序讀取數(shù)據(jù)。
RandomAccessFile inOut = new RandomAccessFile("peoplerandom.dat",
"rw");
Persons[] inPeople = readDataReverse(inOut);
// 輸出讀入的數(shù)據(jù)。
System.out.println("原始數(shù)據(jù)：");
for (int i = 0; i inPeople.length; i++) {
System.out.println(inPeople[i]);
}
// 修改文件的第三條記錄。
inPeople[2].setSalary(4500);
// 將修改結(jié)果寫入文件。
inPeople[2].writeData(inOut, 3);
// 關(guān)閉流。
inOut.close();
// 從文件中讀入的第三條記錄，并輸出，以驗證修改結(jié)果。
RandomAccessFile in = new RandomAccessFile("peoplerandom.dat", "r");
Persons in3People = new Persons();
// 隨機讀第三條記錄。
in3People.readData(in, 3);
// 關(guān)閉流。
in.close();
System.out.println("修改后的記錄");
System.out.println(in3People);
} catch (IOException exception) {
System.err.println("IOException");
}
}
// 將數(shù)據(jù)寫入輸出流。
static void writeData(Persons[] p, DataOutputStream out) throws IOException {
for (int i = 0; i p.length; i++) {
p[i].writeData(out);
}
}
// 將數(shù)據(jù)從輸入流中逆序讀出。
static Persons[] readDataReverse(RandomAccessFile in) throws IOException {
// 獲得記錄數(shù)目。
int record_num = (int) (in.length() / Persons.RECORD_LENGTH);
Persons[] p = new Persons[record_num];
// 逆序讀取。
for (int i = record_num - 1; i = 0; i--) {
p[i] = new Persons();
// 文件定位。
in.seek(i * Persons.RECORD_LENGTH);
p[i].readData(in, i + 1);
}
return p;
}
}
class Persons {
private String name;
private int age; // 4個字節(jié)
private double salary; // 8個字節(jié)
private String married;
public static final int NAME_LENGTH = 20; // 姓名長度
public static final int MARRIED_LENGTH = 2; // 婚否長度
public static final int RECORD_LENGTH = NAME_LENGTH * 2 + 4 + 8
+ MARRIED_LENGTH * 2;
public Persons() {
}
public Persons(String n, int a, double s) {
name = n;
age = a;
salary = s;
married = "F";
}
public Persons(String n, int a, double s, String m) {
name = n;
age = a;
salary = s;
married = m;
}
public String getName() {
return name;
}
public int getAge() {
return age;
}
public double getSalary() {
return salary;
}
public String getMarried() {
return married;
}
public String setName(String n) {
name = n;
return name;
}
public int setAge(int a) {
age = a;
return age;
}
public double setSalary(double s) {
salary = s;
return salary;
}
public String setMarried(String m) {
married = m;
return married;
}
// 設(shè)置輸出格式。
public String toString() {
return getClass().getName() + "[name=" + name + ",age=" + age
+ ",salary=" + salary + ",married=" + married + "]";
}
// 寫入一條固定長度的記錄，即一個人的數(shù)據(jù)到輸出流。
public void writeData(DataOutput out) throws IOException {
FixStringIO.writeFixString(name, NAME_LENGTH, out);
out.writeInt(age);
out.writeDouble(salary);
FixStringIO.writeFixString(married, MARRIED_LENGTH, out);
}
// 寫入一條固定長度的記錄到隨機讀取文件中。
private void writeData(RandomAccessFile out) throws IOException {
FixStringIO.writeFixString(name, NAME_LENGTH, out);
out.writeInt(age);
out.writeDouble(salary);
FixStringIO.writeFixString(married, MARRIED_LENGTH, out);
}
// 隨機寫入一條固定長度的記錄到輸出流的指定位置。
public void writeData(RandomAccessFile out, int n) throws IOException {
out.seek((n - 1) * RECORD_LENGTH);
writeData(out);
}
// 從輸入流隨機讀入一條記錄，即一個人的數(shù)據(jù)。
private void readData(RandomAccessFile in) throws IOException {
name = FixStringIO.readFixString(NAME_LENGTH, in);
age = in.readInt();
salary = in.readDouble();
married = FixStringIO.readFixString(MARRIED_LENGTH, in);
}
// 從輸入流隨機讀入指定位置的記錄。
public void readData(RandomAccessFile in, int n) throws IOException {
in.seek((n - 1) * RECORD_LENGTH);
readData(in);
}
}
// 對固定長度字符串從文件讀出、寫入文件
class FixStringIO {
// 讀取固定長度的Unicode字符串。
public static String readFixString(int size, DataInput in)
throws IOException {
StringBuffer b = new StringBuffer(size);
int i = 0;
boolean more = true;
while (more i size) {
char ch = in.readChar();
i++;
if (ch == 0) {
more = false;
} else {
b.append(ch);
}
}
// 跳過剩余的字節(jié)。
in.skipBytes(2 * (size - i));
return b.toString();
}
// 寫入固定長度的Unicode字符串。
public static void writeFixString(String s, int size, DataOutput out)
throws IOException {
int i;
for (i = 0; i size; i++) {
char ch = 0;
if (i s.length()) {
ch = s.charAt(i);
}
out.writeChar(ch);
}
}
}
package IO;
import java.io.*;
import java.util.*;
public class FileRW {
// 需要輸入的person數(shù)目。
public static int NUMBER = 3;
public static void main(String[] args) {
Person[] people = new Person[NUMBER];
// 暫時容納輸入數(shù)據(jù)的臨時字符串數(shù)組。
String[] field = new String[4];
// 初始化field數(shù)組。
for (int i = 0; i 4; i++) {
field[i] = "";
}
// IO操作必須捕獲IO異常。
try {
// 用于對field數(shù)組進行增加控制。
int fieldcount = 0;
// 先使用System.in構(gòu)造InputStreamReader，再構(gòu)造BufferedReader。
BufferedReader stdin = new BufferedReader(new InputStreamReader(
System.in));
for (int i = 0; i NUMBER; i++) {
fieldcount = 0;
System.out.println("The number " + (i + 1) + " person");
System.out
.println("Enter name,age,salary,married(optional),please separate fields by ':'");
// 讀取一行。
String personstr = stdin.readLine();
// 設(shè)置分隔符。
StringTokenizer st = new StringTokenizer(personstr, ":");
// 判斷是否還有分隔符可用。
while (st.hasMoreTokens()) {
field[fieldcount] = st.nextToken();
fieldcount++;
}
// 如果輸入married，則field[3]不為空，調(diào)用具有四個參數(shù)的Person構(gòu)造函數(shù)。
if (field[3] != "") {
people[i] = new Person(field[0],
Integer.parseInt(field[1]), Double
.parseDouble(field[2]), field[3]);
// 置field[3]為空，以備下次輸入使用。
field[3] = "";
}
// 如果未輸入married，則field[3]為空，調(diào)用具有三個參數(shù)的Person構(gòu)造函數(shù)。
else {
people[i] = new Person(field[0],
Integer.parseInt(field[1]), Double
.parseDouble(field[2]));
}
}
// 將輸入的數(shù)據(jù)保存至“people.dat”文本文件中。
PrintWriter out = new PrintWriter(new BufferedWriter(
new FileWriter("people.dat")));
writeData(people, out);
// 關(guān)閉流。
out.close();
// 從文件“people.dat”讀取數(shù)據(jù)。
BufferedReader in = new BufferedReader(new FileReader("people.dat"));
Person[] inPeople = readData(in);
// 關(guān)閉流。
in.close();
// 輸出從文件中讀入的數(shù)據(jù)。
for (int i = 0; i inPeople.length; i++) {
System.out.println(inPeople[i]);
}
} catch (IOException exception) {
System.err.println("IOException");
}
}
// 將所有數(shù)據(jù)寫入輸出流。
static void writeData(Person[] p, PrintWriter out) throws IOException {
// 寫入記錄條數(shù)，即人數(shù)。
out.println(p.length);
for (int i = 0; i p.length; i++) {
p[i].writeData(out);
}
}
// 將所有數(shù)據(jù)從輸入流中讀出。
static Person[] readData(BufferedReader in) throws IOException {
// 獲取記錄條數(shù)，即人數(shù)。
int n = Integer.parseInt(in.readLine());
Person[] p = new Person[n];
for (int i = 0; i n; i++) {
p[i] = new Person();
p[i].readData(in);
}
return p;
}
}
class Person {
private String name;
private int age;
private double salary;
private String married;
public Person() {
}
public Person(String n, int a, double s) {
name = n;
age = a;
salary = s;
married = "F";
}
public Person(String n, int a, double s, String m) {
name = n;
age = a;
salary = s;
married = m;
}
public String getName() {
return name;
}
public int getAge() {
return age;
}
public double getSalary() {
return salary;
}
public String getMarried() {
return married;
}
// 設(shè)置輸出格式。
public String toString() {
return getClass().getName() + "[name=" + name + ",age=" + age
+ ",salary=" + salary + ",married=" + married + "]";
}
// 寫入一條記錄，即一個人的數(shù)據(jù)到輸出流。
public void writeData(PrintWriter out) throws IOException {
// 格式化輸出。
out.println(name + ":" + age + ":" + salary + ":" + married);
}
// 從輸入流讀入一條記錄，即一個人的數(shù)據(jù)。
public void readData(BufferedReader in) throws IOException {
String s = in.readLine();
StringTokenizer t = new StringTokenizer(s, ":");
name = t.nextToken();
age = Integer.parseInt(t.nextToken());
salary = Double.parseDouble(t.nextToken());
married = t.nextToken();
}
}
package IO;
import java.io.IOException;
public class FileStdRead {
public static void main(String[] args) throws IOException {
int b = 0;
char c = ' ';
System.out.println("請輸入：");
while (c != 'q') {
int a = System.in.read();
c = (char) a;
b++;
System.out.println((char) a);
}
System.err.print("counted\t" + b + "\ttotalbytes.");
}
}
//讀取輸入的數(shù)據(jù),直到數(shù)據(jù)中有Q這個字母然
package IO;
import java.io.*;
public class IOStreamExample {
public static void main(String[] args) throws IOException {
// 1. 讀入一行數(shù)據(jù):
BufferedReader in = new BufferedReader(new FileReader(
"FileStdRead.java"));
String s, s2 = new String();
while ((s = in.readLine()) != null) {
s2 += s + "\n";
}
in.close();
BufferedReader stdin = new BufferedReader(new InputStreamReader(
System.in));
System.out.print("Enter a line:");
System.out.println(stdin.readLine());
// 2. 從內(nèi)存中讀入
StringReader in2 = new StringReader(s2);
int c;
while ((c = in2.read()) != -1) {
System.out.print((char) c);
}
// 3. 格式化內(nèi)存輸入
try {
DataInputStream in3 = new DataInputStream(new ByteArrayInputStream(
s2.getBytes()));
while (true) {
System.out.print((char) in3.readByte());
}
} catch (EOFException e) {
System.err.println("End of stream");
}
// 4. 文件輸入
try {
BufferedReader in4 = new BufferedReader(new StringReader(s2));
PrintWriter out1 = new PrintWriter(new BufferedWriter(
new FileWriter("IODemo.out")));
int lineCount = 1;
while ((s = in4.readLine()) != null) {
out1.println(lineCount++ + ": " + s);
}
out1.close();
} catch (EOFException e) {
System.err.println("End of stream");
}
// 5. 接收和保存數(shù)據(jù)
try {
DataOutputStream out2 = new DataOutputStream(
new BufferedOutputStream(new FileOutputStream("Data.txt")));
out2.writeDouble(3.14159);
out2.writeUTF("That was pi");
out2.writeDouble(1.41413);
out2.writeUTF("Square root of 2");
out2.close();
DataInputStream in5 = new DataInputStream(new BufferedInputStream(
new FileInputStream("Data.txt")));
System.out.println(in5.readDouble());
System.out.println(in5.readUTF());
System.out.println(in5.readDouble());
System.out.println(in5.readUTF());
} catch (EOFException e) {
throw new RuntimeException(e);
}
// 6. 隨機讀取文件內(nèi)容
RandomAccessFile rf = new RandomAccessFile("rtest.dat", "rw");
for (int i = 0; i 10; i++) {
rf.writeDouble(i * 1.414);
}
rf.close();
rf = new RandomAccessFile("rtest.dat", "rw");
rf.seek(5 * 8);
rf.writeDouble(47.0001);
rf.close();
rf = new RandomAccessFile("rtest.dat", "r");
for (int i = 0; i 10; i++) {
System.out.println("Value " + i + ": " + rf.readDouble());
}
rf.close();
}
}
package IO;
import java.io.*;
/**
* p
* Title: JAVA進階訣竅
* /p
*
* @author 張峰
* @version 1.0
*/
public class MakeDirectoriesExample {
private static void fileattrib(File f) {
System.out.println("絕對路徑: " + f.getAbsolutePath() + "\n 可讀屬性: "
+ f.canRead() + "\n 可定屬性: " + f.canWrite() + "\n 文件名: "
+ f.getName() + "\n 父目錄: " + f.getParent() + "\n 當前路徑: "
+ f.getPath() + "\n 文件長度: " + f.length() + "\n 最后更新日期: "
+ f.lastModified());
if (f.isFile()) {
System.out.println("輸入的是一個文件");
} else if (f.isDirectory()) {
System.out.println("輸入的是一個目錄");
}
}
public static void main(String[] args) {
if (args.length 1) {
args = new String[3];
}
args[0] = "d";
args[1] = "test1.txt";
args[2] = "test2.txt";
File old = new File(args[1]), rname = new File(args[2]);
old.renameTo(rname);
fileattrib(old);
fileattrib(rname);
int count = 0;
boolean del = false;
if (args[0].equals("d")) {
count++;
del = true;
}
count--;
while (++count args.length) {
File f = new File(args[count]);
if (f.exists()) {
System.out.println(f + " 文件己經(jīng)存在");
if (del) {
System.out.println("刪除文件" + f);
f.delete();
}
} else { // 如果文件不存在
if (!del) {
f.mkdirs();
System.out.println("創(chuàng)建文件： " + f);
}
}
fileattrib(f);
}
}
}
import?java.io.File;
import?java.io.FileInputStream;
import?java.io.IOException;
import?java.io.InputStream;
public?class?Jie?{
public?static?void?main(String?[]?args)?throws?IOException{
File?file=new?File("C:\\Users\\Administrator.ZJ2IWINY6JJYMTT\\Desktop\\2.txt");
InputStream?isr=new?FileInputStream(file);
int?r=isr.read();
String?result="";
while(r!=-1){
result=result+(char)r;
r=isr.read();
}
String?sp[]=result.split(",");
System.out.print(sp[11]);
isr.close();
}
}
第二題：
import?java.util.Scanner;
public?class?UpCase?{
public?static?void?main(String?[]?args){
Scanner?input=new?Scanner(System.in);
System.out.print("請輸入字母:");
String?a=input.next();
String?b=a.toUpperCase();
System.out.print(b);
}
}
第三題:那個編碼表是啥意思?
重慶分公司
重慶分公司
