1 import java.io.File;
2
3 /**
4 * File类型基本操作
5 */
6
7 /**
8 * @author Administrator
9 *
10 */
11 public class FileDemo {
12
13 /**
14 * @param args
15 */
16 public static void main(String[] args) {
17 // TODO Auto-generated method stub
18 final String PATH = "c:\\text.txt"
;
19 File file =
new File(PATH);
20 if (file.exists()) {
21 if (file.isFile()) {
22 System.out.println("名称：" +
file.getName());
23 System.out.println("相对路径：" +
file.getPath());
24 System.out.println("绝对路径：" +
file.getAbsolutePath());
25 System.out.println("文件大小：" + file.length() + "字节"
);
26 }
else if (file.isDirectory()) {
27 System.out.println("这是一个目录！"
);
28 }
29 }
else {
30 System.out.println("文件不存在！"
);
31 }
32 }
33
34 }
View Code
1 import java.io.FileInputStream;
2 import java.io.FileOutputStream;
3
4 /**
5 * 使用字节流写入文件、读取文件。
6 */
7 /**
8 * @author Administrator
9 *
10 */
11 public class ByteStreamDemo {
12
13 /**
14 * @param args
15 * @throws Exception
16 */
17 public static void main(String[] args)
throws Exception {
18 // TODO Auto-generated method stub
19 final String PATH = "c:\\text.txt"
;
20
21 FileOutputStream fos =
null;
22 try {
23 String content = "王云鹏是帅哥！"
;
24 byte[] contents =
content.getBytes();
25 fos =
new FileOutputStream(PATH);
26 fos.write(contents, 0
, contents.length);
27 fos.flush();
28 }
catch (Exception e) {
29 // TODO: handle exception
30 throw e;
31 }
finally {
32 if (fos !=
null) {
33 fos.close();
34 }
35 }
36
37 FileInputStream fis =
null;
38 try {
39 fis =
new FileInputStream(PATH);
40 int length =
fis.available();
41 byte[] contents =
new byte[length];
42 while(fis.read(contents, 0, length)!=-1
){
43 String content =
new String(contents);
44 System.out.println(content);
45 }
46 }
catch (Exception e) {
47 // TODO: handle exception
48 throw e;
49 }
50 finally{
51 if(fis!=
null){
52 fis.close();
53 }
54 }
55 }
56
57 }
View Code
1 import java.io.DataInputStream;
2 import java.io.DataOutputStream;
3 import java.io.FileInputStream;
4 import java.io.FileOutputStream;
5
6 /**
7 * 采用二进制流方式写入文件、读取文件。
8 */
9
10 /**
11 * @author Administrator
12 *
13 */
14 public class BinaryStreamDemo2 {
15
16 /**
17 * @param args
18 * @throws Exception
19 */
20 public static void main(String[] args)
throws Exception {
21 // TODO Auto-generated method stub
22 final String PATH = "c:\\text.txt"
;
23
24 java.io.FileOutputStream fos =
null;
25 java.io.DataOutputStream dos =
null;
26 try {
27 fos =
new FileOutputStream(PATH);
28 dos =
new DataOutputStream(fos);
29
30 dos.writeInt(1
);
31 dos.writeLong(2
);
32 dos.writeUTF("王云鹏是帅哥！"
);
33 dos.flush();
34
35 }
catch (Exception e) {
36 // TODO: handle exception
37 throw e;
38 }
finally {
39 if (dos !=
null) {
40 dos.close();
41 }
42 if (fos !=
null) {
43 fos.close();
44 }
45 }
46
47 java.io.FileInputStream fis =
null;
48 java.io.DataInputStream dis =
null;
49 try {
50 fis =
new FileInputStream(PATH);
51 dis =
new DataInputStream(fis);
52
53 int i =
dis.readInt();
54 long l =
dis.readLong();
55 String content =
dis.readUTF();
56 System.out.println(i);
57 System.out.println(l);
58 System.out.println(content);
59 }
catch (Exception e) {
60 // TODO: handle exception
61 throw e;
62 }
finally {
63 if (dis !=
null) {
64 dis.close();
65 }
66 if (fis !=
null) {
67 fis.close();
68 }
69 }
70 }
71
72 }
View Code
1 import java.io.DataInputStream;
2 import java.io.DataOutputStream;
3 import java.io.FileInputStream;
4 import java.io.FileOutputStream;
5
6 /**
7 * 采用二进制流方式写入文件、读取文件。
8 */
9
10 /**
11 * @author Administrator
12 *
13 */
14 public class BinaryStreamDemo {
15
16 /**
17 * @param args
18 * @throws Exception
19 */
20 public static void main(String[] args)
throws Exception {
21 // TODO Auto-generated method stub
22 java.io.FileOutputStream fos =
null;
23 java.io.DataOutputStream dos =
null;
24 java.io.FileInputStream fis =
null;
25 java.io.DataInputStream dis =
null;
26 try {
27 fis =
new FileInputStream("c:\\source.jpg"
);
28 dis =
new DataInputStream(fis);
29
30 fos =
new FileOutputStream("c:\\desc.jpg"
);
31 dos =
new DataOutputStream(fos);
32
33 int temp = -1
;
34 while((temp=dis.read())!=-1
){
35 dos.write(temp);
36 }
37 }
catch (Exception e) {
38 // TODO: handle exception
39 throw e;
40 }
41 finally
42 {
43 if(dos!=
null)
44 {
45 dos.close();
46 }
47 if(fos!=
null){
48 fos.close();
49 }
50 if(dis!=
null){
51 dis.close();
52 }
53 if(fis!=
null){
54 fis.close();
55 }
56 }
57 System.out.println("copy file success!"
);
58 }
59
60 }
View Code
1 import java.io.FileReader;
2 import java.io.FileWriter;
3 import java.io.IOException;
4 import java.util.Arrays;
5
6 /**
7 * 使用字符流写入文件、读取文件。
8 */
9
10 /**
11 * @author Administrator
12 *
13 */
14 public class CharStreamDemo {
15
16 /**
17 * @param args
18 * @throws Exception
19 */
20 public static void main(String[] args)
throws Exception {
21 // TODO Auto-generated method stub
22 final String PATH = "c:\\text.txt"
;
23
24 FileWriter fw =
null;
25 try{
26 fw =
new FileWriter(PATH);
27 fw.write("王云鹏是帅哥！"
);
28 fw.flush();
29 }
catch(IOException ex){
30 throw ex;
31 }
32 finally{
33 if(fw!=
null){
34 fw.close();
35 }
36 }
37
38 FileReader fr =
null;
39 try {
40 fr =
new FileReader(PATH);
41 char[] chars =
new char[1024
];
42 StringBuilder sb =
new StringBuilder();
43 int length = 0
;
44 while((length=fr.read(chars))!=-1
){
45 if(length==1024
){
46 sb.append(chars);
47 }
else
48 {
49 char[] less =
Arrays.copyOf(chars, length);
50 sb.append(less);
51 }
52 Arrays.fill(chars, ' ');
//清空数组
53 }
54 System.out.println(sb.toString());
55
56 }
catch (Exception e) {
57 // TODO: handle exception
58 throw e;
59 }
60 finally{
61 if(fr!=
null){
62 fr.close();
63 }
64 }
65 }
66
67 }
View Code
1 import java.io.BufferedReader;
2 import java.io.BufferedWriter;
3 import java.io.FileReader;
4 import java.io.FileWriter;
5
6 /**
7 * 使用字符流+缓冲器写入文件、读取文件。
8 */
9
10 /**
11 * @author Administrator
12 *
13 */
14 public class CharBufferStreamDemo {
15
16 /**
17 * @param args
18 * @throws Exception
19 */
20 public static void main(String[] args)
throws Exception {
21 // TODO Auto-generated method stub
22 final String PATH = "c:\\text.txt"
;
23
24 FileWriter fw =
null;
25 BufferedWriter bw =
null;
26 try {
27 fw =
new FileWriter(PATH);
28 bw =
new BufferedWriter(fw);
29 bw.write("王云鹏是帅哥！"
);
30 bw.newLine();
31 bw.write("王云鹏是北大青鸟趟城中心的帅哥！"
);
32 bw.flush();
33 }
catch (Exception e) {
34 // TODO: handle exception
35 throw e;
36 }
finally {
37 if (bw !=
null) {
38 bw.close();
39 }
40 if (fw !=
null) {
41 fw.close();
42 }
43 }
44
45 FileReader fr =
null;
46 BufferedReader br =
null;
47 try {
48 fr =
new FileReader(PATH);
49 br =
new BufferedReader(fr);
50 String line =
null;
51 while ((line = br.readLine()) !=
null) {
52 System.out.println(line);
53 }
54 }
catch (Exception e) {
55 // TODO: handle exception
56 throw e;
57 }
finally {
58 if (br !=
null) {
59 br.close();
60 }
61 if (fr !=
null) {
62 fr.close();
63 }
64 }
65 }
66
67 }
View Code
转载于:https://www.cnblogs.com/qiyebao/p/3642325.html
