打印流、数据流使用
package fifteen;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintStream;
import org.junit.Test;
public class TestOtherStream1 {
@Test
public void testData1(){
DataInputStream dis = null;
try{
dis = new DataInputStream(new FileInputStream(new File("data.txt")));
// byte[] b = new byte[20];
// int len;
// while((len = dis.read(b)) != -1){
// System.out.println(new String(b,0,len));
// }
String str = dis.readUTF();//读字符串
System.out.println(str);
boolean b = dis.readBoolean();
System.out.println(b);
long l = dis.readLong();
System.out.println(l);
}catch(Exception e){
e.printStackTrace();
}finally{
if(dis != null){
try {
dis.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
//数据流:用来处理基本数据类型、String、字节数组的数据:DataInputStream DataOutputStream
@Test
public void testData(){
DataOutputStream dos = null;
try {
FileOutputStream fos = new FileOutputStream("data.txt");
dos = new DataOutputStream(fos);
dos.writeUTF("我爱你,而你却不知道!");
dos.writeBoolean(true);
dos.writeLong(1432522344);
}catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
if(dos != null){
try {
dos.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
// 打印流:字节流:PrintStream 字符流:PrintWriter
@Test
public void printStreamWriter() {
FileOutputStream fos = null;
try {
fos = new FileOutputStream(new File("print.txt"));
} catch (FileNotFoundException e) {
e.printStackTrace();
}
// 创建打印输出流,设置为自动刷新模式(写入换行符或字节 '\n' 时都会刷新输出缓冲区)
PrintStream ps = new PrintStream(fos, true);
if (ps != null) { // 把标准输出流(控制台输出)改成文件
System.setOut(ps);
}
for (int i = 0; i <= 255; i++) { // 输出ASCII字符
System.out.print((char) i);
if (i % 50 == 0) { // 每50个数据一行
System.out.println(); // 换行
}
}
ps.close();
}
}
韧桂 2020-01-04