java_I/O操作_WriterAndReaderDemo

package testjava_13;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.io.Writer;

public class WriterAndReaderDemo {

public static void main(String[] args) throws Exception {
String sReaderPath = "E:"
+File.separatorChar+"mytest"
+File.separatorChar+"1.txt";
String sWriterPath = "E:"
+File.separatorChar+"mytest"
+File.separatorChar+"2.txt";

File readerFile = createFile(sReaderPath);
Reader reader = new FileReader(readerFile);
char[] c1 = new char[reader.read()];
int i = reader.read(c1);

File writerFile = createFile(sWriterPath);
Writer writer =new FileWriter(writerFile,true);//输出的内容附加到文件尾部
writer.write(c1);
writer.write("hhhaa");
writer.close();//关闭字符流，将内存缓冲区中转换好的字符流刷新输出到外部文件中。flush()强制清空缓冲区也可以保证数据输出到外部文件中。
reader.close();
}

//根据路径创建File
private static File createFile(String filePath) {
File file = new File(filePath);
if (!file.getParentFile().exists()) { //如果父级路径不存在就创建父级目录
file.getParentFile().mkdirs();
if (!file.exists()) { //如果文件不存在就创建文件
try {
file.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return file;
}
}