InputStreamReader 和 OutputStreamWriter类用法简介，及演示。
InputStreamReader 和 OutputStreamWriter类用法简介。一、InputStreamReader类
InputStreamReader 将字节流转换为字符流。是字节流通向字符流的桥梁。如果不指定字符集编码，该解码过程将使用平台默认的字符编码，如：GBK。
构造方法：
InputStreamReader isr = new InputStreamReader(InputStream in);//构造一个默认编码集的InputStreamReader类
InputStreamReader isr = new InputStreamReader(InputStream in,String charsetName);//构造一个指定编码集的InputStreamReader类。
参数 in对象通过 InputStream in = System.in;获得。//读取键盘上的数据。
或者 InputStream in = new FileInputStream(String fileName);//读取文件中的数据。可以看出FileInputStream 为InputStream的子类。
主要方法：int read();//读取单个字符。
int read(char []cbuf);//将读取到的字符存到数组中。返回读取的字符数。
public static void transReadNoBuf() throws IOException {/** * 没有缓冲区，只能使用read()方法。 *///读取字节流//InputStream in = System.in;//读取键盘的输入。InputStream in = new FileInputStream("D:\\demo.txt");//读取文件的数据。//将字节流向字符流的转换。要启用从字节到字符的有效转换，可以提前从底层流读取更多的字节.InputStreamReader isr = new InputStreamReader(in);//读取//InputStreamReader isr = new InputStreamReader(new FileInputStream("D:\\demo.txt"));//综合到一句。char []cha = new char[1024];int len = isr.read(cha);System.out.println(new String(cha,0,len));isr.close();}public static void transReadByBuf() throws IOException {/** * 使用缓冲区 可以使用缓冲区对象的 read() 和 readLine()方法。 *///读取字节流//InputStream in = System.in;//读取键盘上的数据InputStream in = new FileInputStream("D:\\demo.txt");//读取文件上的数据。//将字节流向字符流的转换。InputStreamReader isr = new InputStreamReader(in);//读取//创建字符流缓冲区BufferedReader bufr = new BufferedReader(isr);//缓冲//BufferedReader bufr = new BufferedReader(new InputStreamReader(new FileInputStream("D:\\demo.txt")));可以综合到一句。/*int ch =0;ch = bufr.read();System.out.println((char)ch);*/String line = null;while((line = bufr.readLine())!=null){System.out.println(line);}isr.close();}
OutputStreamWriter 将字节流转换为字符流。是字节流通向字符流的桥梁。如果不指定字符集编码，该解码过程将使用平台默认的字符编码，如：GBK。
构造方法：
OutputStreamWriter osw = newOutputStreamWriter(OutputStream out);//构造一个默认编码集的OutputStreamWriter类
OutputStreamWriter osw = newOutputStreamWriter(OutputStream out,String charsetName);//构造一个指定编码集的OutputStreamWriter类。
参数 out对象通过 InputStream out = System.out;获得。//打印到控制台上。
或者 InputStream out = new FileoutputStream(String fileName);//输出到文件中。可以看出FileoutputStream 为outputStream的子类。
主要方法：void write(int c);//将单个字符写入。
viod write(String str,int off,int len);//将字符串某部分写入。
void flush();//将该流中的缓冲数据刷到目的地中去。
public static void transWriteNoBuf() throws IOException {OutputStream out = System.out;//打印到控制台//OutputStream out = new FileOutputStream("D:\\demo.txt");//打印到文件OutputStreamWriter osr = new OutputStreamWriter(out);//输出//OutputStreamWriter osr = new OutputStreamWriter(new FileOutputStream("D:\\demo.txt"));//两句可以综合到一句。//int ch = 97;//a//int ch = 20320;//你//osr.write(ch);String str = "你好吗？";//你好吗？osr.write(str);osr.flush();osr.close();}public static void transWriteByBuf() throws IOException {//OutputStream out = System.out;//打印到控制台。OutputStream out = new FileOutputStream("D:\\demo.txt");//打印到文件。OutputStreamWriter osr = new OutputStreamWriter(out);//输出//OutputStreamWriter osr = new OutputStreamWriter(new FileOutputStream("D:\\demo.txt"));//综合到一句。BufferedWriter bufw = new BufferedWriter(osr);//缓冲//int ch = 97;//a//int ch = 20320;//你//osr.write(ch);String str = "你好吗？\r\n我很好！";//你好吗？bufw.write(str);bufw.flush();bufw.close();}流转换程序1：
package IOtest;import java.io.BufferedReader;import java.io.BufferedWriter;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.io.OutputStream;import java.io.OutputStreamWriter;public class TransStreamtest {/** * 主要的类：in1,InputStream * 创建对象 InputStream in = System.in; * in2,InputStreamReader 没有readLine()方法 * 主要方法： * read()读取单个字符，一个汉字也为一个字符。 * read(char[] cbuf)将字符读入数组。 * close().关闭此流和相关联资源。 * in3,BufferedReader 有read(),readLine()方法。 * out1,OutputStream * 创建对象 OutputStream in = System.out; * out2,OutputStreamWriter * 主要方法： * write(int c)//写入单个字符。 * write(char[] cbuf,int off,int len)//写入数组的某一部分 * write(String str,int off,int len)//写入字符串烦人某一部分。 * flush();//刷新该流中的缓冲。 * close(); * out3,BufferedWriteer 有Write(int ch),newLine()方法。 * * * @throws IOException */public static void main(String[] args) throws IOException {//transReadByBuf();//transReadNoBuf();transWriteNoBuf();//transWriteByBuf();}public static void transWriteNoBuf() throws IOException {OutputStream out = System.out;//打印到控制台//OutputStream out = new FileOutputStream("D:\\demo.txt");//打印到文件OutputStreamWriter osr = new OutputStreamWriter(out);//输出//OutputStreamWriter osr = new OutputStreamWriter(new FileOutputStream("D:\\demo.txt"));//两句可以综合到一句。//int ch = 97;//a//int ch = 20320;//你//osr.write(ch);String str = "你好吗？";//你好吗？osr.write(str);osr.flush();osr.close();}public static void transWriteByBuf() throws IOException {//OutputStream out = System.out;//打印到控制台。OutputStream out = new FileOutputStream("D:\\demo.txt");//打印到文件。OutputStreamWriter osr = new OutputStreamWriter(out);//输出//OutputStreamWriter osr = new OutputStreamWriter(new FileOutputStream("D:\\demo.txt"));//综合到一句。BufferedWriter bufw = new BufferedWriter(osr);//缓冲//int ch = 97;//a//int ch = 20320;//你//osr.write(ch);String str = "你好吗？\r\n我很好！";//你好吗？bufw.write(str);bufw.flush();bufw.close();}public static void transReadNoBuf() throws IOException {/** * 没有缓冲区，只能使用read()方法。 *///读取字节流//InputStream in = System.in;//读取键盘的输入。InputStream in = new FileInputStream("D:\\demo.txt");//读取文件的数据。//将字节流向字符流的转换。要启用从字节到字符的有效转换，可以提前从底层流读取更多的字节.InputStreamReader isr = new InputStreamReader(in);//读取//InputStreamReader isr = new InputStreamReader(new FileInputStream("D:\\demo.txt"));//综合到一句。char []cha = new char[1024];int len = isr.read(cha);System.out.println(new String(cha,0,len));isr.close();}public static void transReadByBuf() throws IOException {/** * 使用缓冲区 可以使用缓冲区对象的 read() 和 readLine()方法。 *///读取字节流//InputStream in = System.in;//读取键盘上的数据InputStream in = new FileInputStream("D:\\demo.txt");//读取文件上的数据。//将字节流向字符流的转换。InputStreamReader isr = new InputStreamReader(in);//读取//创建字符流缓冲区BufferedReader bufr = new BufferedReader(isr);//缓冲//BufferedReader bufr = new BufferedReader(new InputStreamReader(new FileInputStream("D:\\demo.txt")));可以综合到一句。/*int ch =0;ch = bufr.read();System.out.println((char)ch);*/String line = null;while((line = bufr.readLine())!=null){System.out.println(line);}isr.close();}}流转换程序2：
package readKey;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.FileReader;import java.io.FileWriter;import java.io.IOException;import java.io.InputStreamReader;import java.io.OutputStreamWriter;public class TransStreamDemo3 {/** * @param args * @throws IOException */public static void main(String[] args) throws IOException {//writeText_1();//writeText_2();//writeText_3();//ReadTest_1();//ReadTest_2();//ReadTest_3();} public static void ReadTest_3() throws IOException {InputStreamReader isr = new InputStreamReader(new FileInputStream("D:\\utf-8.txt"),"UTF-8");char []ch = new char[20];int len = isr.read(ch);System.out.println(new String(ch,0,len) );isr.close();}public static void ReadTest_2() throws IOException {InputStreamReader isr = new InputStreamReader(new FileInputStream("D:\\utf-8.txt"),"GBK");char []ch = new char[20];int len = isr.read(ch);System.out.println(new String(ch,0,len) );isr.close();}public static void ReadTest_1() throws IOException {FileReader fr = new FileReader("D:\\demo.txt");char []ch = new char[20];int len = fr.read(ch);System.out.println(new String(ch,0,len) );fr.close();}public static void writeText_3() throws IOException {OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream("D:\\utf-8.txt"),"UTF-8");osw.write("你好吗");osw.close();}public static void writeText_2() throws IOException {FileWriter fw = new FileWriter("D:\\gbk1.txt");fw.write("你好啊");fw.close();}public static void writeText_1() throws IOException {OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream("D:\\gbk.txt"),"GBK");/* *和上面的等同 * FileWriter fw = new FileWriter("D:\\gbk1.txt"); * 操作文件的字节流 + 默认的编码表 */osw.write("你好吗");osw.close();}}