How to convert strings and input streams in Java

Mutual conversion between strings and input streams

When reading network resources, the mutual conversion between strings and input streams is often used. I found some methods and recorded them.

Convert the string into an input stream, the code is as follows:

public static InputStream getStringStream(String sInputString){ 
　　if (sInputString != null && !sInputString.trim().equals("")){ 
　　    try{ 
　　        ByteArrayInputStream tInputStringStream = new ByteArrayInputStream(sInputString.getBytes()); 
　　        return tInputStringStream; 
　　    }catch (Exception ex){ 
　　        ex.printStackTrace(); 
　　    } 
　　} 
　　return null; 
}

Convert the input stream into a string, the code is as follows:

public static String getStreamString(InputStream tInputStream){ 
　　if (tInputStream != null){ 
　　     try{ 
　　          BufferedReader tBufferedReader = new BufferedReader(new InputStreamReader(tInputStream)); 
　　          StringBuffer tStringBuffer = new StringBuffer(); 
　　          String sTempOneLine = new String(""); 
　　          while ((sTempOneLine = tBufferedReader.readLine()) != null){ 
　　              tStringBuffer.append(sTempOneLine); 
　　          } 
　　         return tStringBuffer.toString(); 
　　    }catch (Exception ex){ 
　　         ex.printStackTrace(); 
　　    } 
　　} 
　　return null; 
}

Or the following method, the code is as follows ：

public class StreamTool {
    /**
     * 把输入流的内容转化成字符串
     * @param is
     * @return
     */
    public static String readInputStream(InputStream is){
        try {
            ByteArrayOutputStream baos=new ByteArrayOutputStream();
            int length=0;
            byte[] buffer=new byte[1024];
            while((length=is.read(buffer))!=-1){
                baos.write(buffer, 0, length);
            }
            is.close();
            baos.close();
            //或者用这种方法
            //byte[] result=baos.toByteArray();
            //return new String(result);
            return baos.toString();
        } catch (Exception e) {
            e.printStackTrace();
            return "获取失败";
        }
    }
}

Character input and output stream

Character input stream

java.io.Reader abstraction is the parent class of all character input streams, used to read file content

Character input stream structure:

For the convenience of reading, Java provides a convenient class for reading character files.

FileReader class

Construction method:

• FileReader(File file); Create a new FileReader given a File to read data from.

• FileReader(String fileName); Creates a new FileReader given the name of a file to read data from.

Commonly used reading methods:

##Method nameDescriptionint read()Read one character, and return -1 if all characters are reached to the endint read(char[] cbuf)Read the read cbuf.length characters into the char arrayint read(char[] cbuf, int off , int len)Read offset off to len characters from this character input stream into the char arrayvoid reset()Reset the streamboolean ready()Judge whether the stream is ready to be readvoid close() Close the character input stream and release all system resourceslong skip(long n)Skip reading n characters and return The number of skipped charactersvoid mark(int readLimit)Mark this input stream. When the reset method is used, it returns to this position and starts reading from this position. Enter characters #1. Single reading, not recommended if the file is too large.

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
public class dome2{
	public static void main(String[] args){
	  File file=new File("D:/../...txt");   //创建file对象
	  FileReader fr=null;
	  
	  try {
		fr=new FileReader(file);
		int c;  
		while((c=fr.read())!=-1) { 
			System.out.print((char)c);  //强制转换成字符
		}
	} catch (FileNotFoundException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	} catch (IOException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}finally {
		if(fr!=null) {
			try {
				fr.close();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
   }
}

2. Read multiple characters and output.

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
public class dome2{
	public static void main(String[] args){
	  File file=new File("D:/../...txt");   
	  FileReader fr=null;
	  
	  try {
		fr=new FileReader(file);
		char[] c=new char[100];
		int length;
		while((length=fr.read(c))!=-1) {
			System.out.println(new String(c,0,length));  
		}
	} catch (FileNotFoundException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	} catch (IOException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}finally {
		if(fr!=null) {
			try {
				fr.close();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
   }
}

Character output stream

java.io.Writer abstract class is the parent class of all character output streams and is used to write data to files.

Character output stream structure:

In order to write Java provides a convenient class for character writing.

FileWriter class

Construction method:

• FileWriter(File file) and FileWriter(String fileName); Construct a FileWriter object using the given file object or the given file path name.

• FileWriter(File file, boolean append) and FileWriter(String fileName, boolean append); Through the given file object or file The pathname constructs the FileWriter object and whether it is appended or overwritten.

Common reading methods

Method nameDescriptionvoid write(char[] cbuf)Write all character arrays specified by cbuf to the character output streamvoid write(int c)Write a character to the character output streamvoid write(char[] cbuf,int off,int len )Write the characters in the cbuf array from offset off to length len characters into this output stream. void write(String str )Write a string to the character input streamvoid write(String str, int off, int len)Write str string from offset off, length len string to this output stream. Abstract void flush()Refresh the current output stream and force writing of all character dataabstract void close ()Close this output stream1.writer(int c);Write a character

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
public class dome2{
	public static void main(String[] args){
	  File file=new File("D:/../...txt");   //创建file对象
       FileWriter  fw=null;
       
       try {
		fw=new FileWriter(file);
		char c='你';
		fw.write((int)c);
	} catch (IOException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}finally {
		if(fw!=null) {
			try {
				fw.close();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}       
   }
}

2.writer( String str); Write a string

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
public class dome2{
	public static void main(String[] args){
	  File file=new File("D:/../...txt");   //创建file对象
       FileWriter  fw=null;
       
       try {
		fw=new FileWriter(file);
		String str="你好,java";
		fw.write(str);  //写入一个字符串，等价于write(str,0,str.length);
	} catch (IOException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}finally {
		if(fw!=null) {
			try {
				fw.close();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}       
   }
}

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