Common Java class 4: Typical use of I/O streams

Package HTTP; import Java. io. bufferedreader; import Java. io. bufferedwriter; import Java. io. filereader; import Java. io. filewriter; import Java. io. ioexception;/** the read and write operations correspond to inputstream and outputstream * respectively, the latter is used for byte stream * filereader and filewrite, respectively. They correspond to fileinputstream and fileoutputstream * bufferedreader and bufferedwrite respectively, respectively, to bufferedinputstream and * bufferedoutputstream * This example implements character read/write operations Feredreaderdemo {public static string read (string filename) throws ioexception {stringbuilder STR = new stringbuilder (); bufferedreader in = new bufferedreader (New filereader (filename); string S; while (S = in. readline ())! = NULL) Str. append (S + '\ n'); In. close (); Return Str. tostring ();} public static void write (string filename, Boolean append) throws ioexception {bufferedwriter out = new bufferedwriter (New filewriter (filename, append); out. write ("I Am a Dahai! Java hello! "); Out. close ();} public static void main (string [] ARGs) {try {write ("file/test3.txt", false); system. out. println (read ("file/test3.txt");} catch (ioexception e) {// todo auto-generated catch blocke. printstacktrace ();}}}

 

Package HTTP; import Java. io. bytearrayinputstream; import Java. io. datainputstream; import Java. io. ioexception;/** datainputstream is used to read formatted data */public class datainputstreamandbytearrayinputstreamdemo {public static void main (string [] ARGs) throws ioexception {datainputstream in = new datainputstream (New bytearrayinputstream (filereaderandbufferedreaderdemo. read ("file/test3.txt "). getbytes (); While (in. A Vailable ()! = 0) system. Out. Print (char) in. readbyte ());}}

 

Package test; import HTTP. filereaderandbufferedreaderdemo; import Java. io. ioexception; import Java. io. stringreader;/** stringreader operates on the string */public class stringreaderdemo {public static void main (string [] ARGs) throws ioexception {stringreader in = new stringreader (filereaderandbufferedreaderdemo. read ("file/test3.txt"); int C; while (C = in. read ())! =-1) system. Out. Print (char) c );}}

 

Package test; import HTTP. filereaderandbufferedreaderdemo; import Java. io. ioexception; import Java. io. printwriter;/** corresponds to printstream * used to format the output to a file */public class printwriterdemo {public static void main (string [] ARGs) throws ioexception {// simplified creation method printwriter out = new printwriter ("file/test4.txt"); // You can also create it like this: out = new printer (New bufferedwriter (new // filewriter ("file/test4.txt"); // format the output to the text out. print Ln ('A'); Out. println (3); Out. println (3.5); Out. Print ("I love you! I Love You "); Out. Close (); // read the system. Out. println (filereaderandbufferedreaderdemo. Read (" file/test4.txt "));}}

 

Package test; import Java. io. filenotfoundexception; import Java. io. ioexception; import Java. io. randomaccessfile;/** randomaccessfile directly inherits objects and can carry out random input and output. It is similar to file operations in C language. * specify the method to open the file. When using this class, you must know the file layout, this class has a variety of methods to read and write the basic type and UTF-8 string *, can be located to a certain position of the file to read and write */public class randomaccessfiledemo {public static void main (string [] ARGs) throws filenotfoundexception {randomaccessfile out = new randomaccessfile ("file/test5 ", "RW"); try {out. writeint (1); Out. writedouble (3.3); Out. writechar ('A'); Out. writeutf ("Hello, Java! "); Out. close ();} catch (ioexception e) {e. printstacktrace ();} randomaccessfile in = new randomaccessfile ("file/test5", "R"); try {In. seek (4); system. out. println (in. readdouble (); In. seek (4 + 8 + 2); system. out. println (in. readutf (); In. close ();} catch (ioexception e) {e. printstacktrace ();}}}

 

Package test; import Java. io. fileinputstream; import Java. io. filenotfoundexception; import Java. io. fileoutputstream; import Java. io. ioexception; import Java. io. objectinputstream; import Java. io. objectoutputstream; import Java. io. serializable;/** objectinputstream (objectoutputstream) used for Object serialization * directly reads and writes an object. The object must be serializable */public class objectinputstreamdemo {public static void writeobject (string filena Me, object o, Boolean isappend) throws filenotfoundexception, ioexception {objectoutputstream out = new objectoutputstream (New fileoutputstream (filename, true); out. writeobject (o); out. close ();} public static object readobject (string filename) throws filenotfoundexception, ioexception, classnotfoundexception {objectinputstream in = new objectinputstream (New fileinputstream (filename); object o = in. rea Dobject (); In. close (); return O;} public static void main (string [] ARGs) {try {objectinputstreamdemo. writeobject ("file/object", new person (), false); (person) objectinputstreamdemo. readobject ("file/object ")). display ();} catch (ioexception e) {e. printstacktrace ();} catch (exception e) {e. printstacktrace () ;}} class person implements serializable {private string name = "liuhaifang"; private int sex = 0; Person (string name, int sex) {This. name = Name; this. sex = sex;} person () {} void display () {system. out. println ("My name is:" + name); string S = (sex = 0 )? "Male": "female"; system. Out. println (s );}}