Java: how to read and write multiple object streams to files

Idea: store serialized objects into containers (such as the serialized list <?>) And then use objectinputstream and objectoutputstream to list the instantiated objects <?> Object.

Test main program:

/*** @ Title: filerw. Java * @ package com. File * @ Description: exercises for creating and writing files and folders. Read/write is implemented using object streams. * @ Author jogging Android * @ date 2011-11-19 03:53:01 * @ version V1.0 */package COM. file; import Java. io. file; 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. util. optional list; public class filerw {private string dirpath; private string filename; Public Static void main (string [] ARGs) {string Path = "C :\\ Xiaosheng"; string filename = "test.txt"; filerw = new filerw (path, filename ); shortlist <testmessage> msgout = new shortlist <testmessage> (); shortlist <testmessage> msgin = NULL; msgout. add (New testmessage ("Conan", "Idol"); msgout. add (New testmessage ("Kakashi", "good sample"); msgout. add (New testmessage ("android", "android"); msgout. add (New testmessage ("Haha", "test ") ); Filerw. writeobject (path, filename, msgout); msgin = filerw. readobject (path, filename); For (testmessage temp: msgin) {system. out. println (temp. getname () + temp. getdata () ;}} public filerw (string dirpath, string filename) {This. dirpath = dirpath; this. filename = filename; If (creatdir () {creatfile () ;}} private Boolean creatdir () {If (null! = Dirpath) {File Path = new file (dirpath); If (path. exists () {return true;} If (true = path. mkdirs () {return true;} return false;} private void creatfile () {If (null! = Filename) {file = new file (dirpath, filename); If (false = file. exists () {try {file. createnewfile ();} catch (ioexception e) {e. printstacktrace () ;}}}/*** @ title: writeobject * @ Description: Write a object to a file. * @ Param path the directory of the target file * @ Param filename the name of the target file * @ Param MSG the type of the object * @ return void * @ throws */private void writeobject (string path, string filename, parameter list <testmessage> MSG) {file = new file (path, filename); If (false = file. isfile () {return;} Try {// the value "false" for fileoutputstream means that overwrite this file, // if it is "true ", append the new data to this file. objectoutputstream OOS = new objectoutputstream (New fileoutputstream (file, false); OOS. writeobject (MSG); OOS. flush (); OOS. close ();} catch (filenotfoundexception e) {e. printstacktrace ();} catch (ioexception e) {e. printstacktrace () ;}/ *** @ title: readobject * @ Description: Read a object from a file. * @ Param path the directory of the target file * @ Param filename the name of the target file * @ return parameter list <testmessage> * @ throws */@ suppresswarnings ("unchecked ") private jsonlist <testmessage> readobject (string path, string filename) {file = new file (path, filename); objectinputstream OIS = NULL; jsonlist <testmessage> msgall = NULL; try {OIS = new objectinputstream (New fileinputstream (File); try {msgall = (writable list <testmessage>) Ois. readobject ();} catch (classnotfoundexception e) {e. printstacktrace () ;}} catch (filenotfoundexception e) {e. printstacktrace ();} catch (ioexception e) {e. printstacktrace ();} finally {try {Ois. close ();} catch (ioexception e) {e. printstacktrace () ;}} return msgall ;}}

Definition of the message package in the test program:

/*** @ Title: testmessage. java * @ package COM. file * @ Description: the message stream of filerw * @ author jogging Android * @ date 2011-11-19 04:35:11 * @ version V1.0 */package COM. file; public class testmessage implements Java. io. serializable {private string name; private string data; Public String getname () {return name;} public void setname (string name) {This. name = Name;} Public String getdata () {return data;} public void setdata (string data) {This. data = data;} public testmessage (string name, string MSG) {This. name = Name; Data = MSG ;}}

Program running result:

References: Use of objectinputstream and objectoutputstream