Preliminary use of protobuf

 

Java Tutorial: http://code.google.com/intl/zh-CN/apis/protocolbuffers/docs/javatutorial.html
Environment preparation:
(1) download protoc code generator and source package: http://code.google.com/p/protobuf/downloads/list
Protobuf-2.4.1.tar.bz2
Protoc-2.4.1-win32.zip
(2zip decompress protoc-2.4.1-win32.zip to D: \ doc \ protobuf \ protoc-2.4.1-win32and add protoc.exe to Path Environment Variable
(3)decompress protobuf-2.4.1.tar.bz2 to D: \ doc \ protobuf \ protobuf-2.4.1,copy protoc.exe to D: \ doc \ protobuf \ protobuf-2.4.1 \ SRC,
Enter the D: \ doc \ protobuf \ protobuf-2.4.1 \ Java directory, and then execute: MVN-install, will be in D: the protobuf-2.4.1 package is generated under the target directory under the \ doc \ protobuf \ protobuf-java-2.4.1.jar \ Java directory.
[Note] Maven must be installed on the machine.
(4) Add the protobuf-java-2.4.1.jar to classpath.

In D: \ doc \ protobuf \ protobuf-2.4.1 \ examples contains a demo:
(1) switch to D: \ doc \ protobuf \ protobuf-2.4.1 \ examples, you can see there is a addressbook. proto
Package tutorial;
Option java_package = "com. example. Tutorial ";
Option java_outer_classname = "addressbookprotos ";

Message person {
Required string name = 1;
Required int32 id = 2;
Optional string email = 3;

Enum phonetype {
Mobile = 0;
Home = 1;
Work = 2;
}

Message phonenumber {
Required string number = 1;
Optional phonetype type = 2 [default = Home];
}

Repeated phonenumber phone = 4;
}

Message addressbook {
Repeated person = 1;
}
Command line switch to D: \ doc \ protobuf \ protobuf-2.4.1 \ examples, execute: protoc -- java_out =. addressbook. proto
COM \ example \ tutorial \ addressbookprotos. Java is generated under the D: \ doc \ protobuf \ protobuf-2.4.1 \ examples directory
Continue: javac-cp d: \ doc \ protobuf \ protobuf-2.4.1 \ examples \ protobuf-java-2.4.1.jar com \ example \ tutorial \ addressbookprotos. Java
A large number of class files are generated, all of which are internal classes.
(2) In the D: \ doc \ protobuf \ protobuf-2.4.1 \ examples directory, there is a addperson. Java
Import com. example. Tutorial. addressbookprotos. addressbook;
Import com. example. Tutorial. addressbookprotos. person;
Import java. Io. bufferedreader;
Import java. Io. fileinputstream;
Import java. Io. filenotfoundexception;
Import java. Io. fileoutputstream;
Import java. Io. inputstreamreader;
Import java. Io. ioexception;
Import java. Io. printstream;
Class addperson {// This function fills in a person message based on user
// Input.
Static person promptforaddress (bufferedreader stdin, printstream stdout)
Throws ioexception {
Person. Builder person = person. newbuilder ();
Stdout. Print ("Enter person ID :");
Person. setid (integer. valueof (stdin. Readline ()));
Stdout. Print ("Enter name :");
Person. setname (stdin. Readline ());
Stdout. Print ("enter email address (blank for none ):");
String email = stdin. Readline ();
If (email. Length ()> 0 ){
Person. setemail (email );
}
While (true ){
Stdout. Print ("enter a phone number (or leave blank to finish ):");
String number = stdin. Readline ();
If (number. Length () = 0 ){
Break;
}
Person. phonenumber. Builder phonenumber = person. phonenumber
. Newbuilder (). setnumber (number );
Stdout. Print ("Is this a mobile, home, or work phone? ");
String type = stdin. Readline ();
If (type. Equals ("mobile ")){
Phonenumber. settype (person. phonetype. Mobile );
} Else if (type. Equals ("home ")){
Phonenumber. settype (person. phonetype. Home );
} Else if (type. Equals ("work ")){
Phonenumber. settype (person. phonetype. Work );
} Else {
Stdout. println ("unknown phone type. Using default .");
}
Person. addphone (phonenumber );
}
Return person. Build ();
}

// Main function: reads the entire address book from a file,
// Adds one person based on user input, then writes it back out to the same
// File.
Public static void main (string [] ARGs) throws exception {
If (ARGs. length! = 1 ){
System. Err. println ("Usage: addperson address_book_file ");
System. Exit (-1 );
}
Addressbook. Builder addressbook = addressbook. newbuilder ();
// Read the existing address book.
Try {
Addressbook. mergefrom (New fileinputstream (ARGs [0]);
} Catch (filenotfoundexception e ){
System. Out. println (ARGs [0]
+ ": File not found. Creating a new file .");
}
// Add an address.
Addressbook. addperson (promptforaddress (New bufferedreader (
New inputstreamreader (system. In), system. Out ));
// Write the new address book back to disk.
Fileoutputstream output = new fileoutputstream (ARGs [0]);
Addressbook. Build (). writeto (output );
Output. Close ();
}
}
Enter: javac-cp d: \ doc \ protobuf \ protobuf-2.4.1 \ examples \ protobuf-java-2.4.1.jar; D: \ doc \ protobuf \ protobuf-2.4.1 \ examples addperson. Java
Generated under D: \ doc \ protobuf \ protobuf-2.4.1 \ examples: addperson. Class
In the command line enter: Java-CP javac-cp d: \ doc \ protobuf \ protobuf-2.4.1 \ examples \ protobuf-java-2.4.1.jar; D: \ doc \ protobuf \ protobuf-2.4.1 \ examples addperson 1.txt
Command Line prompt:
1. txt: file not found. Creating a new file.
Enter person ID: 1
Enter name: xujsh
Enter email address (blank for none): xjs@163.com
Enter a phone number (or leave blank to finish): 13612341234
Is this a mobile, home, or work phone? Mobile
Enter a phone number (or leave blank to finish): 01012345678
Is this a mobile, home, or work phone? Home
Enter a phone number (or leave blank to finish ):

Generate: 1.txt under D: \ doc \ protobuf \ protobuf-2.4.1 \ examples

(3) In the D: \ doc \ protobuf \ protobuf-2.4.1 \ examples directory, there is a listpeople. Java
Import java. Io. fileinputstream;
Import com. example. Tutorial. addressbookprotos. addressbook;
Import com. example. Tutorial. addressbookprotos. person;

Class listpeople {
// Iterates though all people in the addressbook and prints
// Info about them.
Static void print (addressbook ){
For (person: addressbook. getpersonlist ()){
System. Out. println ("person ID:" + person. GETID ());
System. Out. println ("name:" + person. getname ());
If (person. hasemail ()){
System. Out. println ("e-mail address:" + person. getemail ());
}
For (person. phonenumber: person. getphonelist ()){
Switch (phonenumber. GetType ()){
Case Mobile:
System. Out. Print ("Mobile Phone #:");
Break;
Case home:
System. Out. Print ("Home Phone #:");
Break;
Case Work:
System. Out. Print ("work phone #:");
Break;
}
System. Out. println (phonenumber. getnumber ());
}
}
}

// Main function: reads the entire address book from a file and prints all
// The information inside.
Public static void main (string [] ARGs) throws exception {
If (ARGs. length! = 1 ){
System. Err. println ("Usage: listpeople address_book_file ");
System. Exit (-1 );
}

// Read the existing address book.
Addressbook = addressbook. parsefrom (New fileinputstream (
ARGs [0]);
Print (addressbook );
}
}
Enter: javac-cp d: \ doc \ protobuf \ protobuf-2.4.1 \ examples \ protobuf-java-2.4.1.jar; D: \ doc \ protobuf \ protobuf-2.4.1 \ examples listpeople. Java
Generated under D: \ doc \ protobuf \ protobuf-2.4.1 \ examples: listpeople. Class
In the command line enter: Java-CP javac-cp d: \ doc \ protobuf \ protobuf-2.4.1 \ examples \ protobuf-java-2.4.1.jar; D: \ doc \ protobuf \ protobuf-2.4.1 \ examples listpeople 1.txt
Output result:
Person ID: 1
Name: xujsh
E-mail address: xjs@163.com
Mobile Phone #: 13612341234
Home Phone #: 01012345678