什么是protobuf
简单讲就是一种类似于json,xml的通用数据交换格式，但是效率更高，更省空间，目前官方支持c++,java,python,ruby。其他语言有一些第三方做的开发包，需要自己选择比较好的。
Ubuntu下快速使用
编译
2.1 编译protoc工具，这里可以直接看解压出来的protobuf-2.6.0文件夹下的README.txt文件，这里需要有c++编译器
$ ./configure $ make $ make check $ make install
2.2 测试安装
$ protoc --version
如果无法运行提示 error while loading shared libraries，我们可以直接把protoc默认安装的共享库文件路径直接加入到共享库配置文件中去（实际上很多开源软件的共享库文件默认安装的位置也在/usr/local/lib下）
$ echo "/usr/local/lib" >> /etc/ld.so.conf $ ldconfig
再执行一下应该就可以了
$ protoc --versionjava使用示例
3.1 把java源代码编译成我们方便使用的jar包形式，这里需要用到maven，没有的话可以在这里下载apache，安装说明这页上也有
3.2 打包，先test一下
$ mvn test
通过了的话直接
$ mvn package
在target目录下就能看到打完包的protobuf-java-2.6.0.jar文件了
3.3 用protoc工具将.proto文件生成java类
这里直接用刚刚下载的protobuf-2.6.0中example文件夹下的addressbook.proto文件作为示例
$ protoc -I=$SRC_DIR --java_out=$DST_DIR $SRC_DIR/addressbook.proto
上面的$SRC_DIR表示存放addressbook.proto文件的路径，$DST_DIR表示生成java类存放的路径
至此将protobuf-java-2.6.0.jar和刚刚生成的AddressBookProtos.java文件引用到你自己的项目中就可以了-
使用
4.1 写：AddPerson.java,为了方便直接在IDE里面使用，对官网程序做了一点修改，直接运行输入Person的相关信息就好了package com.example.tutorial; import java.io.BufferedReader; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOError; import java.io.IOException; import java.io.InputStreamReader; import java.io.PrintStream; import com.example.tutorial.AddressBookProtos.AddressBook; import com.example.tutorial.AddressBookProtos.Person; public 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.parseInt(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); // } String filePath = "myPerson"; AddressBook.Builder addressBook = AddressBook.newBuilder(); // Read the existing address book. try { addressBook.mergeFrom(new FileInputStream(filePath)); } catch (FileNotFoundException e) { System.out.println(filePath + ": 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(filePath); addressBook.build().writeTo(output); output.close(); } }
4.2 读：可以读取刚刚写在文件里的Person
package com.example.tutorial;
import java.io.FileInputStream;
import com.example.tutorial.AddressBookProtos.AddressBook;
import com.example.tutorial.AddressBookProtos.Person;
public class ListPeople {
// Iterates though all people in the AddressBook and prints info about them.
static void Print(AddressBook addressBook) {
for (Person 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 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 {
String filePath = "myPerson";
// Read the existing address book.
AddressBook addressBook = AddressBook.parseFrom(new FileInputStream(filePath));
Print(addressBook);
}
}
