Thrift RPC实战 thrift序列化揭秘

namespace java com.yangyang.thrift.api
struct Pair {
? ? 1: required string key
? ? 2: required string value
}

private static ?String datafile = "1.dat";
// *) 把对象写入文件
public static ?void writeData() throws IOException, TException {
? ? Pair pair = new Pair();
? ? pair.setKey("key1").setValue("value1");
? ? FileOutputStream fos = new FileOutputStream(new File(datafile));
? ? pair.write(new TBinaryProtocol(new TiostreamTransport(fos)));
? ? fos.close();
}
// *) 从文件恢复对象
public static ?void readData() throws TException, IOException {
? ? FileInputStream fis = new FileInputStream(new File(datafile));
? ? Pair pair = new Pair();
? ? pair.read(new TBinaryProtocol(new TIOStreamTransport(fis)));
? ? System.out.println("key => " + pair.getKey());
? ? System.out.println("value => " + pair.getValue());
? ? fis.close();
}
public static void main(String[] args) throws Exception{
? ? //writeData();
? ? readData();
}

namespace java com.yangyang.thrift.api
struct Pair {
? ? 2: required string key
? ? 1: required string value
}

Versioning in Thrift is implemented via ?eld identi?ers. The ?eld header for every member of a struct in Thrift is encoded with a unique ?eld identi?er. The combination of this ?eld identi?er and its type speci?er is used to uniquely identify the ?eld. The Thrift de?nition language supports automatic assignment of ?eld identi?ers, but it is good programming practice to always explicitly specify ?eld identi?ers.

public void read(org.apache.thrift.protocol.TProtocol iprot, Pair struct) throws org.apache.thrift.TException {
? org.apache.thrift.protocol.TField schemeField;
? //读取结构开始标记
? iprot.readStructBegin();
? while (true)
? {
? ? // 读取Field属性开始标记
? ? schemeField = iprot.readFieldBegin();
? ? if (schemeField.type == org.apache.thrift.protocol.TType.STOP) {
? ? ? break;
? ? }
? ? // field标记包含 id + type, switch根据(id+type)来分配相关的值
? ? switch (schemeField.id) {
? ? ? case 2: // KEY
? ? ? ? if (schemeField.type == org.apache.thrift.protocol.TType.STRING) {
? ? ? ? ? struct.key = iprot.readString();
? ? ? ? ? struct.setKeyIsSet(true);
? ? ? ? } else {
? ? ? ? ? org.apache.thrift.protocol.TProtocolUtil.skip(iprot, schemeField.type);
? ? ? ? }
? ? ? ? break;
? ? ? case 1: // VALUE
? ? ? ? if (schemeField.type == org.apache.thrift.protocol.TType.STRING) {
? ? ? ? ? struct.value = iprot.readString();
? ? ? ? ? struct.setValueIsSet(true);
? ? ? ? } else {
? ? ? ? ? org.apache.thrift.protocol.TProtocolUtil.skip(iprot, schemeField.type);
? ? ? ? }
? ? ? ? break;
? ? ? default:
? ? ? ? org.apache.thrift.protocol.TProtocolUtil.skip(iprot, schemeField.type);
? ? }
? ? // 读取Field属性结束标记
? ? iprot.readFieldEnd();
? }
? 　// 读取结构体结束标记
? iprot.readStructEnd();
? // check for required fields of primitive type, which can't be checked in the validate method
? struct.validate();
}