一、前言
在完成了前面的理论学习后，现在可以从源码角度来解析Zookeeper的细节，首先笔者想从序列化入手，因为在网络通信、数据存储中都用到了序列化，下面开始分析。
二、序列化
序列化主要在zookeeper.jute包中，其中涉及的主要接口如下
· InputArchive
· OutputArchive
· Index
· Record
2.1 InputArchive
其是所有反序列化器都需要实现的接口，其方法如下
InputArchive的类结构如下
1. BinaryInputArchive
2. CsvInputArchive
3. XmlInputArchive
2.2 OutputArchive
其是所有序列化器都需要实现此接口，其方法如下。
OutputArchive的类结构如下
1. BinaryOutputArchive
2. CsvOutputArchive
3. XmlOutputArchive
2.3 Index
其用于迭代反序列化器的迭代器。
Index的类结构如下
1.BinaryIndex
2. CsxIndex
3.XmlIndex
2.4 Record
所有用于网络传输或者本地存储的类型都实现该接口，其方法如下
所有的实现类都需要实现seriallize和deserialize方法。
三、示例
下面通过一个示例来理解OutputArchive和InputArchive的搭配使用。
Java
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package com.leesf.zookeeper_samples;
import org.apache.jute.OutputArchive;
import org.apache.jute.Record;
public class ArchiveTest {
public static void main( String[] args ) throws IOException {
String path = "F:\\test.txt";
// write operation
OutputStream outputStream = new FileOutputStream(new File(path));
BinaryOutputArchive binaryOutputArchive = BinaryOutputArchive.getArchive(outputStream);
binaryOutputArchive.writeBool(true, "boolean");
byte[] bytes = "leesf".getBytes();
binaryOutputArchive.writeBuffer(bytes, "buffer");
binaryOutputArchive.writeDouble(13.14, "double");
binaryOutputArchive.writeFloat(5.20f, "float");
binaryOutputArchive.writeInt(520, "int");
Person person = new Person(25, "leesf");
binaryOutputArchive.writeRecord(person, "leesf");
TreeMap<String, Integer> map = new TreeMap<String, Integer>();
map.put("leesf", 25);
map.put("dyd", 25);
Set<String> keys = map.keySet();
binaryOutputArchive.startMap(map, "map");
int i = 0;
for (String key: keys) {
String tag = i + "";
binaryOutputArchive.writeString(key, tag);
binaryOutputArchive.writeInt(map.get(key), tag);
i++;
}
binaryOutputArchive.endMap(map, "map");
// read operation
InputStream inputStream = new FileInputStream(new File(path));
BinaryInputArchive binaryInputArchive = BinaryInputArchive.getArchive(inputStream);
System.out.println(binaryInputArchive.readBool("boolean"));
System.out.println(new String(binaryInputArchive.readBuffer("buffer")));
System.out.println(binaryInputArchive.readDouble("double"));
System.out.println(binaryInputArchive.readFloat("float"));
System.out.println(binaryInputArchive.readInt("int"));
Person person2 = new Person();
binaryInputArchive.readRecord(person2, "leesf");
System.out.println(person2);
Index index = binaryInputArchive.startMap("map");
int j = 0;
while (!index.done()) {
String tag = j + "";
System.out.println("key = " + binaryInputArchive.readString(tag)
+ ", value = " + binaryInputArchive.readInt(tag));
index.incr();
j++;
}
}
static class Person implements Record {
private int age;
private String name;
public Person() {
}
public Person(int age, String name) {
this.age = age;
this.name = name;
}
public void serialize(OutputArchive archive, String tag) throws IOException {
archive.startRecord(this, tag);
archive.writeInt(age, "age");
archive.writeString(name, "name");
archive.endRecord(this, tag);
}
public void deserialize(InputArchive archive, String tag) throws IOException {
archive.startRecord(tag);
age = archive.readInt("age");
name = archive.readString("name");
archive.endRecord(tag);
}
public String toString() {
return "age = " + age + ", name = " + name;
}
}
}
输出结果
true |
四、总结
这里只需要知道
●序列化涉及的类存放在：org.zookeeper.jute包下
●常用的类有：
○InputArchive
○OutputArchive
○Index
○Record
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