在该类的122行左右有这么一个方法：readObject（），是一个私有的方法且该类中也没有对其进行调用~
代码如下：（红色字体标示为多余的代码），要是大家页发现了请继续跟帖子
/*
* @(#)InetSocketAddress.java 1.15 03/01/23
*
* Copyright 2003 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package java.net;
import java.io.ObjectInputStream;
import java.io.IOException;
import java.io.InvalidObjectException;
/**
*
* This class implements an IP Socket Address (IP address + port number)
* It can also be a pair (hostname + port number), in which case an attempt
* will be made to resolve the hostname. If resolution fails then the address
* is said to be <I>unresolved</I> but can still be used on some circumstances
* like connecting through a proxy.
* <p>
* It provides an immutable object used by sockets for binding, connecting, or
* as returned values.
* <p>
* The <i>wildcard</i> is a special local IP address. It usually means "any"
* and can only be used for <code>bind</code> operations.
*
* @see java.net.Socket
* @see java.net.ServerSocket
* @since 1.4
*/
public class InetSocketAddress extends SocketAddress {
/* The hostname of the Socket Address
* @serial
*/
private String hostname = null;
/* The IP address of the Socket Address
* @serial
*/
private InetAddress addr = null;
/* The port number of the Socket Address
* @serial
*/
private int port;
private static final long serialVersionUID = 5076001401234631237L;
/**
* Creates a socket address where the IP address is the wildcard address
* and the port number a specified value.
* <p>
* A valid port value is between 0 and 65535.
* A port number of <code>zero</code> will let the system pick up an
* ephemeral port in a <code>bind</code> operation.
* <p>
* @param port The port number
* @throws IllegalArgumentException if the port parameter is outside the specified
* range of valid port values.
*/
public InetSocketAddress(int port) {
this(InetAddress.anyLocalAddress(), port);
}
/**
*
* Creates a socket address from an IP address and a port number.
* <p>
* A valid port value is between 0 and 65535.
* A port number of <code>zero</code> will let the system pick up an
* ephemeral port in a <code>bind</code> operation.
* <P>
* A <code>null</code> address will assign the <i>wildcard</i> address.
* <p>
* @param addr The IP address
* @param port The port number
* @throws IllegalArgumentException if the port parameter is outside the specified
* range of valid port values.
*/
public InetSocketAddress(InetAddress addr, int port) {
if (port < 0 || port > 0xFFFF) {
throw new IllegalArgumentException("port out of range:" + port);
}
this.port = port;
if (addr == null)
this.addr = InetAddress.anyLocalAddress();
else
this.addr = addr;
}
/**
*
* Creates a socket address from a hostname and a port number.
* <p>
* An attempt will be made to resolve the hostname into an InetAddress.
* If that attempt fails, the address will be flagged as <I>unresolved</I>.
* <p>
* A valid port value is between 0 and 65535.
* A port number of <code>zero</code> will let the system pick up an
* ephemeral port in a <code>bind</code> operation.
* <P>
* @param hostname the Host name
* @param port The port number
* @throws IllegalArgumentException if the port parameter is outside the range
* of valid port values, or if the hostname parameter is <TT>null</TT>.
* @see #isUnresolved()
*/
public InetSocketAddress(String hostname, int port) {
if (port < 0 || port > 0xFFFF) {
throw new IllegalArgumentException("port out of range:" + port);
}
if (hostname == null) {
throw new IllegalArgumentException("hostname can't be null");
}
try {
addr = InetAddress.getByName(hostname);
} catch(UnknownHostException e) {
this.hostname = hostname;
addr = null;
}
this.port = port;
}
private void readObject(ObjectInputStream s)
throws IOException, ClassNotFoundException {
s.defaultReadObject();
// Check that our invariants are satisfied
if (port < 0 || port > 0xFFFF) {
throw new InvalidObjectException("port out of range:" + port);
}
if (hostname == null && addr == null) {
throw new InvalidObjectException("hostname and addr " +
"can't both be null");
}
}
/**
* Gets the port number.
*
* @return the port number.
*/
public final int getPort() {
return port;
}
/**
*
* Gets the <code>InetAddress</code>.
*
* @return the InetAdress or <code>null</code> if it is unresolved.
*/
public final InetAddress getAddress() {
return addr;
}
/**
* Gets the <code>hostname</code>.
*
* @return the hostname part of the address.
*/
public final String getHostName() {
if (hostname != null)
return hostname;
if (addr != null)
return addr.getHostName();
return null;
}
/**
* Checks wether the address has been resolved or not.
*
* @return <code>true</code> if the hostname couldn't be resolved into
* an <code>InetAddress</code>.
*/
public final boolean isUnresolved() {
return addr == null;
}
/**
* Constructs a string representation of this InetSocketAddress.
* This String is constructed by calling toString() on the InetAddress
* and concatenating the port number (with a colon). If the address
* is unresolved then the part before the colon will only contain the hostname.
*
* @return a string representation of this object.
*/
public String toString() {
if (isUnresolved()) {
return hostname + ":" + port;
} else {
return addr.toString() + ":" + port;
}
}
/**
* Compares this object against the specified object.
* The result is <code>true</code> if and only if the argument is
* not <code>null</code> and it represents the same address as
* this object.
* <p>
* Two instances of <code>InetSocketAddress</code> represent the same
* address if both the InetAddresses (or hostnames if it is unresolved) and port
* numbers are equal.
* If both addresses are unresolved, then the hostname & the port number
* are compared.
*
* @param obj the object to compare against.
* @return <code>true</code> if the objects are the same;
* <code>false</code> otherwise.
* @see java.net.InetAddress#equals(java.lang.Object)
*/
public final boolean equals(Object obj) {
if (obj == null || !(obj instanceof InetSocketAddress))
return false;
InetSocketAddress sockAddr = (InetSocketAddress) obj;
boolean sameIP = false;
if (this.addr != null)
sameIP = this.addr.equals(sockAddr.addr);
else if (this.hostname != null)
sameIP = (sockAddr.addr == null) &&
this.hostname.equals(sockAddr.hostname);
else
sameIP = (sockAddr.addr == null) && (sockAddr.hostname == null);
return sameIP && (this.port == sockAddr.port);
}
/**
* Returns a hashcode for this socket address.
*
* @return a hash code value for this socket address.
*/
public final int hashCode() {
if (addr != null)
return addr.hashCode() + port;
if (hostname != null)
return hostname.hashCode() + port;
return port;
}
}