启动客户端 报错信息

服务器不启动 直接启动客户端

objc[1252]: Class JavaLaunchHelper is implemented in both /Library/Java/JavaVirtualMachines/jdk1.7.0_80.jdk/Contents/Home/bin/java (0x105f504c0) and /Library/Java/JavaVirtualMachines/jdk1.7.0_80.jdk/Contents/Home/jre/lib/libinstrument.dylib (0x105fe64e0). One of the two will be used. Which one is undefined.java.net.ConnectException: Connection refused //报错信息 是在哪里？ at java.net.PlainSocketImpl.socketConnect(Native Method)at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)at java.net.Socket.connect(Socket.java:579)at java.net.Socket.connect(Socket.java:528)at java.net.Socket.<init>(Socket.java:425)at java.net.Socket.<init>(Socket.java:208)at serverMaxConn.Client.main(Client.java:22)复制代码

应用层代码

//创建客户端套接字 连接服务器Socket s = new Socket("127.0.0.1", 8888); 复制代码

源码分析

abstract class AbstractPlainSocketImpl extends SocketImpl{/*** The workhorse of the connection operation.  Tries several times to* establish a connection to the given <host, port>.  If unsuccessful,* throws an IOException indicating what went wrong.*/synchronized void doConnect(InetAddress address, int port, int timeout) throws IOException {synchronized (fdLock) {if (!closePending && (socket == null || !socket.isBound())) {NetHooks.beforeTcpConnect(fd, address, port);}}try {acquireFD();try {socketConnect(address, port, timeout); //没有进入实现类方法 而是进入ClassLoader的方法？而且直接报错了 连接服务器 遭到拒绝/* socket may have been closed during poll/select */synchronized (fdLock) {if (closePending) {throw new SocketException ("Socket closed");}}// If we have a ref. to the Socket, then sets the flags// created, bound & connected to true.// This is normally done in Socket.connect() but some// subclasses of Socket may call impl.connect() directly!if (socket != null) {socket.setBound();socket.setConnected();}} finally {releaseFD();}} catch (IOException e) {close();throw e; //捕获异常}}复制代码

public abstract class ClassLoader {// Invoked in the VM class linking code.static long findNative(ClassLoader loader, String name) {Vector<NativeLibrary> libs =loader != null ? loader.nativeLibraries : systemNativeLibraries;synchronized (libs) {int size = libs.size();for (int i = 0; i < size; i++) {NativeLibrary lib = libs.elementAt(i);long entry = lib.find(name);if (entry != 0)return entry;}}return 0;}复制代码

原因分析

stackoverflow.com/questions/6…

This exception means that there is no service listening on the IP/port you are trying to connect to:You are trying to connect to the wrong IP/port.
You have not started your server. //没有启动服务器
Your server is not listening for connections.
On Windows servers, the listen backlog queue is full.
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