Spring cloud config client 技術體系

　　一：為什麼配置環境跟這兩個類有關ApplicationEnvironmentPreparedEvent和ConfigFileApplicationListener

　　①當一個spring應用程式啟動時釋出的事件，環境第一個可用來進行檢查和修改。

　　　　建立一個環境事件的例項：public ApplicationEnvironmentPreparedEvent(SpringApplication application, String[] args, 　　 org.springframework.core.env.ConfigurableEnvironment environment)　　

　　②通過從已知的檔案位置載入屬性來配置上下文環境。預設屬性將從“應用程式”載入。屬性“和/或”應用程式。下面是yml的檔案

　　　　可以使用setsearchlocation(字串)和setSearchNames(字串)指定可選的搜尋位置和名稱。

　　　　另外的檔案也會基於活動概要檔案載入。例如，如果一個“web”配置檔案是活動的“應用程式web”。屬性”和“即web。yml將被考慮。

　　　　“spring.config.name”屬性可以用來指定要載入的替代名稱和“spring.config”。位置屬性可用於指定可選的搜尋位置或特定的檔案。

　　　　如果看詳細的解釋可以上官方的

　　二： Bootstrap 配置屬性與 Spring Framework / Spring Boot 配置架構的關係

  1 //
  2 // Source code recreated from a .class file by IntelliJ IDEA
  3 // (powered by Fernflower decompiler)
  4 //
  5 
  6 package io.netty.bootstrap;
  7 
  8 import io.netty.bootstrap.AbstractBootstrap;
  9 import io.netty.channel.Channel;
 
 10 import io.netty.channel.ChannelFuture;
 11 import io.netty.channel.ChannelFutureListener;
 12 import io.netty.channel.ChannelHandler;
 13 import io.netty.channel.ChannelOption;
 14 import io.netty.channel.ChannelPipeline;
 15 import io.netty.channel.ChannelPromise;
 16 import io.netty.util.AttributeKey;
 17 import io.netty.util.internal.logging.InternalLogger;
 18 import io.netty.util.internal.logging.InternalLoggerFactory;
 19 import java.net.InetAddress;
 20 import java.net.InetSocketAddress;
 21 import java.net.SocketAddress;
 22 import java.util.Iterator;
 23 import java.util.Map;
 24 import java.util.Map.Entry;
 25 
 26 public class Bootstrap extends AbstractBootstrap<Bootstrap, Channel> {
　　　　　//
 27     private static final InternalLogger logger = InternalLoggerFactory.getInstance(Bootstrap.class);
 28     private volatile SocketAddress remoteAddress;
 29 
 30     public Bootstrap() {
 31     }
 32 
 33     private Bootstrap(Bootstrap bootstrap) {
 34         super(bootstrap);
 35         this.remoteAddress = bootstrap.remoteAddress;
 36     }
 37 
 38     public Bootstrap remoteAddress(SocketAddress remoteAddress) {//遠端地址
 39         this.remoteAddress = remoteAddress;
 40         return this;
 41     }
 42 
 43     public Bootstrap remoteAddress(String inetHost, int inetPort) {//主機是字元
 44         this.remoteAddress = new InetSocketAddress(inetHost, inetPort);
 45         return this;
 46     }
 47 
 48     public Bootstrap remoteAddress(InetAddress inetHost, int inetPort) { //主機是類的資料
 49         this.remoteAddress = new InetSocketAddress(inetHost, inetPort);
 50         return this;
 51     }
 52 
 53     public ChannelFuture connect() {
 54         this.validate();
 55         SocketAddress remoteAddress = this.remoteAddress;
 56         if(remoteAddress == null) {
 57             throw new IllegalStateException("remoteAddress not set");
 58         } else {
 59             return this.doConnect(remoteAddress, this.localAddress());
 60         }
 61     }
 62 
 63     public ChannelFuture connect(String inetHost, int inetPort) {
 64         return this.connect(new InetSocketAddress(inetHost, inetPort));
 65     }
 66 
 67     public ChannelFuture connect(InetAddress inetHost, int inetPort) {
 68         return this.connect(new InetSocketAddress(inetHost, inetPort));
 69     }
 70 
 71     public ChannelFuture connect(SocketAddress remoteAddress) {
 72         if(remoteAddress == null) {
 73             throw new NullPointerException("remoteAddress");
 74         } else {
 75             this.validate();
 76             return this.doConnect(remoteAddress, this.localAddress());
 77         }
 78     }
 79 
 80     public ChannelFuture connect(SocketAddress remoteAddress, SocketAddress localAddress) {
 81         if(remoteAddress == null) {
 82             throw new NullPointerException("remoteAddress");
 83         } else {
 84             this.validate();
 85             return this.doConnect(remoteAddress, localAddress);
 86         }
 87     }
 88 
 89     private ChannelFuture doConnect(final SocketAddress remoteAddress, final SocketAddress localAddress) {
 90         final ChannelFuture regFuture = this.initAndRegister();
 91         final Channel channel = regFuture.channel();
 92         if(regFuture.cause() != null) {
 93             return regFuture;
 94         } else {
 95             final ChannelPromise promise = channel.newPromise();
 96             if(regFuture.isDone()) {
 97                 doConnect0(regFuture, channel, remoteAddress, localAddress, promise);
 98             } else {
 99                 regFuture.addListener(new ChannelFutureListener() {
100                     public void operationComplete(ChannelFuture future) throws Exception {
101                         Bootstrap.doConnect0(regFuture, channel, remoteAddress, localAddress, promise);
102                     }
103                 });
104             }
105 
106             return promise;
107         }
108     }
109 
110     private static void doConnect0(final ChannelFuture regFuture, final Channel channel, final SocketAddress remoteAddress, final SocketAddress localAddress, final ChannelPromise promise) {
111         channel.eventLoop().execute(new Runnable() {
112             public void run() {
113                 if(regFuture.isSuccess()) {
114                     if(localAddress == null) {
115                         channel.connect(remoteAddress, promise);
116                     } else {
117                         channel.connect(remoteAddress, localAddress, promise);
118                     }
119 
120                     promise.addListener(ChannelFutureListener.CLOSE_ON_FAILURE);
121                 } else {
122                     promise.setFailure(regFuture.cause());
123                 }
124 
125             }
126         });
127     }
128 
129     void init(Channel channel) throws Exception {
130         ChannelPipeline p = channel.pipeline();
131         p.addLast(new ChannelHandler[]{this.handler()});
132         Map options = this.options();
133         synchronized(options) {
134             Iterator i$ = options.entrySet().iterator();
135 
136             while(true) {
137                 if(!i$.hasNext()) {
138                     break;
139                 }
140 
141                 Entry i$1 = (Entry)i$.next();
142 
143                 try {
144                     if(!channel.config().setOption((ChannelOption)i$1.getKey(), i$1.getValue())) {
145                         logger.warn("Unknown channel option: " + i$1);
146                     }
147                 } catch (Throwable var10) {
148                     logger.warn("Failed to set a channel option: " + channel, var10);
149                 }
150             }
151         }
152 
153         Map attrs = this.attrs();
154         synchronized(attrs) {
155             Iterator i$2 = attrs.entrySet().iterator();
156 
157             while(i$2.hasNext()) {
158                 Entry e = (Entry)i$2.next();
159                 channel.attr((AttributeKey)e.getKey()).set(e.getValue());
160             }
161 
162         }
163     }
164 
165     public Bootstrap validate() {
166         super.validate();
167         if(this.handler() == null) {
168             throw new IllegalStateException("handler not set");
169         } else {
170             return this;
171         }
172     }
173 
174     public Bootstrap clone() {
175         return new Bootstrap(this);
176     }
177 
178     public String toString() {
179         if(this.remoteAddress == null) {
180             return super.toString();
181         } else {
182             StringBuilder buf = new StringBuilder(super.toString());
183             buf.setLength(buf.length() - 1);
184             return buf.append(", remoteAddress: ").append(this.remoteAddress).append(')').toString();
185         }
186     }
187 }

　　Environment 端點：介紹/env 端點的使用場景，並且解讀其原始碼，瞭解其中奧祕

/*
 * Copyright (c) 1996, 1999, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 */

package org.omg.CORBA;

/**
 * A container (holder) for an exception that is used in <code>Request</code>
 * operations to make exceptions available to the client.  An
 * <code>Environment</code> object is created with the <code>ORB</code>
 * method <code>create_environment</code>.
 *
 * @since   JDK1.2
 */

public abstract class Environment {

    /**
     * Retrieves the exception in this <code>Environment</code> object.
     *
     * @return                  the exception in this <code>Environment</code> object
     */

    public abstract java.lang.Exception exception();

    /**
     * Inserts the given exception into this <code>Environment</code> object.
     *
     * @param except            the exception to be set
     */

    public abstract void exception(java.lang.Exception except);

    /**
     * Clears this <code>Environment</code> object of its exception.
     */

    public abstract void clear();

}