安裝composer，在Linux上。
curl -sS https://getcomposer.org/installer | php
mv composer.phar /usr/local/bin/composer第二步：安裝完成之後輸入
# composer -v顯示如下說明成功。Do not run Composer as root/super user! See https://getcomposer.org/root for details
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Composer version 1.5.2 2017-09-11 16:59:25
Usage:
command [options] [arguments]
Options:
-h, --help Display this help message
-q, --quiet Do not output any message
-V, --version Display this application version
--ansi Force ANSI output
--no-ansi Disable ANSI output
-n, --no-interaction Do not ask any interactive question
--profile Display timing and memory usage information
--no-plugins Whether to disable plugins.
-d, --working-dir=WORKING-DIR If specified, use the given directory as working directory.
-v|vv|vvv, --verbose Increase the verbosity of messages: 1 for normal output, 2 for more verbose output and 3 for debug
第二步：接下來進入項目目錄
初始化composer
composer init
出現：
Do not run Composer as root/super user! See https://getcomposer.org/root for details
Welcome to the Composer config generator
This command will guide you through creating your composer.json config
Package name (<vendor>/<name>) [root/test]: 輸入名字
Description []: 輸入描述
Author [, n to skip]:作者信息
Minimum Stability []: stable 資源包的最低穩定版本，默認爲 stable
Package Type (e.g. library, project, metapackage, composer-plugin) []: 選擇你的類型：庫、項目。一般用project
License []: 協議 MIT
Would you like to define your dependencies (require) interactively [yes]? no
Would you like to define your dev dependencies (require-dev) interactively [yes]? no
{
"name": "mly/test",
"description": "a test",
"type": "project",
"license": "MIT",
"authors": [
{
"name": "mly",
"email": "[email protected]"
}
],
"minimum-stability": "stable",
"require": {}
}
Do you confirm generation [yes]?生成上面的文件？ yes
在目錄下就生成了composer.json文件切換到中國鏡像，外國網站太慢
composer config repo.packagist composer https://packagist.phpcomposer.com 在composer.json所在目錄下執行composer install在當前目錄下生成了一個文件夾vendor
vendor目錄結構：
vendor----autoload.php
----composer ----autoload_classmap.php
----autoload_namespaces.php
----autoload_psr4.php(自動加載)
----autoload_real.php
----autoload_static.php
----ClassLoader.php
----installed.json
----LICENSE第三：文件自動加載：例如thinkPHP的function.php的加載
回到項目目錄，新建一個common目錄，在common下創建function.php文件，隨便寫個方法。
<?php
function test($str){
return md5($str);
}
然後到項目中，打開composer.json文件，添加紅色部分，中括號裏面就是要引入文件的路徑，需要引入其他文件的時候在中括號中加“,”繼續寫上路徑就可以，之後執行composer dump
{
"name": "mly/test",
"description": "a test",
"type": "project",
"license": "MIT",
"authors": [
{
"name": "mly",
"email": "[email protected]"
}
],
"minimum-stability": "stable",
"require": {},
"repositories": {
"packagist": {
"type": "composer",
"url": "https://packagist.phpcomposer.com"
}
}
"autoload":{
"files":["common/function.php"]
}
}然後在項目中需要的地方引入vendor下的autoload.php就可以使用。
自動加載類：
{
"name": "mly/test",
"description": "a test",
"type": "project",
"license": "MIT",
"authors": [
{
"name": "mly",
"email": "[email protected]"
}
],
"minimum-stability": "stable",
"require": {},
"repositories": {
"packagist": {
"type": "composer",
"url": "https://packagist.phpcomposer.com"
}
}
"autoload":{
"files":["common/function.php"]//文件的自動加載
"psr-4":{"類的命名空間要雙斜槓（App\\Home\\）":"文件路徑（相對於composer.json的）"}
}
}之後運行composer dump
用到的地方引入autoload.php 然後實例化類就可以了（實例化的時候要加上那個類的命名空間或者use那個命名空間）psr-4:類名要和文件名一樣
如果要用其他的工具類或者別人寫好的類或功能
訪問：https://packagist.org/ 可以在裏面搜索，選擇★高的或者下載量大的可能bug比較少，並且有使用文檔。
在項目中運行 composer require +你查找到的類，完成之後到vendor目錄下就會看到多了剛纔下載的文件
然後在項目中引入autoload.php 實例化就可以用了