1.package —— org.apache.ibatis.builder.xml

2.extends —— BaseBuilder

3.参数

private boolean parsed; //判断是否已经解析过，使用于parse()    private XPathParser parser;//xml配置文件Context内容    private String environment;//环境参数    private ReflectorFactory localReflectorFactory;

4.构造方法

public XMLConfigBuilder(Reader reader) {        this((Reader)reader, (String)null, (Properties)null);    }    public XMLConfigBuilder(Reader reader, String environment) {        this((Reader)reader, environment, (Properties)null);    }    public XMLConfigBuilder(Reader reader, String environment, Properties props) {        this(new XPathParser(reader, true, props, new XMLMapperEntityResolver()), environment, props);    } 　　    public XMLConfigBuilder(InputStream inputStream) {        this((InputStream)inputStream, (String)null, (Properties)null);    }    public XMLConfigBuilder(InputStream inputStream, String environment) {        this((InputStream)inputStream, environment, (Properties)null);    }    public XMLConfigBuilder(InputStream inputStream, String environment, Properties props) {        this(new XPathParser(inputStream, true, props, new XMLMapperEntityResolver()), environment, props);    }    private XMLConfigBuilder(XPathParser parser, String environment, Properties props) {        super(new Configuration());        this.localReflectorFactory = new DefaultReflectorFactory();        ErrorContext.instance().resource("SQL Mapper Configuration");        this.configuration.setVariables(props);        this.parsed = false;        this.environment = environment;        this.parser = parser;    }

　　6个public和1个private的构造方法，前6个public构造方法都是根据mybatis配置文件的文件流创建XPathParser对象，然后调用private的构造方法，显示调用了父类构造方法，然后给本地参数赋值。

5.成员方法

　　 public Configuration parse() {        if (this.parsed) {//初始化时候赋值为false，判断是否解析过，Configuration是全局变量，只需要解析一次            throw new BuilderException("Each XMLConfigBuilder can only be used once.");        } else {            this.parsed = true; 　　　　　　　　//调用下面的方法，parser.evalNode("/configuration")是解析xml配置的configuration节点的内容，得到XNode对象            this.parseConfiguration(this.parser.evalNode("/configuration"));            return this.configuration;        }    } 　　//解析xml配置的的根节点    private void parseConfiguration(XNode root) {        try {            this.propertiesElement(root.evalNode("properties"));            Properties settings = this.settingsAsProperties(root.evalNode("settings"));            this.loadCustomVfs(settings);            this.typeAliasesElement(root.evalNode("typeAliases"));            this.pluginElement(root.evalNode("plugins"));            this.objectFactoryElement(root.evalNode("objectFactory"));            this.objectWrapperFactoryElement(root.evalNode("objectWrapperFactory"));            this.reflectorFactoryElement(root.evalNode("reflectorFactory"));            this.settingsElement(settings);            this.environmentsElement(root.evalNode("environments"));            this.databaseIdProviderElement(root.evalNode("databaseIdProvider"));            this.typeHandlerElement(root.evalNode("typeHandlers"));            this.mapperElement(root.evalNode("mappers"));        } catch (Exception var3) {            throw new BuilderException("Error parsing SQL Mapper Configuration. Cause: " + var3, var3);        }    }

　　parse的作用是解析mybatis-config.xml的configuration节点的内容，挨个赋值给configuration对象的属性节点，剩余方法都为私有方法，根据XNode对象来给全局变量configuration的属性进行赋值