XMLConfigBuilder文件

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