MyBatis源码阅读–SqlSessionFactoryBuilder说明

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MyBatis源码阅读-总索引

构造器

public SqlSessionFactoryBuilder() {
 }

build 方法创建SqlSessionFactory

//Reader 字符流
    public SqlSessionFactory build(Reader reader) {
        return this.build((Reader)reader, (String)null, (Properties)null);
    }

    public SqlSessionFactory build(Reader reader, String environment) {
        return this.build((Reader)reader, environment, (Properties)null);
    }

    public SqlSessionFactory build(Reader reader, Properties properties) {
        return this.build((Reader)reader, (String)null, properties);
    }
//InputStream 字节流
  public SqlSessionFactory build(InputStream inputStream) {
        return this.build((InputStream)inputStream, (String)null, (Properties)null);
    }

    public SqlSessionFactory build(InputStream inputStream, String environment) {
        return this.build((InputStream)inputStream, environment, (Properties)null);
    }

    public SqlSessionFactory build(InputStream inputStream, Properties properties) {
        return this.build((InputStream)inputStream, (String)null, properties);
    }

可以看到，上面最终都是调用下面的方法

//reader : 配置文件字符流
//environment ： 配置文件中的environment id 
//properties :
    public SqlSessionFactory build(Reader reader, String environment, Properties properties) {
        SqlSessionFactory var5;
        try {
            //解析配置文件
            XMLConfigBuilder parser = new XMLConfigBuilder(reader, environment, properties);
            //通过配置信息创建SqlSessionFactory
            //parser.parse() 返回的是Configuration对象
            var5 = this.build(parser.parse());
        } catch (Exception var14) {
            throw ExceptionFactory.wrapException("Error building SqlSession.", var14);
        } finally {
            ErrorContext.instance().reset();

            try {
                reader.close();
            } catch (IOException var13) {                ;
            }
        }
        return var5;
    }
 //inputStream : 配置文件字节流
//environment ： 配置文件中的environment id 
//properties :
   public SqlSessionFactory build(InputStream inputStream, String environment, Properties properties) {
        SqlSessionFactory var5;
        try {
             //解析配置文件
            XMLConfigBuilder parser = new XMLConfigBuilder(reader, environment, properties);
            //通过配置信息创建SqlSessionFactory
            //parser.parse() 返回的是Configuration对象
            var5 = this.build(parser.parse());
        } catch (Exception var14) {
            throw ExceptionFactory.wrapException("Error building SqlSession.", var14);
        } finally {
            ErrorContext.instance().reset();

            try {
                inputStream.close();
            } catch (IOException var13) {
                ;
            }
        }
        return var5;
    }

通过配置信息创建SqlSessionFactory

    public SqlSessionFactory build(Configuration config) {
        return new DefaultSqlSessionFactory(config);
    }

读取配置文件，从上面build方法可知，参数可以为Reader或者InputStream对象。
通过Resources类来读取配置文件

//Resources是org.apache.ibatis.io.Resources类
//mybatis-config.xml存放在resource目录下，如果是放在resource/config,就写成"configure/mybatis-config.xml"
//读取为字符流
Reader reader = Resources.getResourceAsReader("mybatis-config.xml");
//读取为字节流
 InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");            

通过io流创建SqlSessionFactory

Reader reader = Resources.getResourceAsReader("mybatis-config.xml");
SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(reader);