解析xml以构造从源到目标的路径

Question

需要一个从xml获取详细信息的方法来构造从源到目标的路径

例如：

<CONNECTOR FROMFIELD ="col1" FROMINSTANCE ="table1"  TOFIELD ="col1" TOINSTANCE ="table4" />
<CONNECTOR FROMFIELD ="col2" FROMINSTANCE ="table2"  TOFIELD ="col2" TOINSTANCE ="table3" />
<CONNECTOR FROMFIELD ="col4" FROMINSTANCE ="table4"  TOFIELD ="col4" TOINSTANCE ="table2" />

应生成为输出：table1->table4->table2->table3

表中可用的列也是如此，因为映射是表中的列级别 table1.col1->table4.col4->table2.col2->table3.col3