sparksql中保存数据的⼏种⽅式从官⽹来copy过来的⼏种模式描述：
how do you do是什么意思gotta get thatScala/Java Python Meaning
SaveMode.ErrorIfExists(default)"error"(default)When saving a DataFrame to a data source, if data already exists, an exception is expected to be thrown.
SaveMode.Append"append"When saving a DataFrame to a data source, if data/table already exists, contents of the DataFrame are expected to be appended to existing data.
SaveMode.Overwrite"overwrite"Overwrite mode means that when saving a DataFrame to a data source, if data/table already exists, existing data is expected to be overwritten by the contents of the DataFrame.
SaveMode.Ignore"ignore"Ignore mode means that when saving a DataFrame to a data source, if data already exists, the save operation is expected to not save the contents of the DataFrame and to not change the existing data. This is similar to a `CREATE TABLE IF NOT EXISTS` in SQL.
ErrorIfExists就是出现错误后，抛出错误
Append顾名思义，就是追加信息
intellectualOverwrite是覆盖
北京火星时代Ignore是如果存在则忽略
另外，如果没有指定存储模式，那么默认应该是SaveMode.ErrorIfExists，因为我重复保存后报了：already exists错误来着。
如何使⽤：
瓜子脸发型设计import org.apache.spark.sql._
card phoneval sqlContext = new org.apache.spark.sql.SQLContext(sc)草你吗
val df = sqlContext.load("/opt/modules/spark1.3.1/examples/src/main/resources/people.json")make的用法
英语日记
df.save("/opt/test/1","json", SaveMode.Overwrite) //可以把SaveMode.Overwrite换成其他的⼏种形式喽一建分数线
