如果数据太大直接用dataframe转list内存会不够，所以可以通过foreachPartition遍历读取

System.setProperty("hadoop.home.dir","h:\\hadoop2.3.7");string mastor="local"string name="wordcount"+system.currentTimeMillis()sparkSeesion spark=sparkSeesion.builder().appName(neme).master(mastor).getOrCreate();Data
     
       dataset=spark.read().json("src/j.json") Dataset
      
        jsons=dataset.toJSON(); JavaRDD
       
         rdd=json.javaRDD(); rdd.foreachPartition(new VoidFunction
        
         
          >() {
                 @Override  public void call(Iterator
          
            iter) throws Exception {           while(iter.hasNext()) {               String next=iter.next();               System.out.println("获取"+next);           }                        }  });          
          
         
        
       
      
     

参考https://blog.csdn.net/wyqwilliam/article/details/81142324