解决java读取大文件内存溢出问题、如何在不重复读取与不耗尽内存的情况下处理大文件

<div class="article_title" style="margin:5px 0px; font-size:20px; line-height:30px; font-family:'Microsoft YaHei'">
<h1 style="margin:0px; padding:0px; display:inline; font-weight:normal; font-size:20px; vertical-align:middle"> <span class="link_title"><a href="http://blog.csdn.net/mr_smile2014/article/details/49928773" rel="noopener noreferrer" style="color:rgb(0,0,0); text-decoration:none" target="_blank">解决java读取大文件内存溢出问题、如何在不重复读取与不耗尽内存的情况下处理大文件</a></span></h1>
</div>
<div class="article_manage clearfix" style="padding:0px 20px 5px; color:rgb(153,153,153); line-height:22px; font-family:Arial; text-align:right; border-bottom-style:solid; border-bottom-width:1px; border-bottom-color:rgb(237,237,237); margin:0px -20px; overflow:hidden">
<div class="article_l" style="width:946px; float:left">
  <span class="link_categories" style="margin:0px 5px; float:left">标签： <a href="http://www.csdn.net/tag/java" rel="noopener noreferrer" style="color:rgb(202,0,0); text-decoration:none; display:inline-block; margin-right:10px" target="_blank">java</a><a href="http://www.csdn.net/tag/%e6%96%87%e4%bb%b6%e6%b5%81" rel="noopener noreferrer" style="color:rgb(202,0,0); text-decoration:none; display:inline-block; margin-right:10px" target="_blank">文件流</a><a href="http://www.csdn.net/tag/Apache%20Commons%20IO%e6%b5%81" rel="noopener noreferrer" style="color:rgb(202,0,0); text-decoration:none; display:inline-block; margin-right:10px" target="_blank">Apache Commons IO流</a></span>
</div>
<div class="article_r">
  <span class="link_postdate" style="margin:0px 5px 0px 0px">2015-11-19 15:50</span>
  <span class="link_view" style="margin:0px 5px; padding:0px 0px 0px 14px" title="阅读次数">5197人阅读</span>
  <span class="link_comments" style="margin:0px 5px; padding:0px 0px 0px 14px" title="评论次数"><a href="http://blog.csdn.net/mr_smile2014/article/details/49928773#comments" rel="noopener noreferrer" style="color:rgb(202,0,0); text-decoration:none" target="_blank">评论</a>(3)</span>
  <span class="link_report" style="margin:0px 5px"><a href="http://blog.csdn.net/mr_smile2014/article/details/49928773#report" rel="noopener noreferrer" style="color:rgb(202,0,0); text-decoration:none" target="_blank" title="举报">举报</a></span>
</div>
</div>
<div class="category clearfix" style="border-bottom-style:solid; border-bottom-width:1px; border-bottom-color:rgb(237,237,237); margin:0px -20px; padding:5px 20px; font-family:Arial,Console,Verdana,'Courier New'">
<div class="category_l" style="font-size:14px; float:left; display:inline-block; color:rgb(51,51,51); width:70px; line-height:28px">
  <img alt="" src="https://beijingoptbbs.oss-cn-beijing.aliyuncs.com/cs/5606289-b367fdce88ee208da19a58e7fab01f44.jpg" style="border:none; vertical-align:middle">
  <span style="vertical-align:middle; display:inline-block">分类：</span>
</div>
<div class="category_r" style="font-size:14px; float:left; display:inline-block; color:rgb(223,52,52); width:851.390625px">
  <label style="display:inline-block; margin-left:15px; line-height:28px; position:relative">JAVA（44） <img alt="" class="arrow-down" src="https://beijingoptbbs.oss-cn-beijing.aliyuncs.com/cs/5606289-b16356edc9d65f9de5798055c2b20c3c.jpg" style="border:none; display:inline"></label>
  <label style="display:inline-block; margin-left:15px; line-height:28px; position:relative">问题集锦（27） <img alt="" class="arrow-down" src="https://beijingoptbbs.oss-cn-beijing.aliyuncs.com/cs/5606289-b16356edc9d65f9de5798055c2b20c3c.jpg" style="border:none; display:inline"></label>
</div>
</div>
<div style="font-family:Arial,Console,Verdana,'Courier New'; clear:both"></div>
<div style="font-family:Arial,Console,Verdana,'Courier New'; border:1px solid rgb(204,204,204); background-color:rgb(238,238,238); float:left; min-width:200px; padding:4px 10px">
<p style="margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; text-align:right"> <span style="float:left">目录<a href="http://blog.csdn.net/mr_smile2014/article/details/49928773#" rel="noopener noreferrer" style="color:rgb(202,0,0); text-decoration:none" target="_blank" title="系统根据文章中H1到H6标签自动生成文章目录">(?)</a></span><a href="http://blog.csdn.net/mr_smile2014/article/details/49928773#" rel="noopener noreferrer" style="color:rgb(202,0,0); text-decoration:none" target="_blank" title="展开">[+]</a></p>
</div>
<div style="font-family:Arial,Console,Verdana,'Courier New'; clear:both"></div>
<div class="article_content tracking-ad" id="article_content" style="margin:20px 0px 0px; font-size:14px; line-height:26px; font-family:Arial">
<h3 style="margin:-8px 0px 20px; padding:0px; border:0px; font-size:20px; font-weight:normal; line-height:30px; font-family:'Microsoft YaHei','Myriad Pro',Lato,'Helvetica Neue',Helvetica,Arial,sans-serif"> <a name="t0" style="color:rgb(202,0,0)" target="_blank"></a><span style="border:0px; margin:0px; padding:0px">1、传统的在内存中读取</span></h3>
<p style="margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; border:0px; font-family:'Microsoft YaHei',宋体,'Myriad Pro',Lato,'Helvetica Neue',Helvetica,Arial,sans-serif; line-height:21px"> 读取文件行的标准方式({LL