android实现文件读写功能

本文实例为大家分享了android实现文件读写功能的具体代码，供大家参考，具体内容如下

读取：

public static string _getjsonstring(string filename)
   throws ioexception {
  if ((filename == null) || filename.isempty()) {
   return "";
  }
  string retstring = "";
  fileinputstream fis = null;
  string state = environment.getexternalstoragestate();
  if (state.equals(environment.media_mounted)) {
   file file = new file(environment.getexternalstoragedirectory()
     + "/" + filename + ".json");
   if (file.exists()) {
    fis = new fileinputstream(file);
    byte[] buffer = new byte[fis.available()];
    fis.read(buffer);
    fis.close();
 
    retstring = new string(buffer);
   } else {
 
   }
  }
  return retstring;
 }

写：

public static void savesettingfile(string filename, string content) {
  fileoutputstream fos = null;
  string state = environment.getexternalstoragestate();
  if (state.equals(environment.media_mounted)) {
   file file = new file(environment.getexternalstoragedirectory()
     + "/" + filename + ".json");
   try {
    fos = new fileoutputstream(file);
    byte[] buffer = content.getbytes();
    fos.write(buffer);
    fos.close();
   } catch (filenotfoundexception e) {
    e.printstacktrace();
   } catch (ioexception e) {
    e.printstacktrace();
   }
  }
 }

gson 读写：

public static void saveserverinfo(string filename, string content) {
  fileoutputstream fos = null;
  string state = environment.getexternalstoragestate();
  if (state.equals(environment.media_mounted)) {
   file file = new file(environment.getexternalstoragedirectory()
     + "/" + filename + ".json");
   try {
    fos = new fileoutputstream(file);
    byte[] buffer = content.getbytes();
    fos.write(buffer);
    fos.close();
   } catch (filenotfoundexception e) {
    e.printstacktrace();
   } catch (ioexception e) {
    e.printstacktrace();
   }
  }
 }
 
 public static serverinfo getserverinfo(string filename)
   throws ioexception {
  serverinfo serverinfo = new serverinfo();
  if ((filename == null) || filename.isempty()) {
   serverinfo = null;
   return serverinfo;
  }
  fileinputstream fis = null;
  string state = environment.getexternalstoragestate();
  if (state.equals(environment.media_mounted)) {
   file file = new file(environment.getexternalstoragedirectory()
     + "/" + filename + ".json");
   if (file.exists()) {
    fis = new fileinputstream(file);
    byte[] buffer = new byte[fis.available()];
    fis.read(buffer);
    fis.close();
 
    gson gson = new gson();
    serverinfo = gson.fromjson(new string(buffer),
      serverinfo.class);
   } else {
    serverinfo = null;
   }
  }
  return serverinfo;
 }

调用：

public void onsetipandport(view view) {
  serverinfo serverinfo = new serverinfo();
  try {
   serverinfo = jsonfilewriteandread.getserverinfo("videochat");
  } catch (ioexception e) {
   e.printstacktrace();
  }
 
  //写入ip和端口
  string ip = ipset.gettext().tostring();
  string port = portset.gettext().tostring();
  serverinfo.setipstring(ip);
  serverinfo.setportstring(port);
  gson gson = new gson();
  if (ip.isempty() || port.isempty()) {
   toast.maketext(this, "地址或端口为空", toast.length_short).show();
  } else {
   jsonfilewriteandread.saveserverinfo("videochat", gson.tojson(serverinfo));
   toast.maketext(this, "地址和端口已经写入文件", toast.length_short).show();
  }
 }

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。