将Json文件转换为Java中的Json字符串(String)

public static String getJsonStr(String jsonFileUrl){//json的文件路径
	  File jsonFile = new File(jsonFileUrl);
      String jsonStr = "";
      try {
           FileReader fileReader = new FileReader(jsonFile);
           Reader reader = new InputStreamReader(new FileInputStream(jsonFile),"utf-8");
           int ch = 0;
           StringBuffer sb = new StringBuffer();
           while ((ch = reader.read()) != -1) {
               sb.append((char) ch);
           }
           fileReader.close();
           reader.close();
           jsonStr = sb.toString();
           return jsonStr;
       } catch (IOException e) {
           e.printStackTrace();
           return null;
       }
}