public String fileToString(String fileName) {
    StringBuilder fileContent = new StringBuilder();
    File file = new File(fileName);
    BufferedReader br = null;
    try {
        br = new BufferedReader(new FileReader(file));

        String string;
        while ((string = br.readLine()) != null) {
        fileContent.append(string);
        fileContent.append("\n");
        }
    } catch (IOException e) {
        throw new RuntimeException(e);
    } finally {
        if (br != null)
        try {
            br.close();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    return fileContent.toString();
    }

------解决方案--------------------
这个帖子和你要做的是一回事如何用java 读取一个txt 文件内的内容并把它赋值与String 里？

------解决方案--------------------
Java code
   public String fileToString(String fileName) {
   StringBuilder fileContent = new StringBuilder();
   File file = new File(fileName);
   BufferedReader br = null;
   try {
       br = new BufferedReader(new FileReader(file));

       String string;
       while ((string = br.readLine()) != null) {
       fileContent.append(string);
       fileContent.append("\n");
       }
   } catch (IOException e) {
       throw new RuntimeException(e);
   } finally {
       if (br != null)
       try {
           br.close();
       } catch (IOException e) {
           throw new RuntimeException(e);
       }
   }

   return fileContent.toString();
   }

对的

------解决方案--------------------
按行读取文件内容，然后做你想做的事。
楼主想把所有内容读出来然后放到一个字符串中，2楼的代码能说明问题了，
然后对于你的代码：
Java code

fileContent += br.readLine();