Android中读取中文字符的文件与文件读取相关介绍

一、如何显示assets/license.txt（中文）的内容？
(1)方法1：inputstream.available()得到字节数，然后一次读取完。

private string readuseragreementfromasset(string assetname) {
string content ="";
try {
inputstream is= getassets().open(assetname);
if (is != null){
datainputstream dis = newdatainputstream(is);
intlength = dis.available();
byte[] buffer = new byte[length];
dis.read(buffer);
content= encodingutils.getstring(buffer, "utf-8");
is.close();
}
} catch (ioexception e) {
e.printstacktrace();
}
return content;
}

(2)方法2：用bufferedreader.readline()行读取再加换行符，最后用stringbuilder.append()连接成字符串。
a.以下是先行读取再转码utf8：

private string readuseragreementfromasset(string assetname) {
stringbuilder sb = newstringbuilder("");
string content ="";
try {
inputstream is= getassets().open(assetname);
if (is != null){
bufferedreader d = newbufferedreader(new inputstreamreader(is));
while (d.ready()) {
sb.append(d.readline() +"\n");
}
content =encodingutils.getstring(sb.tostring().getbytes(), "utf-8");
is.close();
}
} catch (ioexception e) {
e.printstacktrace();
}
return content;
}

b.以下是inputstreamreader先指定以utf8读取文件，再进行读取读取操作：

private string readuseragreementfromasset(string assetname) {
stringbuilder sb = newstringbuilder("");
string content ="";
try {
inputstream is= getassets().open(assetname);
if (is != null){
bufferedreaderd = new bufferedreader(new inputstreamreader(is, "utf-8"));
while(d.ready()) {
sb.append(d.readline() +"\n");
}
content= sb.tostring();
is.close();
}
} catch (ioexception e) {
e.printstacktrace();
}
return content;
}

另外，utf8转码也可以用new string(buffer, “utf-8”)。
(3)替代方法3：将license.txt内容作为string.xml的string，如：
<stringname="license_content">用户协议
\n \n一、服务条款的确认和接纳
\n…
</string>
需要注意的是：string里需要加\n作为换行符，原来txt里的换行符在取得string后无效。
不可取方法4：每次读取4096字节，以utf8转码，最后连接字符串。因为汉字可能被截断，导致4096的倍数附近的中文可能出现乱码。

private string readuseragreementfromasset(string assetname) {
stringbuilder sb = newstringbuilder("");
string content ="";
try {
inputstream is= getassets().open(assetname);
if (is != null){
datainputstream dis = new datainputstream(is);
byte[] buffer = new byte[1024*4];
int length = 0;
while ((length = dis.read(buffer)) >0) {
content =encodingutils.getstring(buffer, 0, length, "utf-8");
sb.append(content);
}
is.close();
}
} catch (ioexception e) {
e.printstacktrace();
}
return sb.tostring();
}

//www.jb51.net/kf/201207/140312.html
http://blog.sina.com.cn/s/blog_933d50ba0100wq1h.html
二、android中读写文件
(1) 从resource中的raw文件夹中获取文件并读取数据（资源文件只能读不能写，\res\raw\test.txt）

string res = "";
try{
inputstream in = getresources().openrawresource(r.raw.test);
int length = in.available();
byte [] buffer = newbyte[length];
in.read(buffer);
res = encodingutils.getstring(buffer,"utf-8");//选择合适的编码，如果不调整会乱码
in.close();
}catch(exception e){
e.printstacktrace();
}

(2) 从asset中获取文件并读取数据（资源文件只能读不能写，\assets\test.txt）
与raw文件夹类似，只是：
inputstream is = getassets().open(“test.txt”);
(3) 私有文件夹下的文件存取（/data/data/包名/files/test.txt）
使用openfileoutput写文件：

public void writefiledata(string filename,string message){
try{
fileoutputstream fout =openfileoutput(filename,mode_private);
byte [] bytes =message.getbytes();
fout.write(bytes);
fout.close();
}
catch(exception e){
e.printstacktrace();
}
}

使用openfileinput读文件：

public string readfiledata(string filename){
string str = “”;
try{
fileinputstream fin =openfileinput(filename);
int length = in.available();
byte [] bytes = newbyte[length];
fin.read(bytes);
str = encodingutils.getstring(bytes,"utf-8");
fin.close();
}
catch(exception e){
e.printstacktrace();
}
return str;
}

(4) sdcard目录下的文件存取（/mnt/sdcard/）
使用fileoutputstream写文件：

public void writefile2sdcard(string filename,string message){
try{
fileoutputstream fout = new fileoutputstream(filename);
byte [] bytes =message.getbytes();
fout.write(bytes);
fout.close();
}
catch(exception e){
e.printstacktrace();
}
}

使用fileinputstream读文件：

public string readfilefromsdcard(string filename){
string res="";
try{
fileinputstream fin = newfileinputstream(filename);
int length =fin.available();
byte [] buffer = newbyte[length];
fin.read(buffer);
res =encodingutils.getstring(buffer, "utf-8");
fin.close();
}
catch(exception e){
e.printstacktrace();
}
return res;
}

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