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http断点续传简单实现(java)

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/* 9;sebqC?  
**SiteFileFetch.java fg^$F9@  
*/ D$!(Iae  
package NetFox; \:%e 6M  
import java.io.*; 34&n { xv  
import java.net.*; @=isN'>]O  
|^8l8u  
#4DEb<D  
public class SiteFileFetch extends Thread { }e&   
o-yZ$+V  
#-Ehg4W  
SiteInfoBean siteInfoBean = null; //文件信息Bean +t,JCY6  
long[] nStartPos; //开始位置 (Lp<T!"  
long[] nEndPos; //结束位置 ENr\+{{%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 -Wb/3 X  
long nFileLength; //文件长度 i4JqU\((]  
boolean bFirst = true; //是否第一次取文件 <TC\Nb$~  
boolean bStop = false; //停止标志 I Bo)fE\O  
File tmpFile; //文件下载的临时信息 (O"Wa  
DataOutputStream output; //输出到文件的输出流 o{37}if  
G?#f@N0.5p  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) U# G0  
public SiteFileFetch(SiteInfoBean bean) throws IOException bb}|"m .  
{ n&p i  
siteInfoBean = bean; ,n-M!y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); :Fm;0R@/k  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); N/4`afiV.  
if(tmpFile.exists ()) )t0Y-),vA  
{ vB hpD  
bFirst = false; QcU&G*   
read_nPos(); u|BD=4*  
} *G7/  
else DwMq  
{ {D={>0  
nStartPos = new long[bean.getNSplitter()]; [daUtKz  
nEndPos = new long[bean.getNSplitter()]; q5p!Ty"  
} [>U'P1@ql  
pIXbr($  
/2Y t\=S=  
dmgoVF_qR  
} G\@ uj>Z  
>WVos 4  
< HlS0J9  
public void run() l c?9B  
{ {U= Mfo?AH  
//获得文件长度 )! Jo7SR  
//分割文件 b MZ-{<+i  
//实例FileSplitterFetch 8' M4 3n  
//启动FileSplitterFetch线程 Y`eUWCD  
//等待子线程返回 h8iic  
try{ )*}2L_5]  
if(bFirst) {ZP0%MD  
{ _a|-_p  
nFileLength = getFileSize(); @eU;oRVc{  
if(nFileLength == -1) =]X_wA;%  
{ dUegHBw_`R  
System.err.println("File Length is not known!"); $@QF<?i~  
} ue"?n2  
else if(nFileLength == -2) V+G.TI P  
{ nd_+g2x'  
System.err.println("File is not access!"); (S3\O `5  
} HRS^91aK  
else TmZ sC5  
{ #&u9z5ywM  
for(int i=0;i<nStartPos.length;i++) ~4IkQ|,  
{ l|TiUjs  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6jyS]($q  
} Kx==vq%39  
for(int i=0;i<nEndPos.length-1;i++) 2#%@j6  
{ >1q W*  
nEndPos = nStartPos[i+1]; wK>a&`<  
} us%dw&   
nEndPos[nEndPos.length-1] = nFileLength; 4HG;v|Cp  
} XRA RgWj  
} -9W)|toWb"  
O~D>F*_^j  
YGFE(t;lPU  
//启动子线程 2NMS '"8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; xvn@zi  
for(int i=0;i<nStartPos.length;i++) j]Y`L?!Q  
{ !:"$1kh1("  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), WD.td  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), hilgl<UF  
nStartPos,nEndPos,i); c~ x  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jRdmQ mTJ  
fileSplitterFetch.start(); h]W PWa)M  
} `#J0@ -  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y=0D[o8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #2 Gy=GvV  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 7-S?\:J  
nEndPos = " + nFileLength); %+gK5aVab  
// fileSplitterFetch[nPos.length-1].start(); %QYW0lE  
2E7vuFH4c  
gkkT<hEV=  
//等待子线程结束 -|_#6-9  
//int count = 0; g }\ G@7Q  
//是否结束while循环 xb8S)zO]Q  
boolean breakWhile = false; 5A Fy6Ab  
F%|F-6  
PiQs Vk  
while(!bStop) my|]:(_0d  
{ DD$YMM  
write_nPos(); F{,<6/ayRz  
Utility.sleep(500); E^'f'\m  
breakWhile = true; hJ|zX  
'LC-/_g  
aUZh_<@  
for(int i=0;i<nStartPos.length;i++) SrVo0$5)  
{ =*2_B~`  
if(!fileSplitterFetch.bDownOver) * z85 2@  
{ g_8A1lt  
breakWhile = false; e97Ll=>  
break; ZhvZe/  
} bEvlk\iql  
} ) oypl+y  
if(breakWhile) % )o'9  
break; IZ2(F,{o  
2&b?NqEeZ  
%mF:nU4  
//count++; *.F^`]yz  
//if(count>4) 1 >}x9D  
// siteStop(); b9Fd}WZz  
} X>-|px$vy  
k4i*80  
o*5iHa(Qm  
System.err.println("文件下载结束!"); yq7gBkS  
} ~(v7:?  
catch(Exception e){e.printStackTrace ();} )/87<Y;o  
} B:X,vE  
=5l20 Um  
_EEOBaZ  
//获得文件长度 3aX/)v.:4  
public long getFileSize() 2wX4e0cOI4  
{ Xg4i H5!E  
int nFileLength = -1; oeKVcVP|'&  
try{ xa"8"8  
URL url = new URL(siteInfoBean.getSSiteURL()); ~6nY5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); azBYh*s=5{  
httpConnection.setRequestProperty("User-Agent","NetFox"); .dwy+BzS  
e #!YdXSx  
GBg~NkC7.  
int responseCode=httpConnection.getResponseCode(); f$y`tT %o  
if(responseCode>=400) 70Z#Ej  
{ /BN_K8nb`  
processErrorCode(responseCode); fex<9'e  
return -2; //-2 represent access is error > a?K ![R  
} y]U]b G{  
@'AjEl:&-_  
_-+xzdGvX  
String sHeader; j:>_1P/  
9'" F7>d  
4it^-M  
for(int i=1;;i++) Ea,L04K  
{ x9!3i{_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {r>iUgg  
//Utility.log(in.readLine()); j0wpaIp  
sHeader=httpConnection.getHeaderFieldKey(i); |d)*,O4s  
if(sHeader!=null) :HiAjaA1pg  
{ 9\ulS2d  
if(sHeader.equals("Content-Length")) d!P3<:+R[  
{ 5Q$.q &,  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); iZ( U]  
break; a +$'ULK+r  
} |O';$a1S  
} " ZYdJHM  
else sF4+(9=  
break; *Ei(BrL/;  
} ^Ay>%`hf*  
} m%s&$  
catch(IOException e){e.printStackTrace ();} c>b!{e@*  
catch(Exception e){e.printStackTrace ();} ZZ*+Tl\ s  
eJ ;a}{ 4%  
b0| ;v-v  
Utility.log(nFileLength); f`W)Z$fN5  
) Vf!U"  
G4;5$YGG  
return nFileLength; Abc%VRsT  
} -_?U/k(Hi  
x>!bvZ2  
+Y! P VMF  
//保存下载信息(文件指针位置) V] 0T P#  
private void write_nPos() UTS.o#d  
{ _c$F?9:  
try{ 'c/S$_r  
output = new DataOutputStream(new FileOutputStream(tmpFile)); k}&7!G@T  
output.writeInt(nStartPos.length); 4 \Ig<C9  
for(int i=0;i<nStartPos.length;i++) q]2t3aY%  
{ S HxD(6  
// output.writeLong(nPos); X/BcS[a  
output.writeLong(fileSplitterFetch.nStartPos); wrhGZ=k{  
output.writeLong(fileSplitterFetch.nEndPos); ^B?brH}  
}  eQU~A9  
output.close(); SNOML7pd  
}  DJJd_  
catch(IOException e){e.printStackTrace ();} MXa(Oi2Gg  
catch(Exception e){e.printStackTrace ();} j;yKL-ycB  
} p>=i'~lQ6  
v$)ZoM6E  
G%F}H/|R  
//读取保存的下载信息(文件指针位置) uc>]-4  
private void read_nPos() =@ d/SZ|(E  
{ or qL0i  
try{ OpD%lRl  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); p#aB0H3  
int nCount = input.readInt(); <8iu:nR  
nStartPos = new long[nCount]; fNk0&M  
nEndPos = new long[nCount]; ;k:17&:8ue  
for(int i=0;i<nStartPos.length;i++) y2M]z:Y U  
{ &WKAg:^k)  
nStartPos = input.readLong(); 1:;S6{oQ  
nEndPos = input.readLong(); S;K5JBX0#  
} /<VR-yr  
input.close();  SH6+'7  
} 5V*R  Dh  
catch(IOException e){e.printStackTrace ();} hX)PdRk#  
catch(Exception e){e.printStackTrace ();} ^xX1G _{  
} N;` jz(r  
) #l&BV5  
-P:o ^_)g  
private void processErrorCode(int nErrorCode) eA_]%7+`  
{ J{U 171  
System.err.println("Error Code : " + nErrorCode); ]%2y`Jrl^W  
} Y(&rlL(sPK  
Y !%2vOt  
:|%1i>O  
//停止文件下载 8J)Kn4jq  
public void siteStop() ZJ8"5RW  
{ }eAV8LU  
bStop = true; ><xJQeW  
for(int i=0;i<nStartPos.length;i++) ?mHu eX  
fileSplitterFetch.splitterStop(); tGJJ|mle>  
|OiM(E(  
/ ?'FSWDU  
} BG8`B'i  
} &3$FkU^F6  
//负责部分文件的抓取 |Ae7wXOs  
**FileSplitterFetch.java * hmoi  
*/ *]:J@KGf  
package NetFox; s`en8%  
]E $bK  
watTV\b  
import java.io.*; Vg~10Q  
import java.net.*; FQ>y2n=<d  
9]vy#a#  
ye-[l7  
public class FileSplitterFetch extends Thread { `ES+$O>  
`96MXP  
(#BOcx5J]  
String sURL; //File URL M%Zh{  
long nStartPos; //File Snippet Start Position w>e+UW25Y  
long nEndPos; //File Snippet End Position NG8 F'=<  
int nThreadID; //Thread's ID <+UJgB A-  
boolean bDownOver = false; //Downing is over mwutv8?  
boolean bStop = false; //Stop identical =I0J1Ob  
FileAccessI fileAccessI = null; //File Access interface f#McTC3C  
wb>"'%  
A,EuUp  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException i9Eh1A3Y  
{ AC*SmQ\>!  
this.sURL = sURL; PqMu2 e  
this.nStartPos = nStart; wf_ $#.;m  
this.nEndPos = nEnd; ;` h$xB(  
nThreadID = id; .%+anVXS  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Dy*K;e-+  
} E|A~T7G=  
8 ,W*)Q  
Bbtc[@"X  
public void run() 3^iVDbAW{  
{ &b'{3o_KN  
while(nStartPos < nEndPos && !bStop) @RZbo@{~  
{ %~:@}C%A  
9iV9q]($0  
gZBb /<  
try{ 2 sj: &][R  
URL url = new URL(sURL); ; xL8W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nErr&{C  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5me#/NqLHY  
String sProperty = "bytes="+nStartPos+"-"; >sZ_I?YDs  
httpConnection.setRequestProperty("RANGE",sProperty); 8)>4ZNXz  
Utility.log(sProperty); BOD!0CR5  
y;%\ w-.\  
M/,lP  
InputStream input = httpConnection.getInputStream(); NHcA6y$Cz  
//logResponseHead(httpConnection); J+T tM>  
{e1sq^>|  
X]D:vuB  
byte[] b = new byte[1024]; a'g&1N0Rc  
int nRead; 'w=aLu5dY  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :`>tCYy;  
{ CzI s_/  
nStartPos += fileAccessI.write(b,0,nRead); 2%| n}V[  
//if(nThreadID == 1) 4+89 M  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [_`@ V4  
} k;K-6<^h  
0+k..l  
+R7pdi  
Utility.log("Thread " + nThreadID + " is over!"); BSL+Gjj~}  
bDownOver = true; Fkg%_v$  
//nPos = fileAccessI.write (b,0,nRead); ^Rtxef  
} IBUFXzl  
catch(Exception e){e.printStackTrace ();} h;@>E:4Tg  
} #ro$$I;  
} 4];>O  
5LZs_%#  
P @Fx6  
//打印回应的头信息 QX42^]({;c  
public void logResponseHead(HttpURLConnection con) 2.^CIJc  
{ CfVL'  
for(int i=1;;i++) r?w>x`  
{ jxZf,]>T  
String header=con.getHeaderFieldKey(i); Dk&(QajL  
if(header!=null) ~pHuh#>  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); h/2@4XKj  
Utility.log(header+" : "+con.getHeaderField(header)); eFotV.T!#  
else  F&lH5  
break; @NL37C  
} 1!yd(p=cL  
} xLms|jS  
ArScJ\/Nwv  
RN}joKV  
public void splitterStop() D2J)qCK1)  
{ C ^c <s  
bStop = true; bc NyB$S  
} \qTp#sF  
^y%8_r&  
JDW/Mc1bh  
} -0TI7 @  
HXX9D&c4R  
?B@3A)a  
/* Gm &jlN  
**FileAccess.java O.Y|},F  
*//文件访问(定位,写) r;{ggwY&J  
package NetFox; $Ld-lQsL  
import java.io.*; 2 6 >9$S  
&gr  T@  
H/k]u)Gtv  
public class FileAccessI implements Serializable{ Y]^*mc0fE  
eA{A3.f"Hz  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _z1Qr?cY  
RandomAccessFile oSavedFile; -8vGvI>  
long nPos; 'T(Q  
|onLJY7)  
s Ytn'&$\  
public FileAccessI() throws IOException VbTX;?  
{ |`pBI0Sjo  
this("",0); <WnIJum  
} #DARZhU)  
um%s9  
'+ mI  
public FileAccessI(String sName,long nPos) throws IOException 66sgs16k  
{ feH&Ug4?G  
oSavedFile = new RandomAccessFile(sName,"rw"); g-,lY|a  
this.nPos = nPos; -[&Z{1A4x4  
oSavedFile.seek(nPos); gI9nxy  
} Y^C(<N$  
2 E?]!9T~|  
Y]Z&  
public synchronized int write(byte[] b,int nStart,int nLen)  deq5u>  
{ 6)W8HX~+  
int n = -1; JG&E"j#q  
try{ 0LYf0^P  
oSavedFile.write(b,nStart,nLen); +t&+f7  
n = nLen; Z [l+{  
} c}|} o^  
catch(IOException e) .3jijc j  
{ >o%X;U 3  
e.printStackTrace (); &y7=tEV  
} p!)PbSw#  
2pv by`P4  
S4c-i2Rq  
return n; i3KAJ@  
} U#- 5",X|  
1 <m.Q*  
TaaCl#g$?  
} 3sIdwY)ZS_  
'4D7:  
8N$Xq\Da+>  
/* *_m ER`  
**SiteInfoBean.java Q[%G`;e#  
*/ eu8a<  
package NetFox; st~ l||  
^UhqV"[7k  
$FDGHFM  
public class SiteInfoBean { P #8+1iC1  
R4'>5.M  
k {vd1,HZ  
private String sSiteURL; //Site's URL 4E}Q<?UYSt  
private String sFilePath; //Saved File's Path b|G~0[g  
private String sFileName; //Saved File's Name :7X{s4AU6  
private int nSplitter; //Count of Splited Downloading File Vq/hk  
,\1Rf.  
N)a5~<fBG  
public SiteInfoBean() {?++T 0  
{//nSplitter的缺省值为5 QFN9j  
//default value of nSplitter is 5 M?;YpaSe+  
this("","","",5);  _VM}]A  
} ;49sou  
m6H+4@Z-;(  
#Ye0*`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) p&0 G  
{ .wTb/x  
sSiteURL= sURL; ;Xqi;EA  
sFilePath = sPath; PR AP~P&^  
sFileName = sName; [3ggJcUgW>  
this.nSplitter = nSpiltter; K6)IBV;  
I>w|80%%  
'vZy-qHrV  
} 9eE FX7  
;PqC *iz  
?5;wPDsK  
public String getSSiteURL() jsF5q~F  
{ ME$J?3r  
return sSiteURL; .QA1'_9  
} Im};wJ&  
(lq%4h  
j~=<O<P  
public void setSSiteURL(String value) sFvYCRw /  
{ ()$m9%x  
sSiteURL = value; [9}<N2,9z  
} ,J<+Wxz  
w@YPG{"j  
3h%Nd &_9  
public String getSFilePath() /QCg E ~  
{ aI}htb{m`  
return sFilePath; FPZ@6  
} O-pH~E  
|5q,%9_  
D vN0h(?  
public void setSFilePath(String value) paYS< 8In  
{ P1]F0fR  
sFilePath = value; $]W*;MTI}  
} &uV|Ie8@q  
q1 BpE8  
Qw_> l}k/  
public String getSFileName() ;NAKU  
{ o/vD]Fs  
return sFileName; P]2 /}\f  
} Q84XmXm|  
t-iQaobF  
_`laP5~  
public void setSFileName(String value) hv#LKyp%  
{ ^)$T`  
sFileName = value; vfVF^ WOd  
} )7AjRtb!/  
_W,?_"[R=  
rJtk4hOF  
public int getNSplitter() nJ1<8 p  
{ F4~O-g.<  
return nSplitter; sebuuL.l0<  
} jxq89x  
P8 w56  
}XRfHQk  
public void setNSplitter(int nCount) 8u"C7} N_  
{ x #|t#N%  
nSplitter = nCount; JuRWR0@`  
} An,TunX  
} .Rb1%1bdc  
N>g6KgX{K  
=BV_ ?  
/* s%m?Yh3  
**Utility.java bHTTxZ-%  
*/ X*bOE}  
package NetFox; i\4dd)p-  
:Fh_Ya0  
@)z?i  
public class Utility { e;"%h%'  
)IIWXN2A  
gy#G;9p  
public Utility() _?bF;R  
{ EU Oa8Z  
YW8Odm  
8)b*q\ O'  
} `V*$pHo  
JiXN"s^mcb  
//线程睡眠 =~dXP  
public static void sleep(int nSecond) K8QEHc:  
{ M{Vi4ehOq  
try{ + eZn  
Thread.sleep(nSecond); N]|)O]/[  
} $UdFm8&  
catch(Exception e) 7L]Y.7>  
{ :/fT8KCwo  
e.printStackTrace (); Ro2!$[P  
} =trLL+vGw'  
} fCv.$5  
-9s&OKo`({  
//日志 H]M[2C7#N  
public static void log(String sMsg) nQfSQMg  
{ ytfr'sr/  
System.err.println(sMsg); 9~l8QaK  
} )S@TYzdAN  
SK,UW6h  
,twm)%caU  
public static void log(int sMsg) G49`a*Jn  
{ !4$o*{9Lx:  
System.err.println(sMsg); "T>;wyGW  
} }\W^$e-  
} 0F &(}`V  
VlxHZ  
edlsS}8^  
/* UGA` `;f  
**TestMethod.java v.Q+4 k  
*/ 3nUC,T%  
package NetFox; 'W~6-c9y  
<2^ F'bQV  
x!?$y_t  
public class TestMethod { zogl2e+  
E/>kvs%  
5d)\Z0s  
public TestMethod() 4L&Rs;  
{ ///xx/weblogic60b2_win.exe l?x'R("{  
try{ L@G~9{U>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); M,DwBEF?  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 4zqO!nk  
SiteFileFetch fileFetch = new SiteFileFetch(bean); u#$sO;8s  
fileFetch.start(); ]"\sd"  
} Cs^'g'  
catch(Exception e){e.printStackTrace ();} w?R#ly  
aR%E"P-6l  
@ | (Tg  
} "^VPe[lA  
(<Kf  
q]P$NeEiZ"  
public static void main(String[] args) uCf _O~  
{ E*}1_,q)  
new TestMethod(); C4eQ.ep  
} /nNrvMt v  
} 0?'v|5}  
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