http断点续传简单实现（java)

/* X#(?V[F]  
**SiteFileFetch.java *;O$=PE  
*/ ;*+jCL2F  
package NetFox; /+Xv(B  
import java.io.*; }@}jwi)l  
import java.net.*; y1/$dn  
A[Juv]X  
p,@_A'  
public class SiteFileFetch extends Thread { u Y/Q]NT  
rZ1${/6  
iD_NpH q  
SiteInfoBean siteInfoBean = null; //文件信息Bean y`=A$>A  
long[] nStartPos; //开始位置 yjpV71!M  
long[] nEndPos; //结束位置 ?K{CjwE.M  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ycRy!0l  
long nFileLength; //文件长度 dV8mI,h  
boolean bFirst = true; //是否第一次取文件 !tF
s(![  
boolean bStop = false; //停止标志 vKDRjrF-  
File tmpFile; //文件下载的临时信息 Se*GR"Z+  
DataOutputStream output; //输出到文件的输出流 sW#6B+5_k  
5FnWlFc  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） z:|4S@9  
public SiteFileFetch(SiteInfoBean bean) throws IOException ) ]U-7  
{ Uw5z]Jck  
siteInfoBean = bean; &?/h#oF@\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ?I`']|I  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); S?*v p=  
if(tmpFile.exists ()) N|T%cdh:/  
{ qp^O\>c  
bFirst = false; xRJv_=dT  
read_nPos(); "Q#/J)N  
} 'i{kuTv  
else _UYt  
{ |SZRO,7x  
nStartPos = new long[bean.getNSplitter()]; 3.?PdK&C  
nEndPos = new long[bean.getNSplitter()]; Ej ip%m  
} 4\Y2{Z>P?  
g` 6Xrf  
_NA0$bGN9  
GrW+P[j9  
} .#6Dad=S*  
<u*~RYA2  
 s6rdQI]  
public void run() M/
0!B_(R  
{ P8Fq %k  
//获得文件长度 d /jO~+jP  
//分割文件  .-'  
//实例FileSplitterFetch Gb<)U[Hfd  
//启动FileSplitterFetch线程 t%n1TY,  
//等待子线程返回 UBrYN'QRNt  
try{ Ja|! fT  
if(bFirst)
,-&ler~[  
{ VieC+Kk  
nFileLength = getFileSize(); $[6:KV  
if(nFileLength == -1) _LFZ0  
{ { o=4(RC  
System.err.println("File Length is not known!"); I`}-*%ki(  
} $xyG0Q.  
else if(nFileLength == -2) lKrD.iYt8  
{ OOGqtA;  
System.err.println("File is not access!"); s9PD[u/y  
} )
$I;)`q  
else /<9VKMR_k  
{ :z56!qU  
for(int i=0;i<nStartPos.length;i++) vX]\Jqy  
{ v-3In\T=^  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .ZFs+8qU>  
} * 'WzIk
2  
for(int i=0;i<nEndPos.length-1;i++) YW}q@AY7  
{ |rka/_  
nEndPos = nStartPos[i+1]; >lU[ lf+/  
} 4iBp!k7  
nEndPos[nEndPos.length-1] = nFileLength; KY<>S/  
} B@Ez,u5  
} +#}I^N  
7@$Hua,GY  
|Ma"B4  
//启动子线程 13I 7ah  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; {j+w|;dZF  
for(int i=0;i<nStartPos.length;i++) Gmi4ffIb3  
{ ``)ys^V  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), j8$
*$|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $U<so{xn%  
nStartPos,nEndPos,i); b-'41d}Hn  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R)"Ds}1G  
fileSplitterFetch.start(); v9(->X'  
} 4*g`!~)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H2l/9+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ~z$vF  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", z/)HJo2#  
nEndPos = " + nFileLength); (GJ)FWen0"  
// fileSplitterFetch[nPos.length-1].start(); wbshKkUh_*  
AqZ{x9g!  
3XYCtp8  
//等待子线程结束 Ra}%:  
//int count = 0; \C5YVl#  
//是否结束while循环 k)UF.=$d  
boolean breakWhile = false; f ."bq43(  
~C6d
5\  
?1K|.lr  
while(!bStop) 3xWeN#T0  
{ !5wm9I!5^  
write_nPos(); W
p`wIe6  
Utility.sleep(500); 2--"@@  
breakWhile = true; 3k py3z[%  
jxU1u"WU  
%Wkvo-rOq  
for(int i=0;i<nStartPos.length;i++) ;t{Ew+s  
{ dFFJw[$8w  
if(!fileSplitterFetch.bDownOver) nR-`;lrF~  
{ XZLo*C!MG  
breakWhile = false; @tWyc%t  
break; cJd~UQ<k  
} t8DySFT  
}  iUJqAi1o  
if(breakWhile) {5QIQ  
break; IqJ7'X  
uIvy1h9m  
NJ^`vWi  
//count++; z 0]K:YV_  
//if(count>4) 6e3s |  
// siteStop(); >KmOTM<{  
} G.OAzA13!t  
`[p*qsp_  
9>\P]:  
System.err.println("文件下载结束！"); "Kx2k>ym  
} GoP,_sd\O  
catch(Exception e){e.printStackTrace ();} +dw$IMwb  
} RO+B/)~0<  
zZ&L#  
`,gGmh  
//获得文件长度 -B-?z?+(O  
public long getFileSize() 17AJT  
{ $_CE!_G&)  
int nFileLength = -1; +b"RZ:tKp  
try{ aT1T.3 a  
URL url = new URL(siteInfoBean.getSSiteURL()); y|f`sBMM  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~G|u
n}g=  
httpConnection.setRequestProperty("User-Agent","NetFox"); knrR%e;  
_xT=AF9~o  
dznHR6x  
int responseCode=httpConnection.getResponseCode(); 2\h}6DGx2  
if(responseCode>=400) /fC@T  
{ _PD RUJ  
processErrorCode(responseCode); f_a.BTtNO  
return -2; //-2 represent access is error >Y=HP&A<  
} )nmLgsg  
{j i;~9'Q  
#va|&QBZxM  
String sHeader; 0`.3`Mk   
_9!*laR!2  
X_GR{z%  
for(int i=1;;i++) =<mpZ'9gW  
{ [lZo'o  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); /z:pid,_0  
//Utility.log(in.readLine()); [~03Z[_"/  
sHeader=httpConnection.getHeaderFieldKey(i); XDs )  
if(sHeader!=null) 8}9|hT;  
{ dzJ\+ @4  
if(sHeader.equals("Content-Length")) [5K&J-W  
{ '{=dEEi  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); kXimJL_<g  
break; V^fSrW]  
} i bAZ*I  
} td!WgL,m  
else *fyC@fI>  
break; *#+e_)d  
} ;AyE(|U+  
} B;Pws$J  
catch(IOException e){e.printStackTrace ();} /N6sH!w  
catch(Exception e){e.printStackTrace ();} pW ]+a0j  
tYV%izE  
`L p3snS  
Utility.log(nFileLength); \Y.&G,?  
KWtLrZ(j  
Hik8u!#P  
return nFileLength; _~!*|<A_  
} 6&/H XqP  
8tq6.%\  
?^]29p_  
//保存下载信息（文件指针位置） s/[15  
private void write_nPos() Ar&]/X,WG  
{ :&D>?{b0  
try{ N<c98  
output = new DataOutputStream(new FileOutputStream(tmpFile)); mNkS!(L6  
output.writeInt(nStartPos.length); ]D|sQPi]F  
for(int i=0;i<nStartPos.length;i++) 0CXh|AU  
{ !wH7;tU  
// output.writeLong(nPos); *p!K9$4  
output.writeLong(fileSplitterFetch.nStartPos); g-^Cf  
output.writeLong(fileSplitterFetch.nEndPos); W\09hZ
6  
} ECHl9; +  
output.close(); T' O5>e  
} (?MRbX]@  
catch(IOException e){e.printStackTrace ();} 8joJe>9VJ  
catch(Exception e){e.printStackTrace ();} jR~2mf!h*e  
} }'HJVB_  
0l#{7^e  
d"zbY\`  
//读取保存的下载信息（文件指针位置） s8w7/*<d  
private void read_nPos() pT Yq#9  
{ y[7*^9J  
try{ `P;fD/I  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); K
j[X1X5  
int nCount = input.readInt(); {XYv&K  
nStartPos = new long[nCount]; (WT0j  
nEndPos = new long[nCount]; `jY*0{  
for(int i=0;i<nStartPos.length;i++) )@DT^#zR  
{ Hb&-pR@e\?  
nStartPos = input.readLong(); X\3IY:Q@T  
nEndPos = input.readLong(); 0:-i  
} )W^Wqa8mG|  
input.close(); ,aI 6P-  
} s=`1wkh0  
catch(IOException e){e.printStackTrace ();} }9T$XF~  
catch(Exception e){e.printStackTrace ();} G'c!82;,?  
} ]p3hq1u3&  
U85t !U  
NJ8QI(^"  
private void processErrorCode(int nErrorCode) >T3HkOT  
{ [uO
W\)`  
System.err.println("Error Code : " + nErrorCode); ,=KJ7zIK?  
} }N;c  
:32  
M ,.++W\  
//停止文件下载 9:0JWW^so  
public void siteStop() yO Cv-zm  
{ `X?l`H;#  
bStop = true; 2GRh8G&5  
for(int i=0;i<nStartPos.length;i++) EgIFi{q=0  
fileSplitterFetch.splitterStop(); xQs2)  
2%g)0[1  
}vBk,ED  
} .Ajs0 T2  
} ^T\JFzV  
//负责部分文件的抓取 Ikiv+Fq(  
**FileSplitterFetch.java k>#,1GbNZy  
*/ ai"Kd=R  
package NetFox; CFD& -tED&  
}x% ;y]S  
L+Q"z*W  
import java.io.*; +=I_3Wtth  
import java.net.*; u->UV:
u  
]D&$k P(  
* bmdY=#7  
public class FileSplitterFetch extends Thread { xy`aR< L  
w2y{3O"p=  
KfJF9!U*?  
String sURL; //File URL mMO:m8W  
long nStartPos; //File Snippet Start Position _QCspPT' c  
long nEndPos; //File Snippet End Position YBQO]3f  
int nThreadID; //Thread's ID P(fTlrb  
boolean bDownOver = false; //Downing is over E@QsuS2&  
boolean bStop = false; //Stop identical }8 A]  
FileAccessI fileAccessI = null; //File Access interface 88Yp0T<1  
%w7J
0p  
cT^,[3i:c  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Ty\&ARjb 8  
{ *EOIgQp  
this.sURL = sURL; }S'+Ytea  
this.nStartPos = nStart; p"ht|x  
this.nEndPos = nEnd; '7[{ISBXU  
nThreadID = id; w#k'RuOw5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 PIP2(-{ai  
} SiHZco I  
k<ds7k1m  
R^P~iAO  
public void run() hfP}+on%  
{ # 4`*`)%  
while(nStartPos < nEndPos && !bStop) V_Kpb*3
 
{ ,eD@)K_:  
"_jczr$*  
]qL#/ 
 
try{ cl{x5>.'#  
URL url = new URL(sURL); f5zxy!dhKS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H?ssV^k  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4\<[y]pv  
String sProperty = "bytes="+nStartPos+"-"; R{)Sv|+`  
httpConnection.setRequestProperty("RANGE",sProperty); YcE:KRy  
Utility.log(sProperty); c ;`  
7}(LO^,A  
> taT;[Oa  
InputStream input = httpConnection.getInputStream(); Z 2Fm=88  
//logResponseHead(httpConnection); %b'ic  
ohusL9D  
2H fP$.  
byte[] b = new byte[1024]; wG2lCv`
d  
int nRead; ON _uu]=  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) G\tTwX4  
{ 
]OZZPo  
nStartPos += fileAccessI.write(b,0,nRead); "?lirOD  
//if(nThreadID == 1) yi%A*q~MT  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #B:J7&@fn  
} K^?yD   
VcIsAK".4[  
:6PWU$z$7  
Utility.log("Thread " + nThreadID + " is over!"); XLp tJ4~v  
bDownOver = true;  f]q3E[?/  
//nPos = fileAccessI.write (b,0,nRead); *ghkw9/  
} )zI<C=])"  
catch(Exception e){e.printStackTrace ();} g*\u8fpRq  
} "t~I;%$[  
} h>$,97EU  
' ^gF  
hFuS>Hx  
//打印回应的头信息
ovzIJbf  
public void logResponseHead(HttpURLConnection con) P (jlWr$$  
{ UZMo(rG.]{  
for(int i=1;;i++) d6,%P6  
{ o\h[K<^>)  
String header=con.getHeaderFieldKey(i); WaF<qhu*  
if(header!=null) qdm5dQ (c  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); U*,8,C  
Utility.log(header+" : "+con.getHeaderField(header)); J]nb;4w  
else EnA) Rz  
break; C*ZgjFvB  
} &M=12>ah]  
} Ki}PO`s  
}qT @.  
Hkg^  
public void splitterStop() 6G7B&"&  
{ z,}1K!  
bStop = true; )y'`C@ijI  
} oP5G*AFUq  
}b2U o&][  
I>bLgt]u3  
} b*qkox;j  
jJ?M
T#v  
UtG@0(6C  
/* p9XHYf72  
**FileAccess.java !tv3.:eT  
*//文件访问(定位，写) KM< +9`  
package NetFox; !Zgb|e8<  
import java.io.*; Wt()DG|[  
>BMJA:j  
~ygiKsD6b  
public class FileAccessI implements Serializable{ jpZX5_o  
2V/A%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 =t<!W  
RandomAccessFile oSavedFile; +`u]LOAyP=  
long nPos; 6g29!F`y  
NS-u,5Jt  
_a8^AG  
public FileAccessI() throws IOException 8|{:N>7  
{ %MU<S9k  
this("",0); |;6FhDW+'  
} ,f0cy\.?  
7on$}=%  
$%`OJf*k  
public FileAccessI(String sName,long nPos) throws IOException LTS3[=AB  
{ f|WNPFQ$x  
oSavedFile = new RandomAccessFile(sName,"rw"); b.47KJzt  
this.nPos = nPos; #l2wF>0  
oSavedFile.seek(nPos); f,d @*E  
}  S&]+r<  
4?><x[l2{  
&qz&@!`  
public synchronized int write(byte[] b,int nStart,int nLen) #p&iH9c_  
{ 91E!4t
}I  
int n = -1; e%`gD*8  
try{ VvSD&r^qI  
oSavedFile.write(b,nStart,nLen); :RzcK>Gub=  
n = nLen; 5ap}(bO  
} Y~dRvt0_w  
catch(IOException e) )M#~/~^f+  
{ <d#9d.<  
e.printStackTrace (); (3 8.s:-  
} ?(*KQ#d  
@7 &rDZ  
/XEcA5C<  
return n; eg~$WB;1  
} vlw2dY@^  
/8q7pwV  
|iLeOztuE  
} i cQsA  
lEQ63)Z  
zu(/c  
/* Ec8Y}C,{7<  
**SiteInfoBean.java cInzwdh7  
*/ BqvOi~l  
package NetFox; )_NQ*m  
FfI$3:9  
xVuGeanCv  
public class SiteInfoBean { j +@1frp  
=
y,_FFoS  
_:+W0YS  
private String sSiteURL; //Site's URL D2E~c? V  
private String sFilePath; //Saved File's Path D`3}j   
private String sFileName; //Saved File's Name vpvPRwJ  
private int nSplitter; //Count of Splited Downloading File aN).G1  
L;Nz\sJ  
#?}k0Y  
public SiteInfoBean() @bmu4!"d  
{//nSplitter的缺省值为5 yb*SD!  
//default value of nSplitter is 5 ([_ls8  
this("","","",5); )+RGXVp  
} 2[[pd&MJZ  
bICi'`  
?%{bMqYJD{  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *1ekw#
'  
{ ZWG$MFEjl  
sSiteURL= sURL;  8yOzD  
sFilePath = sPath; :)g=AhBF  
sFileName = sName; {K*l,U  
this.nSplitter = nSpiltter; kR%CSLOVy  
N12K*P[!  
702&E(rx,  
} -1Lh="US  
i:&Y{iPQp  
ZUQ1\Iw  
public String getSSiteURL() N1\u~%AT"  
{ \x(J vDt  
return sSiteURL; d5T0#ue/e  
} |ZJ]`qmZ  
@8DBLn w  
4Mi*bN,  
public void setSSiteURL(String value) bo 
<.7  
{ l4O}>#  
sSiteURL = value; P{)&#HXUVb  
} 5f=e JDo=x  
FxKH?Rl  
wDem }uO  
public String getSFilePath() 2xni! *T+  
{ O#H`/z  
return sFilePath; YCeE?S1gk3  
} ZJP.-`U  

A_{QY&%m  
b?CmKiM%  
public void setSFilePath(String value) W+H27qsv  
{ yT-m9$^v  
sFilePath = value; r@e_cD] M  
} %HL@O]ftS  
TqKL(Qw E  
|w>"oaLN|Q  
public String getSFileName() W`eYd|+C  
{ 5ii`!y  
return sFileName; 67}y/C]
<  
} [\V]tpl!  
#|A @  
cI?dvfU?  
public void setSFileName(String value) S@Yb)">ZQ  
{ JXftQOn  
sFileName = value; ah"2^x  
} UQPd@IVu6  
aPcO9  
$$A{|4,aI  
public int getNSplitter() y`mEs
j  
{ *.Y!ZaK  
return nSplitter; |B)e!#  
} nDiD7:e7=  
Y_p  
M7eO
5  
public void setNSplitter(int nCount) g5V9fnb!d  
{ ;g^QHr  
nSplitter = nCount; ?.v!RdM+  
} S%Pk@n`z]  
} 6%U1%
;  
w{F8]N>0<  
cGsP0LkHC  
/* {h&*H[Z z  
**Utility.java {Ylj]  
*/ 9H1R0iWW  
package NetFox; \r324Bw>2  
q}ZZqYk  
"o<:[c9/  
public class Utility { 9V.)=*0hp  
k#JFDw\  
fR5 NiH  
public Utility() ?5$\8gZ  
{ @D9c  
.#5<ZAh/?  
M4nM%qRGQ  
} v_{`O'#j^  
'}P)iS2  
//线程睡眠 <H}"xp)j0  
public static void sleep(int nSecond) nl*{@R.q @  
{ #n{wK+lz  
try{ gSZNsiH  
Thread.sleep(nSecond); &^63*x;hE  
} e~'y%|D  
catch(Exception e) 2i |wQU5w  
{ ]v rpr%K  
e.printStackTrace (); p tv  
} 6:-qL}  
} @r+ErFI  
P6i4Dr  
//日志 KbMgat
I/  
public static void log(String sMsg) X[j4V<4O  
{ gBYL.^H^l  
System.err.println(sMsg); Hi,_qlc+  
} D<L]'  
]'~'V2Ey  
1^!=J<`K;  
public static void log(int sMsg) |]+m<Dpyr2  
{ Arir=q^2  
System.err.println(sMsg); 0Hff/~J  
} H",yVD  
} 73Mh65  
r$k *:A$%  
o$d;
Y2K  
/* y\5V(Q\  
**TestMethod.java S,G=MI"  
*/ +_:Ih,-   
package NetFox; 0m7J'gm{  
XLqS{r~?  
`q7I;w+g  
public class TestMethod { 9@QP?=\Y  
1_7x'5GdA  
TjD`<k  
public TestMethod() %j2YCV7  
{ ///xx/weblogic60b2_win.exe eK/[jxNO  
try{ U QXT&w  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Haj`mc!<D0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >bz}IcZP  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 4mNL;O  
fileFetch.start(); n3isLNvIp  
} ETSBd[  
catch(Exception e){e.printStackTrace ();} Vfg144FG'  
;lW0p8  
0u'2f`p*  
} TQE3/IL  
OjJlGElw  
(mt,:hX  
public static void main(String[] args) [g=yuVXNZZ  
{ }4cLU
.L8O  
new TestMethod(); U g]6i+rp  
} d";+8S  
} cFGP3Q4{  
点击下载更多相关资料