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http断点续传简单实现(java)

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/* ;pG5zRe  
**SiteFileFetch.java G5UNW<P2C  
*/ hmI> 7@&  
package NetFox; %V92q0XW  
import java.io.*; x) R4_ 3  
import java.net.*; )jMk ~;'r  
Zig3WiD&  
+XAM2uN5_.  
public class SiteFileFetch extends Thread { fwSI"cfM  
RA}Y$}^#'  
`rpmh7*WV  
SiteInfoBean siteInfoBean = null; //文件信息Bean v"dl6%D"  
long[] nStartPos; //开始位置 B \.0 5<  
long[] nEndPos; //结束位置 US&:UzI.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 B~%SB/eu  
long nFileLength; //文件长度 9w-;d=(Q  
boolean bFirst = true; //是否第一次取文件 MX7$f (Hy  
boolean bStop = false; //停止标志 VVc-Dx  
File tmpFile; //文件下载的临时信息 "Jg* /F  
DataOutputStream output; //输出到文件的输出流 d V3R)  
hne}G._b  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) \n-.gG  
public SiteFileFetch(SiteInfoBean bean) throws IOException 2lxA/.f  
{ Rc}#4pM8  
siteInfoBean = bean; 3# idXc  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Bb7Vf7>  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); gh% Q9Ni-  
if(tmpFile.exists ()) T8Ye+eP}  
{ q]v{o8:U  
bFirst = false; 2 '8I/>-  
read_nPos(); Sv[+~co<l  
} Obc wmL  
else u9{Z*w3L7  
{ 2Iq*7n:v0  
nStartPos = new long[bean.getNSplitter()]; =64Ju Wvo  
nEndPos = new long[bean.getNSplitter()]; avd`7eH2  
} '3B7F5uLx"  
Lp{/  
on f7V  
]"i^ VVw  
} #3YYE5cB  
S>R40T=e  
Zc=#Y  
public void run() Z`ZML+;~6  
{ >"D0vj  
//获得文件长度 V""3#Tw   
//分割文件 SKJ'6*6  
//实例FileSplitterFetch xsg55`  
//启动FileSplitterFetch线程 kj`h{Wc[)  
//等待子线程返回 T>m|C}yy  
try{ 1fV\84m^  
if(bFirst) -\g@s@5  
{ {QIdeB[  
nFileLength = getFileSize(); ]GzfU'fOn|  
if(nFileLength == -1) #wF6WxiG  
{ d4LH`@SUZ-  
System.err.println("File Length is not known!"); n&FRjq9y  
} -V:7j8  
else if(nFileLength == -2) 2MDY nMy  
{ `%=!_|  
System.err.println("File is not access!"); ];Y tw6A  
} 0~ cbB  
else HCaEETk5  
{ B`|H }KU  
for(int i=0;i<nStartPos.length;i++) *4g:V;L  
{ |k)Nf+(}W  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); k'K 1zUBj  
} }Q_ }c9?  
for(int i=0;i<nEndPos.length-1;i++) - S%8  
{ n ZzGak  
nEndPos = nStartPos[i+1]; S~{ }j vc  
} /?:q9Wy  
nEndPos[nEndPos.length-1] = nFileLength; sB<y(}u  
} 2bTM0-  
} 3NrWt2?  
i",oPz7  
( Uk\O`)m  
//启动子线程 ,h'omU7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; vVH*\&H\T  
for(int i=0;i<nStartPos.length;i++) 7@ mP;K0  
{ rv %^2h<&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]dnB ,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), I(+%`{Wv  
nStartPos,nEndPos,i); 3E;<aCG?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %F]:nk`  
fileSplitterFetch.start(); fCi1JH;  
} 0vcFX)]yW  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Wp//SV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \PK}4<x}  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |$c~Jq  
nEndPos = " + nFileLength); 6"La`}B(T8  
// fileSplitterFetch[nPos.length-1].start(); 4z,n:>oH  
+qmV|$rmM  
j.UO>1{7  
//等待子线程结束 ./}W3  
//int count = 0; _Zbgmasb  
//是否结束while循环 incUa;  
boolean breakWhile = false; ASaNac-3  
tN&X1  
;h7O_|<%  
while(!bStop) E^t}p[s  
{ 2$?j'i!  
write_nPos(); V e4@^Jy;  
Utility.sleep(500); +<n8O~h  
breakWhile = true; pv,I_"  
P>ZIP* Gr  
>Q|S#(c  
for(int i=0;i<nStartPos.length;i++) =%9j8wHX  
{ 0/zgjT|fe  
if(!fileSplitterFetch.bDownOver) 3 ~\S]  
{ `6y\.6j  
breakWhile = false; axdRV1+s  
break; xMo'SpVz:  
} ?4lDoP{  
} B0:/7Ld$Ml  
if(breakWhile) Ml9  
break; J.n-4J#@  
i UW.$1l  
G0v<`/|>}  
//count++; go5l<:9  
//if(count>4) BY??X=  
// siteStop(); HH'5kE0;d  
} |1Pi`^  
s F3M= uz  
w-?Cg8bq<  
System.err.println("文件下载结束!"); x-@6U  
} ZVz`-h B  
catch(Exception e){e.printStackTrace ();} f}+8m .g2  
} D2Dk7//82Y  
G:{\-R'  
Mt+gg F.  
//获得文件长度 \FjY;rqfKe  
public long getFileSize() ;.b^A  
{ (Kaunp5_`  
int nFileLength = -1; K"9V8x3Wg  
try{ y`-5/4  
URL url = new URL(siteInfoBean.getSSiteURL()); CFiO+p&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F[==vte|  
httpConnection.setRequestProperty("User-Agent","NetFox"); RTvzS]  
oHkjMqju  
qn~:B7f  
int responseCode=httpConnection.getResponseCode(); 5`[B:<E4  
if(responseCode>=400) w1 tg7^(@  
{ Q)}z$h55  
processErrorCode(responseCode); 5tl uS  
return -2; //-2 represent access is error HDT-f9%}<4  
} D^\2a;[AxA  
2V=bE-  
"3:TrM$|A  
String sHeader; ]$?\,`  
f)!7/+9>  
%R LGO&  
for(int i=1;;i++) f2RIOL,  
{ o:Q.XWa@MG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); jd?NN:7  
//Utility.log(in.readLine()); Af7&;8pM  
sHeader=httpConnection.getHeaderFieldKey(i); HU+zzTgI  
if(sHeader!=null) =CjN=FM  
{ nwPU{4#l<  
if(sHeader.equals("Content-Length")) UvM_~qo  
{ dLy-J1h\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {]dH+J7  
break; M[,G#GO  
} z+6%Ya&ls  
} DU1\K  
else Gu@Znh-D  
break; bdkxCt  
} 1PjqXgN5p  
} lF.yQ  
catch(IOException e){e.printStackTrace ();} !0 -[}vvU  
catch(Exception e){e.printStackTrace ();} '7TT4~F  
d3K-|  
Q!"W)tD  
Utility.log(nFileLength); ,7|Wf %X  
I 6Mr[#*  
UIi`bbJ  
return nFileLength; mL[Y{t#N  
} * IBCThj  
k>q}: J9V  
e&J_uG  
//保存下载信息(文件指针位置) qI#ow_lL#  
private void write_nPos() uV+.(sjH  
{ %t<ba[9F  
try{ UV8K$n<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ZMI vzQYI  
output.writeInt(nStartPos.length); N"rZK/@}  
for(int i=0;i<nStartPos.length;i++) dt|f4 XWF  
{ ~ 6-6aYhe  
// output.writeLong(nPos); h`b[c.%  
output.writeLong(fileSplitterFetch.nStartPos); *]RCfHo\=  
output.writeLong(fileSplitterFetch.nEndPos); a #4 'X*  
} Seb J}P1x  
output.close(); N_),'2  
} *oU-V#   
catch(IOException e){e.printStackTrace ();} Y]>Qu f.!  
catch(Exception e){e.printStackTrace ();} O)Mf/P'  
} "/}cV5=Z  
J{bNx8.&  
#Bgq]6G2  
//读取保存的下载信息(文件指针位置)  _F9O4Q4  
private void read_nPos() ,3E9H&@j  
{ zS+_6s  
try{ R x.]m0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {f<\`  
int nCount = input.readInt(); K JX@?1"  
nStartPos = new long[nCount]; e<[0H 8  
nEndPos = new long[nCount]; OGqsQ  
for(int i=0;i<nStartPos.length;i++) ,%%}d9  
{ fK{[=xMr@  
nStartPos = input.readLong(); JDy;Jb  
nEndPos = input.readLong(); I~.d/!>Z  
} b&1-tYV  
input.close(); <m3or  
} /)E'%/"A  
catch(IOException e){e.printStackTrace ();} du k:: |{F  
catch(Exception e){e.printStackTrace ();} KGoHn6jM  
} l`A4)8Y@  
Lb} cjI:  
,dO$R.h  
private void processErrorCode(int nErrorCode) )mbRG9P  
{ XU19+mW=P  
System.err.println("Error Code : " + nErrorCode); J%n{R60b  
} SS/t8Y4W  
SJdi*>  
r9d dVD  
//停止文件下载 t@O4 !mFH  
public void siteStop() 9M$N>[og  
{ f8'$Mn,  
bStop = true; $ZOKB9QccC  
for(int i=0;i<nStartPos.length;i++) (66DKG   
fileSplitterFetch.splitterStop(); 1KtPq,  
(ATCP#lF  
8 K/o/  
} mC}!;`$8p  
} >7^+ag~&  
//负责部分文件的抓取 r!7e:p JLO  
**FileSplitterFetch.java /NDuAjp[@  
*/ [Ifhh2  
package NetFox; 8xEOR!\!`k  
f; "6I  
4fCg{  
import java.io.*; -=A W. Z o  
import java.net.*; ;dh8|ujh  
\O7Vo<B&D  
"<J%@  
public class FileSplitterFetch extends Thread { 0u"/7OU  
 j{;RuNt  
6Q6l?!|W4  
String sURL; //File URL b88Zk*  
long nStartPos; //File Snippet Start Position |_P-  
long nEndPos; //File Snippet End Position .V\ M/q\Tv  
int nThreadID; //Thread's ID !dW77kLTg  
boolean bDownOver = false; //Downing is over qJ|n73yn  
boolean bStop = false; //Stop identical r4D 6I,  
FileAccessI fileAccessI = null; //File Access interface -MqWcB9&  
C,!}WB@VME  
E(&GZ QE  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #Rkldv'  
{ ) -C9W7?I  
this.sURL = sURL; XI*_ti  
this.nStartPos = nStart; C;jV{sb9c  
this.nEndPos = nEnd; Q#i^<WUpg  
nThreadID = id; _x.D< n=X  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 g}-Ch#  
} XT|!XC!|  
weOzs]uc  
&z\]A,=T c  
public void run() ;|hEXd?b  
{ -|DSfI#j  
while(nStartPos < nEndPos && !bStop) @M V%&y*z.  
{ PZdYkbj  
epH48)2  
yO6 _G q{  
try{ ^!*?vHx:  
URL url = new URL(sURL); Z-{!Z;T)z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (&6C,O~n^.  
httpConnection.setRequestProperty("User-Agent","NetFox"); /I' n]  
String sProperty = "bytes="+nStartPos+"-"; Y,bw:vX  
httpConnection.setRequestProperty("RANGE",sProperty); 9 o7d3ir)  
Utility.log(sProperty); #f'(8JjY  
Y"uFlHN&i  
Jb~-)n2  
InputStream input = httpConnection.getInputStream(); E00zf3Jgv'  
//logResponseHead(httpConnection); xmDX1sL**  
Ohm>^N;  
>q&Q4E0  
byte[] b = new byte[1024]; (Jw[}&+  
int nRead; !k&~|_$0@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [LonY49  
{ axY-Vj  
nStartPos += fileAccessI.write(b,0,nRead); ?[W(r$IaE  
//if(nThreadID == 1) _e.b #{=9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~EU[?  
} f$E66yG  
~PNO|]8j  
."Yub];H  
Utility.log("Thread " + nThreadID + " is over!"); xrT_ro8  
bDownOver = true; j}R4m h  
//nPos = fileAccessI.write (b,0,nRead); JXlFo3<  
} v`hv5wQ  
catch(Exception e){e.printStackTrace ();} \ooqa<_  
} Gc9^Z=  
} ~^.&nph  
6,xoxNoPP3  
0<L@f=i  
//打印回应的头信息 lO9{S=N  
public void logResponseHead(HttpURLConnection con) g[;iVX^1&  
{ \2<2&=h?  
for(int i=1;;i++) =3=KoH/'  
{ zJMKgw,i*  
String header=con.getHeaderFieldKey(i); KrkZv$u,  
if(header!=null) JXeqVKF  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); YF{K9M!  
Utility.log(header+" : "+con.getHeaderField(header)); 2t { Cpw  
else {K'SOh H4?  
break; =tcPYYD  
} Vk_*]wU  
} |Z;w k&  
$EJ*x$  
|?Q(4(D`*  
public void splitterStop() u,F d[[t  
{ nRQIrUNq  
bStop = true; xgR*j  
} 7o z(hO~  
Ut-6!kAm  
>B~jPU  
} *:.0c  
i,")U)b  
K23_1-mbe  
/* p8"(z@T  
**FileAccess.java "|DR"rr'j  
*//文件访问(定位,写) RQ,(?I*8\  
package NetFox; 8"LaP3U  
import java.io.*; )O- x1U  
%FFw!eVi  
dr6 dK  
public class FileAccessI implements Serializable{ o33{tUp'  
+lha^){  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 GIVs)~/Eq  
RandomAccessFile oSavedFile; 8 (^2  
long nPos; hqD;<:.  
lO $M6l  
0]oQ08  
public FileAccessI() throws IOException 3R#<9O  
{ W,{`)NWg  
this("",0); ,f?#i%EF&  
} Ql*/{#$  
z3*G(,  
=w A< F  
public FileAccessI(String sName,long nPos) throws IOException 0v7;Z xD  
{ 2K*-uT#$~  
oSavedFile = new RandomAccessFile(sName,"rw"); nv$  
this.nPos = nPos; )Elr8XLw  
oSavedFile.seek(nPos); 9jPb-I-   
} 2Bjp{)*  
'fA D Dh}  
a3c4#'c|D  
public synchronized int write(byte[] b,int nStart,int nLen) nnGA_7-t  
{ .`'SL''c  
int n = -1; Bhq(bV  
try{ !RcAJs'  
oSavedFile.write(b,nStart,nLen); T (2,iG8  
n = nLen; y]jh*KD[  
} Mz++SPG7  
catch(IOException e) ^Js9E  
{ 3Xh&l[.  
e.printStackTrace (); 8&C(0H]1  
} Jj6kZK  
tiE+x|Ju"  
$m=z87hX  
return n; \[oHt:$do  
} C]=E$^ |{  
<dYk|5AdLF  
;5|EpoM  
} &yA<R::o  
g?$9~/h :;  
CLkVe  
/* I(<G;ft<}  
**SiteInfoBean.java 4P~<_]yf  
*/ GC\/B0!  
package NetFox; kN$70N7I;  
QNJG}Upl  
D1Sl+NOV  
public class SiteInfoBean { f.P( {PN  
 yY| .  
H);'\]_'x  
private String sSiteURL; //Site's URL ]czy8n$+  
private String sFilePath; //Saved File's Path iE Oyc59  
private String sFileName; //Saved File's Name #] GM#.  
private int nSplitter; //Count of Splited Downloading File 5?fk;Q9+\  
2DC#PX)i  
#`fT%'T!  
public SiteInfoBean() >ATW/9r  
{//nSplitter的缺省值为5 eLYFd,?9  
//default value of nSplitter is 5 f!J^vDl  
this("","","",5); 8 KkpXaz  
} +-nQ, fOV  
&rd(q'Vi  
h[8y$.YsC  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) S }n;..{  
{ 2bJFlxEU  
sSiteURL= sURL; <di_2hN  
sFilePath = sPath; L&N"&\K2U  
sFileName = sName; f lB,_  
this.nSplitter = nSpiltter; \+u qP:Ty  
biG9?  
84[^#ke  
} r9Z/y*q  
u7=[~l&L  
'JMa2/7CG  
public String getSSiteURL() $a A.d^  
{ K(d!0S  
return sSiteURL; \$C 4H  
} SHk[X ]Uo  
+Y~+o-_  
W =zG  
public void setSSiteURL(String value) g=C<E2'i*  
{ E%^28}dN  
sSiteURL = value; yx2.7h3  
} }SV3PdE  
v/czW\z  
fI1;&{f   
public String getSFilePath() Du>HF;Fv  
{ 3I5WDuq  
return sFilePath; QRlzGRueR&  
} Ng"vBycy  
i-?zwVmn  
@;6}xO2  
public void setSFilePath(String value) cWc)sb  
{ $P(nh'\  
sFilePath = value; #FB>}:L{h*  
} [!&k?.*;<  
A,{D9-%  
xiF%\#N  
public String getSFileName() M: "ci;*$  
{ rl%Kn^JJ~  
return sFileName; 9>R|k$`  
} .e"Qv*[^  
(g m^o{  
X^Y9T`mQ}  
public void setSFileName(String value) pCmJY  
{ Fw9``{4w  
sFileName = value; GX)QIe~;qJ  
} :*@|"4  
*$(CiyF!  
@WHd(ka!  
public int getNSplitter() 5S]P#8  
{ `5-#M/J  
return nSplitter; FA9e(Ha   
} w.aFaR)04  
{0e{!v  
a{*'pY(R0$  
public void setNSplitter(int nCount) ({KAh?  
{ dCP Tpm  
nSplitter = nCount;  s7 o*|Xv  
} #`4^zU)  
} t4@g;U?o  
6\Vu#r  
MNqyEc""  
/* g u =fq\`  
**Utility.java \hW73a!  
*/ eH955[fVd4  
package NetFox; q "D L6 >j  
!>y}Xq{bm3  
+)JqEwCrq  
public class Utility { |u;BAb  
/ JeqoM"x  
W<91m*  
public Utility() &PuJV +y  
{ 3cO[t\/up  
+g6j =%  
)ek 5  
} \a2oM$PX  
GFdJFQio  
//线程睡眠 sK-|xU.  
public static void sleep(int nSecond) jL+}F/~r  
{ 'uAC oME@  
try{ hav?mnVJ  
Thread.sleep(nSecond); N#['fg'  
} ~_db<!a  
catch(Exception e) P .4b+9T x  
{ L*01l"5  
e.printStackTrace (); l;}7A,u  
} ,beR:60)  
} jfPJ5]Z  
bNjaCK<  
//日志 fC GDL6E  
public static void log(String sMsg) J5p!-N`NS  
{ ,35: Srf|  
System.err.println(sMsg); mUyv+n,  
} $v<hW A]>  
}t D!xI;  
&9dr+o-(~  
public static void log(int sMsg) y2"S\%7$h  
{ z!C4>,  
System.err.println(sMsg); G\>\VA  
} +.#S[G  
} x";.gjI |g  
sx<+ *Trl  
s.`%ZDl@Y  
/* *!]Epb  
**TestMethod.java 199hQxib:  
*/ _2X6bIE  
package NetFox; 8wpwJs&V  
renmz,dJ,  
Be>c)90bO_  
public class TestMethod { O<Sc.@~  
_HHJw""j  
VWA-?%r  
public TestMethod() 2PP-0 E  
{ ///xx/weblogic60b2_win.exe W[X!P)=w]  
try{ 5?{ >9j5  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _l!U[{l*d  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); g1 Wtu*K3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); yp2'KES>  
fileFetch.start(); TQ\wHJ  
} fFZ` rPb  
catch(Exception e){e.printStackTrace ();} MZMS ?}.2  
xK),:+G(  
S,Wl)\  
} b8{h[YJL2  
b!5tFX;J  
OwiWnS<  
public static void main(String[] args) gvc' $9%  
{ v>y8s&/  
new TestMethod(); *fvI.cKiGP  
} 3w^J"O/T  
} ^,Y~M_=  
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