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http断点续传简单实现(java)

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/* )h&*b9[B=  
**SiteFileFetch.java WokQ X"  
*/ QN'v]z  
package NetFox; ywl7bU-f  
import java.io.*; `B GU  
import java.net.*; n@e[5f9?x  
oKlOcws}  
z!0 }Kj  
public class SiteFileFetch extends Thread { Do\YPo_Mr  
OpT0V]k^"9  
XY*KWO  
SiteInfoBean siteInfoBean = null; //文件信息Bean V!3.MQM  
long[] nStartPos; //开始位置 =#Qm D=  
long[] nEndPos; //结束位置 rf:C B&u  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Jemb0Qv  
long nFileLength; //文件长度 Z^?YTykH  
boolean bFirst = true; //是否第一次取文件 >RL|W}tI4  
boolean bStop = false; //停止标志 /U1 jCLR'  
File tmpFile; //文件下载的临时信息 J]=2] oI2  
DataOutputStream output; //输出到文件的输出流 ,TdL-a5  
>8>}o4Q/X  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) \@eC^D2  
public SiteFileFetch(SiteInfoBean bean) throws IOException o@!!I w  
{ gvi]#|  
siteInfoBean = bean; tG"lI/  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 50Kv4a"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); lDd8dT-Q.  
if(tmpFile.exists ()) (!iGQj(m  
{ rQ!X  
bFirst = false; H5 'Le{  
read_nPos(); UN"U#Si)  
} IY=CTFQ8lm  
else ~l@-gAyw  
{  @U;U0  
nStartPos = new long[bean.getNSplitter()]; ~?x `f +  
nEndPos = new long[bean.getNSplitter()]; RE?j)$y?`  
} 4t<l9Ilp  
AWqc?K@   
HsQ\xQ"k!  
d mj T$a|  
} s/=.a2\  
^HM9'*&KJ  
6d% |yl  
public void run() ~5xs$ub  
{ |x ~<Dc>0*  
//获得文件长度 i( l'f#  
//分割文件 Jjgy;*hM  
//实例FileSplitterFetch x(UOt;  
//启动FileSplitterFetch线程 J91O$szA  
//等待子线程返回 F]"Hs>  
try{ lbg^ 2|o~~  
if(bFirst) nP+]WUnY  
{ zs_^m1t1s  
nFileLength = getFileSize(); Z%uDz3I\Q"  
if(nFileLength == -1) ji(Y?vhQt  
{ w&E*{{otJ  
System.err.println("File Length is not known!"); dAZh# i[  
}  XM" {"  
else if(nFileLength == -2) e=<%{M&  
{ >dTJ  
System.err.println("File is not access!"); ,cqZb0VP{t  
} 6x _tX  
else [Tq\K ^!^  
{ J% t[{  
for(int i=0;i<nStartPos.length;i++) , 7kS#`P  
{ \;%DDw  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1D pRm(  
} t'F_1P^*/  
for(int i=0;i<nEndPos.length-1;i++) R>YDn|cWI  
{ .-(s`2  
nEndPos = nStartPos[i+1]; .eSMI!Y=  
} nU6WT|  
nEndPos[nEndPos.length-1] = nFileLength; <X{hW^??)  
} f/VrenZ_  
} NIQX?|;b{  
YyZ>w2_MTi  
h"-}BjL  
//启动子线程 BW61WH?  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; tUp'cG  
for(int i=0;i<nStartPos.length;i++) 3?"JFfYU,'  
{ WRWcB  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NSPa3NE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;~>E^0M  
nStartPos,nEndPos,i); )= ,Lfj8x  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Yom,{;Bv  
fileSplitterFetch.start(); =:!$'q:  
} N]k(8K  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z z4.gkU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); xTJ-v/t3<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", m#(tBfH[  
nEndPos = " + nFileLength); i~k9s  
// fileSplitterFetch[nPos.length-1].start(); R&Oqm hT!  
\*_@`1m  
_v+mjDdQ  
//等待子线程结束 .skR4f,h  
//int count = 0; -C7IUat<  
//是否结束while循环 t!g9,xG<X  
boolean breakWhile = false; Px>Gc:!>  
bwm?\l.A  
6#JdQ[IP6  
while(!bStop) G|p3NhLgO=  
{ ~4Gs\U:!Q  
write_nPos(); kUdl2["MZ  
Utility.sleep(500); A!K/92[#@  
breakWhile = true; Eoj 2l&\  
'Gw;@[  
CulU?-[i  
for(int i=0;i<nStartPos.length;i++) \rw/d5.  
{ iE|qU_2Y  
if(!fileSplitterFetch.bDownOver) S!<1C Fh  
{ 8"#Ix1#  
breakWhile = false; b$24${*'  
break; KXgC]IO~  
} &tULSp@J  
} q]\bJV^/U  
if(breakWhile) 2g6G\F  
break; F=29"1 ._  
*hT1_  
u7e g:0Y  
//count++; e*Gm()Vu,  
//if(count>4) bHr2LhQCN  
// siteStop(); t ._PS3  
} R7L:U+*V"  
btfjmR<Tp  
ohdWEU,  
System.err.println("文件下载结束!"); K$H>/*&'~  
} `FP)-^A8  
catch(Exception e){e.printStackTrace ();} Dm=Em-ST6  
} G n_AXN  
nC3U%*l  
uh~/ybR  
//获得文件长度 P~)ndaQ  
public long getFileSize() <&?gpRK   
{ .Z!!x  
int nFileLength = -1; RsYn6ozb  
try{ %G<!&E!0h  
URL url = new URL(siteInfoBean.getSSiteURL()); QL>G-Rp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G36}4  
httpConnection.setRequestProperty("User-Agent","NetFox"); U#O 6l-xe]  
(;V=A4F-D  
w>IYrSaa>  
int responseCode=httpConnection.getResponseCode(); FT1h\K|a  
if(responseCode>=400) b[^=GF>e  
{ KUdpOMYX  
processErrorCode(responseCode); >+[uV ^2[  
return -2; //-2 represent access is error ZD9UE3-  
} ~h~K"GbC?  
Fr}e-a  
Y2 &N#~l*  
String sHeader; T4 dYC'z  
S^@I4Z  
mGjxc}  
for(int i=1;;i++) N#;k;Z'iL  
{ r@&d88U:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); y@;4F n/  
//Utility.log(in.readLine()); oh '\,zpL  
sHeader=httpConnection.getHeaderFieldKey(i); LF'M!C9|  
if(sHeader!=null) 1Ftl1uf  
{ JD^&d~n_  
if(sHeader.equals("Content-Length")) :<OInKE>Cx  
{ y(K?mtQ   
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !@ml^&hP  
break; aW8Bx\q  
} ?-g=Rfpag  
} y)W.xR  
else Ge+&C RhyX  
break; W^2Q"c#7F  
} 4]N`pD5  
} !8"516!d|p  
catch(IOException e){e.printStackTrace ();}  H}NW?  
catch(Exception e){e.printStackTrace ();} C7(kV{h$d  
Jy'ge4]3  
H!Y`?Rc  
Utility.log(nFileLength); eH2.,wY1  
%d+:0.+`n  
_/"m0/,  
return nFileLength; ?-,v0#  
} V8>%$O sw  
H1uNlPT  
_wWh7'u~G  
//保存下载信息(文件指针位置) b;&J2:`  
private void write_nPos() ]@op  
{ (9h{7<wD`  
try{ fW Vd[zuD4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); D-.XSIEMu  
output.writeInt(nStartPos.length); Ox"4 y  
for(int i=0;i<nStartPos.length;i++) ?aInn:FE  
{ k/vE|  
// output.writeLong(nPos); Q)}sX6TB  
output.writeLong(fileSplitterFetch.nStartPos); hq.z:D  
output.writeLong(fileSplitterFetch.nEndPos); cLH|;  
} x.r~e)x=  
output.close(); t;9f7~  
} [8/E ;h  
catch(IOException e){e.printStackTrace ();} 3LZ0EYVL  
catch(Exception e){e.printStackTrace ();} ^f{+p*i}:  
} tvptaw A.  
 Hw34wQX  
s> JmLtT  
//读取保存的下载信息(文件指针位置) vJ$#m_aa  
private void read_nPos() `j088<?j  
{ yzhr"5_  
try{ o}p6qB=;1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); YJ]]6 K+  
int nCount = input.readInt(); !!ZNemXct$  
nStartPos = new long[nCount]; KIdlndGs  
nEndPos = new long[nCount]; /<Cl\q2 A  
for(int i=0;i<nStartPos.length;i++)  tFvti5  
{ :8U=L'4  
nStartPos = input.readLong(); hq/k}Y  
nEndPos = input.readLong(); 6hSj)  
} SX|b0S,  
input.close(); $kJvPwRO  
} GLA,,i'i9  
catch(IOException e){e.printStackTrace ();} @R>4b  
catch(Exception e){e.printStackTrace ();} +nRO<  
} -p`hevRr  
KcVCA    
Wx"bW ICc  
private void processErrorCode(int nErrorCode) b/oJ[Vf  
{ pYJv|`+  
System.err.println("Error Code : " + nErrorCode); &C3J6uCm+  
} #rzq9}9tB  
wH[@#UP3l  
v\:>} <gc  
//停止文件下载 >Vc_.dR)E  
public void siteStop() Py6c=&*  
{ Zi/l.=9n  
bStop = true; $O&P@8:Z  
for(int i=0;i<nStartPos.length;i++) o[^%0uVF  
fileSplitterFetch.splitterStop(); 6}2vn5 E//  
,U2 /J  
J0w[vrs&]  
} lyKV^7}  
} Mw7 ~:O`  
//负责部分文件的抓取 ,;C92XY  
**FileSplitterFetch.java a3 wUB  
*/ E0}`+x  
package NetFox; [i.2lt#]  
 N\DEY]  
GAbX.9[V  
import java.io.*; v')Fq[H  
import java.net.*; }4Lv-9s,  
$k*E^~qT  
[g/Hf(&  
public class FileSplitterFetch extends Thread { !1!;}uzt  
\uQB%yMoz  
A[v]^pv'  
String sURL; //File URL t/HMJ  
long nStartPos; //File Snippet Start Position Uf{cUY,j_  
long nEndPos; //File Snippet End Position ]7v-qd  
int nThreadID; //Thread's ID _h7!  
boolean bDownOver = false; //Downing is over +Tde#T&[  
boolean bStop = false; //Stop identical ? )-*&1cv  
FileAccessI fileAccessI = null; //File Access interface eh nN  
Afo(! v  
|h(!CFR  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException gA~BhDS  
{ (w?@qs!  
this.sURL = sURL; b&~rZ  
this.nStartPos = nStart; 83:m 7;  
this.nEndPos = nEnd; nX<!n\J T  
nThreadID = id; nK1XJp  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Fkj\U^G  
} +ww paR`  
9*RfOdnNe  
=(K;z9OR  
public void run() m C_v!nL.  
{ tTe\#o`  
while(nStartPos < nEndPos && !bStop) |HI =ykfI  
{ EbuOPa  
q .nsGbl  
[3;J,P=&  
try{ pNr3u  
URL url = new URL(sURL); I5>HB;Q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w<&Nn`V  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]K?z|&N|HK  
String sProperty = "bytes="+nStartPos+"-"; 4vPQuk!  
httpConnection.setRequestProperty("RANGE",sProperty); EU TTeFp  
Utility.log(sProperty); beEdH>  
`,tv&siSA  
/!oi`8D  
InputStream input = httpConnection.getInputStream(); /A[AHJ<[?  
//logResponseHead(httpConnection); J %jf uj  
AnG/A!G  
AF ZHS\  
byte[] b = new byte[1024]; [Nr6 qxWg  
int nRead;  .VuZ=  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) (A\qZtnyl  
{ ]IXKoJUf  
nStartPos += fileAccessI.write(b,0,nRead); PDvqA{  
//if(nThreadID == 1) 1wuLw Ad  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <a2t"rc  
} D$;mur'  
1[D~Ee p  
h&L+Qx  
Utility.log("Thread " + nThreadID + " is over!"); oat*ORL  
bDownOver = true; 'g^;_=^G  
//nPos = fileAccessI.write (b,0,nRead); 0wB ?U~  
} BQ,]]}e43z  
catch(Exception e){e.printStackTrace ();} p82&X+v/p  
} a"EP`  
} 8#2PJHl;  
L{N9h1]  
KR%p*Nh+C  
//打印回应的头信息 HviL4iO  
public void logResponseHead(HttpURLConnection con) >&RpfE[  
{ \gki!!HQ  
for(int i=1;;i++) Nj*J~&6G  
{ U: ~O^  
String header=con.getHeaderFieldKey(i); Xgn^)+V:  
if(header!=null) 5@P2Z]Q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "X's>uM  
Utility.log(header+" : "+con.getHeaderField(header)); >e($T!}Z  
else :g}WN  
break; Ti#2D3  
} ,E$^i~OO  
} X_Is#&6;  
}I}RqD:`  
x,@cU}D  
public void splitterStop() ? Sj,HLo@U  
{ [m?eSq6e2b  
bStop = true; {[61LQ6V9  
} UMpC2)5  
)i0\U  
Ra&HzK?  
} WM*[+8h  
|0ACapp!  
c>:}~.~T  
/* o>311(:  
**FileAccess.java L0qo/6|C  
*//文件访问(定位,写) Z9cch- u~  
package NetFox; @ T'!;)  
import java.io.*; Dh BUMDoB  
.8uJ%'$)  
`fu(  
public class FileAccessI implements Serializable{ BOrfKtG\  
~zi6wu(3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 R#`hT  
RandomAccessFile oSavedFile; q%bNT  
long nPos; L:IaJ?+?  
fJn;|'H!  
l6:k|hrm;  
public FileAccessI() throws IOException D!Owm&We  
{ Ry,_ %j3  
this("",0); aU<0<Dx  
} v2gK(&?  
$fPf/yQmC  
ba1zu|@w  
public FileAccessI(String sName,long nPos) throws IOException ah>;wW!6/  
{ ,u-i9`B  
oSavedFile = new RandomAccessFile(sName,"rw"); fCJ:QK!  
this.nPos = nPos; s+2\uMwf*  
oSavedFile.seek(nPos); J1cD)nM<A  
} XG@_Lcv*  
]QJLES  
L}P<iB   
public synchronized int write(byte[] b,int nStart,int nLen) |F-_YR  
{ [a53H$`\5  
int n = -1; ZtlF]k:MV  
try{ e]!C Aj7uS  
oSavedFile.write(b,nStart,nLen); P+:FiVj@~  
n = nLen; &1ASWllD  
} kn 5q1^  
catch(IOException e) T#DJQ"$  
{ mLd=+&M  
e.printStackTrace (); UtIwrR[  
} ;gc Q9L  
ib/B!?/  
'vgw>\X(  
return n; ?y>xC|kt  
} eG72=l)Mz  
yeFt0\=H  
$u|p(E:*  
} /FJAI  
KXL]Qw FN  
#*BcO-N  
/* QKL5! L9`  
**SiteInfoBean.java 30-XFl  
*/ #.$p7]  
package NetFox; rtS(iD@B"  
YT+fOndjaF  
UO5^4  
public class SiteInfoBean { ,}2M'DSWa  
x|<rt96 6A  
>:4}OylhM  
private String sSiteURL; //Site's URL tQ< ou,   
private String sFilePath; //Saved File's Path T)6p,l  
private String sFileName; //Saved File's Name BEPeK  
private int nSplitter; //Count of Splited Downloading File ;Z-xum{  
\m1r(*Ar  
lsCD%P  
public SiteInfoBean() wA|m/SZx  
{//nSplitter的缺省值为5 *>n<7T0  
//default value of nSplitter is 5 ~P 1(%FZ  
this("","","",5); K||9m+  
} ^&am]W;T  
^*#5iT8/  
tj;<Z.  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) NC)Iu  
{ TFb9gOTJ  
sSiteURL= sURL; +yiGZV/X  
sFilePath = sPath; rBye%rQRq  
sFileName = sName; 1/c7((]7(,  
this.nSplitter = nSpiltter; mg[=~&J^  
<_=a1x  
P#\L6EO.  
} -^=gQ7f9  
r"x|]nvg^  
}o0R`15dA  
public String getSSiteURL() i64a]=  
{ "1$OPt5  
return sSiteURL; {(U?)4@  
} 8`Q8Mct$<  
q]T{g*lT  
}i!hzkK#  
public void setSSiteURL(String value) F&<si:}KB  
{ /B.\6  
sSiteURL = value; wqx@/--E(  
} 8G; t[9  
?DzKqsS'  
x* *]@v"g  
public String getSFilePath() S75wtz)e  
{ hn{]Q@(I  
return sFilePath; >0~|iRySi  
} m{9m.~d  
\< <u  
1q0DOf]!T  
public void setSFilePath(String value) RJYuyB  
{ fdc ?`4  
sFilePath = value; \-a^8{.^E  
} -"YQo  
|'9%vtbM  
TUHC[#Vb?  
public String getSFileName() f]L`^WU  
{ /5 B{szf  
return sFileName; 9G_bM(q'^2  
} *&9_+F8ly  
<e-9We."  
0+jR,5 |  
public void setSFileName(String value) :CH "cbo  
{ yoGe^gar  
sFileName = value; ~UA-GWb  
} X1?7}VO  
=kH7   
DygMavA.  
public int getNSplitter() [g`9C!P-G  
{ e` Z;}& ,  
return nSplitter; .I$ Q3%s  
} )XV|D  
P +ONQN|  
j|gQe .,1  
public void setNSplitter(int nCount) 28 [hp[<  
{ VHwb 7f]gq  
nSplitter = nCount; B38_1X7  
} EtvZk9d6h*  
} vM!lL6T:  
o%XAw   
kW0|\  
/* DP ,owk  
**Utility.java ,*$L_itL  
*/ `WQz_}TqB  
package NetFox; /yPFts_q  
:@x24wN/  
N7Vv"o  
public class Utility { l5_RG,O0A  
0h/gqlTK1  
T;K@3]FbX  
public Utility() E/2kX3}  
{ O32p8AxEz  
F^.w:ad9<  
@{ *z1{  
} o7 ^t- L  
"| cNY_$&s  
//线程睡眠 rOQ@(aUAZ  
public static void sleep(int nSecond) )'3(=F$+l  
{ ATl.Qku@  
try{ 9Jd{HI=  
Thread.sleep(nSecond); BOClMeA4  
} dZcRLLR  
catch(Exception e) RnC96"";R.  
{ s ;EwAd(  
e.printStackTrace (); /.B7y(  
} 0t[|3A~Q  
} 2z+Vt_%  
kDI(Y=Fg  
//日志 X3&-kU  
public static void log(String sMsg) t`=TonLb8  
{ PDQC^2Z  
System.err.println(sMsg); T n.Cj5  
} ,{==f7|w  
c-3-,pyM_T  
Ks'msSMC  
public static void log(int sMsg) reseu*5  
{ h&@ A'om~  
System.err.println(sMsg); ZGO% lkZ.  
} 0?OTa<c  
} $I*ye+a*{q  
.<&o,D  
aVkgE>  
/* NwPGH= V  
**TestMethod.java j#L"fW^GM  
*/ s |B  
package NetFox; 4M4Y2f BH  
DP{kin"4I  
K8`Jl=}z%&  
public class TestMethod { JL gk?  
!SRElb A;i  
)y>o;^5'  
public TestMethod() qQK0s*^W  
{ ///xx/weblogic60b2_win.exe =nPIGI72VO  
try{ Mh [TZfV  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); IIrh|>d_7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?pSb,kN}'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 1./ uJB/  
fileFetch.start(); (ndXz  
} u'Ja9m1  
catch(Exception e){e.printStackTrace ();} 3h t>eaHi  
n^vL9n_N  
fLkZ'~e!  
} N zrHWVD  
LpRl!\FY$  
#9{N[t  
public static void main(String[] args) (=#[om( A  
{ u\-WArntc  
new TestMethod(); $Ro]]NUz|  
} Mn$w_Z?  
} I ACpUB  
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