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http断点续传简单实现(java)

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/* :C_/K(Rkl  
**SiteFileFetch.java iI<c  
*/ X_2N9$},  
package NetFox; kD#n/R Bgf  
import java.io.*; naaKAZ!S  
import java.net.*; NIQ}A-b  
MZz9R*_VS  
G^ GIHdo  
public class SiteFileFetch extends Thread { %f'pAc|#  
\na$Sb+  
r^ Dm|^f#  
SiteInfoBean siteInfoBean = null; //文件信息Bean 'mZ v5?  
long[] nStartPos; //开始位置 Sl8+A+  
long[] nEndPos; //结束位置 Dd1k?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Yd3lL:M  
long nFileLength; //文件长度 3?B1oIHQ  
boolean bFirst = true; //是否第一次取文件 [k$GUU,jY  
boolean bStop = false; //停止标志 L~5f*LE$1  
File tmpFile; //文件下载的临时信息 <Z-Pc?F&(k  
DataOutputStream output; //输出到文件的输出流 Gt*<Awn8  
'aEK{#en  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) wK2$hsque  
public SiteFileFetch(SiteInfoBean bean) throws IOException {LiJ=Ebt  
{ V<9L-7X 8  
siteInfoBean = bean; ~S('\h)1  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); eI ( S)q  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ]izHn;+  
if(tmpFile.exists ()) 1T#-1n%[k(  
{ 'yCVB&`b  
bFirst = false; p1'q{E+o*  
read_nPos(); G T~rr*X  
} RP2$(%  
else Y!j/,FU  
{ +}m`$B}mJ  
nStartPos = new long[bean.getNSplitter()]; <*J"6x  
nEndPos = new long[bean.getNSplitter()]; zmQQ/ 7K  
} oL~1M=r  
nN&dtjoF  
#om Gj&  
n}Z%-w$K#  
} dXDyY  
9 5!xJdq  
RK@K>)"f  
public void run() EJ {vJZO  
{ (A2ga):Pk  
//获得文件长度 nrE.0Ue1  
//分割文件 ^N7cXK*  
//实例FileSplitterFetch Pm P&Qje7  
//启动FileSplitterFetch线程 /mJb$5=1  
//等待子线程返回 *As"U99(  
try{ V+y|C[A F  
if(bFirst) 4%}iKoT   
{ +mG"m hF  
nFileLength = getFileSize(); R[j'<gd.  
if(nFileLength == -1) A]iT uu5p  
{ ug}u>vQ>  
System.err.println("File Length is not known!"); ?ZTA3mV?+  
} q !}~c  
else if(nFileLength == -2) s-6$C  
{ xX%{i0E  
System.err.println("File is not access!"); Jm=3 %H  
} k_1;YO BF  
else 'xuxMav6m  
{ V,zFHXO  
for(int i=0;i<nStartPos.length;i++) b!-=L&V  
{ LTx,oa:ma  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); l^tRy_T:-  
} yEB#*}K?  
for(int i=0;i<nEndPos.length-1;i++) \1?'JdN  
{ 8fQfu'LyjY  
nEndPos = nStartPos[i+1]; c;KMox/  
} tw 3zw`o:  
nEndPos[nEndPos.length-1] = nFileLength; &n?RKcH}d  
} q(EN]W],  
} yz>S($u  
kg(}%Ih  
 ^0{t  
//启动子线程 |d\1xTBLp  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 5l,Lp'k  
for(int i=0;i<nStartPos.length;i++) Q4Wz5n1yp7  
{ ( ?e Et&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f\hQ>MLzt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), oG hMO  
nStartPos,nEndPos,i); B)d 4]]4\\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); B}zBbB  
fileSplitterFetch.start(); |A|K);  
} giIPK&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y9T 5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `S3)uV]I  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", FBrh!vQ<  
nEndPos = " + nFileLength); =yRv *C  
// fileSplitterFetch[nPos.length-1].start(); ]l=CiG4!M  
+s7w@  
lkp$rJ#6  
//等待子线程结束 ?hrz@k|  
//int count = 0; RP 6<#tq,  
//是否结束while循环 c[3x>f0  
boolean breakWhile = false; $E8}||d  
re4z>O*  
(B*,|D[J@i  
while(!bStop) IW}Wt{'m  
{ 2h@&yW2j  
write_nPos(); ,l,q;]C%  
Utility.sleep(500); iTT7<x  
breakWhile = true; =|fB":vk  
SpIiMu(  
<jaQ 0S{|  
for(int i=0;i<nStartPos.length;i++) xMpgXB!'  
{ l%u8Lq  
if(!fileSplitterFetch.bDownOver) mtLiS3Nk8  
{ V~-tp^  
breakWhile = false; R%9,.g <  
break; }dU!PZ9N)  
} 4,=;:#n,J  
} 6 !Mm")  
if(breakWhile) k O.iJcZg  
break; tQ.H/;  
fCX8s(|F  
gTLBR  
//count++; c:B` <  
//if(count>4) )g^O'e=m  
// siteStop(); 5CfD/}{:#I  
} p%#'`*<a_  
g">^#^hBE  
[{>1wJ Pdj  
System.err.println("文件下载结束!"); rzvKvGd#N  
} r&F 6ZCw  
catch(Exception e){e.printStackTrace ();} `Hu2a]e9  
} Vkf{dHjW  
?1LRR ;-x  
(bB"6 #TI  
//获得文件长度 9pWSvalw9  
public long getFileSize() B)P]C5KRD  
{ {([`[7B>a<  
int nFileLength = -1; >4+KEK  
try{ <29K! [  
URL url = new URL(siteInfoBean.getSSiteURL()); wL>;_KdU`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5-&"nn2*}1  
httpConnection.setRequestProperty("User-Agent","NetFox"); P%!=Rj^2m  
Otf{)f  
{/,AMJ<:G]  
int responseCode=httpConnection.getResponseCode(); 1FT3d  
if(responseCode>=400) $++O@C5  
{ p|BoEITL  
processErrorCode(responseCode); Tv 5J  
return -2; //-2 represent access is error bUYjmb2g)  
} V"}Jsr  
Ua=r24fy  
m4'jTC$  
String sHeader; O,NVhU7,  
(I35i!F+tY  
YPCitGBl  
for(int i=1;;i++) B`jq"[w]-  
{ 3Y&4yIx  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); GY^;$?  
//Utility.log(in.readLine()); &rl;+QS  
sHeader=httpConnection.getHeaderFieldKey(i); [%~yY&  
if(sHeader!=null) lJT"aXt'M  
{ $~%h4  
if(sHeader.equals("Content-Length")) j"VDqDDz  
{ lWT`y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); d9%P[(yM^  
break; :AI%{EV-L  
} ( 5uSqw&U  
} /{ W6]6^  
else ;BKU _}k=  
break; )8SWU)/  
} ,(f W0d#  
} j0(jXAc;UB  
catch(IOException e){e.printStackTrace ();} JO90TP $  
catch(Exception e){e.printStackTrace ();} WJ[>p ELT,  
=);@<Jp  
)OVa7[-T  
Utility.log(nFileLength); nr,Z0  
1X9s\JKQ  
jp^Sw|  
return nFileLength; ]]3rSXs2}J  
} (mKH,r  
 X>P|-n#  
yf4L0.  
//保存下载信息(文件指针位置) U4yl{?  
private void write_nPos() ='m%Iq7X  
{ ()F {kM8  
try{ 5NH4C  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ItZYOt|Hn  
output.writeInt(nStartPos.length); x}V&v?1{5  
for(int i=0;i<nStartPos.length;i++) =;b3i1'U  
{ +%u3% }  
// output.writeLong(nPos); e?*Teb ?R  
output.writeLong(fileSplitterFetch.nStartPos); cUdS{K&K  
output.writeLong(fileSplitterFetch.nEndPos); %\n|2*r  
} 4RYH^9;>K  
output.close(); r\Yh'cRW{  
} cO 5zg<wF  
catch(IOException e){e.printStackTrace ();} m8e()8lZ3  
catch(Exception e){e.printStackTrace ();} Xtz:^tg  
} 5,g +OY=\  
tMp! MQ  
n|XheG7:  
//读取保存的下载信息(文件指针位置) U V*Ruy-  
private void read_nPos() -B&(& R  
{ %Ta"H3ZW  
try{ ~(kqq#=s  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); w`V6vYd@  
int nCount = input.readInt(); 't0M+_J  
nStartPos = new long[nCount]; "J=Cy@SSa  
nEndPos = new long[nCount]; 1EEcNtpub]  
for(int i=0;i<nStartPos.length;i++) hh&$xlO)(v  
{ pt,L  
nStartPos = input.readLong(); aekke//y  
nEndPos = input.readLong(); |?8nO.C~V  
} J ou*e%  
input.close(); l:uQ#Z)  
} +>K&zS  
catch(IOException e){e.printStackTrace ();} Qz#By V:  
catch(Exception e){e.printStackTrace ();} VJ&<6  
} 'wG1un;t  
!*NDsC9  
|D"L!+J-$  
private void processErrorCode(int nErrorCode) ipbhjK$  
{ Y%;X7VxU*  
System.err.println("Error Code : " + nErrorCode); FpA t  
} >(S)aug$1  
%oTBh*K'o  
P=jsOuW  
//停止文件下载 'yq?xlIj  
public void siteStop() 1BU97!  
{ $5)#L$!,]  
bStop = true; YZ4`b-  
for(int i=0;i<nStartPos.length;i++) n9}BT^4 v  
fileSplitterFetch.splitterStop(); WcNQF!f  
Babzrt-  
8Sj<,+XFq  
} UNa "\  
} ":M]3.  
//负责部分文件的抓取 tjb$MW$('  
**FileSplitterFetch.java dR1IndZl  
*/ u@#%SX  
package NetFox; ,#3Aaw   
S3Gr}N  
{/,(F^T>2  
import java.io.*; $Z#~wsw  
import java.net.*; 'WP~-}(  
nLz;L r!  
!~~KM?g  
public class FileSplitterFetch extends Thread { !6=;dX  
Jj>Rzj!m  
-6kX?sNl)X  
String sURL; //File URL D!,5j_,j%  
long nStartPos; //File Snippet Start Position ~Dq-q6-@t  
long nEndPos; //File Snippet End Position 1Ys=KA-!_x  
int nThreadID; //Thread's ID M*gvYo  
boolean bDownOver = false; //Downing is over 04Zdg:[3-!  
boolean bStop = false; //Stop identical fGlvum  
FileAccessI fileAccessI = null; //File Access interface ="& GU%$  
~ O#\$u  
%QEBY>|lI  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException p;}`PW  
{ 6LCtWX  
this.sURL = sURL; E b[;nk?  
this.nStartPos = nStart; PljPhAce  
this.nEndPos = nEnd; :a;F3NJ  
nThreadID = id; ?;~E*kzO&  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 k}fC58q  
} JT0j2_*Rr  
5WHz_'c  
7gf(5p5ZV  
public void run() :k1?I'q%  
{ _F6<ba}o3  
while(nStartPos < nEndPos && !bStop) Gkuqe3  
{ '=E;^'Rl  
V*\hGNV  
/ZV2f3;t  
try{ U| Fqna  
URL url = new URL(sURL); )mm0PJF~q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $ uTrM8  
httpConnection.setRequestProperty("User-Agent","NetFox"); (2H GV+Dg  
String sProperty = "bytes="+nStartPos+"-"; 6}E>B{Y  
httpConnection.setRequestProperty("RANGE",sProperty); 1(BLdP3&  
Utility.log(sProperty); #G]IEO$M6  
;99oJD,  
Qpmq@iL  
InputStream input = httpConnection.getInputStream(); Ak@!F6~  
//logResponseHead(httpConnection); Hj{.{V  
b:F;6X0~Hl  
#[=kQ&  
byte[] b = new byte[1024]; &B(z**+9  
int nRead; n5d8^c!2  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) gd0)s1{9  
{ <K^a2 D  
nStartPos += fileAccessI.write(b,0,nRead); PSq?8.  
//if(nThreadID == 1) 2QaE&8vW  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w~6UOA8}  
} s;TB(M~i[  
B.G6vx4yp  
5m~9Vl-&  
Utility.log("Thread " + nThreadID + " is over!"); \bdKLcKI,  
bDownOver = true; {4 Yx h8  
//nPos = fileAccessI.write (b,0,nRead); 7e+C5W*9b  
} rlKR <4H  
catch(Exception e){e.printStackTrace ();} BZW03e8|  
} N[W#wYbH  
} s*Qyd{"z  
XF(D%ygeC  
4O-LLH  
//打印回应的头信息 b+qd' ,.Z  
public void logResponseHead(HttpURLConnection con) $}su 'EIo  
{ o.!o4&W H  
for(int i=1;;i++) tR>zBh_b  
{ }BC%(ZH6  
String header=con.getHeaderFieldKey(i); ExtC\(X;  
if(header!=null) >)M1X?HI5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); zF`a:dD$d  
Utility.log(header+" : "+con.getHeaderField(header)); Kb+SssF  
else ~o_JZ:  
break; .*` ^dt  
} "e"#k}z9  
} 5c::U=  
l[i4\ CT  
F62 uDyY  
public void splitterStop() mce qZv  
{ oVK:A;3T|  
bStop = true; 3/]1m9x  
} y\_+,G0  
/o4e n  
[mv? \HDa~  
} SN@>mpcJS  
.Qrpz^wdt  
`C: 7 N=9  
/* >niv >+!N  
**FileAccess.java %/I:r7UR{  
*//文件访问(定位,写) m OUO)[6y  
package NetFox; P+f}r^4}  
import java.io.*; Mbxl{M >  
hiVa\s  
[w<_Wj  
public class FileAccessI implements Serializable{ h.K"v5I*  
a&JY x  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 2gO@   
RandomAccessFile oSavedFile; C0f%~UMwd  
long nPos; 4eB'mPor  
E\D,=|Mul  
nmiJ2edx  
public FileAccessI() throws IOException )zO|m7  
{ >/\TG8t,f  
this("",0); By6O@ .\V  
} Zocuc"j  
r1 :TM|5L  
qZ!kVrmg&  
public FileAccessI(String sName,long nPos) throws IOException NB<8M!X/  
{ <VD7(j]'^  
oSavedFile = new RandomAccessFile(sName,"rw"); BC!) g+8  
this.nPos = nPos; KC}G_"f.$  
oSavedFile.seek(nPos); &Y1h=,KR9  
} < xeB9  
pBe1:  
(5] [L<L  
public synchronized int write(byte[] b,int nStart,int nLen) Vf:.C|Z  
{ $s=` {vv  
int n = -1; .X3n9]  
try{ OP+*%$wR  
oSavedFile.write(b,nStart,nLen); 9~=zD9,|iA  
n = nLen; yHE\Q  
} 6t7FklM%  
catch(IOException e) l4$ sku-  
{ 'V%w{ZiiV  
e.printStackTrace (); >x%HqP#_V  
} 'eBD/w5U  
'%/=\Q`  
e%pohHI  
return n; (t3gNin  
} #@-dT,t  
&;?+ ^L>  
wM[Z 0*K  
} D8! Y0  
5q@s6_"{  
4P?`<K'  
/* Q'jGNWep  
**SiteInfoBean.java I-8I/RRkmP  
*/ z l`m1k-X  
package NetFox; mI<sf?.  
7./WS,49  
=/j!S|P  
public class SiteInfoBean { QsKnaRT  
RLex#j  
9ec?L  
private String sSiteURL; //Site's URL e~*tQ4  
private String sFilePath; //Saved File's Path A#']e8  
private String sFileName; //Saved File's Name LtwfL^#  
private int nSplitter; //Count of Splited Downloading File D]fgBW-  
fz VN;h  
&b,A-1`w_  
public SiteInfoBean() kz}Bc F  
{//nSplitter的缺省值为5 Pbbi*&i  
//default value of nSplitter is 5 .KG9YGL#  
this("","","",5); P//nYPyzg  
} f'"PQr^9  
N!<l~[rc  
!|V_DsP  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8cvSA&l(D  
{ cGo_qR/B(>  
sSiteURL= sURL; Ui"$A/  
sFilePath = sPath; WoN JF6=?  
sFileName = sName; @\gE{;a8  
this.nSplitter = nSpiltter; mHW%^R=  
+>eX1WoTy  
nfZe"|d  
} ^vVAuO  
sqF.,A,  
-;6uN\gq  
public String getSSiteURL() FeZWS>N  
{ 6^jrv [d  
return sSiteURL; ] !1HN3  
} ~#so4<A`3  
Q$: ,N=%  
(6H 7?nv  
public void setSSiteURL(String value) /_expSPHl  
{ F#Pn]  
sSiteURL = value; * #z@b  
} Ap"%%D^{:  
zA|lbJz=GY  
L`O7-'`  
public String getSFilePath() ow`F 7  
{ ; %AgKgV  
return sFilePath; \%}]wf}  
} (}T},ygQ  
D > U(&n  
Z3Ww@&bU  
public void setSFilePath(String value) 6v}q @z  
{ c9nv=?/}f  
sFilePath = value; OFcP4hDi  
} 2.@IfBF6  
'tQp&p j  
 N`X|z  
public String getSFileName() C[ KMaB  
{ wwR}h I(  
return sFileName; 8W Qc8  
} })PU`?f  
(bNoe(<qU  
4}0YLwgJ  
public void setSFileName(String value) /UR;,ts  
{ p? VDBAx  
sFileName = value; A3q#,%  
} |{%$x^KyJ  
vkYiO]y  
?vik2RW  
public int getNSplitter() Y@Ry oJ  
{ ;3Z?MQe"NQ  
return nSplitter; &`]T# ">  
} R:^jQ'1  
ZRr.kN+F  
Sq2 8=1%  
public void setNSplitter(int nCount) ]_!NmB_3  
{ VS~+W=5}  
nSplitter = nCount; Nd;pkssd  
} HB<>x  
} * +6Z^ 7  
 = ~*Vfx  
r0\C2g_X  
/* $RC)e 7  
**Utility.java olHmRJ  
*/ Vhn Ir#L+  
package NetFox; NJ$Qm.S  
0uGTc[^^M  
c[vFh0s"m  
public class Utility { ?ZhBS3L  
;<F^&/a|yQ  
t`eIkq|NxI  
public Utility() LS-_GslE7\  
{ ^7:UC\_  
[*H h6  
G]Im.x3O-  
} J'I1NeK  
(@* %moo  
//线程睡眠 gla'urb[i|  
public static void sleep(int nSecond) {"N:2  
{ |*8X80<  
try{ Pvm pWa  
Thread.sleep(nSecond); G}]'}FUp  
} TTo?BVBK  
catch(Exception e) ]4FAbY2'h  
{ 3]&le[.  
e.printStackTrace (); kFfNDM#D  
} x|Ms2.!  
} YEB7X>p#  
Pn ?gB}l  
//日志 4~d:@Gmk&  
public static void log(String sMsg)  \5HVX/  
{ sr<\fW  
System.err.println(sMsg); raMtTL+  
} >G vd?r  
)L"J?wTe  
?uF3Q)rCk  
public static void log(int sMsg) |g<l|lqz|  
{ GIS,EwA  
System.err.println(sMsg); h;OHpvk  
} Lr "V  
} >5t]Zlb`  
\`*]}48Z  
2Fbg"de3-  
/* _|COnm  
**TestMethod.java Yg;7TKy  
*/ +4[Je$qYa  
package NetFox; u*T#? W?  
"(p&Oz  
z;&J9r $`  
public class TestMethod { QC1\Sn/  
@8cn<+"b  
@Fb 2c0?Y  
public TestMethod() U6YQ*%mZ_  
{ ///xx/weblogic60b2_win.exe d(,M  
try{ V'l9fj*E  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ]-w.x ]I  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); '*K%\]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =o[H2o y  
fileFetch.start(); 1f$1~5Z  
} jZ<f-Ff0  
catch(Exception e){e.printStackTrace ();} b C"rQJg  
v;s^j  
R]d934s  
} YG#{/;^nm)  
h- %RSei5  
DV!0zzJ  
public static void main(String[] args) )kE1g&  
{ [tJp^?6*  
new TestMethod(); Tqx  
} PWS5s^WM  
} LUA<N:  
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