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http断点续传简单实现(java)

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/* A*b>@>2  
**SiteFileFetch.java Xlg 0u.  
*/ >_esLsPWh]  
package NetFox; EUGN`t-M  
import java.io.*; Lfr>y_i;F  
import java.net.*; $<DcbJW  
m6wrG`-di  
 {@E(p4W  
public class SiteFileFetch extends Thread { S~GL_#a  
<e)u8+(  
7:Cq[u fl  
SiteInfoBean siteInfoBean = null; //文件信息Bean Le,e,#hiY  
long[] nStartPos; //开始位置 6Z ,GD  
long[] nEndPos; //结束位置 ?R#?=<VkG  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ^p7g[E&  
long nFileLength; //文件长度 U]Pl` =SL  
boolean bFirst = true; //是否第一次取文件 3]MSS\uB  
boolean bStop = false; //停止标志 xQU$E|I  
File tmpFile; //文件下载的临时信息 n.L/Xp@gc  
DataOutputStream output; //输出到文件的输出流 @T 5dPmn  
o%j[]P@4G  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) /U@T#S  
public SiteFileFetch(SiteInfoBean bean) throws IOException #I &#x59  
{ i (qPD_  
siteInfoBean = bean; caH!(V}6  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Aq3.%,X2H  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); zb_nU7Eg  
if(tmpFile.exists ()) T>P[0`*)  
{ rP%B#%;S"  
bFirst = false; sR;^7(f!m  
read_nPos(); Lkf}+aY  
} _-6IB>  
else 5yl[#>qt  
{ I_"Kh BM  
nStartPos = new long[bean.getNSplitter()]; 8slOB>2#Y  
nEndPos = new long[bean.getNSplitter()]; ,Y+J.8.H   
} u*"mdL2  
JbR;E`8  
e^%>_U  
dsrKHi  
} oZS.pi  
Ul{{g$  
Fi3k  
public void run() P&kjtl68 Y  
{ \A%s" O/  
//获得文件长度 )}3!iDA  
//分割文件 W`k||U9  
//实例FileSplitterFetch 9$Dsm@tX  
//启动FileSplitterFetch线程 Z23*`yR  
//等待子线程返回 VC T~"T2R  
try{ .ey=gI!x0  
if(bFirst) z Go*N,'  
{ ] -}Zd\Rs  
nFileLength = getFileSize(); +CaA%u  
if(nFileLength == -1) lk(.zYaaN  
{ ud`!X#e~  
System.err.println("File Length is not known!"); n`TXm g  
} Pbo759q 1  
else if(nFileLength == -2) aK+jpi4?  
{ IUZ@n0/T  
System.err.println("File is not access!"); K (!+l  
} ?7k%4~H t  
else =jEh#  
{ yRdME>_L  
for(int i=0;i<nStartPos.length;i++) >Y>>lE! k  
{ =[Z uE0c  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); i*l-w4D^U  
} ]>T4\?aC  
for(int i=0;i<nEndPos.length-1;i++) |A/)b78'u  
{ >0c4C< _  
nEndPos = nStartPos[i+1]; @b]?Gg  
} 9vL n#_  
nEndPos[nEndPos.length-1] = nFileLength; z]d2 rzV(_  
} Kh' 7N!  
} MpCK/eiC  
/&jh10}H  
j~;kh_  
//启动子线程 bd & /B&a  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Xe. az  
for(int i=0;i<nStartPos.length;i++) xhTiOt6l  
{ > 3SZD  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yKb+bm&5:'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), NpLO_-  
nStartPos,nEndPos,i); YEiQ`sYKG  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Lbwc2Q,.-  
fileSplitterFetch.start(); TDY2 M  
} <RaUs2Q3.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6aMG!_jC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {1VMwANj  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", :d{-"RAG"  
nEndPos = " + nFileLength); !M*$p Qi}  
// fileSplitterFetch[nPos.length-1].start(); XI/LVP,.  
kaG@T,pH(  
&CcUr#|  
//等待子线程结束 s%OPoRE  
//int count = 0; PN"s ^]4  
//是否结束while循环 oEN^O:9e  
boolean breakWhile = false; ed\umQ]   
%K/zVYGm&  
Z!eW_""wp  
while(!bStop) tQYkH$e`/{  
{ u301xc,N<z  
write_nPos(); lk/[xQ/  
Utility.sleep(500); B3 NDx+%m  
breakWhile = true; #fQ}8UxU,  
[5T{`&  
e0 &x?U*/  
for(int i=0;i<nStartPos.length;i++) Wm#F~<$  
{ 6-6ha7]s  
if(!fileSplitterFetch.bDownOver) X:kqX[\>  
{ q37d:Hp  
breakWhile = false; x<gP5c>zm  
break; s-lNpOi  
} Xub<U>e;b  
} (_.0g}2  
if(breakWhile) E#A%aLp0E  
break; D.:6X'hp  
aEvW<jHh  
kh5VuXpe  
//count++; )/mBq#ZS  
//if(count>4) d")TH3pG  
// siteStop(); gi#g)9HG  
} !Sj0!\  
W9M~2< L  
%}/|/=  
System.err.println("文件下载结束!"); tmVGJ+gz  
} v3I-i|L<)  
catch(Exception e){e.printStackTrace ();} P g.j]  
} Bh0hUE  
FzM<0FJRX  
<Y"h2#M"  
//获得文件长度 mR3-+dB/  
public long getFileSize() 5!V%0EQqw  
{ q>5 K:5  
int nFileLength = -1; NO'37d  
try{ ^X\SwgD2w  
URL url = new URL(siteInfoBean.getSSiteURL()); Uz$.sa  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =b_/_b$q  
httpConnection.setRequestProperty("User-Agent","NetFox"); QFX/x  
(Rs052m1  
K}a3Bj,  
int responseCode=httpConnection.getResponseCode(); (@nE e?  
if(responseCode>=400)  J]4pPDm  
{ <%b a 3<sg  
processErrorCode(responseCode); Z#znA4;)  
return -2; //-2 represent access is error T6^ H%;G  
} "f N=Y$G  
qS?uMms7w  
`E:&a]ul  
String sHeader; kPvR ,  
J<h! H  
/c|X:F!;X#  
for(int i=1;;i++) RTQtXv6mD  
{ -F~"W@9r  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 4uy:sCmu  
//Utility.log(in.readLine()); O;83A  
sHeader=httpConnection.getHeaderFieldKey(i); !HCuae3_  
if(sHeader!=null) =tQ^t4_  
{ 0/TP`3$X#"  
if(sHeader.equals("Content-Length")) D4IP$pAD  
{ oUNuM%g9Dy  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Dhze2q)o  
break; Ra)AQ n  
} _/[}PQC6G  
} S17 c#6vT  
else ^_5t5>  
break; d]r?mnN W  
} 155vY  
} F!qt=)V@w  
catch(IOException e){e.printStackTrace ();} o8c5~fG1  
catch(Exception e){e.printStackTrace ();} <Gw>}/-^  
reI4!,x  
.9VhDrCK  
Utility.log(nFileLength); k^ Qd%;bdF  
Z3qr2/  
AQm#a;  
return nFileLength; >hv8zHOO:  
} ?)V|L~/  
M'5PPBSR  
6.6;oa4j  
//保存下载信息(文件指针位置) E x )fXQ+  
private void write_nPos() vp&N)t_  
{ m bZn[D_zi  
try{ (U([T-H  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Lc! t  
output.writeInt(nStartPos.length); cTa$t :K@  
for(int i=0;i<nStartPos.length;i++) 6R#.AD\  
{ PTP0 _|K  
// output.writeLong(nPos); ##5e:<c&[  
output.writeLong(fileSplitterFetch.nStartPos); G}LOQ7  
output.writeLong(fileSplitterFetch.nEndPos); _ZHDr[  
} GAU7w"sE  
output.close(); (MzThGJK_  
} ]47!Zo,  
catch(IOException e){e.printStackTrace ();} !t!'  
catch(Exception e){e.printStackTrace ();} k< $(  
} .g>0FP  
8;y\Ln?B  
.kc{)d*0K  
//读取保存的下载信息(文件指针位置) }DFZ9,gQ  
private void read_nPos() &1FyauH  
{ 7-("pp YX=  
try{ 4Hq6nT/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]FEsN6  
int nCount = input.readInt(); ^KUM4. 6  
nStartPos = new long[nCount]; 3eN(Sw@p  
nEndPos = new long[nCount]; hka`STK{  
for(int i=0;i<nStartPos.length;i++) [13NhF3.P  
{ D!rD-e  
nStartPos = input.readLong(); r1a/'+   
nEndPos = input.readLong(); &UIS17cT  
} xp%LXx j  
input.close(); Z+agS8e(  
} v(`5exWV  
catch(IOException e){e.printStackTrace ();} /E^j}H{  
catch(Exception e){e.printStackTrace ();} KvmXRf*z  
} 6yK"g7  
C)BVsHT4  
seiE2F[  
private void processErrorCode(int nErrorCode) !laOiH  
{ IeAUVR S)  
System.err.println("Error Code : " + nErrorCode); j"9Zaq_  
} 'tY y_  
4%*`' o$_  
, %A2wV  
//停止文件下载 g-<[* nF  
public void siteStop() >x8~?)7z  
{ rq|>z.  
bStop = true; ,B$e'KQ  
for(int i=0;i<nStartPos.length;i++) e_dsBmTh  
fileSplitterFetch.splitterStop(); cdTG ]n  
Z&5cJk W  
B&?xq)%*#  
} 9&Ny;oy#6  
} K-n]m#U4o  
//负责部分文件的抓取  \z?-  
**FileSplitterFetch.java X!K:V~WG  
*/ #Ti5G"C  
package NetFox; eb7~\|9l1i  
Hr/Q?7g  
`q+Ug  
import java.io.*; \4n9m  
import java.net.*; lFD/hz7lc  
[cT7Iqip  
LEA^o"NW.  
public class FileSplitterFetch extends Thread { m_b_)/  
[Y8ot-6  
G&#l3bkQ  
String sURL; //File URL |3=tF"h  
long nStartPos; //File Snippet Start Position :s#&nY  
long nEndPos; //File Snippet End Position Xagz(tm/  
int nThreadID; //Thread's ID VV"1IR  
boolean bDownOver = false; //Downing is over \= Wrh3  
boolean bStop = false; //Stop identical w C-x'  
FileAccessI fileAccessI = null; //File Access interface T^H`$;\  
M 9/J!s  
I ka V g L  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >:P-3#e*  
{ M3YC@(N% k  
this.sURL = sURL; 8g6G},Y0  
this.nStartPos = nStart; `.YMbj#T  
this.nEndPos = nEnd; E[tEW0ub  
nThreadID = id; #$v,.Yk  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 o_?A^u  
} >qci $  
6mC% zXR5  
V?4G~~F  
public void run() V#\iO  
{ 1VB{dgr  
while(nStartPos < nEndPos && !bStop) aKw7m= {  
{ \g:Bg%43h  
gkld}t*U  
&I?d(Z=:\  
try{ kRB2J3Nt.  
URL url = new URL(sURL); %-3wR@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !\|L(Paf  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;\gHFG}  
String sProperty = "bytes="+nStartPos+"-"; y-vQ4G5F|  
httpConnection.setRequestProperty("RANGE",sProperty); Te@=8-u-  
Utility.log(sProperty); rNeSg=j  
zwdi$rM5  
Q9sxI}D )R  
InputStream input = httpConnection.getInputStream(); qrY]tb^K  
//logResponseHead(httpConnection); $GX9-^og=T  
B2)SNhF2Y  
?#VkzT  
byte[] b = new byte[1024]; tkf^sGgNO  
int nRead; *Zz hN]1  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) LAv!s/O$=  
{ |oTA $bln  
nStartPos += fileAccessI.write(b,0,nRead); 5 DvD  
//if(nThreadID == 1) }+BbwBm&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); z?Qt%1q  
} P*{*^D N  
T<~?7-O"  
)U:W 9%  
Utility.log("Thread " + nThreadID + " is over!"); <9aa@c57  
bDownOver = true; ~k/GmH  
//nPos = fileAccessI.write (b,0,nRead); 8% `Jf`  
} 3<ry/{#%  
catch(Exception e){e.printStackTrace ();} j(];b+>  
} BYXMbx  
} +{@hD+  
gIcm`5+T  
#B8V2_M  
//打印回应的头信息 6"_ytqw7  
public void logResponseHead(HttpURLConnection con) rPF2IS(5  
{ XV:icY  
for(int i=1;;i++) k{.`=j  
{ >kG: MJj  
String header=con.getHeaderFieldKey(i); 'Y:ZWac,  
if(header!=null) wQ~F%rQ$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :DR}lOi`  
Utility.log(header+" : "+con.getHeaderField(header)); k+y>xI,  
else ^Mi&2AvS  
break; .eG_>2'1  
} KU)~p"0[6]  
} ^fT?(y_= e  
*N3X"2X:  
Xjnv8{X  
public void splitterStop() _U`1BmTC2  
{ %$}* y   
bStop = true; <#No t1R  
} GB` G(a  
av4g/7=  
ip2BvN&  
} {igVuZ(>en  
Evb %<`gd  
ewp&QH4  
/* Nt P=m @  
**FileAccess.java FOD_m&+  
*//文件访问(定位,写) ?;?$\ b=  
package NetFox; [Z{0|NR  
import java.io.*; `HJRXoLySW  
9zD^4j7  
TaE&8;H#N  
public class FileAccessI implements Serializable{ br_D Orq|  
iBy &#^  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @#KZ2^  
RandomAccessFile oSavedFile; <hM`]/J55  
long nPos; A]q"+Z]  
Tq`rc"&7u  
R[{s\  
public FileAccessI() throws IOException iK <vr  
{ 7S)u7  
this("",0); eBxOa  
} 1 8kzR6(W  
o2r)K AA  
d6;"zW|Ec  
public FileAccessI(String sName,long nPos) throws IOException >Sua:Uff  
{ D}6~2j  
oSavedFile = new RandomAccessFile(sName,"rw"); CiTjRJ-ZW)  
this.nPos = nPos; pv){R;f  
oSavedFile.seek(nPos); `w/`qG:dK  
} GV(@(bI*  
DSc:>G  
p:CpY'KV_  
public synchronized int write(byte[] b,int nStart,int nLen) D+xHTQNTL  
{ )TV{n#n  
int n = -1; R3ru<u>k&  
try{ sqP (1|9  
oSavedFile.write(b,nStart,nLen); 1*u i|fuK  
n = nLen; xix: = a  
} jj8h>"d  
catch(IOException e) @O Rk  
{ euc|G Xs  
e.printStackTrace (); *mTx0sQz(J  
} 1Wy0#?L  
N)N\iad^  
y:+4-1  
return n; f*& 4d  
} @ob4y  
 (zL(  
}[m,HA<j  
} WwBs_OMc  
z~y=(T  
:q,tmk h  
/* gS$?#!f  
**SiteInfoBean.java N#"(  
*/ U jrML  
package NetFox; zs@xw@  
}* s%|!{H  
Me XGE  
public class SiteInfoBean { 380M &Guh  
cas5  
I# U"DwM  
private String sSiteURL; //Site's URL E ) iEWc  
private String sFilePath; //Saved File's Path |SfmQ;  
private String sFileName; //Saved File's Name 9et%Hn.K'  
private int nSplitter; //Count of Splited Downloading File N5\]VCX  
z c7P2@  
!HPye@Ua  
public SiteInfoBean() L5-Kw+t  
{//nSplitter的缺省值为5 d2XS w>  
//default value of nSplitter is 5 ,U^V]jC  
this("","","",5); 2J5RZg9jL  
} B8sc;Z.  
B%Vz -t  
Tz{f 5c&  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) N|53|H  
{ xvx+a0 A  
sSiteURL= sURL; / >q?H)6  
sFilePath = sPath; 1so9w89  
sFileName = sName; ueD_<KjE=  
this.nSplitter = nSpiltter; 4itadQS  
%;-] HI  
u~y0H  
} fce~a\y0  
r[ }5<S Q  
,8^QV3  
public String getSSiteURL() y m~  
{ i{+W62k*  
return sSiteURL; Sdn4y(&TP  
} Td"_To@jd  
"cVJqW  
K~DQUmU@  
public void setSSiteURL(String value) ] 3UlF'{  
{ AYnk.H-v  
sSiteURL = value; -cqR]'u  
} 9p{7x[C  
r{pbUk  
*t3uj  
public String getSFilePath() &W@#p G  
{ WMw^zq?hd@  
return sFilePath; Nxd<#p  
} gc KXda(  
>.X& v  
1U(P0$C  
public void setSFilePath(String value) fCa*#ME  
{ }cPH}[ $zF  
sFilePath = value; rM y(NAo_  
} zs<2Ozv  
d=v{3*a_4,  
=Mby;wQ?|  
public String getSFileName() ;Or]x?-  
{ q{:]D(   
return sFileName; nhZ^`mP  
} v3 q.,I_  
nS5g!GYY,k  
b|KlWt'  
public void setSFileName(String value) f0 d*%  
{ Y"dUxv1Ap  
sFileName = value; X}@'FxIF  
} 4u.Fy<+@4M  
c>}f y  
(0W)Jd[  
public int getNSplitter() 9yrSCDu00  
{ oZCjci-  
return nSplitter; xP61^*-2  
} $ 9%UAqk9  
@cC@(M~Ru  
9H6%\#rw  
public void setNSplitter(int nCount) 6hX[5?}  
{ {/E_l  
nSplitter = nCount; CqkY_z  
} @7j$$  
} yy(.|  
5tG\5  
C1ZuDL)e  
/* {)L*\r  
**Utility.java r-aCa/4y!  
*/ }JlrWJRi  
package NetFox; i+&o%nK2  
t 8,VRFV  
'] $mt  
public class Utility { 5dXDL~/2p  
j : $Ruy  
4!k 0  
public Utility() li7"{+ct  
{ #P)(/>nF  
u P&<  
Mr6q7  
} l?Qbwv}  
HV}*}Ty  
//线程睡眠 OB5t+_ s  
public static void sleep(int nSecond) 4;D>s8dgG  
{ fUV;3du  
try{ :% m56  
Thread.sleep(nSecond); hqwDlapTt  
} ?Fp2W+M j  
catch(Exception e) ?Zv>4+Y'  
{ ["7]EW\!:  
e.printStackTrace (); >)6d~  
} id:6O+\  
} iR39lOr  
\>N"{T  
//日志 L2}p<?f  
public static void log(String sMsg) H2oD0f|  
{ xwjiNJ Gj  
System.err.println(sMsg); *\"+/   
} ,JONc9  
3U!#rz"  
(\o &Gl  
public static void log(int sMsg) <#%kmYSL  
{ dm`:']?  
System.err.println(sMsg); U0fr\kM  
} z5q(  
} c)B <d#  
9JBVG~m+  
25wvB@0&  
/* -?Kd[Ma  
**TestMethod.java o)r%4YOL  
*/ x4^* YZc$,  
package NetFox; qtYVX:M@,  
h'|J$   
=OR "Bd:O  
public class TestMethod { <S@XK%  
>m'n#=yap  
jx[g;7~X  
public TestMethod() ( *Fb/  
{ ///xx/weblogic60b2_win.exe 2'T uS?  
try{ MNWuw;:v  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \VAm4   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,WgEl4  
SiteFileFetch fileFetch = new SiteFileFetch(bean); qx2M"uFJ  
fileFetch.start(); ? e<D +  
} T'${*NVn  
catch(Exception e){e.printStackTrace ();} wG}Rh,  
d*tn&d~k,  
.\}nDT  
} W~Ae&gcn#  
%z "${ zw  
SsfHp  
public static void main(String[] args) +5xk6RP   
{ I6lWB(H!u  
new TestMethod(); n1r'Y;G  
} R!y`p:O C  
} 7?W1i{(  
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