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http断点续传简单实现(java)

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/* +(x^5~QX  
**SiteFileFetch.java L@HPU;<  
*/ jGl8y!aM  
package NetFox; QM2Y?."#  
import java.io.*; "XT7;!  
import java.net.*; l Q]&:%^\  
=@AWw:!:,  
_G|hKk^,  
public class SiteFileFetch extends Thread { a|SgGtBtT4  
Ve*NM|jg  
jl;_lcO  
SiteInfoBean siteInfoBean = null; //文件信息Bean <vJPKQ`=:  
long[] nStartPos; //开始位置 /vll*}}  
long[] nEndPos; //结束位置 au@ LQxKQ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 'MRvH lCM  
long nFileLength; //文件长度 oG M Ls  
boolean bFirst = true; //是否第一次取文件 -G e5gQ=  
boolean bStop = false; //停止标志 Ig}G"GR  
File tmpFile; //文件下载的临时信息 PElC0 qCn[  
DataOutputStream output; //输出到文件的输出流 L^bt-QbhO  
lPx4=O  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 8] skAh  
public SiteFileFetch(SiteInfoBean bean) throws IOException reR><p  
{ t ~ruP',~\  
siteInfoBean = bean; ) DXN|<A  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); u\wdb^8ds  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >J[Bf9)>  
if(tmpFile.exists ()) k"D6Vyy`  
{ D9,609w  
bFirst = false; 5b45u 6  
read_nPos(); w`=_|4wFw  
} 7[h_"@_A7  
else '?=SnjMX  
{ Rt:k4Q   
nStartPos = new long[bean.getNSplitter()]; XI:8_F;Q  
nEndPos = new long[bean.getNSplitter()]; TG7Ba[%  
} PLU8:H@X  
HM57b>6  
qX{"R.d  
*p:`F:  
} IhnHNY]<g  
K~ ,| ~  
A}WRpsA9  
public void run() nfpkWyIu{  
{ DP\s-JpI[  
//获得文件长度 N`XJA-DE  
//分割文件 0 zm)MSg  
//实例FileSplitterFetch 6hDK;J J&  
//启动FileSplitterFetch线程 pYZ6-s  
//等待子线程返回 uT'_}cw  
try{ D FDC'E  
if(bFirst) L1=3_fO  
{ sqTBlP  
nFileLength = getFileSize(); \$:KfN>WY  
if(nFileLength == -1) J$6h% Eyo  
{ Z0&^U#]  
System.err.println("File Length is not known!"); >dKK [E/[d  
} =OfU#i"c  
else if(nFileLength == -2) xw_VK1  
{ j !^Tw.Ty  
System.err.println("File is not access!"); h'VN& T,  
} +Go(y S  
else 0\v98g<[+  
{ :#D?b.=  
for(int i=0;i<nStartPos.length;i++) Fe 3*pUt  
{ @sQ^6FK0G  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); r /v'h@  
} O@JgVdgf  
for(int i=0;i<nEndPos.length-1;i++) #o Rm-yDr  
{ $YZsaw  
nEndPos = nStartPos[i+1]; Ow7NOhw  
} K&FGTS,  
nEndPos[nEndPos.length-1] = nFileLength; C!Cg.^;  
} bwh7.lDAl  
} QZy+`  
v|5:;,I  
s( @w1tS.  
//启动子线程 $=dp)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @L^Fz$Sx  
for(int i=0;i<nStartPos.length;i++) DxjD/? R8  
{ u@|izRk  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y.I-h l1<r  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), wMy$T<:   
nStartPos,nEndPos,i); a<X8l^Ln  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &gJKJ=7  
fileSplitterFetch.start(); Pn@k)g  
} [8*Ovd  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8r '  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); (]7*Kq  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", mv@cGdxu  
nEndPos = " + nFileLength); p:M#F:  
// fileSplitterFetch[nPos.length-1].start(); CU =}]Y  
`@GqD  
RZ)sCR  
//等待子线程结束 K/RQ-xd4  
//int count = 0; /CpUq;^  
//是否结束while循环 "8K>Yu17  
boolean breakWhile = false; W- wy<<~f  
 Q(SVJ  
rQiX7  
while(!bStop) "bZV<;y6  
{ wUzQ`h2  
write_nPos(); qh Ezv~  
Utility.sleep(500); U$a Eby.  
breakWhile = true; o?\)!_Z|  
\~xI#S@  
{#q']YDe`  
for(int i=0;i<nStartPos.length;i++) lhg3 }dW  
{ ^_4TDC~h  
if(!fileSplitterFetch.bDownOver) jB }O6u[%  
{  j`^':!  
breakWhile = false; H"(:6 `  
break; d7N;F a3yL  
} 8?] :>  
} eydVWVN  
if(breakWhile) WtI1h`Fo  
break; C%d 4ItB >  
2&91C[da0  
PpMZ-f@  
//count++; tb,.f3;  
//if(count>4) .lu:S;JSnS  
// siteStop(); mY-Z$8r  
} ^B@4 w\t  
J<DV7zV  
|Y3!Lix  
System.err.println("文件下载结束!"); Okk[}G)  
} { frEVHw  
catch(Exception e){e.printStackTrace ();} 9[DQ[bL  
} 5_Yv>tx  
sBuJK'  
2>Kq)Ii  
//获得文件长度 a:@9GmtV&  
public long getFileSize() Bp\io$(%  
{ FW7+!A&F  
int nFileLength = -1; [rqe;00]  
try{ c 5P52_@  
URL url = new URL(siteInfoBean.getSSiteURL()); k Fv\V   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l^xkXj  
httpConnection.setRequestProperty("User-Agent","NetFox"); %Hv$PsSJ  
T\c;Ra  
nzy =0Ox[  
int responseCode=httpConnection.getResponseCode(); m6V1m0M  
if(responseCode>=400) T~$ePVk>L  
{ :w_F<2d0 0  
processErrorCode(responseCode); 6bnAVTL5  
return -2; //-2 represent access is error v,vTRrpK  
} B0=:A  
f[7'kv5S  
4 E3@O  
String sHeader; ^a; V-US  
;0E"4(S.q1  
=D5@PHpv(  
for(int i=1;;i++) <6/XE@"   
{ $Br^c< y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); d1e'!y}R5  
//Utility.log(in.readLine()); Z.6`O1OY}?  
sHeader=httpConnection.getHeaderFieldKey(i); zq!2);,  
if(sHeader!=null) P},S[GaZ  
{ Qm`f5-d  
if(sHeader.equals("Content-Length")) JoW*)3Z  
{ >&^w\"'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); xHsH .f_{  
break; Y@eHp-[  
} |+6Z+-.Hg  
} 3JW9G04.  
else t{~"vD9Am  
break; BT>*xZLpS  
} ^'EEry  
} 344,mnAd  
catch(IOException e){e.printStackTrace ();} ?; )(O2p  
catch(Exception e){e.printStackTrace ();} 8YkP57Y%[Z  
'IfM~9'D  
 (i*1M  
Utility.log(nFileLength); 6FEtq,;0w  
DDAqgx  
3kR- WgVF,  
return nFileLength; N)poe2[  
} :NbD^h)R  
[-6j4D  
GsDSJz  
//保存下载信息(文件指针位置) AX'(xb,  
private void write_nPos() R$6Y\ *L[  
{ /SMp`Q88  
try{ ~fCD#D2KU  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *otJtEI>6  
output.writeInt(nStartPos.length); 0@AK  
for(int i=0;i<nStartPos.length;i++) K:'pK1zy  
{ ?\vJ8H[bD  
// output.writeLong(nPos); 9HTb  
output.writeLong(fileSplitterFetch.nStartPos); NmB0CbB  
output.writeLong(fileSplitterFetch.nEndPos); Y}1|/6eJ  
} U7PA%  
output.close(); B/5C jHz  
} 9!9 Gpi  
catch(IOException e){e.printStackTrace ();} qsJA|z&6x  
catch(Exception e){e.printStackTrace ();} [j93Mp  
} P45q}v  
dDpe$N  
:hMuxHr  
//读取保存的下载信息(文件指针位置) $oxPmELtpe  
private void read_nPos() W;KHLHp-  
{ R1P,0Yf  
try{ !5A nr  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 4uNcp0  
int nCount = input.readInt(); <EBp X   
nStartPos = new long[nCount]; PI{sO |  
nEndPos = new long[nCount]; h+Q ==  
for(int i=0;i<nStartPos.length;i++) d9Q%GG0]  
{ Pi8U}lG;  
nStartPos = input.readLong(); R8],}6,;E}  
nEndPos = input.readLong(); 'kh%^_FH7  
} L3<XWpv  
input.close(); JWn9&WK  
} m7RWuI,  
catch(IOException e){e.printStackTrace ();} Hfc^<q4a.  
catch(Exception e){e.printStackTrace ();} gcv,]v 8  
} C62<pLJf  
@#T?SNIL5  
nmSpNkJ5  
private void processErrorCode(int nErrorCode) dUe"qH29s  
{ U3za}3  
System.err.println("Error Code : " + nErrorCode); 8"<!8Img  
} '6xn!dK  
o_5|L9  
Vm6^'1CY  
//停止文件下载 hVGakp9WE  
public void siteStop() ~Yr.0i.W  
{ \DQ;v  
bStop = true; xE)pj|  
for(int i=0;i<nStartPos.length;i++) _X]?  
fileSplitterFetch.splitterStop(); <=7p~ i5  
{;-$;\D  
+QHhAA$  
} R 7{ rY  
} ZR#UoYjupb  
//负责部分文件的抓取 V!Joh5=a  
**FileSplitterFetch.java zc2,Mn2  
*/ I+<`}  
package NetFox; D^TKv;%d  
ZO;]Zt]  
k[zf`x^  
import java.io.*; >)5vsqGZaK  
import java.net.*; snK9']WXo  
aSK$#Xeu  
my} P\r.  
public class FileSplitterFetch extends Thread { )8k6GO8|  
"Km`B1f`  
?_^9e  
String sURL; //File URL @+ 2Zt%  
long nStartPos; //File Snippet Start Position u(~s$ENl  
long nEndPos; //File Snippet End Position  LSfj7j`  
int nThreadID; //Thread's ID jxoEOEA  
boolean bDownOver = false; //Downing is over q OXL(  
boolean bStop = false; //Stop identical g_x<+3a  
FileAccessI fileAccessI = null; //File Access interface stDn{x .  
<B fwR$  
FE5R ^W#u-  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~Ep&:c4:D  
{ +amvQ];?Q8  
this.sURL = sURL; r'!l` gm,S  
this.nStartPos = nStart; 3gM{lS}h#  
this.nEndPos = nEnd; m:^@AR1%d  
nThreadID = id; 81n%2G  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 =DCQ!02  
} dqkkA/1  
l-Xxv  
IX>|bA;  
public void run() k]JLk"K  
{ Q\r qG  
while(nStartPos < nEndPos && !bStop) i3~!ofTb  
{ t"L:3<U7  
pQ/:*cd+M  
L"Gi~:z  
try{ F;ZLoG*U  
URL url = new URL(sURL); fg9sZ%67]\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0N}5sF  
httpConnection.setRequestProperty("User-Agent","NetFox"); m=K XMX  
String sProperty = "bytes="+nStartPos+"-"; .dfTv/n  
httpConnection.setRequestProperty("RANGE",sProperty); ::R^ w"  
Utility.log(sProperty); z~BB|-kp1  
>hhd9  
Cse0!7_T  
InputStream input = httpConnection.getInputStream(); ! Q#b4f  
//logResponseHead(httpConnection); :X!(^ a;]  
-`RJ k(  
SN+Bmdup  
byte[] b = new byte[1024]; zPmVECS  
int nRead; A/QVotcU  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Za} |Ee  
{ 4/jY;YN,2  
nStartPos += fileAccessI.write(b,0,nRead); 70NHU;&N  
//if(nThreadID == 1) 08f~vw"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^AM_A>HnG  
} q! ,do2T  
*HC8kD a%$  
wx!*fy4hL  
Utility.log("Thread " + nThreadID + " is over!"); 9t[278B6  
bDownOver = true; \(C W?9)  
//nPos = fileAccessI.write (b,0,nRead); y((_V%F}  
} y"hM6JI  
catch(Exception e){e.printStackTrace ();} J'EK5=H  
} EH3G|3^xz  
} W>~%6K>p  
@b/2'  
[vi4,'wm  
//打印回应的头信息 KFhn}C3 i  
public void logResponseHead(HttpURLConnection con) GlZ9k-ZRF  
{ hK"=~\,  
for(int i=1;;i++) KC u6:)6'  
{ q+z\Y?  
String header=con.getHeaderFieldKey(i); ""+*Gn 7^8  
if(header!=null) Fs|;>Up0  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ob7_dWAG  
Utility.log(header+" : "+con.getHeaderField(header)); >(rB[ZJ  
else iK]g3ew|  
break; VB\6S G  
} D5>~'N3b  
} 8_m9CQ6 i  
HH#i.s2  
jq]"6/xxb  
public void splitterStop() _PbfFY #  
{ hn|E<  
bStop = true; 0%F.]+6[O4  
} ;5k|gW  
@,&m`qzd+  
% 4"~O _S  
} Z ~9N  
|w2AB7EU  
0_ \ g  
/* \,!q[nC  
**FileAccess.java P` F'Nf2U  
*//文件访问(定位,写) D,j5k3< #  
package NetFox; 3x0wk9lND  
import java.io.*; RM1uYFs<  
}hitU(5t0  
Pu*HZW3l  
public class FileAccessI implements Serializable{ ()#tR^T  
}.) 43(>]  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 g <4M!gi  
RandomAccessFile oSavedFile; Z{4aGp*  
long nPos; "EYj Y->  
0r ; nz]'  
50aWFJYw  
public FileAccessI() throws IOException W+ '}O<  
{ zZc@;S#  
this("",0); yO;C3q  
} K('l H-3wS  
<1+6O[>{  
NND=Z xl  
public FileAccessI(String sName,long nPos) throws IOException yLO &(Mb  
{ >DUE8hp ;<  
oSavedFile = new RandomAccessFile(sName,"rw"); KBRg95E~]l  
this.nPos = nPos; nl9Cdi]o  
oSavedFile.seek(nPos); \seG2vw$  
} 50GYL5)q  
XQJ^)d00h  
$:E}Nj]{&  
public synchronized int write(byte[] b,int nStart,int nLen) _#D\*0J  
{ N 3yB1_   
int n = -1; {/A)t1nL  
try{ Y-3[KHD  
oSavedFile.write(b,nStart,nLen); ;#yu"6{  
n = nLen; c`i=(D<  
} @ZkAul0@  
catch(IOException e)  LbX6p  
{ nN`Z0?  
e.printStackTrace (); EdAR<VfleA  
} }\939Y  
Ls>u` hG  
$JhZ'Z  
return n; .eabtGO,  
} W-!Bl&jF[  
QI#*5zm  
Cj !i)-  
} v*H &F   
w38c  
Cl9SPz  
/* :q>oD-b$}  
**SiteInfoBean.java - Y8ks7  
*/ Z6R: rq  
package NetFox; Z<N&UFw7QJ  
uspkn1-  
y*}vG}e%  
public class SiteInfoBean { sWsG,v_  
f OM^V{)T  
{\svV 0)~  
private String sSiteURL; //Site's URL jom} _  
private String sFilePath; //Saved File's Path Db#W/8 a8k  
private String sFileName; //Saved File's Name 5y%un  
private int nSplitter; //Count of Splited Downloading File :kb1}Wu  
AB2mt:^  
N75 3  
public SiteInfoBean() +~w?Xw,  
{//nSplitter的缺省值为5 '&-5CpDUs  
//default value of nSplitter is 5 {=bg5I0|a  
this("","","",5); ~KAp\!,  
} Mhb '^\px  
abROFI5.L  
pcI&  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) lL(p]!K'  
{ 5u;Rr 1D  
sSiteURL= sURL; ?w]"~   
sFilePath = sPath; sf |oNOz  
sFileName = sName; &'5@azU  
this.nSplitter = nSpiltter; Q7~'![(a  
t7um [  
2^)D .&  
} SY%A"bC  
/ h}PEu3y  
(dzH3_U  
public String getSSiteURL() je&dioZ>  
{ Rk($lW)  
return sSiteURL; IajD;V  
} Q`.'-iq  
R'Kt=.s<  
)-bD2YA{  
public void setSSiteURL(String value) 9W{,=.%MX$  
{ 0+T*$=?  
sSiteURL = value; dT5J-70Fl  
} BFBR/d[&  
LP.HS'M~u  
![*:.CW  
public String getSFilePath() E2^ KK:4s  
{ BZovtm3 E  
return sFilePath; D:=t*2-Iv  
} @GN(]t&3  
9@:BK;Fi  
8)L'rW{q#  
public void setSFilePath(String value) @ SU8\:(U  
{ jCU=+b=  
sFilePath = value; M{C6rm|  
} $Mdbt o~<  
L +L 9Y}  
QB!jLlg(  
public String getSFileName() K@B" ]6  
{ r eGm>  
return sFileName; b6 $,Xh  
} q_cC7p6t  
3\;v5D:  
+ c`AE  
public void setSFileName(String value) Fj S%n$  
{ \ jE CSV|  
sFileName = value; >xT^RYS  
} ,Kuk_@(}5~  
N? M   
m;dm|4L^  
public int getNSplitter() .:rmA8U[  
{ Rv98\VD"  
return nSplitter; }i(qt&U;  
} IE2CRBfs  
_}D%iJg#  
=4eUAeH {w  
public void setNSplitter(int nCount) :4|M jn  
{ "u_i[[y  
nSplitter = nCount; <0#^7Z  
} UH[<&v  
} j.DHqHx  
R~)ybf{  
2UiR~P]%  
/* `ruNA>M  
**Utility.java xOythvO  
*/ v,{h:  
package NetFox; #b'N}2'p#V  
P|N2R5(>T  
9RH"d[%yc}  
public class Utility { @D)Z{=>{=5  
[& ^RP,N~  
%#u.J  
public Utility() |m)kN2w  
{ 1]T|6N?  
[F+,YV%t  
=Q-k'=6\  
} tmO`|tn&  
B8H75sz  
//线程睡眠 ?R|th Z  
public static void sleep(int nSecond) 6W&_2a7*  
{ y%S})9  
try{ 7NJFWz!  
Thread.sleep(nSecond); eZH~je{1  
} :'}@Al9=>  
catch(Exception e) _\\ -md:  
{ h d2'AlB  
e.printStackTrace (); *nRNg.i3D  
} UX2lPgKdLz  
} +6l]]*H  
px=]bALU  
//日志 RF?DtNuq  
public static void log(String sMsg) T  p<s1'"  
{ d]SYP  
System.err.println(sMsg); RNWX.g)b  
} AOb]qc  
wfR&li{  
X:EEPGE  
public static void log(int sMsg) )&,{?$.  
{ 8AL\ST51x"  
System.err.println(sMsg); }Cj8  
} mrM4RoO  
} [&#/|zH'j:  
c?E{fD"Fc3  
`)K y0&?  
/* eg<pa'Hw  
**TestMethod.java I4t*?  
*/ ,DQjDMjrf  
package NetFox; `VT>M@i/  
qf#)lyr<D6  
iPj~I  
public class TestMethod { C&<~f#lB  
ZVih=Y-w  
5l{Ts04k%  
public TestMethod() S,{tV=&m]  
{ ///xx/weblogic60b2_win.exe mJ5H=&Z  
try{ * F4UAQzYb  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6RoAl$}'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ny*i+4Mb  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [ f/I2  
fileFetch.start(); {tiKH=&J  
} "_1)CDqP  
catch(Exception e){e.printStackTrace ();} `]i []|  
r^fe4b  
[?0d~Q(R#  
} E4z)Mr#  
EGVM)ur  
zM#sOg  
public static void main(String[] args) K> g[k_  
{ Na{Y}0=^y  
new TestMethod(); neZ.`"LV  
} bulS&dAX  
} L%"LlS g  
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