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http断点续传简单实现(java)

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/* wv6rjg:7  
**SiteFileFetch.java R, J(]ew  
*/ doj$chy  
package NetFox; >axf_k  
import java.io.*; Qgel^"t]i  
import java.net.*; kZfUwF:yN  
bVbh| AA  
hj<h]dhp  
public class SiteFileFetch extends Thread { 0>aAI3E  
d9E'4Zm  
"=/YPw^0  
SiteInfoBean siteInfoBean = null; //文件信息Bean qFpRY7eq  
long[] nStartPos; //开始位置 B(z?IW&  
long[] nEndPos; //结束位置 >U2[]fu  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :VB{@ED  
long nFileLength; //文件长度 <h vVh9  
boolean bFirst = true; //是否第一次取文件 r\x"nS  
boolean bStop = false; //停止标志 4uSC>  
File tmpFile; //文件下载的临时信息 2rG;j52))a  
DataOutputStream output; //输出到文件的输出流 dh; L!  
B0&W wa:  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) |Qa[N(  
public SiteFileFetch(SiteInfoBean bean) throws IOException <q dM  
{ Vw P+tM  
siteInfoBean = bean; ZB|y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "F.0(<4)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); YR\pt8(z?  
if(tmpFile.exists ()) $v#\bqY  
{ WF!u2E+  
bFirst = false; Kj+=?R~}S  
read_nPos(); $vQ#ah/k  
} ar#Xe;T!  
else u5LrZt]k  
{ .0gF&>I}  
nStartPos = new long[bean.getNSplitter()]; 555*IT3b  
nEndPos = new long[bean.getNSplitter()]; F79!B  
} 7/:C[J4GTN  
lCznH?[  
4,yS7l  
lls-Nir%  
} P*\h)F/3}t  
H`XE5Hk)P%  
!}[,ODJ4 d  
public void run() @ 7WWoy  
{ {~lVe GBp  
//获得文件长度 6')pM&`t  
//分割文件 XLeQxp=  
//实例FileSplitterFetch L+rMBa  
//启动FileSplitterFetch线程 <%~`!n,t0  
//等待子线程返回 (8$; 4q[!  
try{ 7"iUyZ(  
if(bFirst) Oapv`Z\i~  
{ C@7<0w  
nFileLength = getFileSize(); 9|}u"jJB%E  
if(nFileLength == -1) eOdB<He36  
{ {imz1g;  
System.err.println("File Length is not known!"); H fg2]N  
} @+,J^[ y  
else if(nFileLength == -2) h>A~..  
{ UUuB Rtau  
System.err.println("File is not access!"); w}`TJijl  
} !MNnau%O  
else >;9+4C<z0  
{ YV p sf8R  
for(int i=0;i<nStartPos.length;i++) ! qF U  
{ \*(A1Vk  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); j\o<r0I  
} ^/H9`z;  
for(int i=0;i<nEndPos.length-1;i++) :MIJfr>z  
{ ?)# qBE ]  
nEndPos = nStartPos[i+1]; 5,;>b^gXY`  
} Z/p>>SCak  
nEndPos[nEndPos.length-1] = nFileLength; !T<4em8  
} U<aT%^_  
} Rx}*I00  
B]""%&! O  
)fRZ}7k:  
//启动子线程 xlW`4\ Pa  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @5i m*ubzM  
for(int i=0;i<nStartPos.length;i++) .w .`1 g   
{ S*5hO) C  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \@3B%RW0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ,y'E#_cTgQ  
nStartPos,nEndPos,i); "G&S`8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |lnMT)^D  
fileSplitterFetch.start(); zP F0M(  
} >Fzs%]M  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q3CcXYY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ecZT|X4u  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", D (>,#F  
nEndPos = " + nFileLength); m7|}PH" 7  
// fileSplitterFetch[nPos.length-1].start(); |v'_Co0ki  
VN5UJ!$?J  
p,)~w1|  
//等待子线程结束 D;@nrj`.  
//int count = 0; ^E)*i#."4  
//是否结束while循环 %+=y!  
boolean breakWhile = false; D>U b)i  
$P{|^ou3a#  
19r4J(pV  
while(!bStop) `~0^fSww  
{ 3t*e|Ih&j5  
write_nPos(); 1hz:AUH  
Utility.sleep(500); &"h 9Awn2  
breakWhile = true; ,k,RXgQ  
e?V7<7$  
TVVr<r  
for(int i=0;i<nStartPos.length;i++) 0pC}+ +  
{ 9}=]oX!+V  
if(!fileSplitterFetch.bDownOver) ;F/yS2p  
{ 5}pn5iI  
breakWhile = false; ]I+"";oQGB  
break; }u>F}mUa  
} -_p+4tV  
} h^)R}jy+f  
if(breakWhile) YEbB3N  
break; gq'}LcV  
;VL v2J*  
2NNAsr}L  
//count++; 24}?GO  
//if(count>4) p H5iv>H  
// siteStop(); |3a1hCxt  
} 1;U `e4"  
I|`/#BYbW  
&{x%"Aq/  
System.err.println("文件下载结束!"); GW29Rj1  
} 06Irx^n  
catch(Exception e){e.printStackTrace ();} Zs(I]^w;d  
} g}vOp3 ^  
`2B,+ytW8  
)}G?^rDH(  
//获得文件长度 v4pFts$J  
public long getFileSize() 0Bo7EV  
{ ?tf/#5t}  
int nFileLength = -1; ;j#(%U]Vp  
try{ _0v+g1x  
URL url = new URL(siteInfoBean.getSSiteURL()); |U GmIm%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :c vZk|b%  
httpConnection.setRequestProperty("User-Agent","NetFox"); w6-A-M6hD  
B5nzkJV<X  
qG=>eRR  
int responseCode=httpConnection.getResponseCode(); 9L"Z ~CUL  
if(responseCode>=400) #)qn$&.H  
{  *b$8O  
processErrorCode(responseCode); P$ a `8~w  
return -2; //-2 represent access is error )t$<FP  
} /YyimG7  
_D{V(c<WD  
XMR$I&;G8  
String sHeader; w;=fi}<G|e  
Nx%]dOa  
FE0}V}\=h  
for(int i=1;;i++) 7jj.maK  
{ h6yXW! 8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &pL.hM^  
//Utility.log(in.readLine()); :75$e%'A  
sHeader=httpConnection.getHeaderFieldKey(i); cJ}J4?  
if(sHeader!=null) -=tf)  
{ o!\Q,  
if(sHeader.equals("Content-Length")) ')bas#=uP  
{ 'V*ixK8R0  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ="k9 y  
break; xD:t$~  
} TjU g8k  
} )@IDmz>  
else @y|ZXPC#  
break; X\z `S##kj  
} AM[#AZv  
} 4;rt|X77  
catch(IOException e){e.printStackTrace ();} JTw< 4]  
catch(Exception e){e.printStackTrace ();} vM.Y/,7S  
\1[=t+/  
i42M.M6D$  
Utility.log(nFileLength); @1`!}.Tk  
o~aK[   
3?R56$-+  
return nFileLength; z]^u@]@NC  
} ,n}h_ct  
~x!"(  
d4 Hpe>  
//保存下载信息(文件指针位置) Wk0"U V  
private void write_nPos() p)dD{+"/2  
{ 3@t&5UjwQ  
try{ )&nfV5@"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); \!+#9sq0  
output.writeInt(nStartPos.length); NSsLuM=.  
for(int i=0;i<nStartPos.length;i++) UdIl5P  
{ z'W8t|m}Pb  
// output.writeLong(nPos); C1x"q9| \`  
output.writeLong(fileSplitterFetch.nStartPos); mMz^I7$  
output.writeLong(fileSplitterFetch.nEndPos); y7x&/2  
} )1EF7.|  
output.close(); $X>$)U'p&-  
} 6t,_Xqg*  
catch(IOException e){e.printStackTrace ();} w%3R[Kdzk  
catch(Exception e){e.printStackTrace ();} ~6<'cun@x  
} :EkhF6B/  
hk +@ngh%  
]c Or$O*  
//读取保存的下载信息(文件指针位置) b3zxiq x  
private void read_nPos() s`Y8 &e.Yr  
{ -msfiO  
try{ \8KAK3i'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); + YjK#  
int nCount = input.readInt(); ;cFlZGw   
nStartPos = new long[nCount]; 2b[R^O}   
nEndPos = new long[nCount]; z-J?x-<  
for(int i=0;i<nStartPos.length;i++) 'l&),]|$)  
{ &e-MOM2&  
nStartPos = input.readLong(); #Yqj27&  
nEndPos = input.readLong();  .# Jusd  
} "B$r{ vG  
input.close(); =vpXYj  
} d'x'hp%  
catch(IOException e){e.printStackTrace ();} "1-gMob  
catch(Exception e){e.printStackTrace ();} (]Pr[xB  
} vi4lmkyh^  
fFSQLtm?E  
Z [aKic  
private void processErrorCode(int nErrorCode) pZ IDGy=~  
{ 3YFbT Z  
System.err.println("Error Code : " + nErrorCode); ^z _m<&r  
} #},4m  
kT=KxS{  
1 luRTI8^  
//停止文件下载 }Qqi013E L  
public void siteStop() &>YdX$8x  
{ A~!v+W%vO1  
bStop = true; .!B>pp(9  
for(int i=0;i<nStartPos.length;i++) (FY<% .Pa  
fileSplitterFetch.splitterStop(); M %vZcP  
@[s+5_9nk  
Yp;6.\Z8[  
} k*U(ln  
} ,drcJ  
//负责部分文件的抓取 tn\PxT  
**FileSplitterFetch.java KysJ3G.k\  
*/ C<T)'^7z  
package NetFox; w.:fl4V  
=Qf.  
RyN}Gz/YN  
import java.io.*; FUD M]:XQ  
import java.net.*; Y\e8oIYu7  
Q!T+Jc9N  
&|LP>'H;  
public class FileSplitterFetch extends Thread { Mq#sSBE<K  
z0v|%&IK  
_[kZ:#  
String sURL; //File URL x =7qC#+)  
long nStartPos; //File Snippet Start Position W pdn^=dhL  
long nEndPos; //File Snippet End Position p bT sn  
int nThreadID; //Thread's ID ?kF_C,k/>N  
boolean bDownOver = false; //Downing is over #cF ?a5  
boolean bStop = false; //Stop identical CkHifmc(u-  
FileAccessI fileAccessI = null; //File Access interface X`+8r O[  
^T.icSxP  
8Q*477=I  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Y~fa=R{W  
{ ,t!K? Y  
this.sURL = sURL; j@98UZ{g\  
this.nStartPos = nStart; mZgYR~  
this.nEndPos = nEnd; F s{}bQyQ  
nThreadID = id;  &3:U&}I  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 v?)u1-V0  
} ;r1.Uz(  
NmH:/xU?^  
oE;SZ"$ x  
public void run() d$;1%rRj8  
{ v< Ozr:lL  
while(nStartPos < nEndPos && !bStop) |#Q4e51H  
{ ~R$Ko(N  
pAY[XN  
o=}vK[0u  
try{  yf/c  
URL url = new URL(sURL); vr$zYdV>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M#5*gWfq9  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?!{nNJ  
String sProperty = "bytes="+nStartPos+"-"; w%NT 0J  
httpConnection.setRequestProperty("RANGE",sProperty); Ia'm9Z*  
Utility.log(sProperty); 0\X'a}8Bu  
>(9"D8  
N+V_[qr#  
InputStream input = httpConnection.getInputStream(); X  *f le  
//logResponseHead(httpConnection); L*'3f~@Q  
8YLS/dN0 w  
/5s,< 0Kz  
byte[] b = new byte[1024]; 7XDze(O5  
int nRead; ZQ_&HmgRy  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) vrr` ^UB2  
{ @8$3Q,fF(  
nStartPos += fileAccessI.write(b,0,nRead); q]}1/JZS  
//if(nThreadID == 1) ;V:Cf/@@R  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); h]w5N2$}?  
} qbunP!  
-gzY ~a  
jwW6m@+  
Utility.log("Thread " + nThreadID + " is over!"); L>PPAI  
bDownOver = true; %(v<aEQtt  
//nPos = fileAccessI.write (b,0,nRead); @9}SHS  
} !vQDPLBL  
catch(Exception e){e.printStackTrace ();} n#fc=L1U  
} &58TX[#  
} )`V__^  
t%'0uB#v1  
}2;{ }J  
//打印回应的头信息 D_(K{? KU  
public void logResponseHead(HttpURLConnection con) bpv?$j-j  
{ km[ PbC  
for(int i=1;;i++) q*36/I  
{ <M,A:u\qSQ  
String header=con.getHeaderFieldKey(i); 3L5o8?[  
if(header!=null) Ze:Y"49S+>  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 'aAay*1  
Utility.log(header+" : "+con.getHeaderField(header)); rf:C B&u  
else Jemb0Qv  
break; Z^?YTykH  
} ~p'DPg4  
} S^/:O.X)c,  
Z9+xB"q2  
h=`1sfz  
public void splitterStop() UZ qQ|3  
{ : ~R:[T2P  
bStop = true; y9@DlK  
} =w/S{yC  
8g!C'5  
]B'H(o R<|  
} yS2[V,vS7  
,2y " \_  
p#T^o]+  
/* "v9i;Ba>+  
**FileAccess.java YJ[Jo3M@j0  
*//文件访问(定位,写) c~=yD:$  
package NetFox; 0s%rd>3  
import java.io.*; }F;Nh7?  
KDmzKOl  
SyWLPh  
public class FileAccessI implements Serializable{ R/UL4R,)^  
-1P*4H2a  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^1 P@BRh  
RandomAccessFile oSavedFile; n!>#o 1Qr  
long nPos; ?4 &C)[^  
1MF0HiC  
g12mSbf=9  
public FileAccessI() throws IOException hV6=-QL*B  
{ u3XQ<N{Gj  
this("",0); faJ>,^V#  
} x(UOt;  
J91O$szA  
M^$liS.D  
public FileAccessI(String sName,long nPos) throws IOException w' gKE'c  
{ ~l=Jx*  
oSavedFile = new RandomAccessFile(sName,"rw"); |##rs  
this.nPos = nPos; _?IP}}jA:  
oSavedFile.seek(nPos); )ZP-t!).G#  
} >a aHN1Ca  
_H (:$=$Q  
@jp}WwC/  
public synchronized int write(byte[] b,int nStart,int nLen) eK]$8l|LI  
{ IUJRP  
int n = -1; fsxZQ=-PW  
try{ bR*/d-v^  
oSavedFile.write(b,nStart,nLen); jRv j:H9  
n = nLen; nYv`{0S+m  
} Oy `2ccQ#  
catch(IOException e) (fYrb# ]!y  
{ a=!I(50  
e.printStackTrace (); n~wNee  
} t'F_1P^*/  
Wxxnc#;lv  
?[ts<Ltp  
return n; 1~x=bphS  
} JnT1-=t.  
52L* :|b  
(6WSQqp  
} S/XkxGZ2  
Gw;[maM!%`  
Q6r!=yOEY  
/* OGjeE4  
**SiteInfoBean.java )ZI9n7  
*/ r,` 59  
package NetFox; @Q=P6Rz {S  
L< gp "e  
.L X8ko  
public class SiteInfoBean { 8O)!{gB  
]q2g[D o5  
l*yh(3~}  
private String sSiteURL; //Site's URL H3?HQ>&O7  
private String sFilePath; //Saved File's Path  EK:s#  
private String sFileName; //Saved File's Name qC%[J:RwF  
private int nSplitter; //Count of Splited Downloading File t[.wx.y&0  
;goR0PN  
N!`8-ap\^  
public SiteInfoBean() qhPvU( ,  
{//nSplitter的缺省值为5 V@(7K0  
//default value of nSplitter is 5 ARZ5r48)  
this("","","",5); $|2@of.  
} "?lm`3W"  
@"`{gdB$  
2`o}neF{  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) J01Y%W  
{ #e!4njdM  
sSiteURL= sURL; ;I#S m;  
sFilePath = sPath; x 7;Zwd  
sFileName = sName; y,*>+xk,  
this.nSplitter = nSpiltter; _uR-Z_z  
W:8*Z8?7  
{\?zqIM  
} #()u=)  
4+V+SD  
%>cl0W3x  
public String getSSiteURL() B~/LAD_  
{ _V9 O,"DDc  
return sSiteURL; C y b-}l  
} H8ws6}C  
CXQPbt[5  
9 pGND]tIi  
public void setSSiteURL(String value) 2ja@NT  
{ jQKlJi2xu  
sSiteURL = value; M# sDPT  
} Y{ho[%  
bHr2LhQCN  
\qrSJ=}t  
public String getSFilePath() R7L:U+*V"  
{ btfjmR<Tp  
return sFilePath; 8"M*,?.]  
} K$H>/*&'~  
`FP)-^A8  
Dm=Em-ST6  
public void setSFilePath(String value) G n_AXN  
{ da[u@eNrnX  
sFilePath = value; uh~/ybR  
} q>~\w1%}a\  
<&?gpRK   
Y}bJN%M  
public String getSFileName() `>1"v9eF  
{ idC4yH42  
return sFileName; PC| U]  
} 0`KB|=>  
M1MpR+7S  
5pBQ~m3  
public void setSFileName(String value) ::y+|V/  
{ ]y'/7U+  
sFileName = value; (O N \-*  
} ,_ XDCu @  
UXXN\D  
yn0OPjH  
public int getNSplitter() eB:OvOol*^  
{ >A$J5B >d  
return nSplitter; W |]24  
} !OJ@ =y`i  
,t+5(qi  
S^@I4Z  
public void setNSplitter(int nCount) K)Nbl^6x  
{ N#;k;Z'iL  
nSplitter = nCount; r@&d88U:  
} y@;4F n/  
} oh '\,zpL  
LF'M!C9|  
yJaQcGxE"  
/* JD^&d~n_  
**Utility.java :<OInKE>Cx  
*/ ?"p:6%GFz  
package NetFox; =?`5n|A*  
}}3*tn<6  
SWjOJjn  
public class Utility { Ge+&C RhyX  
ZDZPJp,  
u"K-mr#$[o  
public Utility() ~RVx~hh  
{ J?XEF@?'G  
um@RaU  
`0rEV _$  
} A# W%ud4  
71+J{XOC  
//线程睡眠 K?_4|  
public static void sleep(int nSecond) TxhTK5#f  
{ ,w|f*L$  
try{ uc?QS~H&w  
Thread.sleep(nSecond); zh$[UdY6  
} q/,W'lQ\;  
catch(Exception e) MOJ-q3H^W  
{ 6&=xu|M<x=  
e.printStackTrace (); "HW~|M7>(  
} pa&*n=&cL  
} Aa;R_Jz  
D-.XSIEMu  
//日志 4WnB{9 i`I  
public static void log(String sMsg) YF=@nR$_~j  
{ k/vE|  
System.err.println(sMsg); ?op6_a-wm  
} hq.z:D  
cLH|;  
Bv $;yR  
public static void log(int sMsg) t;9f7~  
{ [R j=k)aBm  
System.err.println(sMsg); <CL0@?*i9  
} D"F5-s7  
} jxL5L[  
byM/LE7)  
\oPW  
/* s> JmLtT  
**TestMethod.java VdR5ZP  
*/ wO!k|7:Z  
package NetFox; AigL:4[  
$|!VP'VI  
{A4"KX(U  
public class TestMethod { A%n l@`s,  
M_V\mYC8I  
M'D;2qo  
public TestMethod() c"%XE#D  
{ ///xx/weblogic60b2_win.exe 2.Ym  
try{ w .l2  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6hSj)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); F;jl0)fBR=  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $kJvPwRO  
fileFetch.start(); GLA,,i'i9  
} !3K6ew>Sf  
catch(Exception e){e.printStackTrace ();} +nRO<  
mq~7v1kw  
u>H^bCXI  
} De[!^/f;T  
,,oiL  
Vw=eC"  
public static void main(String[] args) =^4 vz=2  
{ )'M<q,@<(  
new TestMethod(); mFOuE5  
} <tAn2e!  
} _s!(9  
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