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http断点续传简单实现(java)

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/* A=$oYBB  
**SiteFileFetch.java Vo%d;>!G\;  
*/ w.8~A,5}Dh  
package NetFox; 5-OvPTY`M  
import java.io.*; 1@WGbORc*  
import java.net.*; l;.BlHyu  
Y[!a82MTzn  
lK4+8VZ  
public class SiteFileFetch extends Thread { @I&"P:E0F;  
p[b\x_0%c  
a3;.{6el)H  
SiteInfoBean siteInfoBean = null; //文件信息Bean my1kF%?  
long[] nStartPos; //开始位置 |$PLZ,  
long[] nEndPos; //结束位置 z+*Z<c5d  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :~(im_r  
long nFileLength; //文件长度 K>[H@|k\k  
boolean bFirst = true; //是否第一次取文件 K +~v<F  
boolean bStop = false; //停止标志 c #kV+n<  
File tmpFile; //文件下载的临时信息 }kj6hnQ  
DataOutputStream output; //输出到文件的输出流 -e~U u  
ju]]|  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) D@^ZpN8r  
public SiteFileFetch(SiteInfoBean bean) throws IOException f[b YjIX  
{ +&OqJAu  
siteInfoBean = bean; 2?QJh2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *K|aK p}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5-^%\?,x  
if(tmpFile.exists ()) R(sM(x5a`  
{ iIE(zw)H  
bFirst = false; +,Az\aT/%  
read_nPos(); ` a>vPW  
} ^d80\PXz  
else t\i1VXtO  
{ Jj:6 c  
nStartPos = new long[bean.getNSplitter()]; ?Z>.G{Wm@  
nEndPos = new long[bean.getNSplitter()]; n#Roz5/U  
} zU~..;C  
[+g@@\X4  
gE&W6z0fJ  
xXZKj  
} aMQjoamz  
P/Kit?kngS  
NRisr  
public void run() .dT;T%3fO  
{ {X<4wxeTo  
//获得文件长度 _}OJPahw  
//分割文件 61W/BU7O  
//实例FileSplitterFetch V<4+g/  
//启动FileSplitterFetch线程 y?n2`l7f  
//等待子线程返回 RX5.bVp eE  
try{ =nx:GT3&[  
if(bFirst) |<-F|v9og  
{ XcMJD(!  
nFileLength = getFileSize(); ,|X+/|gm  
if(nFileLength == -1) >:E* 7  
{ 4iNbK~5j  
System.err.println("File Length is not known!"); +'/}[1q1/T  
} xDJ+BQ<1A  
else if(nFileLength == -2) ^ Wfgwmh  
{ 2l@"p!ar=  
System.err.println("File is not access!"); 7sc<dM  
} PKR $I  
else H [Lt%:r  
{ ^8NLe9~p3?  
for(int i=0;i<nStartPos.length;i++) ]}[Yf  
{ 5 n+ e  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); OR\DTLIl  
} ~r^5-\[hZ  
for(int i=0;i<nEndPos.length-1;i++) t {SMSp  
{ jD/7/G*  
nEndPos = nStartPos[i+1]; P:(EU s}0  
} >u5g?yzw  
nEndPos[nEndPos.length-1] = nFileLength; P$18Xno{  
} p x|>v8  
} LR3`=Z9  
/*AJr  
|vfujzRZ  
//启动子线程 :,NFFN  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |'c4er/;#  
for(int i=0;i<nStartPos.length;i++) H 5U x.]y  
{ _7lt(f[S  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M_h8#7{G  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), lC=N:=Mu  
nStartPos,nEndPos,i); 1iJ0Hut}d  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); DhLr^Z!h3;  
fileSplitterFetch.start(); NTm<6Is`  
} OG`|td  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), L/q]QgCoA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4YDT%_h0  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "($Lx  
nEndPos = " + nFileLength); jVad)2D  
// fileSplitterFetch[nPos.length-1].start(); |Bx||=z`  
eC6>yD6D  
;Y'8:ncDn  
//等待子线程结束 x0\e<x9s  
//int count = 0; P>*Fj4 Z~  
//是否结束while循环 EqD^/(,L2  
boolean breakWhile = false; 1l/AKI(!  
| }K  
D:wnO|:  
while(!bStop) 9ZDVy7m\i-  
{ k SB  
write_nPos(); `d7gm;ykp  
Utility.sleep(500); J| SwQE~  
breakWhile = true; PXw| L  
`"a? a5]k  
Dv<wge`  
for(int i=0;i<nStartPos.length;i++) 6xH;: B)d  
{ $!!R:Wn/R  
if(!fileSplitterFetch.bDownOver) )]%e  
{ NWEhAj<w  
breakWhile = false; Wrmgu}q  
break; oW0gU?Rr)u  
} HSNOL  
} <57g{e0I  
if(breakWhile) ,H>W:O  
break; 807al^s x  
b -PSm=`  
q75ky1^1:  
//count++; `9/0J-7*  
//if(count>4) gs?8Wzh90*  
// siteStop(); 5XDgs|8  
} R]Hz8 _X  
& =G)NeT_  
:-z&Y492  
System.err.println("文件下载结束!"); _B)s=Snx  
} d$w(-tV42  
catch(Exception e){e.printStackTrace ();} `M&P[ .9Pz  
} Cl,9yU)1n  
S+r^B?a<oM  
Q|?'(J+  
//获得文件长度 sa*g  
public long getFileSize() B`i$Wt<7  
{ FC{})|yh }  
int nFileLength = -1; tZbFvk2  
try{ @Tm`d ?^  
URL url = new URL(siteInfoBean.getSSiteURL()); V\0E=M*P  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yO00I`5  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7'z(~3D  
}`9jH:q-Z  
tAERbiH  
int responseCode=httpConnection.getResponseCode(); OZf6/10O/  
if(responseCode>=400) S#tY@h@XV  
{ msiu8E  
processErrorCode(responseCode); [ 7g><  
return -2; //-2 represent access is error jXixVNw  
} 28a$NP\KW  
{=67XrWN1  
1c$vLo832  
String sHeader; )n>+m|IqY(  
DSvmVI  
R:M,tL-l  
for(int i=1;;i++) Tg0CE60"  
{ L_Q S0_1  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); c+g@Z"es  
//Utility.log(in.readLine()); ?F_)-  
sHeader=httpConnection.getHeaderFieldKey(i); Ird|C[la  
if(sHeader!=null) 2Q@Y^t   
{ z8"7u /4v{  
if(sHeader.equals("Content-Length")) l(!/Q|Q|  
{ H>XFz(LWh  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2 o4^  
break;  lq>AGw  
} V%*b@zv  
} ?T!)X)A#  
else "hQgLG  
break; VL\t>n  
} 1& ^?U{  
} MjD75hIZ  
catch(IOException e){e.printStackTrace ();} y t5H oy  
catch(Exception e){e.printStackTrace ();} 36vgX=}  
D=+NxR[  
$!B}$I;cd  
Utility.log(nFileLength); 69OF_/23  
'V (,.'  
<%P2qgz5  
return nFileLength; ?6"{!s{v  
} 4<gb36)|4  
S6g<M5^R  
G8J*Wnwu[K  
//保存下载信息(文件指针位置) ;+/o?:AH  
private void write_nPos() _>yoX  
{ (Un_!)  
try{ t9cl"F=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); `$TRleSi  
output.writeInt(nStartPos.length); =d)-Fd2li  
for(int i=0;i<nStartPos.length;i++) ._PzYE|m2  
{ :O= \<t  
// output.writeLong(nPos); :j^FJ@2_  
output.writeLong(fileSplitterFetch.nStartPos); `5~3G2T  
output.writeLong(fileSplitterFetch.nEndPos); AUe# RP  
} n6<V+G)T  
output.close(); .(CP. d  
} {{yZ@>o6  
catch(IOException e){e.printStackTrace ();} $I9qgDJ)  
catch(Exception e){e.printStackTrace ();} 0#cy=*E  
} [7FItlF%I  
F4L;BjnJ  
@]aOyb@  
//读取保存的下载信息(文件指针位置) $*R/tJ.  
private void read_nPos() C3NdE_E  
{ ^-z=`>SrS"  
try{ fw6UhG  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); cWyW~Ek  
int nCount = input.readInt(); {gbn/{  
nStartPos = new long[nCount]; }a AH  
nEndPos = new long[nCount]; f"1>bW>R+  
for(int i=0;i<nStartPos.length;i++) 0 &_UH}10  
{ sZGj"_-Hzu  
nStartPos = input.readLong(); 03E4cYxt5  
nEndPos = input.readLong(); 3jB$2:#  
} b` Hz$8  
input.close(); !`41q=r  
} jO*l3:!~\  
catch(IOException e){e.printStackTrace ();} ?`zXLY9q7  
catch(Exception e){e.printStackTrace ();} +5VLw  
} YQJ==C1  
p~ HW5\4  
I$N8tn+E  
private void processErrorCode(int nErrorCode) GaX[C<Wt  
{ JR CrZW}  
System.err.println("Error Code : " + nErrorCode); EnOU?D  
} ^uv<6  
J Ro?s~Ih  
^WBuMCe  
//停止文件下载 ;qHOOT  
public void siteStop() {pM?5"M MJ  
{ [kE."#  
bStop = true; 4jD2FFG- G  
for(int i=0;i<nStartPos.length;i++) -'~ LjA(  
fileSplitterFetch.splitterStop(); 34\(7JO  
Xd^\@  
.9Y)AtJTS  
} S[WG$  
} o sKKt?^?  
//负责部分文件的抓取 6G=j6gK%P  
**FileSplitterFetch.java UTXSeNP  
*/ sc,Xw:YO  
package NetFox; kbM3  
gz3pX#S  
E Cyyl  
import java.io.*; zOQ>d|p?X  
import java.net.*; bV,}Pp+/"!  
rRFhGQq1m  
fW?o@vlO  
public class FileSplitterFetch extends Thread { y*X_T,K 8  
n=[/Z!  
9-MUX^?u  
String sURL; //File URL J H7<  
long nStartPos; //File Snippet Start Position W*2U="t  
long nEndPos; //File Snippet End Position ght$9>'n  
int nThreadID; //Thread's ID rS;Dmm  
boolean bDownOver = false; //Downing is over yj\Nkh  
boolean bStop = false; //Stop identical 1YH+d0UGn  
FileAccessI fileAccessI = null; //File Access interface uC cYPvm  
6Oy$gW)  
0\eIQp  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [sW3l:^  
{ x9JD\vZ  
this.sURL = sURL; :8OZ#D_Hl  
this.nStartPos = nStart; &G-!qxe  
this.nEndPos = nEnd; ' ET~  
nThreadID = id; ,k;^G>< =  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 % yw?s0  
} 6ZP"p<xX  
3U0`,c\ao*  
]iUx p+  
public void run() B\XKw'   
{ va0{>Dc+  
while(nStartPos < nEndPos && !bStop) S Em Q@1  
{ Ck) * &  
LA}S yt\F  
Kkm>e{0)AY  
try{ 85LAY aw  
URL url = new URL(sURL); ,Pdf,2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0"pAN[=K@  
httpConnection.setRequestProperty("User-Agent","NetFox"); $adbCY \  
String sProperty = "bytes="+nStartPos+"-"; )% ~OH  
httpConnection.setRequestProperty("RANGE",sProperty); 3v1iy / /  
Utility.log(sProperty); ~=uWD&5B4  
pu2 tY7J a  
3`t%g[D1  
InputStream input = httpConnection.getInputStream(); E2Q[ZoVS  
//logResponseHead(httpConnection); '/^qJ7eb  
6">+ ~ G  
n $$SNWgM  
byte[] b = new byte[1024]; "eB$k40-  
int nRead; n[lJLm^(_C  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) w5Y04J  
{ 7$CBx/X50)  
nStartPos += fileAccessI.write(b,0,nRead); Ab{ K<:l  
//if(nThreadID == 1) (>nGQS]H  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X\{LnZ@r4  
} U:^PC x`  
%C| n9*  
TFlet"ge=  
Utility.log("Thread " + nThreadID + " is over!"); )48QBz?  
bDownOver = true; {zQ8)$CQ  
//nPos = fileAccessI.write (b,0,nRead); ;$.J3!  
} 3G}x;Cp\D  
catch(Exception e){e.printStackTrace ();} }fb#G<3  
} D1zBsi94D  
} $u]jy0X<Y;  
3@dL /x4A  
Q(wx nm  
//打印回应的头信息 a_f~N1kq  
public void logResponseHead(HttpURLConnection con) QbkLdM,S*  
{ 7%Gwc?[x  
for(int i=1;;i++) :XZU&Sr"  
{ JtYP E?  
String header=con.getHeaderFieldKey(i); ^o3"#r{:+  
if(header!=null) l;R%= P?'F  
//responseHeaders.put(header,httpConnection.getHeaderField(header));  HN=V"a  
Utility.log(header+" : "+con.getHeaderField(header)); ,':fu  
else \^L`7cBL  
break; TC!Yb_H}gN  
} $q6BP'7  
} Ugu[|,  
EMwS1~3dD  
$WyD^|~SF  
public void splitterStop() -JMdE_h  
{ 5na~@-9p  
bStop = true; Q sZx) bO  
} C7lH]`W|/  
zi|+HM  
be]bZ 1f  
} dgR g>)V  
"& ])lz[u  
$?Yry. 2  
/* `eE&5.   
**FileAccess.java G`SUxhCk  
*//文件访问(定位,写) Sj]T   
package NetFox; diJLZikk  
import java.io.*; Aydm2!l1  
e@Fo^#ImDx  
Wvbf"hq  
public class FileAccessI implements Serializable{ LPZF)@|`  
nygbt<;?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 "'c A2~  
RandomAccessFile oSavedFile; q$I;dOCJ,  
long nPos; S>h;K`  
3LAIl913  
tjIl-IQ  
public FileAccessI() throws IOException $bW3_rl%X  
{ AqWUwK9T  
this("",0); Huy5-[)15  
} $G8E 3|k  
AJh w  
l==``  
public FileAccessI(String sName,long nPos) throws IOException Sh/T,  
{ DK$X2B"cV  
oSavedFile = new RandomAccessFile(sName,"rw"); ~Mx!^  
this.nPos = nPos; GR&z,  
oSavedFile.seek(nPos); -8; 7Sp1  
} I KqQ>Z-q~  
4]yOF_8h  
dYT%  
public synchronized int write(byte[] b,int nStart,int nLen) wG~`[>y (  
{ hlV=qfc  
int n = -1; K~AR*1??[  
try{ {9?JjA  
oSavedFile.write(b,nStart,nLen); W=j[V Oq  
n = nLen; \#f <!R4  
} tXoWwQD;Y  
catch(IOException e) kO,zZF&  
{ Y'1S`.  
e.printStackTrace (); wfNk=)^$  
} zDw5]*R  
[0(B>a3J  
Zo|.1pN  
return n; gYNjzew'  
} !F1M(zFD  
"Om=N@?  
mR&H9 NG  
} -7*ET3NSI/  
u])b,9&En  
tasIDoo+!J  
/* ur3(HL  
**SiteInfoBean.java )Hpa}FGT  
*/ ]ro*G"-_1#  
package NetFox; Q~OxH'>>(  
_oHNkKQ  
wCr(D>iM  
public class SiteInfoBean { v K9E   
H=g`hF]`  
/LvRP yj@  
private String sSiteURL; //Site's URL  Of"  
private String sFilePath; //Saved File's Path ]b\yg2  
private String sFileName; //Saved File's Name &7`^i.fh)  
private int nSplitter; //Count of Splited Downloading File Jll-`b 1  
V#XppYU  
F ~^Jmp7Y  
public SiteInfoBean() :<hXH^n  
{//nSplitter的缺省值为5 6kNrYom  
//default value of nSplitter is 5 EH256f(&  
this("","","",5); j/fzzI0@  
} `+o 2DA)#(  
n@C[@?D  
W+PJZn  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) N>XS=2tzN  
{ Y&S24aql  
sSiteURL= sURL; )2bvQy8K  
sFilePath = sPath; 8zRP (+&W  
sFileName = sName; PmKeF}  
this.nSplitter = nSpiltter; ;D:9+E<>a  
Y0x%sz 5  
P{wF"vf  
} Y~L2  
SZ,YS 4M  
\#Pfj &*  
public String getSSiteURL() In18_ bc  
{ +89*)pk   
return sSiteURL; w8MG(Lq1"  
} P(+&OoY2  
T)H{  
x4E7X_  
public void setSSiteURL(String value) XZ^^%*ew  
{ l|kSsP:GO  
sSiteURL = value; ~]nSSD)\  
} L<ue$'  
wB!Nc Y\p  
f@Zszt  
public String getSFilePath() ^; )8VP6  
{ Cj{1H([-  
return sFilePath; ] Hztb  
} (NF~Ck$#q  
S7/eS)SQR  
[8T^@YN  
public void setSFilePath(String value) 3HcQ(+Z  
{ M<kj_.  
sFilePath = value; X!9 B2w  
} C~o7X^[R\  
mF,Y?ax  
whi`Z:~  
public String getSFileName() f;W|\z'  
{ Rm255z p  
return sFileName; :lf+W  
} TFkZpe;  
Bq D'8zLD  
ki?S~'a  
public void setSFileName(String value) e\!0<d  
{ 19E 8'@  
sFileName = value; qz0;p=$8Z  
} 57umx`m  
+trC,D  
E5I"%9X0H  
public int getNSplitter() /v- 6WSN  
{ +l9!Fl{MK\  
return nSplitter; n1ly y0%u  
} n%-R[vW  
BD_Iz A<wK  
3%E }JU?MM  
public void setNSplitter(int nCount) lku[dQdk  
{ 6{n!Cb[e  
nSplitter = nCount; 62 k^KO6Y  
} 9Iwe2lu  
} mH%yGBp_  
M>~Drul  
.1KhBgy^K  
/* pWK(z[D  
**Utility.java *h!28Ya(~  
*/ ]x RM&=)<  
package NetFox; (tIo:j  
nExU#/*~^  
'ig&$fzb  
public class Utility { ,z;cbsV-{  
CE#gfP  
N/ %WsQp  
public Utility() ^@3sT,M,S  
{ #gz M|  
Sdt`i  
QZ6D7t Uc8  
} l_o@miG/  
4]?<hH9  
//线程睡眠 2%LL Sa  
public static void sleep(int nSecond) 7 n8"/0kc:  
{ Yw^m  
try{ Q.l}NtHwV  
Thread.sleep(nSecond); yXSFjcoB  
} h"X;3b^ m  
catch(Exception e) ,]9P{k]O  
{ % tS,}ze  
e.printStackTrace (); AL9chYP}/  
} R3x3]]D  
} w65K[l;2  
11o.c;  
//日志 ?}wk.gt>  
public static void log(String sMsg) 0 ?s|i :  
{ OLyf8&AU@  
System.err.println(sMsg); 1eS&&J5  
} B<5R   
yA)/Q Yge  
|iakz|])  
public static void log(int sMsg) ur)9x^y  
{ (SpX w,:  
System.err.println(sMsg); Cn,d?H  
} Gr*r=s  
} CAfGH!l!  
E{XH?_xo  
wxKX{Bs  
/* SF7\<'4\N  
**TestMethod.java `, OG7hg  
*/ ff]6aR/ UQ  
package NetFox; "|EM;o  
'~5LY!H(pT  
% Qmn-uZ  
public class TestMethod { }tRm]w  
;Y 00TGU  
CS2 Bo  
public TestMethod() e%svrJ2   
{ ///xx/weblogic60b2_win.exe ~-ia+A6GIV  
try{ ,k24w7K%d  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); s3z$e+A8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); y&6FybIz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &*##bA"!B  
fileFetch.start(); 6V$Avg\6\  
} `.E[}W  
catch(Exception e){e.printStackTrace ();} \HqNAE2T  
Z-^LKe  
Z/W:97M  
} t>L;kRujVJ  
@P#N2:jwj  
=m!-m\B/  
public static void main(String[] args) pV9IHs}  
{ Yrb{ByO&  
new TestMethod(); }u\])I3  
} SON-Z"v  
} y`VyQWW  
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