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http断点续传简单实现(java)

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/* qvs[Gkaa@  
**SiteFileFetch.java ?U,XyxN  
*/ D7v.Xq|  
package NetFox; cr!sq.)s  
import java.io.*; B~3qEdoK5`  
import java.net.*; RRtOBrIedI  
08$l=  
@ 3b-  
public class SiteFileFetch extends Thread { (DM8PtZg  
s="cg0PD  
oTeQY[%$  
SiteInfoBean siteInfoBean = null; //文件信息Bean 8WwLKZ}  
long[] nStartPos; //开始位置 AVp"<Uv  
long[] nEndPos; //结束位置 VKr oikz@]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 } d7o-  
long nFileLength; //文件长度 O.?q8T)n82  
boolean bFirst = true; //是否第一次取文件 Y2>*' nU  
boolean bStop = false; //停止标志 V/8yW3]Xy  
File tmpFile; //文件下载的临时信息 wHErF #xo  
DataOutputStream output; //输出到文件的输出流 !M k]%  
d`KW]HJw  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) e pAC%a  
public SiteFileFetch(SiteInfoBean bean) throws IOException oX-h7;SD  
{ kJ0otr2P  
siteInfoBean = bean; h='@Q_1Sb  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); gjy:o5{vA*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `"|u NVn  
if(tmpFile.exists ()) cs)z!  
{ [u8JqX  
bFirst = false; +'D #VG  
read_nPos(); QsPL^ Ny  
} r)Iq47Uiw  
else ;Z#DB$o\  
{ #]Q.B\\  
nStartPos = new long[bean.getNSplitter()]; ;gW?Fnry;  
nEndPos = new long[bean.getNSplitter()]; p:qj.ukw  
} qC YXkZ%`  
ZSW`/}Dp;  
r/6h}  
M{~KT3c  
} L3X[; |v}  
CFx$r_!~  
Og<UW^VR  
public void run() sm @Ot~;  
{ zI3Bb?4.  
//获得文件长度 8Vqh1<  
//分割文件 2aO.t  
//实例FileSplitterFetch 0Bhf(5  
//启动FileSplitterFetch线程 G |vG5$Nf  
//等待子线程返回 xn 4-^2  
try{ ZfN%JJOz(  
if(bFirst) 9!oNyqQ  
{ <f`G@  
nFileLength = getFileSize(); v/WvT!6V`  
if(nFileLength == -1) )}jXC4  
{ bT{iei]?  
System.err.println("File Length is not known!"); RgT|^|ZA  
} \LpR7D  
else if(nFileLength == -2) (lVHKg&U[  
{ -.X-02  
System.err.println("File is not access!"); /__@a&9t  
} KPSHBv-#  
else ')>&:~  
{ cfd7)(6  
for(int i=0;i<nStartPos.length;i++) vMV}M%~  
{ ?ydqmj2[F  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <)\  
} ^p 4 33  
for(int i=0;i<nEndPos.length-1;i++) u:f.g?!`"  
{ td#B$$[  
nEndPos = nStartPos[i+1]; jRP9e  
} F"<TV&xf  
nEndPos[nEndPos.length-1] = nFileLength; B#T4m]E/  
} usR: -1{  
} 8=U0\<wT  
<,!e*V*U  
@Js^=G2  
//启动子线程 %`[Oz[V  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0qj:v"~Q  
for(int i=0;i<nStartPos.length;i++) EBX+fzjQo  
{ "NgfdLz  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d/O~"d  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #DI%l`B  
nStartPos,nEndPos,i); rVE!mi]%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +q/ j  
fileSplitterFetch.start(); +I {ZW}rA  
} uwcm%N;I"  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), L:ox$RU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .MzVc42<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", *?a rEYc8  
nEndPos = " + nFileLength); S}Q/CT?au  
// fileSplitterFetch[nPos.length-1].start(); 1@)kNg)*$  
#MyR:V*a  
s?8vs%(l  
//等待子线程结束 %)$^_4.g  
//int count = 0; F?wfh7q  
//是否结束while循环 t0 1@h_ WS  
boolean breakWhile = false; G98P<cyD  
I0 78[3b  
CHeU?NtFps  
while(!bStop) n\v;4ly^  
{ qW1d;pt  
write_nPos(); 5v f?E"\r  
Utility.sleep(500); .>Gnb2  
breakWhile = true; -_bnGY%,  
sO,%Ok1  
ETw7/S${  
for(int i=0;i<nStartPos.length;i++) $?.0>0 ,<  
{ hmRnr=2N  
if(!fileSplitterFetch.bDownOver) /A8ua=Kn  
{ WU wH W  
breakWhile = false; (h} 5*u%h  
break; ! z^%$;p  
} CWP),]#n  
} Ry@QJn I<  
if(breakWhile) TSGJ2u5ie%  
break; dr|>P*  
:2'y=t#  
^PnXnH?  
//count++; S_E-H.d"  
//if(count>4) gn2*'_V~3  
// siteStop(); T<hS  
} toq/G,N Q  
o$*aAgS+  
>UUcKq1M:  
System.err.println("文件下载结束!");  ZA u=m  
} !Ez5@  
catch(Exception e){e.printStackTrace ();} 2 L>;M  
} V`/ E$a1&  
w\"~ *(M  
k<.$7Pl3U  
//获得文件长度 zTgY=fuz  
public long getFileSize() Fgx{ s%&-  
{ {|KFgQ'\  
int nFileLength = -1; R cZg/{[{  
try{ :]Nn(},  
URL url = new URL(siteInfoBean.getSSiteURL()); kLsp0% 2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  n[vwwY  
httpConnection.setRequestProperty("User-Agent","NetFox"); YUzx,Y>k  
''bh{ .x  
-0QoVGw  
int responseCode=httpConnection.getResponseCode(); y*F !k{P  
if(responseCode>=400) 04K[U9W3  
{ o1kTB&E4B  
processErrorCode(responseCode); Wq5 }SM  
return -2; //-2 represent access is error |/qwR~  
} J0ys Z]  
;u+k! wn  
`"(FWK=8)"  
String sHeader; j*.K|77WHj  
#r=Jc8J_  
GI se|[p  
for(int i=1;;i++) -w dbH`2Z"  
{ L;7u0Yg  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {Jna' eS  
//Utility.log(in.readLine()); x%v[(*F#y  
sHeader=httpConnection.getHeaderFieldKey(i); %O69A$Q[m  
if(sHeader!=null) .+07 Ui]I!  
{ 43VBx<"  
if(sHeader.equals("Content-Length")) L@5j? N?F  
{ (-no`j  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {\WRW}iO  
break; _o52#Q4   
} wit rC>  
} 9\zasa  
else ,qT^e8E+  
break; fN_qJm#:$y  
} ] 6X;&=H  
} Sx0/Dm  
catch(IOException e){e.printStackTrace ();} g@O H,h/  
catch(Exception e){e.printStackTrace ();} `SH14A*  
? K,d  
4St-Q]Y _  
Utility.log(nFileLength); b9xvLR8  
VnYcqeCm  
V0<g$,W=  
return nFileLength; ~.<QC<dN  
} ]vflx^<?  
mDXG~*1   
@DNwzdP  
//保存下载信息(文件指针位置) bess b>=  
private void write_nPos() hm\UqIt  
{ q'Nafa&a)  
try{ |@1M'  
output = new DataOutputStream(new FileOutputStream(tmpFile));  :I{9k~  
output.writeInt(nStartPos.length); i'QR-B&Z  
for(int i=0;i<nStartPos.length;i++) A>ve|us$  
{ s&4&\Aq}x#  
// output.writeLong(nPos); :4r{t?ytXw  
output.writeLong(fileSplitterFetch.nStartPos); xHD$0eq  
output.writeLong(fileSplitterFetch.nEndPos); zIA)se Js  
} B'e@RhU;  
output.close(); =.qX u+  
} \ iA'^69  
catch(IOException e){e.printStackTrace ();} y9N6!M|'y  
catch(Exception e){e.printStackTrace ();} RW<10:  
} l>?f+70  
QHr'r/0  
c{IL"B6>  
//读取保存的下载信息(文件指针位置) wmA TV/  
private void read_nPos() drxCjuz"  
{ >"+ ho  
try{ .Y0O.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?iZM.$![  
int nCount = input.readInt(); e"%uOuIYX  
nStartPos = new long[nCount]; .EReYZO  
nEndPos = new long[nCount]; '5b0 K1$"  
for(int i=0;i<nStartPos.length;i++) qg/FI#r  
{ 2q(gWhcj  
nStartPos = input.readLong(); 0CvGpM,  
nEndPos = input.readLong(); N4z[=b>  
} C+t0Zen  
input.close(); *8_Dn}u?Jx  
} A0Q`Aqs  
catch(IOException e){e.printStackTrace ();} \*&?o51 !e  
catch(Exception e){e.printStackTrace ();} }d>Xh8:%)  
} Vc;g$Xr[  
lQiw8qD  
C>'G?  
private void processErrorCode(int nErrorCode) 3d]~e  
{ V7}'g6X  
System.err.println("Error Code : " + nErrorCode); A|4om=MO  
} `zrg?  
k<P`  
?PS?_+E\L  
//停止文件下载 8AuE:=?,,  
public void siteStop() )o~/yB7  
{ >tPf.xI|l  
bStop = true; IdMwpru(  
for(int i=0;i<nStartPos.length;i++) .zl[nx[9"D  
fileSplitterFetch.splitterStop(); "G~!J\  
pg!MtuC}  
sVBr6 !v=  
} O$;#GpR  
} zc=G4F01  
//负责部分文件的抓取 n$XEazUb0N  
**FileSplitterFetch.java + kT ]qH  
*/ x/CM)!U)  
package NetFox; I]i( B+D  
_WvVF*Q"k  
&tvtL  
import java.io.*; l$pz:m]Id  
import java.net.*; gKl9Nkd!R  
Y#Q!mbp  
n?$c"}  
public class FileSplitterFetch extends Thread { j{r@>g;3  
NA/`LaJ  
9Bw#VQ  
String sURL; //File URL _Y ;tD  
long nStartPos; //File Snippet Start Position |&{S ~^$  
long nEndPos; //File Snippet End Position wggB^ }~  
int nThreadID; //Thread's ID i!}6FB Z  
boolean bDownOver = false; //Downing is over qEXN} Pq<  
boolean bStop = false; //Stop identical ,mHUo4h1O  
FileAccessI fileAccessI = null; //File Access interface m7y[Y  
W90!*1  
/hu>MZ(\  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException W>i%sHH6  
{ [tof+0Y6  
this.sURL = sURL; O=V_ 7I5  
this.nStartPos = nStart; aQ $sn<-l  
this.nEndPos = nEnd; &.?E[db"h  
nThreadID = id; {pH#zs4Y  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 .l_Nf9=  
} C 'MR=/sd  
#@OPi6.#!<  
(m,H 5  
public void run() o ?vGI=  
{ ?R#$ c]  
while(nStartPos < nEndPos && !bStop) z9[TjTH^}T  
{ qE[YZ(/f0&  
Uzzm2OS`  
P'OvwA  
try{ =xIZJ8e  
URL url = new URL(sURL); PBb&.<   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;j/$%lC  
httpConnection.setRequestProperty("User-Agent","NetFox"); eIalcBY  
String sProperty = "bytes="+nStartPos+"-"; uO LShNo  
httpConnection.setRequestProperty("RANGE",sProperty); }' AY#g  
Utility.log(sProperty); W6i{ yne W  
&H;,,7u  
]$Z:^" JS3  
InputStream input = httpConnection.getInputStream(); iO5g30l  
//logResponseHead(httpConnection); aqI"4v]~b  
D?1fY!C:r  
$xZ ~bE9  
byte[] b = new byte[1024]; B??07j  
int nRead; i^%$ydg  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) (?\+  
{ \6&Ml]1  
nStartPos += fileAccessI.write(b,0,nRead); tj@(0}pi4  
//if(nThreadID == 1) e9KD mX_  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )ciP6WzzbI  
}  rvd $4l^  
hOAZvrfQ4  
`2s@O>RV  
Utility.log("Thread " + nThreadID + " is over!"); 2uE<mjCt-r  
bDownOver = true; {s0%XG1$  
//nPos = fileAccessI.write (b,0,nRead); P+hcj p*  
} bJ!\eI%ld  
catch(Exception e){e.printStackTrace ();} Cr7Zi>sd<!  
} 1W{N6+u  
} . |T=T0^  
E:pk'G0bZ  
#%p44%W  
//打印回应的头信息 MMFwT(l<1  
public void logResponseHead(HttpURLConnection con) `]eJF|"  
{ {g%N(2  
for(int i=1;;i++) AYA{_^#+3  
{ M@A3+ v%K  
String header=con.getHeaderFieldKey(i); ;yt6Yp.6e  
if(header!=null) l:V R8g[  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %vJHr!x  
Utility.log(header+" : "+con.getHeaderField(header)); f)/Z7*Z  
else  l!|c_  
break; NZq-%bE  
} _AX 9 Mu]  
} `Y?VQ~ci>  
N*-tBz  
u-TT;k'  
public void splitterStop() BY6#dlDi  
{ S:_Ms{S  
bStop = true; C$y6^/7)  
} 3^o(\=-JX  
G68KoM  
X1| +9  
} \cIN]=#  
g<:Lcg"u  
X8|H5Y:  
/* K~ eak\=  
**FileAccess.java y *i&p4Y*  
*//文件访问(定位,写) %v0M~J}+  
package NetFox; DK4yAR,g  
import java.io.*; n$/|r  
c?A$Y?|9  
OsgPNy0  
public class FileAccessI implements Serializable{ @Po5AK3cy  
Lzh8-d=HQ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]at$ohS  
RandomAccessFile oSavedFile; YJJ1N/Z1  
long nPos; .a*?Pal@@  
E=sh^Q(A  
j_8 YFz5  
public FileAccessI() throws IOException PF{uaKWk  
{ )(}[S:`  
this("",0); MpCPY"WLL  
} !7N:cx'Qy  
>ED;_L*_o  
0]DOiA  
public FileAccessI(String sName,long nPos) throws IOException kuEXNi1l  
{ -c`xeuzK'  
oSavedFile = new RandomAccessFile(sName,"rw"); |a(KVo  
this.nPos = nPos; `0d 0T~  
oSavedFile.seek(nPos); BhJ>G%  
} O<m46mwM  
O=0p}{3l  
22l'kvo4"  
public synchronized int write(byte[] b,int nStart,int nLen) MP%#)O6  
{ }a]`"_i;[  
int n = -1; "-4|HA  
try{ W5|{A])N  
oSavedFile.write(b,nStart,nLen); -KiPqE%&G  
n = nLen; ?%O>]s  
} V6g*"e/8  
catch(IOException e) 2q?/aw ;Z  
{ LO`0^r  
e.printStackTrace (); X5)D[aE6  
} oC&}lp)q  
mb\T)rj  
i$Y#7^l%k  
return n; Jf^3nBZ  
} CsR[@&n'  
f|> rp[Gk  
9{pT)(Wnb  
} RoqkT|#$  
uLdHE5vr  
# qd!_oN  
/* }e7Rpgu  
**SiteInfoBean.java }&v}S6T  
*/ Q2fxsa[  
package NetFox; RXXHg  
w-).HPe  
pMU\f  
public class SiteInfoBean { Q& [!+s:2J  
1j2U,_-  
XpAJP++  
private String sSiteURL; //Site's URL Ar%*NxX  
private String sFilePath; //Saved File's Path :!i=g+e]  
private String sFileName; //Saved File's Name D0J{pAJ  
private int nSplitter; //Count of Splited Downloading File 5OdsT-y  
r/h\>s+N  
AbNr]w&pXC  
public SiteInfoBean() 'iMzp]V;  
{//nSplitter的缺省值为5 9/"&6,  
//default value of nSplitter is 5 BA a:!p  
this("","","",5); yzEyOz@Q  
} lBP?7`U  
a`Bp^(f}  
ivo3 pibk%  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) LJrH_h8C  
{ :$I "n\  
sSiteURL= sURL; ;(K/O?nrJ  
sFilePath = sPath; W=Syo&;F8  
sFileName = sName; tGOJ4 =  
this.nSplitter = nSpiltter; #X] *kxQ<  
6$"IeBRO  
8j Cho  
} w&@tP^`  
fBX@ MedC  
#8jiz+1 _  
public String getSSiteURL() zd_N' :6  
{ 8 n[(\f:  
return sSiteURL; &zYQ H@  
} @+;.W>^h  
h.-L_!1B7  
$.C\H,H  
public void setSSiteURL(String value) 9#[,{2pJr  
{ uP4yJ/]  
sSiteURL = value; (6c/)MH  
} Z6B$\Q5Od  
W. d',4)  
aVr(*s;/  
public String getSFilePath() >~d'i  
{ 8Z}%,G*n  
return sFilePath; [cDkmRV  
} t=lDN'\P  
Jd `Qa+  
'xd8rN %T  
public void setSFilePath(String value) L0VZ>!*o  
{ j hRr!  
sFilePath = value; R|@~<*  
} 7 cV G?Wr  
Z<<=2Xl(  
UNSXr`9  
public String getSFileName() T5`ML'Dej  
{ zWPX  
return sFileName; {$t*XTY6R  
} z}}P+P/  
?9?A)?O<j~  
\v+>qY<q  
public void setSFileName(String value) eSIG+{;&  
{ {oOUIP  
sFileName = value; %qsl<_&  
} ]Ndy12,M  
;4dFL\KU  
(z;lNl(*C  
public int getNSplitter() ;d>n2  
{ Q(A$ >A  
return nSplitter; Rkg)yme!N  
} 4cy,'B  
N,B!D~@  
W'Ew!]Q3  
public void setNSplitter(int nCount) WnGi;AGH=1  
{ a Z)1SX`D  
nSplitter = nCount; D 9;pjY  
} Fnk@)1  
} <!G\%C  
gT=pO`a  
L1+s0g>  
/*  mVS^HQ:  
**Utility.java m<#^c?u  
*/ =mX26l`B  
package NetFox; \7h>9}wGf  
^AI02`c.  
ab9ecZ  
public class Utility { }oiNgs/N  
gREk,4DAv  
g - !  
public Utility() n(V{ [  
{ nVoWER:  
}&L%c>  
2[=3-1c  
} +-),E.  
>}+R+''nR  
//线程睡眠 N)D+FV29y  
public static void sleep(int nSecond) Y j bp:  
{ wC%qSy'  
try{ 7@g0>1Fz  
Thread.sleep(nSecond); I0H]s/*C%9  
} `YwJ.E  
catch(Exception e) o_b3G  
{ IUEpE9_  
e.printStackTrace (); /;}%E  
} ?%~^PHgZ|  
} dR_6j}  
Id`V`|q  
//日志 6jBi?>[I  
public static void log(String sMsg) <[ 2?~s  
{ #C.  
System.err.println(sMsg); ~4=*kJ#7  
} l(87s^_  
m44a HBwId  
2ry@<88  
public static void log(int sMsg) / yBrlf  
{ o9sPyY$aQ  
System.err.println(sMsg); P%Vq#5  
} [[^95:  
} $+n6V2^K)7  
+'5I8FE-  
zdU 46|!u  
/* _4)z:?G5  
**TestMethod.java VZr:yE  
*/ Ng !d6]  
package NetFox; N8Zz6{rp  
OqciZ@#5n  
=$)M-;6  
public class TestMethod { #z%D d{E  
U'9z.2"}9  
8 I_  
public TestMethod() 4c(Em+ 4  
{ ///xx/weblogic60b2_win.exe N2'aC} I  
try{ QM 3DB  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Kw?3joy  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -j]k^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ;9h;oB@  
fileFetch.start(); J+E,UiZU  
} h ':ZF  
catch(Exception e){e.printStackTrace ();} (oX!D(OI  
rqmb<# Z  
0stc$~~v  
} V+lF|CZb5  
RfTGTz@H  
^O+(eA7E  
public static void main(String[] args) _7;:*'>a4  
{ 1 rhZlmf[r  
new TestMethod(); W!? h2[  
} nDC0^&  
} HVHv,:bPo  
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