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http断点续传简单实现(java)

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/* CTrs\G  
**SiteFileFetch.java LK-6z w5=(  
*/ H6 f; BS  
package NetFox; _2Xu1q.6~5  
import java.io.*; _=^hnv  
import java.net.*; m-KK {{  
LkZo/K~  
He_(JXTP  
public class SiteFileFetch extends Thread { ';CuJ XAj  
'V9aB5O&  
E<G@LT  
SiteInfoBean siteInfoBean = null; //文件信息Bean a]=vq(N'r  
long[] nStartPos; //开始位置 ?`*-QG}  
long[] nEndPos; //结束位置 :iOHc-x  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Z6/~2S@  
long nFileLength; //文件长度 X.4ZLwX=  
boolean bFirst = true; //是否第一次取文件 8JOht(m  
boolean bStop = false; //停止标志 {s^ryv_}  
File tmpFile; //文件下载的临时信息 ;F]|HD9  
DataOutputStream output; //输出到文件的输出流 OFL+Q~~C  
<{xAvN( :  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 5Z1Do^  
public SiteFileFetch(SiteInfoBean bean) throws IOException V-U  ^O45  
{ $$;2jX"I  
siteInfoBean = bean; gwB> oi*OE  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); a:%5.!Vd  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _x|8U'|Ce  
if(tmpFile.exists ()) {hq ;7  
{ ci NTYow  
bFirst = false; A%8`zR  
read_nPos(); 3% 4Mq6Q`  
} D.Cs nfJ  
else y<x_v )k-  
{ JO6vzoS3  
nStartPos = new long[bean.getNSplitter()]; <7-,`   
nEndPos = new long[bean.getNSplitter()]; = Vr[V@  
} ?UhAjtYIS  
W me1w\0  
>,]e[/p  
eHyuO)(xH1  
} oYm{I ~"  
ez:o9)N4  
IV#My9}e  
public void run() ]}L1W`n  
{ Iybpk?,M+  
//获得文件长度 nu%Nt"~[%  
//分割文件 Dt'e<d Is  
//实例FileSplitterFetch -V_S4|>   
//启动FileSplitterFetch线程 SR8Kzk{  
//等待子线程返回 #2'&=?J1r  
try{ Py0 i%pZ  
if(bFirst) )n[Mh!mn  
{ <m gTWv  
nFileLength = getFileSize(); Y'%I at(z  
if(nFileLength == -1) iZUz6  
{ \bl,_{z?  
System.err.println("File Length is not known!"); @' :um  
} ^^Q32XC,  
else if(nFileLength == -2) 8jGoU 9  
{ `ip69 IF2*  
System.err.println("File is not access!"); %f(.OR)6{  
} R.'Gg  
else _p2<7x i   
{ 9 @*>$6  
for(int i=0;i<nStartPos.length;i++) $"n)C  
{ <=2*UD |  
nStartPos = (long)(i*(nFileLength/nStartPos.length));  k*6eZ7  
} /2V',0  
for(int i=0;i<nEndPos.length-1;i++) Wv/5#_  
{ ea}KxLC`,  
nEndPos = nStartPos[i+1]; A-!qO|E[-  
} R$m?&1K  
nEndPos[nEndPos.length-1] = nFileLength; /,%o<Ql9  
} vjRD?kF  
} x(N} ^Hu  
X.Y)'qSf  
R* G>)YH  
//启动子线程 /Z_ [)PTH  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; dY` J,s  
for(int i=0;i<nStartPos.length;i++) Ijro;rsEKM  
{ PCnJ2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), E1w XG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), kV9NFo22  
nStartPos,nEndPos,i); /j\TmcnU^  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V+5 n|L5  
fileSplitterFetch.start(); {#Cm> @')  
} c0p=/*s(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +NMSvu_?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Z'm%3  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %--5bwZi  
nEndPos = " + nFileLength); 4\WkXwoqQO  
// fileSplitterFetch[nPos.length-1].start(); -^Va]Lk  
<Py/uF|  
D5vtZu!"  
//等待子线程结束 CnA)>4E*'  
//int count = 0; emIbGkH  
//是否结束while循环 b>._ r&.  
boolean breakWhile = false; n:)Y'52}  
{X"]92+  
x)mC^  
while(!bStop) 9Bw5 t@  
{ w~?eX/;  
write_nPos(); r_RTtS#  
Utility.sleep(500); . L%@/(r  
breakWhile = true; ToM*tXj  
yvwcXNXR@  
o[6"XJ  
for(int i=0;i<nStartPos.length;i++) XYTcG;_z  
{ HhH'\-[t  
if(!fileSplitterFetch.bDownOver) D+PUi!  
{  Jl,x~d  
breakWhile = false; XKIJ6M~5k  
break; DdBr Jx  
} >G7U7R}R  
} S6Pb V}  
if(breakWhile) ..mz!:Zs0  
break; _J;a[Ky+[  
Hf|:A(vCx  
9DE)5/c`v  
//count++; swbD q  
//if(count>4) YHAg4 eb8  
// siteStop(); P*sCrGO%  
} Sd11ZC6  
e 3oIoj4o  
IvH+94[)  
System.err.println("文件下载结束!"); jK1! \j  
} El} z^e  
catch(Exception e){e.printStackTrace ();} DL{a8t1L  
} F\<i>LWT'  
Sp:de,9@  
j`l K}  
//获得文件长度 _zwuK1e  
public long getFileSize() [}3Y1t{G  
{ .1}(Bywm5  
int nFileLength = -1; ?! Gt. fb  
try{ 7|Y8^T s  
URL url = new URL(siteInfoBean.getSSiteURL());  t/(j8w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )}5r s  
httpConnection.setRequestProperty("User-Agent","NetFox"); b7mP~]V  
&T}e9 3]  
}$U6lh/Ep  
int responseCode=httpConnection.getResponseCode(); =p$Wo  
if(responseCode>=400) 1t'\!  
{ "rJL ^ \r  
processErrorCode(responseCode); ')<$AMy1  
return -2; //-2 represent access is error 5o #8DIal  
} _;W|iUreb  
}qPo%T  
]uf_"D  
String sHeader; P*]g*&*Y +  
GjBQxn  
R?I3xb  
for(int i=1;;i++) VTa8.(i6v  
{ S0yT%V  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); uM#/  
//Utility.log(in.readLine()); mQJGKh&Pk  
sHeader=httpConnection.getHeaderFieldKey(i); dGjvSK<1@  
if(sHeader!=null) XwMC/]lK<  
{ d?.x./1[qi  
if(sHeader.equals("Content-Length")) H R  
{ ysPW<  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 24fWj?A|^  
break; { q<l]jn9  
} f^ qQ 5N  
} TmiQq'm[b  
else plAt +*&  
break; cPSu!u}D  
} ?9A[;j|a0  
} y5}|Y{5  
catch(IOException e){e.printStackTrace ();} HDOaN  
catch(Exception e){e.printStackTrace ();} HY:n{= o  
ok'1  
f [D#QC  
Utility.log(nFileLength); nceF4Ty  
^xrR3m*d  
&-A 7%"  
return nFileLength; duCm+4,.  
} l?~h_8&fT  
6G],t)<A'-  
Hn)=:lI  
//保存下载信息(文件指针位置) RZjR d  
private void write_nPos() sM K/l @7  
{ Ql 1# l:Q  
try{ Mv3Ch'X[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @@QU"8q  
output.writeInt(nStartPos.length); <[bDNe["?  
for(int i=0;i<nStartPos.length;i++) I\_R& v  
{ ;z#9>99rH  
// output.writeLong(nPos); YX(%jcj*  
output.writeLong(fileSplitterFetch.nStartPos); ~S9nLb:O{  
output.writeLong(fileSplitterFetch.nEndPos); C Qebb:y  
} FKP^f\!M  
output.close(); j&9~OXYv  
} )d~Mag+  
catch(IOException e){e.printStackTrace ();} *?S\0a'W@  
catch(Exception e){e.printStackTrace ();} $.kYAsZts  
} gFH_^~7i8p  
{ig@Iy~DT  
|j<'[gB\p  
//读取保存的下载信息(文件指针位置) =Ao;[j)*!  
private void read_nPos() I~I%z'"RQd  
{ F 7=-k/k  
try{ dGg+[?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); s0u$DM2  
int nCount = input.readInt(); 6-~  
nStartPos = new long[nCount]; "?!IPX2\S  
nEndPos = new long[nCount]; b8Qm4b?:4  
for(int i=0;i<nStartPos.length;i++) t j0vB]c  
{ 6yU~^))bx  
nStartPos = input.readLong(); #LZ`kSlv4  
nEndPos = input.readLong(); Jc+U$h4  
} 3^\y>  
input.close(); x9=lN^/4  
} -:QyWw/d  
catch(IOException e){e.printStackTrace ();} `#V"@Go  
catch(Exception e){e.printStackTrace ();} *VU Xw@  
} jL# akV  
*=8)]_=f  
+2?[=g4;}  
private void processErrorCode(int nErrorCode) _ :z~P<%s  
{ 7]Egu D4  
System.err.println("Error Code : " + nErrorCode); ! 9e>J  
} {2nXItso  
:A$6Y*s\  
1\2 m'o  
//停止文件下载 ]k Pco4  
public void siteStop() Dj|S  
{ ` C1LR,J  
bStop = true; (R, eWWF8~  
for(int i=0;i<nStartPos.length;i++) ?OSd8E+itM  
fileSplitterFetch.splitterStop(); i0P+,U  
"YBA$ef$  
,ZSuo4  
} r{btBv  
} V6L_aee}CK  
//负责部分文件的抓取 s-*XAn ot  
**FileSplitterFetch.java >dM'UpN@  
*/ Wwz>tE  
package NetFox; ps]6,@uyB  
3B0%:Jj  
5IepVS(>?v  
import java.io.*; g^idS:GtX5  
import java.net.*; ;9~z_orNQZ  
}yw\+fc  
{*2A% }S  
public class FileSplitterFetch extends Thread { p#&6Ed*V  
'D4NPG`z  
8WH>  
String sURL; //File URL KQqlM  
long nStartPos; //File Snippet Start Position G`n-WP  
long nEndPos; //File Snippet End Position `'93J wYb  
int nThreadID; //Thread's ID /\9Kr;@vk  
boolean bDownOver = false; //Downing is over %guot~S|  
boolean bStop = false; //Stop identical YP7<j*s8  
FileAccessI fileAccessI = null; //File Access interface z7CYYU?  
#wo_  
oeIS&O.K  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException M]W4S4&Y=  
{ YcI]_[  
this.sURL = sURL; c]9OP9F  
this.nStartPos = nStart; 1vThb  
this.nEndPos = nEnd; &qr7yyY  
nThreadID = id; s^U^n//  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 |oM6(px  
} {r"s.|n  
_w26iCnB{  
_k}b  
public void run() 1~*_H_Q't  
{ r}991O<  
while(nStartPos < nEndPos && !bStop) sqy5rug  
{ %6n;B|!  
pp:+SoyN  
5mV'k"Om#"  
try{ >[p+L='  
URL url = new URL(sURL); *-n$n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >A)he!I  
httpConnection.setRequestProperty("User-Agent","NetFox"); ua{eri[  
String sProperty = "bytes="+nStartPos+"-"; %H@fVWe2wT  
httpConnection.setRequestProperty("RANGE",sProperty); }X$>84s>[P  
Utility.log(sProperty); AkF1Hj  
%8ul}}d9  
R6!3Y/Q@  
InputStream input = httpConnection.getInputStream(); 2@H~nw 0  
//logResponseHead(httpConnection); $OJ*Kul  
^,X+ n5q;m  
HCP Be2  
byte[] b = new byte[1024];  [W;14BD7  
int nRead; %!q(zql  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) $lv  g.u  
{ V}(%2W5X+  
nStartPos += fileAccessI.write(b,0,nRead); M:x8]TA  
//if(nThreadID == 1) jJf|Ok:G{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); DJbj@ 2W[  
} \h yTcFb  
koUH>J:  
E>ev/6ox  
Utility.log("Thread " + nThreadID + " is over!"); * T-XslI  
bDownOver = true; -,rl[1ZYZ  
//nPos = fileAccessI.write (b,0,nRead); kTzZj|l^\  
} R38 w!6{  
catch(Exception e){e.printStackTrace ();} n;MoMGnPh,  
} Y 8P  
} $yt|nO  
9uq| VU5  
`w q\K8v  
//打印回应的头信息 7W>T= @  
public void logResponseHead(HttpURLConnection con)  Op|Be  
{ snK/,lm.  
for(int i=1;;i++) 8xNKVj)@  
{ mr;WxxO5  
String header=con.getHeaderFieldKey(i); A[b'MNsv  
if(header!=null) x&f?c=\F  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); > 1r>cZn  
Utility.log(header+" : "+con.getHeaderField(header)); 7#RW4ZM  
else Ghj6&K%b0  
break; ,^'Y7"  
} 5/(Dh![l  
} wCdUYgsPT"  
:s4CWE d  
A*$vk2VWw  
public void splitterStop() wM|-u/9+  
{ UVUHLu|^  
bStop = true; `0so)2ty+  
} B}3s=+L@8  
@ }[)uH  
u%T.XgY=j  
} s_]rje8`  
F'"-4YV>&  
bkY7]'.bz&  
/* z*R"917  
**FileAccess.java Lrk^<:8;  
*//文件访问(定位,写) Xc@4(Nyp  
package NetFox; |GMK@Q'0:  
import java.io.*; l@^RbF['  
2Gj&7A3b  
m7eO T  
public class FileAccessI implements Serializable{ Q8P;AN_JS  
!?KY;3L:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 yyXJ_B  
RandomAccessFile oSavedFile; HezCRtxRcc  
long nPos; YX~H!6l  
2;q6~Y,  
D6 M:pIN*  
public FileAccessI() throws IOException f[X>?{q  
{ 10a=[\ Q  
this("",0); F6fm{  
} 2\7]EW  
(;s \Ip0  
r[hfN2,#  
public FileAccessI(String sName,long nPos) throws IOException alq>|,\x  
{ I5-/K VWb  
oSavedFile = new RandomAccessFile(sName,"rw"); C[[z3tn  
this.nPos = nPos; q-uYfXZ{j  
oSavedFile.seek(nPos); y(q1~73s  
} ]CTu |  
#-@dc  
[@/G?sAQm\  
public synchronized int write(byte[] b,int nStart,int nLen) 04,]upC${W  
{ jdhhvoQ  
int n = -1; v!W,h2:J  
try{ ;ymUMQ%;/  
oSavedFile.write(b,nStart,nLen); y<5s)OehG  
n = nLen; uD+;5S]us  
} V57^0^Zp`  
catch(IOException e) MRiETd"  
{ ysSEgC3  
e.printStackTrace (); Q:%gJ6pa  
} Zaq:l[%  
aE:fMDS|x  
&gq\e^0CRZ  
return n; 1W; +hXx  
} Ex~OT  
M T{^=F ]  
($ae n  
} zRu}lJ1#W$  
b7=]"|c$@  
P$q IB[Xi  
/*  vH` u  
**SiteInfoBean.java Um*{~=;u  
*/ Z EG  
package NetFox; g6nBu  
(/Nw  
K+n6.BzW  
public class SiteInfoBean { f\Pd#$3  
Rh: \/31~  
03# r F@e  
private String sSiteURL; //Site's URL E4WoKuE1$  
private String sFilePath; //Saved File's Path @!K)(B;A0b  
private String sFileName; //Saved File's Name A/ GEDG ?  
private int nSplitter; //Count of Splited Downloading File ]x~H"<V  
QHA<7Wg  
xH*OEzN  
public SiteInfoBean() Ff.gRx  
{//nSplitter的缺省值为5 /\C9FGS  
//default value of nSplitter is 5 vk{dL'  
this("","","",5); [ UQzCqV  
} *-g S u  
+   
tV%M2 DxS  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }`>u+iH#a  
{ <Y9ps`{}:  
sSiteURL= sURL; wxF9lZz  
sFilePath = sPath; Rh~<#"G]  
sFileName = sName; w!tQU9+ *  
this.nSplitter = nSpiltter; 5q" ;R$+j  
:0V<  
0hCJovSG%  
} *p+%&z_<  
skr^m%W  
6 70g|&v.  
public String getSSiteURL() Pgb<;c:4  
{ 1P&c:n  
return sSiteURL; R$NH [Tz  
} WCU[]A  
Wrt3p-N"D  
HlLF<k~}  
public void setSSiteURL(String value) .~C*7_  
{ |VTm5.23  
sSiteURL = value; .}2^YOmd  
} C$Ldz=d  
|f.=Y~aY  
 Trm)7B*  
public String getSFilePath() ?GX 5Pvg  
{ |Q.t]TR'P  
return sFilePath; w#]%I+  
} mG\,T3/*  
hyFq>XFo  
#;>J<>  
public void setSFilePath(String value) uB0/H=<H  
{ y~''r%]   
sFilePath = value; NSj}?hz  
} g,mcxXO  
wbVM'E/&  
Z=4Krfn  
public String getSFileName() ,.G6c=pZ  
{ `dMl5b  
return sFileName; cKdy)T%;  
} ~cQP4 kBD]  
i$$\}2m{L  
>\[sNCkf  
public void setSFileName(String value) ^o65sM  
{ I3p ~pt2  
sFileName = value; 6D@tCmmq  
} 'd(OFE-hn  
KhYGiVA  
cBiv=!n  
public int getNSplitter() On d"Eq=r  
{ R2Lq,(@-  
return nSplitter; 9kWyO:a_(  
} f!eC|:D  
pNCk~OM  
!JJCG  
public void setNSplitter(int nCount) ey@y?X=  
{ 2j*\n|"}{  
nSplitter = nCount; u3w `(3{ <  
} :/K 'P`JaL  
} Ds$FO}KD{  
}|&M@Up  
Y?R;Y:u3Z  
/* p;U[cGHC  
**Utility.java ycIT=AFYqd  
*/ @| qnD  
package NetFox; `N;u#z  
L*11hyyk  
{>pB  
public class Utility { O=G2bdY{,  
uFW4A  
rmk'{"  
public Utility() -|:7<$2#I  
{ <~<I K=n  
SG$/v  
kT[]^Jtc  
} Y6W3WPs(  
rM/*_0[`d  
//线程睡眠 KSMe#Qnw  
public static void sleep(int nSecond) 4cTJ$" v  
{ 0`3ey*  
try{ x.<^L] "  
Thread.sleep(nSecond); 0[x?Q[~S_0  
} 8HxB\ !0F?  
catch(Exception e) t> -cTQm  
{ HRC5z<k%  
e.printStackTrace (); gXE'3  
} > rB7ms/@E  
} f8 B*D4R}  
XK{`x<  
//日志 [`yiD>  
public static void log(String sMsg) RT F9;]Ti  
{ Z[slN5]([  
System.err.println(sMsg); 1Hy  
} tt6ElP|D  
2sk^A ly  
Cx} Yp-  
public static void log(int sMsg) _Oh;._PS  
{ _|g(BK2}  
System.err.println(sMsg); Xa Yx avq  
} >OBuHqC  
} U3&*,xeU@H  
I^qk`5w  
/1gKc}rB2  
/*  7=6p  
**TestMethod.java VQ$=F8ivG  
*/ mdoy1a  
package NetFox; D-8%lGS  
ouPwhB,bg  
~i=/@;wRp  
public class TestMethod { Q{0-pHr}  
ZL+{?1&-  
Wu2#r\  
public TestMethod() T=A7f6`  
{ ///xx/weblogic60b2_win.exe K/, B  
try{ J3}^\k=p"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); +pnT6kU|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); nv2Y6e}dG  
SiteFileFetch fileFetch = new SiteFileFetch(bean); mO?G[?*\  
fileFetch.start(); wGBQ.Ve[  
} '.#KkvE##  
catch(Exception e){e.printStackTrace ();}  i('z~  
a+{YTR>0m  
(|I0C 'Ki  
} ;^=eiurv  
 bXQ(6P  
{MO`0n; rt  
public static void main(String[] args) [f:>tRdH  
{ qF%wl  
new TestMethod(); &bRmr/D  
} ^8 AV#a  
} 'i%Azzv  
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