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http断点续传简单实现(java)

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/* W:VX^8</  
**SiteFileFetch.java [Smqe>U 1  
*/ 7u`:e,'  
package NetFox; Og-v][  
import java.io.*; oL U!x  
import java.net.*; {%Rntb  
Cu! S|Xj.  
S'(IG m4  
public class SiteFileFetch extends Thread { {ui{Yc  
bn:74,GeyK  
U<|*V5   
SiteInfoBean siteInfoBean = null; //文件信息Bean mrQT:B\8  
long[] nStartPos; //开始位置 ~K@p`CRbV  
long[] nEndPos; //结束位置 H0\' ,X  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @$fvhEkrT@  
long nFileLength; //文件长度 RF}R~m9]  
boolean bFirst = true; //是否第一次取文件 <:>[24LJ{  
boolean bStop = false; //停止标志 "_0sW3rG  
File tmpFile; //文件下载的临时信息 zI= 9  
DataOutputStream output; //输出到文件的输出流 Z&|Dp*Z  
eGW h]%  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 3Yf~5csY  
public SiteFileFetch(SiteInfoBean bean) throws IOException 7q&T2?GEN  
{ )i"52!  
siteInfoBean = bean; G:!3X)b  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); uquY z_2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .6c Bx  
if(tmpFile.exists ()) OIs!,G|  
{ {)I&&fSz  
bFirst = false; o'_eLp  
read_nPos(); GdM|?u&s"  
} Mtaky=l8~I  
else *P\OP'o_  
{ =4uO"o  
nStartPos = new long[bean.getNSplitter()]; _"t"orD6  
nEndPos = new long[bean.getNSplitter()]; |RH^|2:x9Q  
} j9/hZqo  
siOyp ]  
KwY6pF*  
8/@*6J  
} P N(<=v&E  
aJ J)ZP2+  
*XI- nH  
public void run() Et'&}NjI  
{ \I7&F82e  
//获得文件长度 <u  ImZC  
//分割文件 _D{{C  
//实例FileSplitterFetch =)%~QK {Y  
//启动FileSplitterFetch线程 79 \SbB  
//等待子线程返回 ]P2Wa   
try{ Wb5n> *  
if(bFirst) N97WI+`  
{ !jg< S>S5  
nFileLength = getFileSize(); f3*SIKi  
if(nFileLength == -1) 8CUl |I ~  
{ MSb0J`  
System.err.println("File Length is not known!"); je74As[  
} n){u!z)Al  
else if(nFileLength == -2)  GG(}#Z5h  
{ b?-KC\}v  
System.err.println("File is not access!"); NftR2  
} %~\I*v04  
else <Q8d{--o  
{ #iT3 aou  
for(int i=0;i<nStartPos.length;i++) }}LjEOvL=  
{ CpU y~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); $'w>doUlA  
} Yq:+.UU  
for(int i=0;i<nEndPos.length-1;i++) @=?#nB&  
{ 7WHq'R{@  
nEndPos = nStartPos[i+1]; !]MGIh#u  
} &S[>*+}{+  
nEndPos[nEndPos.length-1] = nFileLength; z J V>;  
} G)gPL]C0  
} BSY7un+`:  
km,@yU  
nu X`>Oy  
//启动子线程 *>T@3G.{Rm  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; zCrM~  
for(int i=0;i<nStartPos.length;i++) JD ~]aoH  
{ KkSv2 3In  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), h`D+NZtWm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), in>?kbaG+  
nStartPos,nEndPos,i); Np?/r}  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #U6~U6@  
fileSplitterFetch.start(); ,o\~d ?4  
} B7n1'?  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7G%^8 ce{!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); v"sN K  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #&Zj6en}M]  
nEndPos = " + nFileLength); Gdr7d  
// fileSplitterFetch[nPos.length-1].start(); !Xzy:  
V0*9Tnc  
/< \do 1  
//等待子线程结束 .WS7gTw  
//int count = 0; 7Pr5`#x#  
//是否结束while循环 .c@,$z2M  
boolean breakWhile = false; T*#<p;  
QKh vP>  
tj:>o#D  
while(!bStop) O*1la/~m  
{ u:>*~$f   
write_nPos(); t7/a5x  
Utility.sleep(500); ~t^'4"K*  
breakWhile = true; y<)q;fI7  
)C>M74Bt  
b\+9#)Up@  
for(int i=0;i<nStartPos.length;i++) 41o ~5:&  
{  KRh?{  
if(!fileSplitterFetch.bDownOver) rlkg.e6  
{ H?j}!JzAC  
breakWhile = false; -l$-\(,M`#  
break; I_'0!@Nn7  
} jxZd =%7Q  
} }#E~XlX^  
if(breakWhile) %loe8yt  
break; okD7!)cr=  
!qJ|`o Y  
#po}Y  
//count++; 0GnbE2&  
//if(count>4) BoXGoFn  
// siteStop(); $1myf Z  
} ^qPS&G  
Ok_)C+o  
#zKF/H|_R  
System.err.println("文件下载结束!"); -;U3$[T,J7  
} yQ+C}8r5  
catch(Exception e){e.printStackTrace ();} lR3JyYY{X  
} J,^eq@(  
6n'XRfQp)&  
vLh,dzuo  
//获得文件长度 ^BQ*l5K  
public long getFileSize() @Ke3kLQ_\X  
{ xkkW?[&  
int nFileLength = -1; z*&r@P -  
try{ OEs!H]v  
URL url = new URL(siteInfoBean.getSSiteURL()); TYgn X  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~f] I0FK  
httpConnection.setRequestProperty("User-Agent","NetFox"); eX9H/&g  
!e:HE/&>i  
WAp#[mW.fx  
int responseCode=httpConnection.getResponseCode(); n*i1QC  
if(responseCode>=400) b+mh9q'5E  
{ QP4`r#,  
processErrorCode(responseCode); IF.6sJg:  
return -2; //-2 represent access is error F anA~  
} S-)%#  
BW%"]J  
f m'Qif q^  
String sHeader; ( O/+.qb  
0:3<33]x  
0x8aKq\'  
for(int i=1;;i++) P6o-H$ a+  
{  IQCIc@5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); )6Qk|gIu(  
//Utility.log(in.readLine()); ue#Y h  
sHeader=httpConnection.getHeaderFieldKey(i); r!J?Lc])8  
if(sHeader!=null) )qx,>PL  
{ w(vda0  
if(sHeader.equals("Content-Length")) K~aI Y0=<  
{ ^DS+O>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;COZHj9b  
break; & l NHNu[  
} C!aK5rqhv  
} |{H-PH*Iz  
else >L>t$1hXM  
break; ^ql+l~  
} Ga} &%  
} _rf  
catch(IOException e){e.printStackTrace ();} nyR4E}@:O  
catch(Exception e){e.printStackTrace ();} 7ezf.[{R  
l/w<R  
kKR Z79"7s  
Utility.log(nFileLength); t&=]>blIs  
D$ +"n  
Xm}~u?$3  
return nFileLength; 0`dMT>&I  
} o`]u&  
XK4idC  
4`#3p@-  
//保存下载信息(文件指针位置) /|2#s%|-=  
private void write_nPos() -wjvD8fL  
{ UP}5Eh  
try{ yp:_W@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ONw;NaE,  
output.writeInt(nStartPos.length); jPf*qe>U  
for(int i=0;i<nStartPos.length;i++) fUg I*V  
{ QR;E>eEq  
// output.writeLong(nPos); 'Nbae-pf  
output.writeLong(fileSplitterFetch.nStartPos); X#*|_(^  
output.writeLong(fileSplitterFetch.nEndPos); ;n,@[v  
} @dj 2#  
output.close(); P7i G,i  
} px1{=~V/  
catch(IOException e){e.printStackTrace ();} ^N5BJ'[F:  
catch(Exception e){e.printStackTrace ();} H#B~ h4#  
} RuHMD"  
9(( QSX  
aGY F\7  
//读取保存的下载信息(文件指针位置) 51k^?5cO  
private void read_nPos() F! ;0eS"xp  
{ A+lP]Oy0S  
try{ Qpc+1{BQ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); //}[(9b'\  
int nCount = input.readInt(); /U#{6zeM[,  
nStartPos = new long[nCount]; JS<4%@  
nEndPos = new long[nCount]; d= -/'_'  
for(int i=0;i<nStartPos.length;i++) $6X CHVx  
{ N3Jfp3_b@  
nStartPos = input.readLong(); zp2IpYQ,3  
nEndPos = input.readLong(); !`G7X  
} |NcfR"[c  
input.close(); Y(4#b`k3  
} D{aN_0mT  
catch(IOException e){e.printStackTrace ();} IP`;hC  
catch(Exception e){e.printStackTrace ();} N+9`'n^x  
} 1cyX9X  
G,8LF/sR  
Jyx6{O j  
private void processErrorCode(int nErrorCode) / ` 7p'i  
{ ;@@1$mzK  
System.err.println("Error Code : " + nErrorCode); yH8 N8  
} : qKxm(  
+Zx+DW cq  
z6K"}C%  
//停止文件下载 qdB@P  
public void siteStop() ':fq  
{ &Oq& ikw  
bStop = true; T/" 6iv\1  
for(int i=0;i<nStartPos.length;i++) =yf LqU  
fileSplitterFetch.splitterStop(); 3JiDi X"|  
i`^`^Ka  
9T4x1{mO  
} MEQ :[;1  
} XQu~/{A=  
//负责部分文件的抓取 fL8+J]6A6  
**FileSplitterFetch.java p*rBT,'  
*/ pNo<:p  
package NetFox; 05\A7.iy  
{iqH 27\E  
V=}b>Jo2j  
import java.io.*; 9tVA.:FOZ  
import java.net.*; `":ch9rK  
JU7EC~7|2c  
/! kKL$j  
public class FileSplitterFetch extends Thread { g(\FG  
63d' fgVp  
L[d 7@  
String sURL; //File URL Y#_,Ig5.  
long nStartPos; //File Snippet Start Position d* Y&V$?zl  
long nEndPos; //File Snippet End Position .,pGW8Js  
int nThreadID; //Thread's ID > ln%3 =  
boolean bDownOver = false; //Downing is over 9d4PH  
boolean bStop = false; //Stop identical dlC)&Ai  
FileAccessI fileAccessI = null; //File Access interface zLlu% Oc  
M?4)U"_VE  
9}FWO&LiB  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3y%B&W,sm  
{ c,1Yxg]|  
this.sURL = sURL; ?Ovl(4VG  
this.nStartPos = nStart; cbl2D5s+i]  
this.nEndPos = nEnd; 'w`:p{E  
nThreadID = id; M* (]hu0!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Bl-nS{9"  
} }"<|.[V)  
tt`j!!  
_-%A_5lCRE  
public void run() I)AV  
{ 0(;d<u)fS  
while(nStartPos < nEndPos && !bStop) Efb>ZQ  
{ bE2^sx`(  
k~u$&a  
xT I&X9P  
try{ 0A@'w*=  
URL url = new URL(sURL); maLKUSgo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); uYlC*z{  
httpConnection.setRequestProperty("User-Agent","NetFox"); jR S0(8  
String sProperty = "bytes="+nStartPos+"-"; /i$ mIj`  
httpConnection.setRequestProperty("RANGE",sProperty); ^zHBDRsb2F  
Utility.log(sProperty); 15_OtK  
_PrK6M@"L  
.N8AkQ(Ok  
InputStream input = httpConnection.getInputStream(); <jT6|2'  
//logResponseHead(httpConnection); K*Zf^g m  
#CoJ S[t  
%^m6Q!  
byte[] b = new byte[1024]; 2H_|Attoi  
int nRead; >[=q9k  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ,V!s w5_5m  
{ cA1"Nek  
nStartPos += fileAccessI.write(b,0,nRead); yc2c{<Ya5  
//if(nThreadID == 1) <8p53*a  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zCT Wi  
} imAsE;:  
Z VuHO7'  
IpmblC4  
Utility.log("Thread " + nThreadID + " is over!"); >v@R]9  
bDownOver = true; wxXp(o(  
//nPos = fileAccessI.write (b,0,nRead); S1{UVkr  
} PD12gUU?  
catch(Exception e){e.printStackTrace ();} ~AxA ,  
} gvO}u2.:  
} :3$WY<  
.oYUA}  
Fd-PjW/E8  
//打印回应的头信息 v2:A 4Pd:+  
public void logResponseHead(HttpURLConnection con) zR(}X8fP  
{ yHl1:cf(y  
for(int i=1;;i++) _6&x$ *O  
{ ozF>2`K }  
String header=con.getHeaderFieldKey(i);  2&O!<C j  
if(header!=null) &a%|L=FY  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); xSZgQF~  
Utility.log(header+" : "+con.getHeaderField(header)); )y(pd  
else W F<`CQg[  
break; quHq?oXV,  
} );V6YE  
} TU{^/-l  
Y  9]  
0'`>20Y  
public void splitterStop() Iodk1Y;  
{ >6Y\CixN  
bStop = true; /=A?O\B7  
} Z9mY*}:U~  
6wx;grt'Z  
*|ez|*-  
} ~;k-/Z"  
7udMF3;>  
Vm6G5QwM  
/* H#x=eDU|k  
**FileAccess.java \Q<c Y<  
*//文件访问(定位,写) 7OX5"u!2  
package NetFox; PI(;t9]b  
import java.io.*; b;#3X)  
wl #Bv,xf  
Lt0JUUa0  
public class FileAccessI implements Serializable{ u HqPb8  
~~k_A|&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 rvuskXdo  
RandomAccessFile oSavedFile; xal+ buOiP  
long nPos; XRCiv  
%4Cs c  
c1M/:*?%  
public FileAccessI() throws IOException L5! aLv#  
{ R9nW5f Nf  
this("",0); jIwz G+)$P  
} 0P^RciC f  
(:Rj:8{  
AJt *48H*G  
public FileAccessI(String sName,long nPos) throws IOException :@{(^}N8u  
{ JsI` #  
oSavedFile = new RandomAccessFile(sName,"rw"); m07= _4  
this.nPos = nPos; yKF"\^`@  
oSavedFile.seek(nPos); Yo3my>N&g  
} 2apR7  
p 9Zi}!  
=#dW^ ?p  
public synchronized int write(byte[] b,int nStart,int nLen) oBiJiPE=`  
{ A#$oY{"2Y  
int n = -1; Y3+DTR0|'  
try{ iTF`sjL  
oSavedFile.write(b,nStart,nLen); &2[OH}4  
n = nLen; Gs;wx_k^  
} m`gH5vQa  
catch(IOException e) e/JbRbZX  
{ 5xe} ljo  
e.printStackTrace (); &?flH;  
} 3 ha^NjE  
kx0(v1y3gT  
S[(Tpk2_  
return n; |;e K5(|  
} H)z}6[`  
  4Ra  
2%UzCK  
} "C%<R  
G(W/.*  
z ^t6VFM  
/* T#kPn#|  
**SiteInfoBean.java N|-M|1w96  
*/ t=o2:p6&  
package NetFox; |N, KA|Gdq  
I WKq_Zjkz  
F,+nj?i!  
public class SiteInfoBean { vFm8T58 7  
yXP+$oox9  
/ap3>xkt  
private String sSiteURL; //Site's URL ){^o"A?-:  
private String sFilePath; //Saved File's Path nR'!Ui  
private String sFileName; //Saved File's Name OP0KK^#  
private int nSplitter; //Count of Splited Downloading File "j-Z<F]]  
;:2]++G  
F!.Z@y P  
public SiteInfoBean() Qc1NLU9:  
{//nSplitter的缺省值为5 KSkT6_<  
//default value of nSplitter is 5 ieuq9ah#  
this("","","",5); :b t;DJ@  
} Em8q1P$tm>  
BUB$k7{z  
# 4UKkd  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) mU@pRjq=  
{ UW%zR5q  
sSiteURL= sURL; 1;8=,&  
sFilePath = sPath; D! TFb E  
sFileName = sName; ramYSX@  
this.nSplitter = nSpiltter; %;S T7  
E;m]RtvH  
VRden>vKN  
} sZ,xbfZby  
-yyim;Nj  
cW%QKdTQY0  
public String getSSiteURL() ! R rk  
{ j#4 Iu&YJ  
return sSiteURL; 5B6twn~[  
} \%& BK.t  
LB9D6,*t  
khFr%u ?S  
public void setSSiteURL(String value) IBfLb(I  
{ jlaU3qXL  
sSiteURL = value; EHI %QT  
} ][vm4UY  
2kukQj (n  
) 0NKL:u  
public String getSFilePath() 6!F@?3qCyg  
{ (j<FS>##  
return sFilePath; ].ZfTrM]  
} s'$5]9$S  
` mvPbZ0<  
K|^PHe  
public void setSFilePath(String value) 80J87\)  
{ _A]8l52pt  
sFilePath = value; 7Yv1et |  
} rgq~lZ.U4K  
Qc4r?7S<  
@QOlo -u  
public String getSFileName() /wAx#[c[  
{  SXqWq  
return sFileName; Uk1|y\  
} v@,n]"  
H){}28dX  
sr S2v\1:  
public void setSFileName(String value) rF@njw@  
{ /;5U-<qf  
sFileName = value; y5@#le M  
} hHA!.u4&  
4Fu:ov ]M  
h D5NX  
public int getNSplitter() ^Pwtu  
{ |ty?Ah,vb  
return nSplitter; )NF5,eD  
} b@v_db]|t.  
q8Jhs7fv  
"rl(%~Op  
public void setNSplitter(int nCount) "aL.`^.  
{ x."R_>  
nSplitter = nCount; {beu  
} D;1?IeS  
} `GDWy^-Q+!  
-G'U\EXT  
UY5wef2sF  
/* 8'sT zB]  
**Utility.java }H5~@c$  
*/ 7!qO*r  
package NetFox; xdLMy#U2  
()}(3>O-  
'@0Z#A  
public class Utility { #}xw *)3  
s78MXS?py  
/]1$Soo  
public Utility() ^5'pJ/BV  
{ EjA3hHJ  
F>F2Yql&W  
C(%b!Q,2  
} H^3f!\MC;o  
AT6o~u!WU  
//线程睡眠 \k4em{K  
public static void sleep(int nSecond) B}(r>8?dm  
{ /nq\*)S#&  
try{ aRV .;S  
Thread.sleep(nSecond); WWEZTFL:j  
} #"qP4S2  
catch(Exception e) N%f% U  
{ n 9>**&5L  
e.printStackTrace (); C ^IPddw>  
} A:$4cacu9  
} V|{\8&  2  
8@ZZ[9kt  
//日志 Wa5B;X~  
public static void log(String sMsg) e S: 8Pn  
{ +dG3/vV  
System.err.println(sMsg); Hk8lHja+\  
} JW},7Ox  
?S<`*O +  
MvKr~  
public static void log(int sMsg) Q]{ `m  
{ h`n) b  
System.err.println(sMsg); 5i@WBa  
} nl-y0xD9c  
} Nov)'2g7G  
yE#.Q<4  
r!<)CT}D  
/* F~$ay@g  
**TestMethod.java I}sb0 Q&  
*/ OQ&'3hv{  
package NetFox; ?CD[jX}!  
~@\sN+VS  
L,O.XR  
public class TestMethod { +;ylld  
%Ze]6TP/><  
%M*2j%6  
public TestMethod() 2EH0d6nt  
{ ///xx/weblogic60b2_win.exe $(]E$ek  
try{ ?j;,:n   
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); +-!2nk`"a  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); K=Z.<f  
SiteFileFetch fileFetch = new SiteFileFetch(bean); iv ~<me0F  
fileFetch.start(); `]=0oDG:1!  
} e-Z ul.m  
catch(Exception e){e.printStackTrace ();} 7Ucq(,\./  
cN:dy#  
(DkfLadB  
} W)<t7q+  
/5Sd?pW;  
\<HY'[gr  
public static void main(String[] args) ||))gI`3a  
{ 9>@Vk vpY  
new TestMethod(); 4" pU\g  
} twox.@"U  
} s o7.$]aV  
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