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http断点续传简单实现(java)

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/* L4po1  
**SiteFileFetch.java ([8*Py|  
*/ {!I`EN]  
package NetFox; OxJ HhF  
import java.io.*; rEa(1(I  
import java.net.*; QbJ7$ ,4  
f7&ni#^Ztj  
VzT*^PFBg  
public class SiteFileFetch extends Thread { (Y~/9a4X  
59.$;Ip;g  
mS%4  
SiteInfoBean siteInfoBean = null; //文件信息Bean qz` -?,pF  
long[] nStartPos; //开始位置 &* VhtT?=5  
long[] nEndPos; //结束位置 v[$e{Dz(  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 B&MDn']fV/  
long nFileLength; //文件长度 W? G4>zA  
boolean bFirst = true; //是否第一次取文件 CEj_{uf|  
boolean bStop = false; //停止标志 Te+#  
File tmpFile; //文件下载的临时信息 K3zY-yIco  
DataOutputStream output; //输出到文件的输出流 a!o%x  
rCo}^M4Pb  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 0*MUe1{  
public SiteFileFetch(SiteInfoBean bean) throws IOException g3ukx$Q{>  
{ C^$E#|E9N  
siteInfoBean = bean; )v(rEY  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "-:H$  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); rO}1E<g (  
if(tmpFile.exists ()) Y~Uf2(7b5  
{ / B!j`UK  
bFirst = false; $?ss5: S  
read_nPos(); ?8753{wk  
} %g?M?D8Ud3  
else v} !lx)#  
{ 61_PSScSY  
nStartPos = new long[bean.getNSplitter()]; Ja1`S+  
nEndPos = new long[bean.getNSplitter()]; `@y~JNf!  
} TFHYB9vV  
@kSfF[4H  
ZKI8x1>Iq  
Q%6zr9  
} D&fOZVuqZ  
>FeCa h Fn  
/%g@ ;  
public void run() ~vYFQKrb  
{ "C}<umJ'  
//获得文件长度 92j[b_P  
//分割文件 (%6fZ  
//实例FileSplitterFetch O}C*weU  
//启动FileSplitterFetch线程 6EY\  
//等待子线程返回 5xc e1[  
try{ whN<{AG  
if(bFirst) >JNdtP8s/1  
{ CL7_3^2qI  
nFileLength = getFileSize(); 3_RdzW}f  
if(nFileLength == -1) !}} )f/  
{ K7s[Fa6J  
System.err.println("File Length is not known!"); W /v &V#  
} 0<V/[$}\D  
else if(nFileLength == -2) $JOtUB{  
{ y:E$n!  
System.err.println("File is not access!"); =Fe4-B?I  
} {yNeZXA>  
else z}SJ~WY'[  
{ k/F#-},Q.  
for(int i=0;i<nStartPos.length;i++) e>_a (  
{ sC"w{_D@*4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6# bTlmcg  
} otaRA  
for(int i=0;i<nEndPos.length-1;i++) ;~1xhpTk  
{ w.rcYywI  
nEndPos = nStartPos[i+1]; B|o@ |zF  
} J<0sT=/2$  
nEndPos[nEndPos.length-1] = nFileLength; 5ms]Wbh)  
} E;H9]*x/  
} mdbi@ms@  
BJ_"FG  
jcC"vr'u|  
//启动子线程 InL_JobE8r  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %4R1rUrgt|  
for(int i=0;i<nStartPos.length;i++) id,' +<  
{ C`ZU.|R  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), OGW3Pe0Z'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), aQHR=.S]X  
nStartPos,nEndPos,i); ;eo}/-a_Xw  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jp "Q[gR##  
fileSplitterFetch.start(); M:.+^.h  
} XlXt,  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ml2/}}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 'Jek< 5  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", X   
nEndPos = " + nFileLength); @[v,q_^8  
// fileSplitterFetch[nPos.length-1].start(); R:l&2  
\ (`2@  
Y9-F\t=~  
//等待子线程结束 e1b?TF@lz  
//int count = 0; Q e/XEW  
//是否结束while循环 +P 9eE,WR  
boolean breakWhile = false; r(>812^\  
xxg/vaQt=s  
o/&K>]8M  
while(!bStop) gKQs:25  
{ Txl|F\nK`  
write_nPos(); ;Y8>?  
Utility.sleep(500); #I MaN%  
breakWhile = true; v2r|) c,h  
wQ/.3V[  
z&c}  
for(int i=0;i<nStartPos.length;i++) Jza ?DhSAZ  
{ & E6V'*<93  
if(!fileSplitterFetch.bDownOver) )n<p_vz  
{ "\vQVZd-E  
breakWhile = false; _PGd\>Ve  
break; W!"QtEJ,  
} !5h8sD;  
} d"E3ypPK  
if(breakWhile) _B^X3EOc  
break; Xk'Pc0@a  
pyX:$j2R+%  
B[h^]k  
//count++; unqUs08  
//if(count>4) -ON-0L  
// siteStop(); F+NX [  
} U8gj\G\`  
3mopTzs)  
R'vNJDFY  
System.err.println("文件下载结束!"); !?).4yr  
} [+l6x1Am  
catch(Exception e){e.printStackTrace ();} j(k%w  
} KiFTj$w,  
E ?bqEW(  
l{]KA4  
//获得文件长度 Yv)c\hm(7j  
public long getFileSize() m6^#pqSL  
{ _O Jfd  
int nFileLength = -1; [n&ES\o#(  
try{ 2wPc yD  
URL url = new URL(siteInfoBean.getSSiteURL()); \M|:EG%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G; exH$y  
httpConnection.setRequestProperty("User-Agent","NetFox"); *"Iz)Xzc`  
D vU1+ y  
(~bx%  
int responseCode=httpConnection.getResponseCode(); zN;P_@U  
if(responseCode>=400) !;vv-v,LQ  
{ 3G<4rH]  
processErrorCode(responseCode); @PLJ)RL  
return -2; //-2 represent access is error 'Q 7^bF^  
} 8sBT&A6&j  
,uNJz-B8  
dIh+h|:  
String sHeader; g]N'6La  
tcRJ1:d  
cX4]ViXSr  
for(int i=1;;i++) K1R?Qt,qDF  
{ 9c*B%A8J  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -F*vN'  
//Utility.log(in.readLine()); yZm=#.f  
sHeader=httpConnection.getHeaderFieldKey(i); |N)),/R_  
if(sHeader!=null) _Yp~Oj  
{ |v : )9  
if(sHeader.equals("Content-Length")) z$d<ep{6  
{ \o72VHG66  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -&]!ig5v  
break; l\Ww^   
} D:IG;Rsc  
} E^ c *x^  
else f)a0!U 44  
break; KZ#\ >  
} QS\wtTXj  
} P zM yUv  
catch(IOException e){e.printStackTrace ();} <HN{.p{  
catch(Exception e){e.printStackTrace ();} olL? 6)gC  
1ZRkVHiz0  
q &{<HcP  
Utility.log(nFileLength); X's<+hK&  
ZvT>A#R;l~  
u^JsKG+,:  
return nFileLength; YHu]\'Ff  
} )cP)HbOd=  
L@zhbWY  
E]m?R 4  
//保存下载信息(文件指针位置) aHYISjZ]>  
private void write_nPos() -/Wf iE  
{ *TI?tD  
try{ `]@=Hx(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6@8z3JW.A  
output.writeInt(nStartPos.length); U~"Y8g#qgy  
for(int i=0;i<nStartPos.length;i++) ,=[% #gS  
{ FY^Nn  
// output.writeLong(nPos); q TN)2G  
output.writeLong(fileSplitterFetch.nStartPos); H|wP8uQC  
output.writeLong(fileSplitterFetch.nEndPos); 9^8OIv?m8  
} )i[Vq|n  
output.close(); -TG ="U  
} pz)>y&_o  
catch(IOException e){e.printStackTrace ();} <m1v+cnqo  
catch(Exception e){e.printStackTrace ();} -MTYtw(  
} K r|.I2?"  
^[Ka+E^Q  
 O&|<2Qr  
//读取保存的下载信息(文件指针位置) -<5{wQE;|  
private void read_nPos() GQCdB>   
{ Z(Y:  
try{ d(ypFd9z  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); T{f$S  
int nCount = input.readInt(); [ >\|QS|  
nStartPos = new long[nCount]; ]PoWL;E'  
nEndPos = new long[nCount]; B {:a,V7  
for(int i=0;i<nStartPos.length;i++) 0{8L^ jB/  
{ %-.;sO=g  
nStartPos = input.readLong(); rvd%z7Z1o  
nEndPos = input.readLong(); !3mt<i]a"  
} #C?M-  
input.close(); hKWWN`;b !  
} =EA:fq  
catch(IOException e){e.printStackTrace ();} oo7}Hg>  
catch(Exception e){e.printStackTrace ();} Yb/*2iWX  
} 9`Fw}yAt  
s<k2vbhI  
vPz7*w  
private void processErrorCode(int nErrorCode) x(eX.>o\  
{ ^IIy>  
System.err.println("Error Code : " + nErrorCode); v}V[sIs}  
} ^V96l Kt/  
h ! R=t  
p:Lmf8EI  
//停止文件下载 GbL1<P$V  
public void siteStop() Px \cT  
{ .1{{E8Fj  
bStop = true; nR*' 3  
for(int i=0;i<nStartPos.length;i++) Km%L1Cd]  
fileSplitterFetch.splitterStop(); MsP6C)dz  
wB \`3u4  
}$L63;/H  
} }(ORh2Ri  
} "z3rH~q72  
//负责部分文件的抓取 qa )BbK^i  
**FileSplitterFetch.java uXh:/KO  
*/ W [K.|8ho  
package NetFox; Ihf :k_;  
F!0iM)1o  
(A6~mi r!  
import java.io.*; VLkAsM5}%  
import java.net.*; R( FQ+h  
g]2L[4  
.\^0RyJE  
public class FileSplitterFetch extends Thread { Em@:Qm EN  
D5?8`U m=  
n%J=!z3  
String sURL; //File URL BrwC9:  
long nStartPos; //File Snippet Start Position k_0@,b 3  
long nEndPos; //File Snippet End Position !#O [RS  
int nThreadID; //Thread's ID uy3<2L#.  
boolean bDownOver = false; //Downing is over M] /aW  
boolean bStop = false; //Stop identical tMiIlf!>p  
FileAccessI fileAccessI = null; //File Access interface V1V0T ,  
#T^2=7 w  
`/P/2{,~  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException d"#Zp&#  
{ "}fweCBgo  
this.sURL = sURL; Zg(Y$ h\  
this.nStartPos = nStart; L4g%o9G  
this.nEndPos = nEnd; +)jll#}?  
nThreadID = id; Wx GD*%  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $El-pMq  
} Lau@HYW0  
Z,38eQpM  
-y+>^45  
public void run() %7)=k}4  
{ {G:y?q'z  
while(nStartPos < nEndPos && !bStop) "S%t\  
{ zzQWHg]/  
.Q*X5Fc  
5XZ! yYB?  
try{ ^QRg9s,T<  
URL url = new URL(sURL); eyJ07  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); pFd8p@m_2  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6@J=n@J$p  
String sProperty = "bytes="+nStartPos+"-"; B;1qy[  
httpConnection.setRequestProperty("RANGE",sProperty); aKbmj  
Utility.log(sProperty); 6gg8 h>b  
NXY jb(4:  
$RPW/Lyiq  
InputStream input = httpConnection.getInputStream(); az(<<2=  
//logResponseHead(httpConnection); Cl}nP UoL  
/fr>Fd  
`C+<! )2  
byte[] b = new byte[1024]; #@S%?`4,  
int nRead; Ma[EgG  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) V)`2 Kw  
{ @p+;iS1}  
nStartPos += fileAccessI.write(b,0,nRead); x<NPp&GE  
//if(nThreadID == 1) @c3xUK   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @w[i%F,&`  
} yGZsNd {a&  
kXMp()N8`  
+2~k Hrv  
Utility.log("Thread " + nThreadID + " is over!"); [. 5m}V  
bDownOver = true; o\IMYT  
//nPos = fileAccessI.write (b,0,nRead); *v>ZE6CL  
} ISbs l =F  
catch(Exception e){e.printStackTrace ();} jVj5; }  
} J!6FlcsZm  
} }h5i Tc  
`2s!%/  
6o 3 bq|  
//打印回应的头信息 > VG  
public void logResponseHead(HttpURLConnection con) *eVq(R9?T  
{ /0h *(nL  
for(int i=1;;i++) rz?Cn X.t  
{ p*Bty@CRi  
String header=con.getHeaderFieldKey(i); N%y i4  
if(header!=null) {f!/:bM  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `BPTcL<W  
Utility.log(header+" : "+con.getHeaderField(header)); dhl[=Y ` Q  
else %\As  
break; yzA05npTl  
} GP|=4T}Bf  
} pJpapA2l*6  
J~Xv R  
$Gn.G_"v  
public void splitterStop() ) nfoDG#O  
{ WeI+|V$  
bStop = true; yqK4 "F&  
} T5BZD +Ta  
^S9y7b^;r  
bQAznd0  
} !XA3G`}p6s  
=lXj%V^8N  
"q4tvcK.  
/* h$>F}n j  
**FileAccess.java [}X|&`'i  
*//文件访问(定位,写) B*7kX&Uq  
package NetFox; eE;tiX/  
import java.io.*; 7\u+%i;YZ  
d1/emwH  
H^_,e= j  
public class FileAccessI implements Serializable{ y!e]bvN  
x^f<G 6z  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节  w-jElV  
RandomAccessFile oSavedFile; -DDA b(2*  
long nPos; 'X~tt#T  
h\m35'v!  
 idmU.`  
public FileAccessI() throws IOException d{ (,Gy>I  
{ $o"nTl  
this("",0); x "W~m.y$h  
} ^s,3*cAU  
-"(*'hD  
U%{GLO   
public FileAccessI(String sName,long nPos) throws IOException A#u U ]S  
{ SpH|<L3  
oSavedFile = new RandomAccessFile(sName,"rw"); N gNGq\!  
this.nPos = nPos; y48]|%73  
oSavedFile.seek(nPos); eK8H5YE  
} [f6uwp  
PN}+LOD<t  
#mH@ /6,#[  
public synchronized int write(byte[] b,int nStart,int nLen) vwR_2u  
{ 5<?Ah+1  
int n = -1; 337.' |ZE  
try{ P -m_],  
oSavedFile.write(b,nStart,nLen); xh6(~'$  
n = nLen; {+N< 9(O  
} Z:b?^u4.  
catch(IOException e) EZtU6kW"  
{ A`c22Ls]  
e.printStackTrace (); ,"qCz[aDN1  
} ~W'DEpq_  
7KT*p&xm  
:]"5UY?oF  
return n; 5zuwqOD*  
} n}p G&&;q  
%wD#[<BGn>  
T+8Yd(:hX  
} 1- RY5R}VR  
%V_ XY+o  
Jcw^Z,  
/* MVatV[G  
**SiteInfoBean.java +/OSg.  
*/ whI{?NP  
package NetFox; .j6udiv5  
2j\_svw'  
[V}vd@*k  
public class SiteInfoBean { KbJ6U75|f  
o<g?*"TRh  
=g% L$b<i  
private String sSiteURL; //Site's URL Khq\@`RaT  
private String sFilePath; //Saved File's Path ]l7W5$26 @  
private String sFileName; //Saved File's Name S)CsH1Q  
private int nSplitter; //Count of Splited Downloading File HG]ARgOB  
Z'o0::k  
EPo)7<|>  
public SiteInfoBean() )1<0c@g=  
{//nSplitter的缺省值为5 BRFsw`c  
//default value of nSplitter is 5 {R$`YWk  
this("","","",5); 3j#VKj+Uc  
} "$BkO[IS  
1eXMMZ/?  
jAQ{H  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 3G// _f  
{ -]EL|_;  
sSiteURL= sURL; kHg|!  
sFilePath = sPath; ? Fqh i  
sFileName = sName; K#FD$,c~  
this.nSplitter = nSpiltter; OPvPP>0*8  
{/[@uMS_6]  
8~y!X0Ov!  
} Uo3  
qw+ 7.h#V  
 ZllmaI  
public String getSSiteURL() 4DIU7#GG  
{ t/i*.>7  
return sSiteURL; PpRS4*nR  
} S iNgV\('U  
pI@71~|R  
Fd8nR9A  
public void setSSiteURL(String value) PvKGB01_  
{ jLFaf#G]  
sSiteURL = value; ;&lXgC^*  
} (~|)Gmq2  
(4Db%Iw  
za>%hZf\  
public String getSFilePath() P, x" ![6  
{ |E13W  
return sFilePath; Dw=L]i :0v  
} #kQ! GMZH  
TjpyU:R,&|  
IO7z}![V;  
public void setSFilePath(String value) '[r:pwE  
{ dX\OP>  
sFilePath = value; =K@LEZZ'/<  
} f}dlQkZ(  
l_yy;e  
F,YP Il  
public String getSFileName() Iq|h1ie m+  
{ <v ub Q4  
return sFileName; c| %5SA  
} 2tU3p<[  
S5|7D[*  
:F d1k Jm  
public void setSFileName(String value) TT/=0^"  
{ =u0=)\0@r  
sFileName = value; ZW M:Wj192  
} 5ncW s)  
1uo |a  
b$w66q8  
public int getNSplitter() iBWzxPv:z  
{ LBio$67F  
return nSplitter; nA Nl9;G  
} HubG>]  
tE>FL  
^uo,LTq+  
public void setNSplitter(int nCount) !,- 'wT<v  
{ `LH9@Z{  
nSplitter = nCount; u!xgLf'`  
} ,T;sWl  
} 8V(~u^!%_  
M5[#YG'FlQ  
"eoPG#]&  
/* 0MT?}D&TL  
**Utility.java ,%Pn.E* r;  
*/ H!NGY]z*  
package NetFox; T7YJC,^m  
:Gz$(!j1.'  
h-.^*=]R6  
public class Utility { uA`e  
vkLt#yj~  
W)`>'X`  
public Utility() ym p*:lH(  
{ Bl)D/  
'>OEQU5-  
)1 @v<I  
} $_%  
n2aUj(Zs=  
//线程睡眠 y 2k's  
public static void sleep(int nSecond) DvN_}h^nX  
{ z@~Z Mk  
try{ 8<Nz34Y  
Thread.sleep(nSecond); 0?R$>=u  
} /3+E-|4s  
catch(Exception e) 0$XrtnM  
{ XffHF^l9F  
e.printStackTrace (); ;[zZI~wh  
} B8cg[;e81  
} qPN  
%to.'R  
//日志 57 Vn-  
public static void log(String sMsg) 9U9ghWH8  
{ h1)+QLI  
System.err.println(sMsg); +vFqHfmP  
} -vT$UP  
E=v4|/['N  
b6g9!  
public static void log(int sMsg) 9~,!+#  
{ i(u zb<  
System.err.println(sMsg); a"+/fC`  
} CE183l\  
} _ru<1n[4~  
YU87l  
U ;4;>  
/* (^=kV?<  
**TestMethod.java &=8ZGjR< }  
*/ B_r:daCS:  
package NetFox; 4yu=e;C wy  
D -e^b'l  
4!glgEE*  
public class TestMethod { Rlr[uU_  
Yk4ah$}%-^  
xoSBMf  
public TestMethod() 6yaWxpW  
{ ///xx/weblogic60b2_win.exe p8y<:8I  
try{ +'e3YF+'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); yC }x6xG  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); fQU_A  
SiteFileFetch fileFetch = new SiteFileFetch(bean); a.<!>o<t:  
fileFetch.start(); '?|.#D#-c  
} OUHd@up@n  
catch(Exception e){e.printStackTrace ();} Qe<c@i"  
Tq6@ 1j6p  
HV3D$~gF  
} wZ8LY;  
YkV-]%c  
%D^j7`Z  
public static void main(String[] args) :)e/(I]  
{ Yh%  
new TestMethod(); @iz6)2z  
} Io;26F""  
} 9/\=6v C|  
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