http断点续传简单实现（java)

/* {L-{Y<fke  
**SiteFileFetch.java 8^P2GG'+-  
*/ O)$N}V0  
package NetFox; WQIM2_=M  
import java.io.*; GDo)6du
 
import java.net.*; c"%_]7  
Gg}LC+Y  
?j&~vy= T  
public class SiteFileFetch extends Thread { UijuJ(Tle  
!~|"LA!jn  
w{YtTZp3  
SiteInfoBean siteInfoBean = null; //文件信息Bean JL]k:i^`A  
long[] nStartPos; //开始位置 7N}\1Di5  
long[] nEndPos; //结束位置 5H'b4Cyi`  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 (04j4teE  
long nFileLength; //文件长度 Ru9pb~K  
boolean bFirst = true; //是否第一次取文件 m5'__<  
boolean bStop = false; //停止标志 2kp|zX(  
File tmpFile; //文件下载的临时信息 :uT fhr  
DataOutputStream output; //输出到文件的输出流 T_(e(5  
=XRgT1>e  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） .^9/ 0.g8t  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~Me&cT8  
{ /_zF?5h  
siteInfoBean = bean; Y>dg10=  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); BZ\EqB  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @ @3)D%h  
if(tmpFile.exists ()) D:6x*+jah)  
{ r0Y?X\l*  
bFirst = false; {R
1Cxt}  
read_nPos(); 8eS@<[[F#  
} |j5AU  
else T_oW)G  
{ $E4O^0%/p  
nStartPos = new long[bean.getNSplitter()]; X('Q;^`  
nEndPos = new long[bean.getNSplitter()]; `3
>)BV<P  
} L!+[]tB  
=B o4yN  
P60]ps!M  
e$/Zb`k  
} qN`]*baS  
2\z`G  
B!E<uVC  
public void run() 0o"<^] _|  
{ PTI'N%W  
//获得文件长度 vU\w3  
//分割文件 AP?{N:+  
//实例FileSplitterFetch e u=f-HW]  
//启动FileSplitterFetch线程 0\_R|i_`>  
//等待子线程返回 ~qLhZR\g^  
try{ VtPoc(o4]  
if(bFirst) kGBl)0pr`x  
{ zOu$H[  
nFileLength = getFileSize(); i*cE  
if(nFileLength == -1) AVevYbucB  
{ ]uj.uWD  
System.err.println("File Length is not known!"); Tm~#wL +r  
} U*qK*"k  
else if(nFileLength == -2) rY_C3;B  
{ -JyODW#j  
System.err.println("File is not access!"); n4r( Vg1GS  
} <8z[,X}bM  
else \'^Z_6{w  
{ yS.fe[  
for(int i=0;i<nStartPos.length;i++) lA^Kh  
{ Kj<<&_B.H  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {'wU&!  
} 1^H<+0  
for(int i=0;i<nEndPos.length-1;i++) ^)0{42!]  
{ {</$ObK  
nEndPos = nStartPos[i+1]; )S;Xy`vO  
} `w+9j-  
nEndPos[nEndPos.length-1] = nFileLength; 3sg)]3jm2  
} _I70qz8  
} KxTYc  
-
5-SlQu  
$85o%siS'  
//启动子线程 3xCA\*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; C;:1CK  
for(int i=0;i<nStartPos.length;i++) %ucmJ-<y#  
{ CK`3   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Kp=3\)&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $d??(  
nStartPos,nEndPos,i); )i6U$,]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kq.R(z+  
fileSplitterFetch.start(); F0ivL`  
} ks`  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;Q,).@<C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |s3HeY+Co  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", U+}9X^  
nEndPos = " + nFileLength); sxQ,x/O  
// fileSplitterFetch[nPos.length-1].start(); *ej o6>  
_ L:w;Oy9T  
my\oC^/9  
//等待子线程结束 hr}R,BR|  
//int count = 0; Ef*.}gcU  
//是否结束while循环 sFz4^Kn  
boolean breakWhile = false; nTtt$I@hW  
yNMwd.r[  
vheAh`u^&  
while(!bStop) OFAqP1o{$  
{ q2U"k  
write_nPos(); R^O)fL0_  
Utility.sleep(500); LAVt/TcZS|  
breakWhile = true; 2'^OtM,  
N4]6LA6x6  
[N$_@[  
for(int i=0;i<nStartPos.length;i++) ;51!aC  
{ #&8pp8wd,}  
if(!fileSplitterFetch.bDownOver) ~i&< !O&  
{ ToXFMkwY  
breakWhile = false; {8p?we3l1  
break; Qs[EA_  
} 9DAwC:<r  
} OsSiBb,W79  
if(breakWhile) >`V|`Zi ?  
break; _j
<M}  
iuk8c.TAR  
mS;Q8Crh  
//count++; r_<i*l.  
//if(count>4) \C\y'H5  
// siteStop(); OuIW|gIu0  
} cz~11j#  
Ecl7=-y  
2+Y`pz47W  
System.err.println("文件下载结束！"); [Ik B/Xbw|  
} .;v'oR1x5  
catch(Exception e){e.printStackTrace ();} PaI63 !  
} o|n0?bThS-  
 hahD.P<  
>Vm  
//获得文件长度 eS%6hUb  
public long getFileSize() "ZB`fNE  
{ UlZ)|Ya<M  
int nFileLength = -1; [ Zqg"`  
try{ *8eh%3_$h  
URL url = new URL(siteInfoBean.getSSiteURL()); jP6G.aiO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); tfIBsw.  
httpConnection.setRequestProperty("User-Agent","NetFox"); B-p5;h>  
K>JU/(  
kT=|tQ@  
int responseCode=httpConnection.getResponseCode(); ' g!_Flk  
if(responseCode>=400) NP`ll0s  
{ en6AAr:U}  
processErrorCode(responseCode); {
ZI6!zh'  
return -2; //-2 represent access is error _Wsk3AP  
} tJfN6  
bD[W
~ku  
hpes  
String sHeader; 8$tpPOhzb  
Z"nuO\zH~  
x(6.W"-S  
for(int i=1;;i++) 7Ki7N{Kt  
{ m64\@ [  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]`U?<9~Ob  
//Utility.log(in.readLine()); z#67rh{  
sHeader=httpConnection.getHeaderFieldKey(i); D(?#oCCA  
if(sHeader!=null) S5v
MP N  
{ g {wPw  
if(sHeader.equals("Content-Length")) j`M<M[C*4N  
{ BnY|t2r  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (&x\,19U$  
break; c`=hK*  
} 3/<^R}w\  
} J-?(sjIX  
else j'b4Sbs-f  
break; 4KB?g7_*  
} 5.UgJ/  
} J, U~.c  
catch(IOException e){e.printStackTrace ();} j-E>*N}-_  
catch(Exception e){e.printStackTrace ();} D"aQbQP  
6j![m+vo%  
WoR**J?}w  
Utility.log(nFileLength); 5 :>  
v333z<<S  
4B>|Wft{p]  
return nFileLength; _ L6>4  
} DuZ]g#  
Rzj!~`&N  
{]N?DmF  
//保存下载信息（文件指针位置） [NDYJ'VGe  
private void write_nPos() mw.aavB  
{ @D{[Hj`<  
try{ r/:'}os;  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @TG~fJSA12  
output.writeInt(nStartPos.length); )Em,3I/.l  
for(int i=0;i<nStartPos.length;i++) o
: DnZN  
{ Li$k<AM  
// output.writeLong(nPos); 'v)+S;oB  
output.writeLong(fileSplitterFetch.nStartPos); S8<aq P  
output.writeLong(fileSplitterFetch.nEndPos); 0kEq|k9  
} skArocs  
output.close(); WL]'lSHa  
} e.h:9`"*  
catch(IOException e){e.printStackTrace ();} 88U  
catch(Exception e){e.printStackTrace ();} N=x,96CF  
} N/.9Aj/h~&  
`N,Jiw;bw  
j0M;2 3@[  
//读取保存的下载信息（文件指针位置） YR#1[fe*_  
private void read_nPos() 0M.[) @  
{ P3>2=qK"E(  
try{ 0']M,iC/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ^<b.j.$<z  
int nCount = input.readInt(); 0+h?Bk  
nStartPos = new long[nCount]; %uMsXa  
nEndPos = new long[nCount];
KwyXM9h6=  
for(int i=0;i<nStartPos.length;i++) M,lu)~H  
{ J(L$pIM  
nStartPos = input.readLong(); p 1fnuN |,  
nEndPos = input.readLong(); (#BA{9T,^  
} Dn!V)T  
input.close(); Fm{y.URo  
} Etk<`GRfA  
catch(IOException e){e.printStackTrace ();} pswppC6f  
catch(Exception e){e.printStackTrace ();} w|#79,&  
} 9 f+7vC
A  
%
QkvBg*  
?os0JQVB  
private void processErrorCode(int nErrorCode) b6VAyTa  
{ 1
Qkuxw  
System.err.println("Error Code : " + nErrorCode); }DwXs`M7  
} evP`&23t
P  
CjCnh7tm  
W5 }zJ)x  
//停止文件下载 4QDzG~N4)|  
public void siteStop() 9`b3=&i\  
{ o!&*4>tF  
bStop = true; sk/Mh8z  
for(int i=0;i<nStartPos.length;i++) bZJ
iubBRI  
fileSplitterFetch.splitterStop(); ea/6$f9^  
N~YeAe~+  
**[p{R]8o  
} $S/8T  
} =="SW"vNi  
//负责部分文件的抓取 *n\qV*|6bI  
**FileSplitterFetch.java )nVx 2m4  
*/ U)6
JJv  
package NetFox; ]5CFL$_Q{  
8'62[e|=7[  
z@}~2K  
import java.io.*; kE}Ib4]J  
import java.net.*; Bf'(JJ7&N  
6ZJQ '9f  
&bNj/n/  
public class FileSplitterFetch extends Thread { #/6X
44 *u  
P*Nl3?T  
%-.GyG$i  
String sURL; //File URL C2T,1=  
long nStartPos; //File Snippet Start Position )c_ll;%  
long nEndPos; //File Snippet End Position _\zfXHp  
int nThreadID; //Thread's ID JKGZ0yn  
boolean bDownOver = false; //Downing is over VB%xV   
boolean bStop = false; //Stop identical 7[PXZT
  
FileAccessI fileAccessI = null; //File Access interface rL
/+`H  
eX/$[SL[  
U
gJHSl  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~f:fOrLE#  
{ }M@pdE  
this.sURL = sURL; 2J5dZYW  
this.nStartPos = nStart; 8h=XQf6k0  
this.nEndPos = nEnd; c@
P,  
nThreadID = id; dEnhNPeRl  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *BV .zbGm  
} Q*5d~Yr]R  
|k0VJi  

V^D#i(5  
public void run() Gy5W;,$q  
{ 0%GWc}o  
while(nStartPos < nEndPos && !bStop) uB?YJf .T@  
{ TnrMR1Zx  
JP]K\nQx'  
H+Wd#7l,  
try{ .0 K8h:I  
URL url = new URL(sURL); 
\$I )}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); e# DAa  
httpConnection.setRequestProperty("User-Agent","NetFox"); A{k@V!A%  
String sProperty = "bytes="+nStartPos+"-"; {u5@Yp  
httpConnection.setRequestProperty("RANGE",sProperty); ? "gy`oCv  
Utility.log(sProperty); }\F>z  
6)8']f  
+}!eAMQ  
InputStream input = httpConnection.getInputStream(); $i hIHl6'  
//logResponseHead(httpConnection); C%&7,F7  
:>5]A6Wi  
0#ph1a<  
byte[] b = new byte[1024]; >_".  
int nRead; pJIH_H  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "#()4.9  
{ _gHJ4(?w  
nStartPos += fileAccessI.write(b,0,nRead); KRQ/wuv  
//if(nThreadID == 1) |cacMgly  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >;Bhl|r~z  
} F&\o1g-L  
0WFZx Ad"  
[g{}0[ew  
Utility.log("Thread " + nThreadID + " is over!"); "v06Fj>q  
bDownOver = true; )]}*oO  
//nPos = fileAccessI.write (b,0,nRead); A,osrv  
} @UA>6F  
catch(Exception e){e.printStackTrace ();} :5(TOF  
} LLMkv!%D  
} Y+N87C<  
sr\MQ?\fB  
DmYm~hzJ  
//打印回应的头信息 z t1Q_;  
public void logResponseHead(HttpURLConnection con) W$&Q.Z  
{ 6 B )   
for(int i=1;;i++) ]PFc8qv{  
{ fAK  
String header=con.getHeaderFieldKey(i); ?'%&2M zM  
if(header!=null) S'WmPv  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); _
n>0!  
Utility.log(header+" : "+con.getHeaderField(header)); sTb/l!=o  
else ^ZsME,  
break; 1_'ZbZv4h  
} tn
sYY  
} &sW/r::,  
v-kH7H"z  
9H<:\-:  
public void splitterStop() o8" [6Ys  
{ c}Qc2D3*  
bStop = true; Zqao4  
} uGv+c.~[j  
1+^c
3Dd`  
%l,Xt"nS#  
} 67e1Y@Xu  
BdceINI  
FvkKM+?F  
/* XDn$=`2  
**FileAccess.java YpWu\oP  
*//文件访问(定位，写) PU8R 0r2k\  
package NetFox; k";;Snk  
import java.io.*; dO=<3W  
j>6{PDaT  
Qcw/>LaL:  
public class FileAccessI implements Serializable{ k_skn3,u  
A4#m&o  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 aoBM_#  
RandomAccessFile oSavedFile; v4&*iT  
long nPos; 5W'T7asOh  
DCNuvrZ  
U{ Y)\hR-  
public FileAccessI() throws IOException A_2ppEG  
{ i,~{{XS<  
this("",0); (<f[$ |%  
} N>/U%01a  
t+&WsCN  
!:>y.^O  
public FileAccessI(String sName,long nPos) throws IOException 6 2LZ}yn_"  
{ 0]Li"Wb  
oSavedFile = new RandomAccessFile(sName,"rw"); ]t,ppFC#  
this.nPos = nPos; NZl
0sX.:  
oSavedFile.seek(nPos); ur'A;B  
} GUK/Xiu  
qvT9d7x  
cgU7)`0j  
public synchronized int write(byte[] b,int nStart,int nLen) # OJD<=")  
{ \dP2xou=  
int n = -1; rsP1?Hxq  
try{ zRz3ot,|  
oSavedFile.write(b,nStart,nLen); ci$o~b6V  
n = nLen; FNUue  
} |ey6Czm  
catch(IOException e) 7==Uoy*O  
{ 4g6d6~098;  
e.printStackTrace (); eX=W+&lj  
} AttDD{Ta  
Q%85,L^U  
lwK Au!l  
return n; 4WNWn#M  
} $,R|$0B7  
mtHw!*  
l<gg5 Zea  
} * @oAM,@  
< B'BlqTS  
3c6#?<%0`  
/*
\}cEHLq  
**SiteInfoBean.java |=SaI%%Be  
*/ ua2SW(C@  
package NetFox; n\d-^ml  
Jo2:0<VL  
s]}P jh8  
public class SiteInfoBean { fHM<6i<C  
)O_Y(^+ $  
:#+VH_%N  
private String sSiteURL; //Site's URL 0"ZRJl<)[I  
private String sFilePath; //Saved File's Path W#ev  
private String sFileName; //Saved File's Name VPf=LSxJe  
private int nSplitter; //Count of Splited Downloading File HQ]g{JVld\  
7ZN0_Qs  
!"_\5$5i<X  
public SiteInfoBean() :sJVklK  
{//nSplitter的缺省值为5 kMUjSa~\  
//default value of nSplitter is 5 65g\WB+/  
this("","","",5); Zj$U_  
} S25&UwUw  
kMK-E<g  
xFgY#F  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) h_H$+!Nzb  
{ 5*~G7/hT  
sSiteURL= sURL; ,%Dn}mWu  
sFilePath = sPath; +Ge-!&.;A  
sFileName = sName; )y._]is)b  
this.nSplitter = nSpiltter; h\jwXMi,tj  
_%Jqyc"-  
0p8(Q  
} u3
kZOsG  
f~t*8rG~m  
WOquG  
public String getSSiteURL() RHeql*`  
{ $O=m/l$  
return sSiteURL; ^hLAMaR  
} `O*+%/(  
9z,V]v=  
85m_jmh[  
public void setSSiteURL(String value) TTu<~GH  
{ !@5B:n*  
sSiteURL = value; -FdhV%5]  
} Eqnc("m)  
RP!X5  
%i$]S`A}  
public String getSFilePath() 'f]\@&Np  
{ :Fu.S1j$  
return sFilePath; O\8_;Gc;  
} WF`y j%0  
]|'Mf;  
r+ k5Bk'  
public void setSFilePath(String value) oF8#gn_  
{ (@[c;+x  
sFilePath = value; SBZqO'}7  
} LL4yafh  
~}PB&`%7  
CB:G4VqOT  
public String getSFileName() ?u/RQ 1  
{ ZXlW_CGO  
return sFileName; :OQx;>'  
} 1ti+ Q0~  
]+Ik/+Nz  
N8_ c%6GE  
public void setSFileName(String value) rK7m(  
{ 4:WN-[xX  
sFileName = value; 3%p^>D\  
} 4At{(fwW  
|Q[[WHqj2f  
t&*X~(Yb!  
public int getNSplitter() #|ETH;HM  
{ +a0q?$\  
return nSplitter; 7
&-B6Y4  
} G&y< lh
 
;%{REa  
PS7ta?V QC  
public void setNSplitter(int nCount) XmJu{RbS  
{ <xv@us7  
nSplitter = nCount; GAI(=  
} &>,c..Ke  
} Ahv%Q%m%2  
!#xk?LyB  
)!+~q!A  
/* P;GRk6  
**Utility.java ER-X1fD  
*/ Rw-!P>S$  
package NetFox; )\ow/XPE  
|L%}@e Vw_  
`v) :|Q  
public class Utility { B~xT:r  
js^+{~
 
DPqk~KCM  
public Utility() RzgA;ZC'  
{ W:VRLT>w>  
}M*yE]LL;Z  
ZgarxV*  
} 3V2dN)\  
D;
nm~O%  
//线程睡眠 Okxuhzn>"  
public static void sleep(int nSecond) F5s Pd  
{ X2\1OWR0  
try{ j%%& G$Tfu  
Thread.sleep(nSecond); yUd>EnQna  
} 9 M>.9~  
catch(Exception e) &![3{G"+>l  
{ ^V,?n@c!  
e.printStackTrace (); JiH^N!  
} p^J=*jm)x  
} {B|)!_M#  
u2\QhP 9  
//日志 apy9B6%PJ+  
public static void log(String sMsg) jAXKp b  
{ J;8M._  
System.err.println(sMsg); e,V @t%  
} ;xqN#mqq  
N5K\h}'%  
Z8 eB5!$  
public static void log(int sMsg) IPHZ~'M  
{ ,y5,+:Y ~  
System.err.println(sMsg); P-]u&m/6  
} :yFUlO:  
} -?%81 z.Qq  
L/*D5k%J  
=2J^ '7  
/* 7H=V|Btnc  
**TestMethod.java 9:
9gam  
*/ 3:wN^!A}ve  
package NetFox; C6` Tck!  
05SK$ Y<<  
\k 9EimT}  
public class TestMethod { <b>g^ `}?D  
6~b)Hc/  
8@rddk  
public TestMethod() Ar{7H)V:  
{ ///xx/weblogic60b2_win.exe Rq@M~;p  
try{ (Y!{ UNq5  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Te d1Ky2O  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); xky +"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Mj!g1Q  
fileFetch.start(); #EG$HX]  
} wa1Qt  
catch(Exception e){e.printStackTrace ();} y\?NB:=%  
z*,J0)<Q  
IEmjWw4  
} 0#y i5U  
(pv6V2i  
y?Cq{(  
public static void main(String[] args) 2r^G;,{  
{ Ah:d2*SR4  
new TestMethod(); [ikW3 '99,  
} yt+d f0l  
} [x[nTIg  
点击下载更多相关资料