http断点续传简单实现（java)

/* aFe`_cnG  
**SiteFileFetch.java T[,/5J  
*/ FP0G]=ME  
package NetFox; {r>.G7P6  
import java.io.*; {%VV\qaC
 
import java.net.*; pl
5P2&k  
u)ev{)$TM  
)I^2k4Cg"  
public class SiteFileFetch extends Thread { :(a]V"(&Eq  
e1>aTu@  
! iptT(2  
SiteInfoBean siteInfoBean = null; //文件信息Bean e'*`.^  
long[] nStartPos; //开始位置 yz-,)GB6  
long[] nEndPos; //结束位置 b B x?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4Sm]>%F':  
long nFileLength; //文件长度 M t*6}Cl  
boolean bFirst = true; //是否第一次取文件 2$14q$eb  
boolean bStop = false; //停止标志 DUL4noq{  
File tmpFile; //文件下载的临时信息 UK$ms~H  
DataOutputStream output; //输出到文件的输出流 Q\GDrdA  
/0W9g  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @*0cMO;SpG  
public SiteFileFetch(SiteInfoBean bean) throws IOException _bzqd" 31I  
{ HJ2*y|u  
siteInfoBean = bean; 21ppSN>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }w/;){gu  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 6\u!E~zy  
if(tmpFile.exists ())
h)6GaJ=  
{ *\wp?s>-t  
bFirst = false; ZxG}ViS4I  
read_nPos(); '8fk+>M  
} SG?Nsp^%`B  
else 7}GK%H-u  
{ LAP6U.m'd  
nStartPos = new long[bean.getNSplitter()]; 6ns! ~g@  
nEndPos = new long[bean.getNSplitter()]; kM'"4[,nz  
} "F3]X)}  
HxBm~Lcqy  
mCs#.%dU  
&X|<@'933  
} {TO
mv  
h'i{&mS_b  
SFb{o<0 =  
public void run() nLwiCfe  
{ Cv>o.Bp|  
//获得文件长度 iweD @b  
//分割文件 .fi/I  
//实例FileSplitterFetch CvPioi  
//启动FileSplitterFetch线程 ( 7ws{)  
//等待子线程返回 Tzt,/e  
try{ [L6w1b,  
if(bFirst) ^9_UUzf\  
{ /Y&02L%\3s  
nFileLength = getFileSize(); *d(SI<j  
if(nFileLength == -1) @v}B6j b;  
{ t ?h kL  
System.err.println("File Length is not known!"); $s4Wkq  
} \eGKkSy  
else if(nFileLength == -2) @)>D)
)+  
{ P_g
Yz!  
System.err.println("File is not access!"); 4"@GNk~e  
} :^'O}2NP  
else b$H
z3TJ(  
{ xq%{}  
for(int i=0;i<nStartPos.length;i++) >#}2J[2HQ  
{ dl5=q\1=  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); KQld YA|m  
} R8
-^RvG  
for(int i=0;i<nEndPos.length-1;i++) R//$r%a  
{ 2oZ9laJO  
nEndPos = nStartPos[i+1]; X 6lH|R  
} ;' nL:\  
nEndPos[nEndPos.length-1] = nFileLength; >sD4R}\})  
} w-b' LP  
} 2$ !D* <  
a`E*\O'd  
6*n
Ao8gl  
//启动子线程 "BKeot[""p  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <&pKc6+{  
for(int i=0;i<nStartPos.length;i++) TwvAj#j  
{ a=xT(G0Re  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Sd))vS^g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), w?mEuXc  
nStartPos,nEndPos,i); K'1~^)*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _Mc>W0'5@  
fileSplitterFetch.start(); "BVdPSDBk  
} ]h!`IX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TFR(
 4W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9Bdt(}0A  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", E2AW7f(/  
nEndPos = " + nFileLength); $P: O/O=>  
// fileSplitterFetch[nPos.length-1].start(); ukuo:P<a  
Jqr

)V2Y  
?0<w  
//等待子线程结束 `@`1pOb  
//int count = 0; 2 ?|gnbE:  
//是否结束while循环 0_yP
\m  
boolean breakWhile = false; ~%#mK:+  
]lS@}W\  
/^#G0f*N  
while(!bStop) oc{EuW{Ag  
{ K3mAXC,d  
write_nPos(); d"~(T:=r  
Utility.sleep(500); {13!vS%5  
breakWhile = true; ekQrW%\3  
*~z#.63oZ  
Uh|>Skic4  
for(int i=0;i<nStartPos.length;i++) -DO&_`kn  
{ 6'OO-o  
if(!fileSplitterFetch.bDownOver) RbQ <m!A  
{ F9XT lA  
breakWhile = false; DFe;4BdC  
break; jN/C'\QL  
} 4p)e}W*  
} Az,- C
q  
if(breakWhile) 9 1P4:6  
break; BH@b1}  
0y%L-:/c|  
*]s&8/Gmb  
//count++; r$nkU4N'  
//if(count>4) h3Fo-]0  
// siteStop(); )QY![&k}1z  
} tSv0" L  
+=cam/A  
We`'>'W0  
System.err.println("文件下载结束！"); ^[-> )  
} gbOCR1PBg  
catch(Exception e){e.printStackTrace ();} \gccQig1CJ  
} }fIqH4
bp  
;vO@m!h}U  
6~5$s1Yc  
//获得文件长度 'pP-rdx  
public long getFileSize() `1p 8C%  
{ tfiqr|z  
int nFileLength = -1; $V8vrT#:  
try{ -!*p*3|03|  
URL url = new URL(siteInfoBean.getSSiteURL()); Q e1oT)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #Ws53mT  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6E9N(kFYs  
5M?mYNQR/H  
X<MpN5%|Wo  
int responseCode=httpConnection.getResponseCode(); 6Dm+'y]l  
if(responseCode>=400) :%_q[}e  
{ HdQj?f3  
processErrorCode(responseCode); Li`hdrO'ii  
return -2; //-2 represent access is error ]TK=>;&  
} 3n(*E_n  
t]m!ee8*X<  
02 f9 wV  
String sHeader; TGWdyIk  
(:$9%,x  
BpT"~4oV5  
for(int i=1;;i++) qj?2%mK`  
{ Sa]Ek*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); V 4qtaHf  
//Utility.log(in.readLine()); 5RA<Z.  
sHeader=httpConnection.getHeaderFieldKey(i); o+)A'S  
if(sHeader!=null) /)1v9<vM"  
{ kl{6]39  
if(sHeader.equals("Content-Length")) (zah890//  
{ Uu2N9.5  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ha'qIT3&  
break; 2uu[52H8d%  
} [V< 1_zqt  
} 5~\Kj#PBx  
else 8[\79|  
break; O@`J_9  
} c2b6B.4  
} _:,.yRez  
catch(IOException e){e.printStackTrace ();} mrnxI#6  
catch(Exception e){e.printStackTrace ();} +Hy4s[_|  
xw%)rm<t  
GAJ~$AiwHH  
Utility.log(nFileLength); P06.1  
(Nt[v;BnO  
D=w9cKa  
return nFileLength; 9H$g?';  
} $y6rvQ 2>S  
5fq.*1f  
@f=RL)$|  
//保存下载信息（文件指针位置） 8*k oxS  
private void write_nPos() G^"H*a  
{ ]IXAucI]  
try{ S1C^+Sla]  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0}-#b7eR  
output.writeInt(nStartPos.length); 3LfTGO  
for(int i=0;i<nStartPos.length;i++) B007x{-L  
{ B/u*<k4  
// output.writeLong(nPos); T+W3_xISX  
output.writeLong(fileSplitterFetch.nStartPos); 8on[%Vk  
output.writeLong(fileSplitterFetch.nEndPos); JFJIls  
} oQBiPN+v.3  
output.close(); 1,u{&%yL"w  
} QJM(UfHUD  
catch(IOException e){e.printStackTrace ();} (wlfMiO  
catch(Exception e){e.printStackTrace ();} r03I*b  
} ho|8U  
'^lUL) R  
8DL hk  
//读取保存的下载信息（文件指针位置） 4^MSX+zt  
private void read_nPos() ^^Bm$9  
{ Uf[T_  
try{ F(G<*lA  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3#<'[TF00t  
int nCount = input.readInt(); y"Ihr5S\  
nStartPos = new long[nCount]; 9C1
b^^Kb  
nEndPos = new long[nCount]; *?b@>_1K  
for(int i=0;i<nStartPos.length;i++) {*nEKPq(_*  
{ _3KZME  
nStartPos = input.readLong(); z qO$  
nEndPos = input.readLong(); Lkp&;+  
} 0i
_  
input.close(); b7qnOjC  
} Ix4jof6(  
catch(IOException e){e.printStackTrace ();}
!a)s`  
catch(Exception e){e.printStackTrace ();} $*aE$O6l  
} As p8qHS  
J{^n=X9M0J  
q1<Fg.-r  
private void processErrorCode(int nErrorCode) o>$|SU!a  
{ 7zi"caY  
System.err.println("Error Code : " + nErrorCode); -Cml0}.O  
} V[To,f  
ylT6h_z1[Y  
mj,qQ=n;p  
//停止文件下载 kYTOldfY2  
public void siteStop() E.U0q
K],  
{ sMN>wbHwh[  
bStop = true; 2Z-,c;21  
for(int i=0;i<nStartPos.length;i++) p( HyRCH  
fileSplitterFetch.splitterStop(); "sSjVu  
[ArO$X3\  
K#iK6)tS  
} #EEG>M*xB  
} s|BX>1  
//负责部分文件的抓取 Y)5)s0}  
**FileSplitterFetch.java @>gD1Q7v b  
*/ #Ul4&QVeg  
package NetFox; gRw.AXRa  
ZtKQ]jV&@  
dqL-'  
import java.io.*; KWtu,~O_u  
import java.net.*; Sn+FV+D  
u% r!?-z  
nh?9R&  
public class FileSplitterFetch extends Thread { 4*YOFU}l  
L;4[ k;5  
@\S]]oLn  
String sURL; //File URL @yCW8]  
long nStartPos; //File Snippet Start Position P7cge  
long nEndPos; //File Snippet End Position % i%ew4  
int nThreadID; //Thread's ID ./';P<)  
boolean bDownOver = false; //Downing is over (v|ixa  
boolean bStop = false; //Stop identical p"g1V7B  
FileAccessI fileAccessI = null; //File Access interface D8q3TyCj%  
Rd .U;>  
J.*[gt%O|  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException mQmBf|Rl  
{ W
{L  
this.sURL = sURL; ;`;G/1]#9  
this.nStartPos = nStart; Z={D0`  
this.nEndPos = nEnd; [..,(  
nThreadID = id; xcAF  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 V@LN 1|  
} .A )\F",X  
0,;E.Py?.  
d*]Dv,#X  
public void run() d'x<-l9  
{ xYT#!K1*  
while(nStartPos < nEndPos && !bStop) &e/@yu)x,  
{ -B<O_*wOj  
}g%KvYB_  
cZCGnzy  
try{ U)SM),bE[  
URL url = new URL(sURL); *4r s  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9k714bnMLX  
httpConnection.setRequestProperty("User-Agent","NetFox"); NvEm,E\|  
String sProperty = "bytes="+nStartPos+"-"; }C_G0'"F  
httpConnection.setRequestProperty("RANGE",sProperty); }R7sj  
Utility.log(sProperty); j` [#Ij  
/UEV8 1  
BUcaj.S  
InputStream input = httpConnection.getInputStream(); 1}i&HIr!b  
//logResponseHead(httpConnection); Usa{J:  
5HWwl.
D  
fF8a 1XV  
byte[] b = new byte[1024]; ?7fQ1/emhO  
int nRead; MLkL.1eGSb  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >cGh|_9  
{ P-/XYZ]`  
nStartPos += fileAccessI.write(b,0,nRead); Z?!JV_K  
//if(nThreadID == 1) {m?K2]](  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5KL9$J9k  
} <^H1)=tlF  
BfD,z  
;zfQ3$@9  
Utility.log("Thread " + nThreadID + " is over!"); < fojX\}3  
bDownOver = true; Fw(b1d>E  
//nPos = fileAccessI.write (b,0,nRead); ZXF
AuF  
} &:!ZT=  
catch(Exception e){e.printStackTrace ();} gaLEhf^  
} cq'}2pob  
} XgwMppacw  
6Tm Rc  
\;3B?8wbIl  
//打印回应的头信息 z5|e\Z  
public void logResponseHead(HttpURLConnection con) hLDch5J5~  
{ c+,7Zu!  
for(int i=1;;i++) x>1iIpBv^  
{ aB$y+`f)@  
String header=con.getHeaderFieldKey(i); dv1x78xG>  
if(header!=null) +cPE4(d  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); \Owful  
Utility.log(header+" : "+con.getHeaderField(header)); nG4Uk2>  
else yFPaWW  
break; 8o8b'tW^  
}  kg/+vJ  
} .IW_DM-  
BCj`WF@8l{  
1Pw(.8P  
public void splitterStop() wW6mYgPN%  
{ s2(w#n)  
bStop = true; 7yqSt)/U  
} ~x
4{P;y  
FqT,4SIR  
=Do3#Xe2V  
} l0:e=q2Ax  
EPE!V>  
E3FW*UNg[y  
/* L|C1C cP  
**FileAccess.java ';;p8bv+  
*//文件访问(定位，写) .NzW@|  
package NetFox; uu WY4j6  
import java.io.*; v -|P_O&z  
%-1BA*J`|  
y(bt56 | z  
public class FileAccessI implements Serializable{ hX>VVeIZ  
${E[pT  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 0gwm gc/#  
RandomAccessFile oSavedFile; &6,Yjs:T m  
long nPos; |d
B1R%  
@dWS*@  
/P?|4D}<  
public FileAccessI() throws IOException oPBg+Bh*  
{ yKe*<\  
this("",0); ^.Ih,@N6  
} sT[av  
E&s'uE=w+  
4BduUH  
public FileAccessI(String sName,long nPos) throws IOException /A[oj2un  
{ *D09P%  
oSavedFile = new RandomAccessFile(sName,"rw"); HX /GLnY/X  
this.nPos = nPos; 'o)ve(  
oSavedFile.seek(nPos); /IrR,bvA  
} 8XS{6<  
AihL>a%  
 s>*Q  
public synchronized int write(byte[] b,int nStart,int nLen) c5wkzY h  
{ <.AC=4@V  
int n = -1; /]MB6E7&  
try{ V. bH$@ej  
oSavedFile.write(b,nStart,nLen); !UgUXN*  
n = nLen; U&]p!DV&;  
} +LI*!(T|lm  
catch(IOException e) 5E\<r/FeJ  
{ Jm);|#y  
e.printStackTrace (); 9znx1AsN  
} |=^#d\?]j  
*Sz{DE1U  
@ (u?=x;  
return n; },Y; (n'  
} JXSqtk
=  
)v!lPpe8  
zV_-rf  
} QNa}M{5>h  
IioE<wS)  
|W~V@n8"6  
/* {!{7zM%u0C  
**SiteInfoBean.java f,`}hFD  
*/ bWQORjnd8  
package NetFox; |qy"%W@  
m`yn9(1Y[  
a7v[l04  
public class SiteInfoBean { lM|WOmD  
@7HOL-i  
+/b4@B7  
private String sSiteURL; //Site's URL A9qO2kq7_  
private String sFilePath; //Saved File's Path Y)4Ny
dq  
private String sFileName; //Saved File's Name ELgae1  
private int nSplitter; //Count of Splited Downloading File NBg
>i7KQ  
-t~B@%  
![P(B0Ct/  
public SiteInfoBean() ~0^,L3M  
{//nSplitter的缺省值为5 LA=>g/+i.X  
//default value of nSplitter is 5 |IcxegE  
this("","","",5); Y?vm%t`K  
} Fzld0p9=  
]tdo&  
uVuToMCp  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) -o!,,XYj .  
{ ]}l+ !NV<  
sSiteURL= sURL; D 5r   
sFilePath = sPath; 0Yzb=QMD  
sFileName = sName; I>8@=V~  
this.nSplitter = nSpiltter; ndCS<ojcBP  
= C'e1=]  
n0_Az2  
} z$BnEd.y=:  
NKUI! [  
/o1)ZC$  
public String getSSiteURL() Ni@e/| 2b  
{ :UhFou_D4l  
return sSiteURL; 6kF uMtjc  
} 4gv XJK-  
'G3OZj8  
$m: a-.I  
public void setSSiteURL(String value) n8O
dRv  
{ hPeKQwzC0  
sSiteURL = value; k>0cTBY&  
} 55\X\> 0C7  
{!g.255+  
GY$?^&OO>  
public String getSFilePath() <9k}CXv2PK  
{ kzVI:  
return sFilePath; +@],$=aE?  
} &9lc\Y4PY  
@H# kvYWmn  
4Ig{#}<  
public void setSFilePath(String value) @xF8' [<  
{ dYqDL<se/I  
sFilePath = value; +81+4{*  
} g/X=#!  
33KPo0g7  
h'y@M+c(  
public String getSFileName() [rQ(ae  
{ wIR[2&b  
return sFileName; 13&>w{S}  
} K<L%@[gi  
^$Io;*N4  
e$^!~+J7  
public void setSFileName(String value) /GSI.tO  
{ JdYF&~  
sFileName = value; PKM$*_LcGI  
} pnA]@FW  
WmVw>.]@~  
MqBATW.pmJ  
public int getNSplitter() 0^lL,rC  
{ 6-X?uaY)os  
return nSplitter; :kx#];2i  
} 4b(irDT3F  
4p.{G%h  
cf!k 9x9Z  
public void setNSplitter(int nCount) Cm}UWX  
{ &CmkNm_B  
nSplitter = nCount; GN;XB b]w  
} =i5:*J  
} >hL'#;:f#  
FHcqu_;J  
.x$T al  
/* /~rO2]rZ@  
**Utility.java [pWDhY  
*/ l/UG+7  
package NetFox; [<fLPa  
8'xnhV  
,0~ {nQj]  
public class Utility { 8Bt-  
fh)`kZDk  
n03SXaU~V  
public Utility() Mh.eAM8_  
{ #DRtMrfat  
2P=~3g*  
;F(01  
} P"~T*Qq-R  
}0nB'0|y  
//线程睡眠 _r5Ild@n  
public static void sleep(int nSecond) (@o />T  
{ ,L:)ZZgN  
try{ h_G7T1;L  
Thread.sleep(nSecond); yaXa8v'oC  
} # +]! u%n  
catch(Exception e) V1>94/
waa  
{ *Z2Q]?:{ i  
e.printStackTrace (); nkj'AH"2  
} 842+KLS  
} x,c68Q)g  
JI,hy <3l0  
//日志 #R PB;#{  
public static void log(String sMsg) BrcXn@tl  
{ BXv)zE=j  
System.err.println(sMsg); -*l[:5m  
} [=1?CD  
Msu2OF *x  
+&zCmkVC7  
public static void log(int sMsg) ye7&y4v+  
{ YY<?w  
System.err.println(sMsg); ^k<$N  
} RWQW/Gwx  
}  Q<ExfJm  
QGj5\{E_  
gq1Y]t|4F  
/* |M>k &p,B-  
**TestMethod.java 4H?Ma|,  
*/ CPeK0(7Zh  
package NetFox; I3$vw7}5Y  
c]R![sa  
3&Rqz9W  
public class TestMethod { RX\O'Zwlj  
@N{Ht)1r  
|+~2sbM  
public TestMethod() q;PzB4#  
{ ///xx/weblogic60b2_win.exe 3D dG$@  
try{ [ =2In;
 
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); L [M8[~Hy  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); h1o+7  
SiteFileFetch fileFetch = new SiteFileFetch(bean); h#ot)m|I  
fileFetch.start(); E+Mdl*  
} b}*bgx@<  
catch(Exception e){e.printStackTrace ();} &Q+V I/p  
eSBf;lr=  
s?#lhI  
} X(z-?6N4  
L/LNX{|  
l>?vjy65  
public static void main(String[] args) DkKD~  
{  /?xn  
new TestMethod(); =I}V PxhE7  
} h*Tiv^a  
} ]qHO{b4k  
点击下载更多相关资料