http断点续传简单实现（java)

/* b5NVQ8Mq  
**SiteFileFetch.java 7=CkZ&(?  
*/ F^u12R)  
package NetFox; >NKJ@4Y  
import java.io.*; xs{pGQ6
Q  
import java.net.*; f jx`|MJ  
WA`A/`taT  
:-1|dE)U  
public class SiteFileFetch extends Thread { R/hIXO  
h !^= c  
8q[; 0  
SiteInfoBean siteInfoBean = null; //文件信息Bean &zEQbHK
6  
long[] nStartPos; //开始位置 Du+W7]yCl  
long[] nEndPos; //结束位置 %\m"Yi]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 jW'YQrj{<Y  
long nFileLength; //文件长度 j7~FR{:j  
boolean bFirst = true; //是否第一次取文件 h:?^0b!@  
boolean bStop = false; //停止标志 U] LDi8  
File tmpFile; //文件下载的临时信息 5'} V`?S  
DataOutputStream output; //输出到文件的输出流 1F@j?)(  
v-{g  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） UT<e/  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5RP kAC  
{ [8iY0m_Qe  
siteInfoBean = bean; #CC5+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); jc5[r;#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "?8)}
"/f  
if(tmpFile.exists ()) |?!i},Ki;  
{ AQ~ xjU  
bFirst = false; N6Mr#A-{  
read_nPos(); IO\4dU)  
} o:Fq|?/e  
else !zA@{gvEc  
{ oW3"J6,S  
nStartPos = new long[bean.getNSplitter()]; m@Z
#  
nEndPos = new long[bean.getNSplitter()]; $h#sb4ek  
} OEW'bT)  
ETp?RWXX  
uZ+bo&  
IzP,)!EE  
} :7v'[b  
BQ-x#[%s  
&`r/+B_W  
public void run() 1MN!  
{ U2 *ORd  
//获得文件长度 U+Y(:  
//分割文件 JVc{vSa!rm  
//实例FileSplitterFetch :"%/u9<A  
//启动FileSplitterFetch线程 G|wtl(}3  
//等待子线程返回 2cMCZuO  
try{ r_T)|||v  
if(bFirst) R/vHq36d  
{ EW `hL~{  
nFileLength = getFileSize(); 6Tl6A>%s  
if(nFileLength == -1) GKBoSSnV&  
{ A8)4nOXM  
System.err.println("File Length is not known!"); XiW1X6  
} <tr]bCu}  
else if(nFileLength == -2)  ;l$$!PJ  
{ GK@OdurAR  
System.err.println("File is not access!"); 6r)P&J  
} ![_x/F9  
else `'YX>u/  
{ idI w7hi4  
for(int i=0;i<nStartPos.length;i++) a1Fx|#! mq  
{ $V~@w.
-Z#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Lljn\5!r<  
} B~]Kqp7yU  
for(int i=0;i<nEndPos.length-1;i++)  Gl~l  
{ -k'<6op  
nEndPos = nStartPos[i+1]; G@8)3 @  
} H[=\_X1o(  
nEndPos[nEndPos.length-1] = nFileLength; (80m'.X  
} s0SzO,Vi  
} 4#$#x=:  
? #K|l*  
]E`<8hRB  
//启动子线程 Pe,>ny^J1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; lTx_E#^s  
for(int i=0;i<nStartPos.length;i++) ^m>4
<~/  
{ ^6s im2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c!6D{(sfh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Itl8#LpLM  
nStartPos,nEndPos,i); l1+l@r\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f"MID6  
fileSplitterFetch.start(); +:MSY p  
} @Cj!MZ=T  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $RD~,<oEm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3lP;=*m.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 'a~@q~!  
nEndPos = " + nFileLength); feej'l }F  
// fileSplitterFetch[nPos.length-1].start(); 2dn^K3  
7({)o
u x  
<kn2
 
//等待子线程结束 -C=0Pg]ga  
//int count = 0; `[/#,*\  
//是否结束while循环 <L
}@p8Lq  
boolean breakWhile = false; ? wS}'  
:j\7</uu  
&jqaW2  
while(!bStop) )x.%P
UA  
{ iU)I"#\l'k  
write_nPos(); T ,lM(2S[  
Utility.sleep(500); }3Es&p$9  
breakWhile = true; Z\!,f.>g  
D!j/a!MaKk  
xl}rdnf}  
for(int i=0;i<nStartPos.length;i++) RT[p!xL  
{ cx\"r  
if(!fileSplitterFetch.bDownOver) .;? Bni  
{ {U5
sRM|I  
breakWhile = false; pBsb>wvej  
break; dY1t3@E  
} :qzg?\(  
} VPMu)1={:p  
if(breakWhile) &[E\2 E  
break; B%F]K<  
L}Z.FqJ  
*$Q>Om]  
//count++; iq&3S0  
//if(count>4) ipSMmpB  
// siteStop(); +H-=`+,  
} Eb3ZM#  
o_:v?Y>0  
)%(ZFn}   
System.err.println("文件下载结束！"); u6|C3,!z"  
} oF%m
  
catch(Exception e){e.printStackTrace ();} )GP;KUVae  
} \/ bd  
U8_{MY-9}  
h
RkCB  
//获得文件长度 |$Yk)z3  
public long getFileSize() sI>w#1.m/&  
{ DE(XSzX  
int nFileLength = -1; ]*0zir/  
try{ [|nK5(e9  
URL url = new URL(siteInfoBean.getSSiteURL()); E7uIur=g!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]c(FgYc  
httpConnection.setRequestProperty("User-Agent","NetFox"); 
+R'8$  
+=tdgw/  
Wf~^,]9N  
int responseCode=httpConnection.getResponseCode(); w-|Rb~XT h  
if(responseCode>=400) @|gG3  
{ UHl3/m7g  
processErrorCode(responseCode); !0{SVsc)  
return -2; //-2 represent access is error ]kj^T?&n.  
} {*xE+ |  
>"W^|2
R  
/}:{(Go  
String sHeader; !(d]f0  
%YG?7PBB  
g~U
(w  
for(int i=1;;i++) [gWeD  
{ k+QGvgP[4@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }">r0v!3  
//Utility.log(in.readLine()); Ycr3$n]e  
sHeader=httpConnection.getHeaderFieldKey(i); VU3RFl  
if(sHeader!=null) HE}0_x.  
{ mxlh\'b  
if(sHeader.equals("Content-Length")) %ZVYgtk;*  
{ } z'Jsy[s  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); De$~ *2  
break; (5T>`7g8  
} 2?,Jn&i5  
} m6Dm1'+  
else TmgC {_  
break; r)<A YX]J  
} OUv)`K  
} 2Kxb(q"  
catch(IOException e){e.printStackTrace ();} v93b8/1  
catch(Exception e){e.printStackTrace ();} {&1L &f<  
!HTOE@  
{gD ED  
Utility.log(nFileLength); `d <`>  
<\229  
)%C.IZ_s2  
return nFileLength; j0l{Mc5  
} J6 ~Sr  
N&8$tJ(hhx  
( 5LCy?-6  
//保存下载信息（文件指针位置） P1F-Wy1  
private void write_nPos() -}7$;QK&a  
{ dL42)HP5  
try{ {"o9pIh{~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *@rA7zPFf  
output.writeInt(nStartPos.length); ]d
*9@+Iu  
for(int i=0;i<nStartPos.length;i++) 1}VaBsEV  
{ yP"2.9\erH  
// output.writeLong(nPos); 5/.W-Q\pl}  
output.writeLong(fileSplitterFetch.nStartPos); yi$CkG}  
output.writeLong(fileSplitterFetch.nEndPos); &xGdKH  
}
{B$CqsvJ  
output.close(); 80nEQT y  
} 7L~*%j  
catch(IOException e){e.printStackTrace ();} :WB uU  
catch(Exception e){e.printStackTrace ();} '#Wx@  
} V]zZb-m=  
'sEnh<  
OZ`cE5"i  
//读取保存的下载信息（文件指针位置） E%w^q9C  
private void read_nPos() k_pv6YrE  
{ poz_=,c  
try{ <) * U/r  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Xi="gxp$%  
int nCount = input.readInt(); yZlT#^$\  
nStartPos = new long[nCount]; Nd0tR3gi7  
nEndPos = new long[nCount]; Nm)3  
for(int i=0;i<nStartPos.length;i++) q1ysT.{p,  
{ )zL@h  
nStartPos = input.readLong(); dGZie.Zx  
nEndPos = input.readLong(); o2fih%p?1  
} KjGu !B
 
input.close(); a>j}@8[J  
} ]B/>=t"E  
catch(IOException e){e.printStackTrace ();} _H$Lu4b)N  
catch(Exception e){e.printStackTrace ();} hjL;B'IL  
} hBU)gP75  
w=GMQ8  
'z} t= ?  
private void processErrorCode(int nErrorCode) 5]O{tSj  
{ gWj-@o\  
System.err.println("Error Code : " + nErrorCode); O:?3B!wF  
} ;yNc7Vl  
$PJ==N  
.IW`?9O$E  
//停止文件下载 J[}H^FR  
public void siteStop() '!m6^*m|c  
{ xpdpD  
bStop = true; 1T|f<ChIF<  
for(int i=0;i<nStartPos.length;i++) eB0exPz%  
fileSplitterFetch.splitterStop(); <8WFaP3,  
(3n "a'  
snaAn?I4  
} "0eX/rY%  
} D!`;vZ\>  
//负责部分文件的抓取 ,X!6|l8  
**FileSplitterFetch.java 'i+L  
*/ tpWGmjfo>  
package NetFox; xQ
sxc  
G+dq */  
sq$v6x sl  
import java.io.*; DI\=udN  
import java.net.*;
3)G~ud  
wfo,r 7  
3d}v?q78  
public class FileSplitterFetch extends Thread { NQ{(G8x9  
)oIh?-WL  
v3r3$(Hr  
String sURL; //File URL ?V6,>e_+  
long nStartPos; //File Snippet Start Position K P]ar.  
long nEndPos; //File Snippet End Position hYoUZ'4  
int nThreadID; //Thread's ID jOGdq;|  
boolean bDownOver = false; //Downing is over kmC@\xTp  
boolean bStop = false; //Stop identical B4.: 9Od3  
FileAccessI fileAccessI = null; //File Access interface ;UQza ]i  

svpQ.Q  
H<d~AurX)J  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7d;|?R-8D  
{ HzTmNm)  
this.sURL = sURL; ,AnD%#o  
this.nStartPos = nStart; 6b|<$Je9  
this.nEndPos = nEnd; R`(2Fy%0\k  
nThreadID = id; 9KVJk</:n  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]B
O:*&O  
} RU)(|;  

wn"}<ka  
"BQnP9  
public void run() nCYkUDnZ  
{ y[m,t}gi  
while(nStartPos < nEndPos && !bStop) 5%}e j)@  
{ ^oi']O  
<r}wQ\F#  
>9H^r\  
try{ ^_]ZZin  
URL url = new URL(sURL); +d3|Up8=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NzgG77>  
httpConnection.setRequestProperty("User-Agent","NetFox"); A3eCI  
String sProperty = "bytes="+nStartPos+"-"; yd;e;Bb7*  
httpConnection.setRequestProperty("RANGE",sProperty); #RlZxtx.O  
Utility.log(sProperty); Q^b&   
;wwc;wQ'  
%7ngAIg  
InputStream input = httpConnection.getInputStream(); hTDK[4e  
//logResponseHead(httpConnection); Qu|CXUk  
=F+v+zP7P  
v~mVf.j1  
byte[] b = new byte[1024]; ?+]=|hN  
int nRead; ZDW9H6ux  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) i<Z%  
{ B|m)V9A%-  
nStartPos += fileAccessI.write(b,0,nRead); a0|hLqI  
//if(nThreadID == 1) V_h&9]RL  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ea=E/HR-  
} _,drOF|e  
hU$aZ  
l5D)UO  
Utility.log("Thread " + nThreadID + " is over!"); 5f*_K6,v  
bDownOver = true; D40 vCax^J  
//nPos = fileAccessI.write (b,0,nRead); 3"x_Y  
} _ $a3lR  
catch(Exception e){e.printStackTrace ();} H$%MIBz>$  
} ^MpMqm1?8;  
} 0GUJc}fgvN  
|Y uf/G%/  
d"XZlEV  
//打印回应的头信息 FJ3S  
public void logResponseHead(HttpURLConnection con) @1*
^ttC  
{ 3L&:  
for(int i=1;;i++) 3m>YR-n$  
{ 7${<u0((!  
String header=con.getHeaderFieldKey(i); # 55>?  
if(header!=null) i(.e=  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~$y"Ldrp  
Utility.log(header+" : "+con.getHeaderField(header)); AQ)gj$ m3  
else 6=f)3!=  
break; =+iY<~8  
} qPPe)IM'Sc  
} S>oEk3zlw  
QoYEWXT|g  
pA!-sp
gX  
public void splitterStop() RRja{*R  
{ Kn^+kHh:  
bStop = true; W1REF9i){  
} ]Q"T8drL  
TsFhrtnx&X  
-lo?16w  
} 9"P+K.%  
M+%Xq0`T  
6 - 3?&+  
/* 'C5id7O&  
**FileAccess.java h7#\]2U$[5  
*//文件访问(定位，写) <q7o"NI6FZ  
package NetFox;
_*AI1/>`  
import java.io.*; %Xh}{o$G  
j:%,lcF  
$5XAS  
public class FileAccessI implements Serializable{ ,-6Oma -  
X7$]qE K  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 YYT;a$GTo  
RandomAccessFile oSavedFile; M86"J:\u]  
long nPos; p)SW(pS  
mOJdx-q?r  
BeUyt  
public FileAccessI() throws IOException ] hT\"5&6  
{ 5M>h[Q"R  
this("",0); x'L=p01  
} 5le
n}){  
)^(gwE  
/5sn*,  
public FileAccessI(String sName,long nPos) throws IOException {8.Zb NEJ  
{ >J;TtNE:  
oSavedFile = new RandomAccessFile(sName,"rw"); z@`o(gh  
this.nPos = nPos; KtaoOe  
oSavedFile.seek(nPos); af|h4.A  
} FGn"j@m0  
/bykIUTKI  
obvE m[x!Z  
public synchronized int write(byte[] b,int nStart,int nLen) f7*Qa!!2p]  
{ :u7BCV|yr  
int n = -1; Ts.2\-+3  
try{ q|ce7HnK  
oSavedFile.write(b,nStart,nLen); atZe`0  
n = nLen; 2.Z#\6Vj  
} ^;F/^_  
catch(IOException e) {<{VJGY7T  
{ x+Yo#u22  
e.printStackTrace (); yhKH} kR  
} uUjjAGZ  
J'2 Yrn  
|YLja87  
return n; wS=vm}}u  
} Gor9&aJ1  
$2W#'_K+  
B :%Vq2`  
} 43k'96[2d  
l0'Yq%Nf  
Nk@-yZ@,8  
/* Mst%]@TG  
**SiteInfoBean.java }-tJ.3Zw  
*/ vN(~}gOd\  
package NetFox; G/JGb2I/7|  
uBts
?02  
bkdXBCBx?  
public class SiteInfoBean { 5ih>x3S1/  
+[ ?!@)  
` +YtTK  
private String sSiteURL; //Site's URL <Z.`X7]Uk  
private String sFilePath; //Saved File's Path \~8W0q.4M  
private String sFileName; //Saved File's Name 8(Az/@=n  
private int nSplitter; //Count of Splited Downloading File ~g!!#ad  
p*PzfSLN  
N~]qQoj,  
public SiteInfoBean() +Kgl/Wg%  
{//nSplitter的缺省值为5 62ru%<x=  
//default value of nSplitter is 5 }36AeJ7L  
this("","","",5); K{d3)lVYCS  
} 9<3( QR  
Tbm ~@k(C  
Osz=OO{  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #[bosb!R  
{ x=H{Rv  
sSiteURL= sURL; 5:r AWq  
sFilePath = sPath; /}1|'?P  
sFileName = sName; z9 0JZA  
this.nSplitter = nSpiltter; J3y
_JoS  
uNI&U7_"  
$Z;8@O3  
} ;>2-  
koT
3~FK  
P?q HzNGi7  
public String getSSiteURL()
@{b5x>KX  
{ v9H t~\>  
return sSiteURL; A!GvfmzqIn  
} Aq(cgTNW  
I'IFBVhaYn  
GDCp@%xW  
public void setSSiteURL(String value) ;#zteqn  
{ 4Yvz-aSyO  
sSiteURL = value; c9c]1XJ  
} #jBmWaP.  
?8$`GyjS  
3~fi#{  
public String getSFilePath() :JSxsA6k  
{ 3F"vK  
return sFilePath; ;q'-<O  
} 1 K}gX>F  
~Q=;L>Qd  
97 SS0J  
public void setSFilePath(String value) k% \;$u=%  
{ :sw5@JdJ  
sFilePath = value; D?y-Y  
} 8/p ]'BLf  
->pU!f)\X  
_f2rz+  
public String getSFileName() jy0aKSn8  
{ ue3 ].:  
return sFileName; ,W+=N"`a'  
} ,l AZ4  
&wU"6E  
(!@gm)#h  
public void setSFileName(String value) ^}2!fRKAmo  
{ Up%XBA  
sFileName = value; _t,aPowX  
} zW\a)~E  
%H?B5y  
f'ld6jt|%  
public int getNSplitter() *[cCY!+Qy  
{ $

|Ol?s  
return nSplitter; R/1e/t  
} ri-&3%%z<  
}{+?>!qDt  
zATOFV  
public void setNSplitter(int nCount) ag8)^p'9  
{ DCa[?|Y  
nSplitter = nCount; i5(qJ/u  
}
n]vCvmt  
} [3=Y 9P:  
,l!>+@  
An>ai N
]  
/* +D @B eQu  
**Utility.java w)J-e gc  
*/ 5.-:)=  
package NetFox; r=.@APZB  
G "+[@|  
f\?Rhyz  
public class Utility { :!Z|_y{b  
[pms>TQ2  
s8A"x`5(  
public Utility() ^%%Rf  
{ "&XhMw4  
Gfx!.[Y  
\$Ky AWrZi  
} DMA7eZf'Hv  
QpzdlB44l  
//线程睡眠 <gX({FA  
public static void sleep(int nSecond) A/9<} m  
{ kqX%y  
try{ pno}`Cer  
Thread.sleep(nSecond); ]~$@x=p2e  
} ~:,}?9  
catch(Exception e) _Cf:\
Xs m  
{ nGTGX  
e.printStackTrace (); Ax|'uvVAPT  
} I`xC0ZUKj  
} [x?9<#T  
":e6s c
o  
//日志 RJ3uu NK7  
public static void log(String sMsg) 8|= c3Z  
{ =KO]w9+\  
System.err.println(sMsg); @fA|y  
} `B&E?x  
[A,!3BN  
/qKor;x  
public static void log(int sMsg) VPYcA>-%u  
{ gCYe^KJ  
System.err.println(sMsg); |H8C4^1Rq  
} Uun0FCA>  
} (MqQ3ys  
KBi(Ns#+  
f@9XSZ<.71  
/* 1Q^u#m3  
**TestMethod.java nT4Ryld  
*/ i.K!;E>  
package NetFox; r25VcY
  
LdOqV'&r  
\N0wf-qa=  
public class TestMethod { |0p@'X1  
w&}<b%l  
vx6lud0k}  
public TestMethod() nIlx?(=pu  
{ ///xx/weblogic60b2_win.exe eo;MFd%;  
try{ AD!w:jT
9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Qhe<(<^J,  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); IuFr:3(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?FS0zc!+  
fileFetch.start(); (VkO[5j  
} r1.zURY  
catch(Exception e){e.printStackTrace ();} =>o !  
Y1AZ%{^0a  
7uUq+dp  
} AW_YlS  
z<P?p  
OP=oSfa  
public static void main(String[] args) T6?03cSE  
{ #CJET  
new TestMethod(); S,|ZCl>+  
} n}9<7e~/  
} 9I5AYa?  
点击下载更多相关资料