http断点续传简单实现（java)

/* quaRVD>s +  
**SiteFileFetch.java %k['<BYG<  
*/ ^AJ 2Y_}v  
package NetFox; V?"U)Y@Y  
import java.io.*; f"*4R kG  
import java.net.*; =P9rOK=  
k\T]*A  
U>.5vK.+  
public class SiteFileFetch extends Thread { >]gB@tn[  
JU5,\3Lz#  
<X4f2z{T{@  
SiteInfoBean siteInfoBean = null; //文件信息Bean H!X*29nX  
long[] nStartPos; //开始位置 W5Pur lu?  
long[] nEndPos; //结束位置 HpIi-Es7C  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 O|=?!|`o  
long nFileLength; //文件长度 j?
]+~  
boolean bFirst = true; //是否第一次取文件 fS|e{!iI"  
boolean bStop = false; //停止标志 dJnKa]X  
File tmpFile; //文件下载的临时信息 ~aQR_S  
DataOutputStream output; //输出到文件的输出流 P, l (4  
Vh?vD:|  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） |zP~/  
public SiteFileFetch(SiteInfoBean bean) throws IOException \#w8~+`Gq  
{ c
7@/<*E+  
siteInfoBean = bean; kv2o.q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); {fl[BX]kZ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); LK*9`dzv=G  
if(tmpFile.exists ()) `fX\pOk~e  
{ g4Dck4^!4  
bFirst = false; 2W_[|.;'  
read_nPos(); BCz4 s{F  
} er1XZ  
else -UzWLVB^  
{ L[*cbjt[  
nStartPos = new long[bean.getNSplitter()]; nXb_\9E  
nEndPos = new long[bean.getNSplitter()]; K8BlEF`  
} Je9Z:s[  
2~g-k3  
F-ofR]|)>  
4f8XO"k7t=  
} @g;DA)!(  
%++: K  
}93FWo.  
public void run() eX"Ecl{  
{ z@\mn  
//获得文件长度 vShB26b  
//分割文件 =+T0[|gc(r  
//实例FileSplitterFetch ,98 F  
//启动FileSplitterFetch线程 o_Y?s+~i[/  
//等待子线程返回 VZ`YbY  
try{ tS3&&t  
if(bFirst) AT3H
HQD  
{ g5Io=e@s  
nFileLength = getFileSize(); !- QB>`7$  
if(nFileLength == -1) 0k?]~f  
{ Y`-q[F?\y  
System.err.println("File Length is not known!"); ]|w~{X!b4  
} L1Yj9i
 
else if(nFileLength == -2) 'w72i/  
{ 1'TS!/ll];  
System.err.println("File is not access!"); tq'hiS(b  
} s%Ph  
else jR\!2!  
{ 40].:9VG  
for(int i=0;i<nStartPos.length;i++) udr|6EjD.  
{ s/11TgJ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ,d_rK\J  
} N!dBF t"  
for(int i=0;i<nEndPos.length-1;i++) $qZ6i  
{ |HY{Q1%
  
nEndPos = nStartPos[i+1]; 30Qp:_D  
} $qg2@X.  
nEndPos[nEndPos.length-1] = nFileLength; )*uotV  
} ;WYzU`<g  
} #sjGju"#_  
$kmY[FWu?  
l"X,[  
//启动子线程 &c&TQkx  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; D^F=:-l m  
for(int i=0;i<nStartPos.length;i++) T9r6,yY  
{ \?8q&o1=]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &;JeLL1J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8 Elhcs  
nStartPos,nEndPos,i); 3jJV5J'"  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); k6z]"[yu  
fileSplitterFetch.start(); \k=%G_W  
} Oz]$zRu/0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +C
SR!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); M($GZ~ b%A  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", v6uRzFw  
nEndPos = " + nFileLength); 0ZI}eZA j  
// fileSplitterFetch[nPos.length-1].start(); y>u|3:z  
7!Im|7Ty  
ttlMZLX{TJ  
//等待子线程结束 W}zq9|p  
//int count = 0; 3?_%|;ga  
//是否结束while循环 'BgR01w J  
boolean breakWhile = false; z/QYy)_j  
i7YUyU  
OR|Jc+LT  
while(!bStop) b~)
2
`l  
{ -T+'3</T  
write_nPos(); a7u*d`3X=  
Utility.sleep(500); z}$.A9yn  
breakWhile = true; +N2ILE8[<  
g@/}SJh/>  
.s41Tc5u  
for(int i=0;i<nStartPos.length;i++) 1LvR,V<  
{ Rd]<591  
if(!fileSplitterFetch.bDownOver) ]{+Y!tD  
{ L %ifl:K  
breakWhile = false; ^4\0,>  
break; unz~vG1Tn  
} .V_5q:tu  
} YG0b*QBY~  
if(breakWhile) [Ran/D\.  
break; uXUuA/O5-  
7'{Vh{.  
;Kg7}4`I  
//count++; D97 vfC  
//if(count>4) >X"\+7bw  
// siteStop(); hPgYKa8u  
} pSYEC,0B  
?pd/cj^  
#RSUChe7w  
System.err.println("文件下载结束！");
z_{_wAuY  
} fF9hL3h?)  
catch(Exception e){e.printStackTrace ();} %i?v)EW  
} gCVOm-*:  
$cm9xW&  
>/%XP_q%`e  
//获得文件长度 }rs>B,=*k  
public long getFileSize() RVs=s}|>*  
{ a gL@A  
int nFileLength = -1; \ZE=WvnhZ  
try{ >$ro\/  
URL url = new URL(siteInfoBean.getSSiteURL()); ,TB$D]u8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M&9urOa`  
httpConnection.setRequestProperty("User-Agent","NetFox"); Au(oKs<  
wPcEv
GBN=  
cb{"1z  
int responseCode=httpConnection.getResponseCode(); \,v+ejhw  
if(responseCode>=400) 2<w vO 9  
{ TK~KM  
processErrorCode(responseCode); @" umY-1f  
return -2; //-2 represent access is error u'DpZ  
} 8=0I4\  
:LdPqFXj  
EUV8H}d5  
String sHeader; &=:3/;c  
oQo5y_o~  
&Ll&A@yU  
for(int i=1;;i++) G)Y,*.,  
{ Wfc~"GQq4  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0B}2~}#  
//Utility.log(in.readLine()); <nN# K{AH  
sHeader=httpConnection.getHeaderFieldKey(i); j}(m$j'  
if(sHeader!=null) "oF)u1_?  
{ =1 S%E  
if(sHeader.equals("Content-Length")) Wa&!1' @  
{ ub`zS-vb  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Jm< uE]9  
break; jPZpJ:  
} b8vZ^8tBV  
} 7~k=t!gTY  
else t&EY$'c  
break; iY&I?o!Ch  
} E8p,l>6(f  
} Mk+G(4p  
catch(IOException e){e.printStackTrace ();} +#<Z/  
catch(Exception e){e.printStackTrace ();} M1*bT@6  
H?xYS| n  
QH,(iX6RY  
Utility.log(nFileLength); o?a3hD  
"QiLu=Rq  
YB2gxZ  
return nFileLength; x#R6Ez7  
} ?0+g.,9  
e:C4f  
nf1 `)tXG  
//保存下载信息（文件指针位置） {[L('MH2|  
private void write_nPos() \ a(ce?C  
{ B_b
5&M@  
try{ [8[<4~{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Y#=MN~##t  
output.writeInt(nStartPos.length); T5.^ w  
for(int i=0;i<nStartPos.length;i++) m&'!^{av  
{
,j.bdlI#  
// output.writeLong(nPos); jcBZ#|B7;  
output.writeLong(fileSplitterFetch.nStartPos); n5IQKYrg  
output.writeLong(fileSplitterFetch.nEndPos); /m 7~-~$V  
} Z{y
H:{Vk  
output.close(); 0\@oqw]6hv  
} ijzwct#.  
catch(IOException e){e.printStackTrace ();} gxAy{ t  
catch(Exception e){e.printStackTrace ();} OIjSH~a.  
} 6CW5ay_,  
*vvm8ik  

~oT*@  
//读取保存的下载信息（文件指针位置） RU~ku{8?  
private void read_nPos() KNj~7aTp  
{ 9tVV?Q@)  
try{ J1~E*t^
  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); f:J-X~T_f  
int nCount = input.readInt(); #Q*V9kvU/H  
nStartPos = new long[nCount]; qc\D=3#Yp  
nEndPos = new long[nCount]; O7uCTB+  
for(int i=0;i<nStartPos.length;i++) ZKpJc'h  
{ <1<xSr  
nStartPos = input.readLong(); WjM7s]ZRv  
nEndPos = input.readLong(); v_WQ<G?  
} U/|JAg#  
input.close(); MxKTKBxQ  
} ]yZ%wU9!  
catch(IOException e){e.printStackTrace ();} *)6\V}`  
catch(Exception e){e.printStackTrace ();} ;^E_BJm  
} pIYXYQ=Z  
.uxM&|0H  
a
JA(UN45  
private void processErrorCode(int nErrorCode) R<{Vgy  
{ ;z N1Qb  
System.err.println("Error Code : " + nErrorCode); +{I" e,Nk  
} %%>nM'4<  
$AE5n>ZD$  
b(Tv
c  
//停止文件下载 (
j??
 
public void siteStop() RtpV08s\  
{ ]t`SCsoo  
bStop = true; : T7(sf*!*  
for(int i=0;i<nStartPos.length;i++) YhS_ ,3E  
fileSplitterFetch.splitterStop(); e3~{l~R
b  
.jk A'i@  
TO"Md["GI  
} 83gWA>Odh  
} 6o(IL-0]c  
//负责部分文件的抓取 NRp  
**FileSplitterFetch.java hwJ>IQ1  
*/ =y)K er  
package NetFox; x|G :;{"+6  
1;V_E2?V  
@DY"~ccH  
import java.io.*; nw%`CnzT  
import java.net.*; yRXWd*9  
gkA_<,38  
+{V`{'  
public class FileSplitterFetch extends Thread { v~x4Y,m%  
OH
sA]7S  
#RaqNu  
String sURL; //File URL *KY:U&*  
long nStartPos; //File Snippet Start Position _N^w5EBC]  
long nEndPos; //File Snippet End Position jlU6keZh`  
int nThreadID; //Thread's ID vB{iw}Hi!  
boolean bDownOver = false; //Downing is over OWT%XUW=  
boolean bStop = false; //Stop identical q`IY;"~  
FileAccessI fileAccessI = null; //File Access interface $[,4Ib_|  
m;MJ{"@A'  
Z${eDl6i  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [YHtBM:y  
{ (=Kv1 HaD  
this.sURL = sURL; o.0tD  
this.nStartPos = nStart; 6kdbbGO-  
this.nEndPos = nEnd; F4==a
8  
nThreadID = id; f(~N+2}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 X~D[CwA|`  
} $8%"bR;Hu  
NjOUe?BQ  
R]&Csr#~  
public void run() e(|Z<6  
{ -bHlFNRm  
while(nStartPos < nEndPos && !bStop) /(51\RYkir  
{ 'hs4k|B  
aK@ Y) Ju'  
4Yik
C  
try{ 4\ Xaou2V[  
URL url = new URL(sURL); PgT8 1u  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?u@jedQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); =f{v:n6  
String sProperty = "bytes="+nStartPos+"-"; rz k;Q@1  
httpConnection.setRequestProperty("RANGE",sProperty); igk<]AwxS  
Utility.log(sProperty); R)Arr77  
 #O\as~-  
$Vq5U9-  
InputStream input = httpConnection.getInputStream(); xn503,5G*7  
//logResponseHead(httpConnection); 5}ftiy[Yc  
:ZIa   
pa+'0Y]71  
byte[] b = new byte[1024]; bHv"
!  
int nRead; ?{B5gaU9F  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "YgpgW  
{ kodd7 AD  
nStartPos += fileAccessI.write(b,0,nRead); nk%v|ZxoFv  
//if(nThreadID == 1) k)S1Zs~G  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3J &Ros  
} eDZ8F^0  
\?T9v  
zHX\h[0f  
Utility.log("Thread " + nThreadID + " is over!"); F
w\Z[nh  
bDownOver = true; ckA\{v  
//nPos = fileAccessI.write (b,0,nRead); 4hwb] Yz  
} J#F5by%8  
catch(Exception e){e.printStackTrace ();} *0!p_Hco  
} Hf]
:mhH  
} 'A7!@hVy  

8lYA6A  
wPjq B{!Q  
//打印回应的头信息 ZxwrlaA  
public void logResponseHead(HttpURLConnection con) %N<5ST>(  
{ `M6"=)twu  
for(int i=1;;i++) >aO.a[AM  
{  c2M  
String header=con.getHeaderFieldKey(i); {&IB[Y6  
if(header!=null) h' !C  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?0qD(cfx<  
Utility.log(header+" : "+con.getHeaderField(header)); pS ](Emn`.  
else :)lG}c  
break; |di(hY|  
} S=!WFKcJR  
} ?`Yu~a{  
.k]`z>
uv  
(is',4^b  
public void splitterStop() $ItmYj.m  
{ D0FX"B
Y7  
bStop = true; 3P2{M}WIl  
} :&vX0 Ce:  
?IHt T3'Rt  
uv/\1N;V3  
} jj2iF/  
Intuda7e1  
zY_J7,0g  
/* AF{uFna  
**FileAccess.java S9Yzvq!(  
*//文件访问(定位，写) : x&R'wX-  
package NetFox; Gc`PO  
import java.io.*; H@1'El\9  
=eU=\td^  
8Re[]bE  
public class FileAccessI implements Serializable{ T:@6(_Z  
yogavCD9b/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 W-s6+DY  
RandomAccessFile oSavedFile; N<rq}^qo  
long nPos; lfHN_fE>Mq  
7s?#y=M  
7! >0  
public FileAccessI() throws IOException z!3=.D
 
{ Qy"Jt]O  
this("",0); &S{r;N5u  
} ,XEIg  
FprdP*/  
]{6/6jl  
public FileAccessI(String sName,long nPos) throws IOException 6~%><C  
{ wkx9@?2*  
oSavedFile = new RandomAccessFile(sName,"rw"); %@Gy<t,  
this.nPos = nPos; \s*UUODWK  
oSavedFile.seek(nPos); B.r^'>jQ  
} =SLG N`m3  
D wJ^ W&*  
mBErU6?X,A  
public synchronized int write(byte[] b,int nStart,int nLen) (`dz37@*  
{ B<SE|~\2  
int n = -1; Ux=~-}<-w  
try{ #("M4}~  
oSavedFile.write(b,nStart,nLen); ,yGbMOV  
n = nLen; &<e18L7a  
} i|1*bZ6'  
catch(IOException e) Nz2VaZ  
{ p*Q-o  
e.printStackTrace (); (a_bU5)  
} D0jV}oz  
u?`{s88_mF  
LsWD^JE.  
return n; ruGJZAhIA^  
} yk8b>.Y\A  
Ljm`KE\Q;t  
+ kKanm[!v  
} n\((#<&
 
v@%4i
~N  
~x,_A>a  
/* 6AJk6W^Z  
**SiteInfoBean.java bs
"J]">(N  
*/ {OEjIT
m  
package NetFox; RlL]p`g  
l'(FM^8jv  
[y9a.*]u/@  
public class SiteInfoBean { .gg0rTf=-  
6U !P8q  
vd ls
s|  
private String sSiteURL; //Site's URL DSwb8q  
private String sFilePath; //Saved File's Path X=whZ\EZ  
private String sFileName; //Saved File's Name AE77i,Xa  
private int nSplitter; //Count of Splited Downloading File N4ZV+ |  
({j8|{)+  
rgVRF44X{  
public SiteInfoBean() P$U"y/  
{//nSplitter的缺省值为5 H\QkU`b  
//default value of nSplitter is 5 W\zZ&*8$  
this("","","",5); /Ot3[B  
} @G2# Z  

zE/l  
wvq4 P  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) +Xs
E  
{ YYn8!FIe  
sSiteURL= sURL; &NBH'Rt  
sFilePath = sPath; BEaF-*?A  
sFileName = sName; yIKpyyC9H  
this.nSplitter = nSpiltter; _!o8s%9be  
$!*>5".A  
/3aW 0/^o  
} @KL&vm(F$  
F^gTID  
BjfVNF;hk:  
public String getSSiteURL() I/njyV)H  
{ $97O7j@  
return sSiteURL; /8e}c`  
} cRf F!EV  
X~jdOaq{F:  

c`xNTr01  
public void setSSiteURL(String value) G
"?7 Z&+  
{ *eoH"UFYQ#  
sSiteURL = value; U/enq,-F^  
} 0]SWyC :  
ikc1,o  
~QbHp|g  
public String getSFilePath() P_5aHeiJ  
{ qhY+<S9  
return sFilePath; Yc]V+NxxQ  
} K2Abu?  
/7D5I\  
.JLJ(WM  
public void setSFilePath(String value) *gwaW!=  
{ 44*#qLN  
sFilePath = value; @6G)(NGD  
} OY{fxBb  
;"nO'wN:h  
>"2jCR$/  
public String getSFileName() i-wRwl4aEF  
{ !-}Q{<2@W  
return sFileName; I9Ohz!RQ  
} t?>}0\1  
-E|"?  
72Bc0Wg  
public void setSFileName(String value) ^!S4?<v  
{ ooJxE\L
  
sFileName = value; M^'1Q.K  
} .9vS4C  
F&6#j  
bBs{PI2(p1  
public int getNSplitter() <CVX[R]U  
{ }3: mn  
return nSplitter; W$`v^1M2o  
} `e,}7zGR  
m .(ja  
dnLjcHFj&  
public void setNSplitter(int nCount) x4v:67_^  
{ &)k=ccm  
nSplitter = nCount; J-<P~9m~I  
} XDCm
 
} @HbRfD/!  
xK6`|/e  
clU ?bF~e1  
/* hhPQ.{]>  
**Utility.java e^eJ!~0  
*/ t}R!i-D|HB  
package NetFox; 8j>V?'Szk  
r7W.}n*  
R7Qj<,  
public class Utility { ~}b0zL  
n3$=&  
Q$U.vF7BnP  
public Utility() &$|~",  
{ >;Hx<FKxP  
(X@\2M4@T#  
qR cSB  
} HjK8y@j  
(5jKUQ8Q>  
//线程睡眠 5b"=m9{g  
public static void sleep(int nSecond) Mrk3r/ 8w  
{ [l^XqD D4  
try{ UUfM7gq  
Thread.sleep(nSecond); 4|_xz;i  
} <2]h$53y!  
catch(Exception e) CCG5:xS  
{ fh`Y2s|:7R  
e.printStackTrace (); XcoX8R%U  
} 9!=4}:+  
} ,5zY1C==Ut  
1L::Qu%E  
//日志 :.AC%'S  
public static void log(String sMsg) (DvPdOT+3  
{ WILa8"M  
System.err.println(sMsg); f.J^HQ_  
} |I1,9ex  
kKF=%J?X  
/b #w.>e  
public static void log(int sMsg) K7C <}y  
{ k+{~#@  
System.err.println(sMsg); -I{op wd  
} JYNnzgd  
} Y&bYaq  
gWHY7rv  
CL2zZk{u_  
/* ?x",VA  
**TestMethod.java BywEoS  
*/ G h+;Vrx  
package NetFox; ?M4ig_  
UZt3Ua&J  
&c-V QP(  
public class TestMethod { WY|~E
%k  
CX/[L)|Ru  
b(N+_= n  
public TestMethod() ;sA 5&a>!  
{ ///xx/weblogic60b2_win.exe 4'D^>z!c  
try{ c),UO^EqV  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); pRjEuOc  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;s,1/ kA  
SiteFileFetch fileFetch = new SiteFileFetch(bean); HAE$Np|>a  
fileFetch.start(); 0>j0L8#^p  
} ds(X[7XGW  
catch(Exception e){e.printStackTrace ();} / P@P1l|I  
Uot(3p!S6  
\68bXY.  
} _lI(!tj(  
8Q/cJ+&  
Tg O]q4  
public static void main(String[] args) H8"RdKwg?  
{ g&/lyQ+G  
new TestMethod(); "n3n-Y#'  
} #vK99S2  
} EIzTbW{p  
点击下载更多相关资料