http断点续传简单实现（java)

/* ^LoUi1j  
**SiteFileFetch.java v0H@Eg_  
*/ SC)g^E#  
package NetFox; 6[ j.@[t  
import java.io.*; ~E2KZm  
import java.net.*; lww!-(<ww  
N
g~FEl  
7%x[q}  
public class SiteFileFetch extends Thread { ',JinE95  
~d|A!S`  
m8d!< h  
SiteInfoBean siteInfoBean = null; //文件信息Bean JR@`2YP-  
long[] nStartPos; //开始位置 hG12ZZD  
long[] nEndPos; //结束位置 /rnu<Q#iH  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 f'EuY17w  
long nFileLength; //文件长度 0dE@c./R i  
boolean bFirst = true; //是否第一次取文件 8c9*\S  
boolean bStop = false; //停止标志 q_MG?re  
File tmpFile; //文件下载的临时信息 __G?0*3G  
DataOutputStream output; //输出到文件的输出流 \o*5  
}HFN3cq;C  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 'h|DO/X~L  
public SiteFileFetch(SiteInfoBean bean) throws IOException *zbNd:i9  
{ |B.Y6L6l  
siteInfoBean = bean; 5K>3My
#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +0nJ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); dMv=gdY  
if(tmpFile.exists ()) EyJJ0  
{ 5B3G @KR  
bFirst = false; o,AAC
  
read_nPos(); ,St#Vla  
} qNB<T('  
else mwHB(7YS,  
{ ^/I 7|u]  
nStartPos = new long[bean.getNSplitter()]; R;&AijS8  
nEndPos = new long[bean.getNSplitter()]; 7&jTtKLj  
} jFL #s&ft  
!Qu"BF  
&=] ~0$  
N8F~8lTi  
} v&DI`xn~  
;-~B)M_S`  
tE<H|_{L  
public void run() 3no%E03p  
{ x[~b2o  
//获得文件长度 Lt?lv2k=L  
//分割文件 gmw|H?]  
//实例FileSplitterFetch cQCSe,$ W  
//启动FileSplitterFetch线程 G|!Tj X7s  
//等待子线程返回 vlmB`T  
try{ @E7DyU|  
if(bFirst) Z'`<5A%;  
{ 5F)C  jQ  
nFileLength = getFileSize(); [%y';`( x  
if(nFileLength == -1) [1g8*j~L  
{ AG`L64B  
System.err.println("File Length is not known!"); bnf'4PAt  
} /?5 1D@  
else if(nFileLength == -2) _.tVSVp  
{ %g{X?  
System.err.println("File is not access!"); K[YI4pt7  
} QwW&\h[8?  
else y-'$(x
 
{ ]7W&JKmA&  
for(int i=0;i<nStartPos.length;i++) :~&~y-14  
{ c}lb%^;)E  
nStartPos = (long)(i*(nFileLength/nStartPos.length));  VA6}  
} 4VJ-,Z  
for(int i=0;i<nEndPos.length-1;i++) D=j-!{zB  
{ BKCA<  
nEndPos = nStartPos[i+1]; q;T{|5/O  
} x9UX!Z5*>  
nEndPos[nEndPos.length-1] = nFileLength; k:t]s_`<  
} e'6/`Evqz  
} aH)}/n  
Hq'`8f8N  
PxWT1 !  
//启动子线程 ]#)()6)2v  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?PuBa`zDE  
for(int i=0;i<nStartPos.length;i++) '}ptj@,  
{ ] {RDVA=]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;w{tv($$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), T"{>t  
nStartPos,nEndPos,i); S'Q@ScJ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @K  &GJ  
fileSplitterFetch.start(); y`Wty@  
} :%lTU  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }MJy +Z8&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Jj; L3S  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", py$Q  
nEndPos = " + nFileLength); z`.<U{5  
// fileSplitterFetch[nPos.length-1].start(); pNG:0  
7Od -I*bt  
y;35WtDVb  
//等待子线程结束 j+i\bks  
//int count = 0; X&tF;<m^  
//是否结束while循环 Ep9nsX*   
boolean breakWhile = false; ;km`P|
<U  
zJq~!#pZ  
Rvqq.I8aC  
while(!bStop) RD!&LFz/}  
{ &jS>UsGh  
write_nPos(); l.67++_  
Utility.sleep(500); |XaIx#n  
breakWhile = true; C.WX.Je  
~Otq %MQ  
#{\J Nb+w%  
for(int i=0;i<nStartPos.length;i++) h9t$Uz^N  
{ MU`1LHg  
if(!fileSplitterFetch.bDownOver) &|s
0P   
{ R6` WN  
breakWhile = false; iOd&BB6  
break; }~YA5^VQ$  
} NH[kNi'  
} u4t7Ie*Q  
if(breakWhile) kYzIp  
break; )X1{  
>nJ\BPx  
F~,Mw8  
//count++; &Qf/>@ l}  
//if(count>4) , Rk9N  
// siteStop(); ax"+0L{  
} ^=GC3%  J  
0!4Ts3qn1  
LK{*sHi$  
System.err.println("文件下载结束！"); sQYkQ81  
} :tz#v`3o  
catch(Exception e){e.printStackTrace ();} 3lf=b~Zi
)  
} Zd3S:),&  
GSoX<*i  
RVZ")Z(  
//获得文件长度 $h+1u$po  
public long getFileSize() J4k=A7^N  
{ 2":pE U{E  
int nFileLength = -1; Q1U\D  
try{ u}#(.)a:  
URL url = new URL(siteInfoBean.getSSiteURL()); 1vS#K=sb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ow+GS{-q  
httpConnection.setRequestProperty("User-Agent","NetFox"); LD+{o4i  
1auIR/=-  
iW)8j 8  
int responseCode=httpConnection.getResponseCode(); n4O]8C'lW9  
if(responseCode>=400) k9<;woOBO  
{ 35h8
O,Y  
processErrorCode(responseCode); 'F/~o1\.  
return -2; //-2 represent access is error fW{(lPx  
} {0L1X6eg  
S(k3 `;K  
^%d\qd`   
String sHeader; OC_+("N  
zykT*V  
piJu+tUy  
for(int i=1;;i++) ~Q Oe##  
{ F|IAiE  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); @D]5civm_  
//Utility.log(in.readLine()); ^ sOQi6pL  
sHeader=httpConnection.getHeaderFieldKey(i); =J18eH!]  
if(sHeader!=null) {JO^tI  
{ *^\Ef4Lh  
if(sHeader.equals("Content-Length")) U'k*_g
 
{ A`N,  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); TEP,Dq  
break; TtJH7  
} T]^62(So  
} Fe#  1  
else &DS/v)]  
break; g&^quZ"H  
} GF"hx`zyJ  
} ]{sU&GqBLe  
catch(IOException e){e.printStackTrace ();} Ryl:a\  
catch(Exception e){e.printStackTrace ();}
-Fi`Z$  
Wvq27YK'  
^-TE([bW  
Utility.log(nFileLength); o8 IL$:  
WO7z  
)!3V/`I  
return nFileLength; /}((l%UE.  
} u0}vWkn\4  
L 8c0lx}Nn  
B |5]Jm]  
//保存下载信息（文件指针位置） kGH}[w  
private void write_nPos() s%vis{2  
{ R6 y#S&]x  
try{ ^+*N%yr  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5 )A1\  
output.writeInt(nStartPos.length); fZ6MSAh  
for(int i=0;i<nStartPos.length;i++) |5X^u+_  
{ jSJqE_1  
// output.writeLong(nPos); M f}~{+  
output.writeLong(fileSplitterFetch.nStartPos); c_
dVWh e  
output.writeLong(fileSplitterFetch.nEndPos); zKyyU}LHH  
} I )~GZ  
output.close(); ;d@#XIS&-(  
} 'S20\hwt-  
catch(IOException e){e.printStackTrace ();} 3#
WT.4k  
catch(Exception e){e.printStackTrace ();} h!M  
} MH =%-S   
FDv<\2+ c  
X1:V<,}"  
//读取保存的下载信息（文件指针位置） 6{@w="VT  
private void read_nPos() k6;?)~.  
{ aH yx_B  
try{ l94b^W}1)W  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1ufp qqk  
int nCount = input.readInt(); J9..P&c\  
nStartPos = new long[nCount]; UZWioxsKr+  
nEndPos = new long[nCount]; :W"~ {~#?  
for(int i=0;i<nStartPos.length;i++) I~[F|d>  
{ el&0}`K  
nStartPos = input.readLong(); 3>3Kwc~E  
nEndPos = input.readLong(); bpOYHc6,*`  
} Ij 79~pn  
input.close(); x/%aM1"X^  
} @tF\p  
catch(IOException e){e.printStackTrace ();} fIM,lt  
catch(Exception e){e.printStackTrace ();} OP;v bZ  
} fPU`/6  
~Q*%DRd&Z-  
Vo4,@scG  
private void processErrorCode(int nErrorCode) hl;u'_AB  
{ Juo^,  
System.err.println("Error Code : " + nErrorCode); >R|/M`<ph  
} *tGY6=7O  
!:)s"|=  
adlV!k7RG  
//停止文件下载 ke!?BZx  
public void siteStop() I.I`6(Cb  
{ ,1hxw<sNR  
bStop = true; )"qa kT  
for(int i=0;i<nStartPos.length;i++) 2Zm0qJ  
fileSplitterFetch.splitterStop(); sZ'nYo  
"x%Htq@  
2v:]tj  
} zlyS}x@p  
} +20G>y=+  
//负责部分文件的抓取 \c,ap49RC  
**FileSplitterFetch.java CZ8KEBl  
*/ 5sdn[Tt##  
package NetFox; N1}c9}  
>d@&2FTO  
W'els)WJ|x  
import java.io.*; 84$nT>c  
import java.net.*; 88Ey12$  
8<5]\X  
# q~e^A b  
public class FileSplitterFetch extends Thread { xg30xC[  
Gw=B:kGk  
?yZ+D z\  
String sURL; //File URL j 7fL7:,T  
long nStartPos; //File Snippet Start Position $yN{-T"  
long nEndPos; //File Snippet End Position K'55O&2  
int nThreadID; //Thread's ID #:jHp44J  
boolean bDownOver = false; //Downing is over V4hiGO[  
boolean bStop = false; //Stop identical  Fiv3 {.  
FileAccessI fileAccessI = null; //File Access interface ,ZaRy$?  
{SOr#{1z*  
X1,I  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException lvdf^b/ j  
{ A8x
vo/n$  
this.sURL = sURL; P|^f0Rw3.  
this.nStartPos = nStart; j >Ht@Wi  
this.nEndPos = nEnd; Hfv7LM  
nThreadID = id; yUeCc"Vf  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ()2I#  
} |rY1US)S  
:D euX  
gK_Ymq5>"M  
public void run() ,%6P0#-  
{ C7XxFh  
while(nStartPos < nEndPos && !bStop) oxC[F*mD  
{ \4&
fxe  
u&^b~#T  
UG'Q]S#!  
try{ i% w3/m  
URL url = new URL(sURL); 8k2?
}/+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F7 5#*  
httpConnection.setRequestProperty("User-Agent","NetFox"); # Nk;4
:[  
String sProperty = "bytes="+nStartPos+"-"; hmvfw:Nq4  
httpConnection.setRequestProperty("RANGE",sProperty); kC WEtbz1  
Utility.log(sProperty); oNr-Q& C,  
H[{F'c[e  
E8!e:l =Q  
InputStream input = httpConnection.getInputStream(); d.3E[AJa(  
//logResponseHead(httpConnection); eS{!)j_^  
k\wW##=v  
"76]u)  
byte[] b = new byte[1024]; <W|3\p6  
int nRead; H6kR)~zhf  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 3e #p@sB  
{ +:8fC$vVfC  
nStartPos += fileAccessI.write(b,0,nRead); -mAUo;O  
//if(nThreadID == 1) Q8C_9r/:N>  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); WM Fb4SUR  
} C`K?7v3$m  
-5 RD)(d  
ccNd'2P  
Utility.log("Thread " + nThreadID + " is over!"); |)nZ^Cc  
bDownOver = true; p s/Ayjk  
//nPos = fileAccessI.write (b,0,nRead); 7zA'ri3w  
} 8R2QZXJb-  
catch(Exception e){e.printStackTrace ();} Jy^u?  
} cU RkP`  
} qUh2hz:  
-jW.TT h]  
6{
x(.=  
//打印回应的头信息 d^Inb!%w  
public void logResponseHead(HttpURLConnection con) u_hD}V^x4  
{ b+,';bW  
for(int i=1;;i++) Mxe}B'  
{ 5
G::wuxk  
String header=con.getHeaderFieldKey(i); S-P/+K6  
if(header!=null) ,">]`|?  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 7_%"BVb"  
Utility.log(header+" : "+con.getHeaderField(header)); {`J)j6;  
else 
Hv!U|L  
break; `lQ3C{}  
} $Oq^jUJ  
} 5)FJ:1-  
?<V?wsp  
b$4"i XSQ  
public void splitterStop() XnDUa3  
{ x8wD0D  
bStop = true; GU4'&#  
} 4P'*umJi  
!5.8]v
 
XJ;D=~  
} 1s%#$ 7  
{K <iih  
`2'#!-  
/* SFO({w(  
**FileAccess.java D'7SAFOM  
*//文件访问(定位，写)
E7NV ^4h  
package NetFox; }0eF~>Df  
import java.io.*; y6LWx:  
cFaaLUZk  
T29Dt  
public class FileAccessI implements Serializable{ YX=a#%vrl  
mZk]l5Lc  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ,ek_R)&[o  
RandomAccessFile oSavedFile; D6%J\C13`  
long nPos; c0PIc^R(@  
|*:'TKzNS  
mX_a^_[G  
public FileAccessI() throws IOException @$lG@I,[  
{ <Pap
skO>  
this("",0); 8s"%u )  
} Q(lo{AFc  
K&bzDzd`  
#,,d>e  
public FileAccessI(String sName,long nPos) throws IOException [ad@*KFxy3  
{ aAJU`=u
q  
oSavedFile = new RandomAccessFile(sName,"rw"); OTy.VT|  
this.nPos = nPos; IzsphBI  
oSavedFile.seek(nPos); }x@2]juJ  
} X<i^qoV  
@HQ`~C#Z'  
xgbJ2Mh  
public synchronized int write(byte[] b,int nStart,int nLen) :ZTc7}  
{ :axRoRg  
int n = -1; ;-9=RI0  
try{ Nd`%5%'::  
oSavedFile.write(b,nStart,nLen); 1xD=ffM>8N  
n = nLen; b6}H$Sx~  
} t\NqR  
catch(IOException e) ?kWC}k{  
{ |?rNy=P,  
e.printStackTrace (); 21 O'M  
} =x!2Ak/)  
.uuO>:  
/s?r`'j[  
return n; %`O
J.:k  
} o}W%I/s  
 `dFq:8v  
*FC=X)_&W  
} P\w\N2  
eCN })An  
=+ytTQc*ot  
/* f47Od-\-  
**SiteInfoBean.java N"8_S0=pw  
*/ #.it]Nv{  
package NetFox; ABF"~=aL  
ko Z  
c\iA89msp  
public class SiteInfoBean { =; ^%(%Y{m  
gXYI\.  
T.@aep\"  
private String sSiteURL; //Site's URL WX=Jl<  
private String sFilePath; //Saved File's Path '$|[R98  
private String sFileName; //Saved File's Name *+-}P|S:  
private int nSplitter; //Count of Splited Downloading File X*&[u7No  
E_k$W5  
'SCidN(n  
public SiteInfoBean() ~Q?a|mV,  
{//nSplitter的缺省值为5 |UK}  
//default value of nSplitter is 5 K<pV  
this("","","",5); hCCiD9gz  
} }2(,K[?  
JQV%fTHS  
My<snmr2d  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) yHs-h   
{ dQ_!)f&w1  
sSiteURL= sURL; O$IEn/%+  
sFilePath = sPath; F{EnOr`,m=  
sFileName = sName; 
TR<<+  
this.nSplitter = nSpiltter; k%D+Y(WGz8  
R($KSui  
jqv-D  
} dik:4;  
4"{ooy^Q  
2ggdWg7
z  
public String getSSiteURL() 0o+6Q8q  
{ y9_K, g  
return sSiteURL; A3|Dz&@:  
} _{r=.W+w  
(@t(?Js  
o>/YAX:.!T  
public void setSSiteURL(String value) /wP@2ADB  
{ 'f[T&o&L/  
sSiteURL = value; &$]vh  
} C!Rs^/  
{P{bOe  
V>R8GSx  
public String getSFilePath() [* @5\NWR}  
{ ;k7xMZs  
return sFilePath; NXNY"r7~  
} ^zt-HDBR_  
{.QEc0-  
@$LWWTr;  
public void setSFilePath(String value) 5D_fXfx_|  
{ Sg6"WV{<  
sFilePath = value; V#cqRE3XNi  
} x
/;buW-  
]T;EdK-  
{) Q@c)'  
public String getSFileName() R,F[XI+=N  
{ q>mE< (-M  
return sFileName; 0BH_'ZW  
} KcK>%%  
VwOW=4`6  
7qj9&bEy  
public void setSFileName(String value) t: #6sF  
{ Ttxqf:OMf  
sFileName = value; GFel(cx:K  
} 7RUofcax  
ZJwrLV  
m9"n4a|:  
public int getNSplitter() T9]HGB{  
{  /o[?D  
return nSplitter; wQwQXNG  
} gF[z fDm  
\|E^v6E%0  
5dB'&8DX  
public void setNSplitter(int nCount) g>dA$h%  
{ PI`jExL  
nSplitter = nCount; =dII- L=`  
} 'Y56+P\u  
} UEozAY  
]`&Yqg  
=!`j7#:  
/* w:?oTuw  
**Utility.java z)9wXo#~  
*/ L ]w/P|  
package NetFox; ?r?jl;A&  
|b*? qf  
2Z3('?\z~  
public class Utility { c05%iv  
JaK}|  
,4ei2`wV  
public Utility() U7I qST  
{ |37 g ~  
Hd,p!_  
]p;FZ4-T  
} /Wy.>YC|  
DqX{'jj  
//线程睡眠 1qf!DMcdZ  
public static void sleep(int nSecond) # g_Bx  
{ tUgEeh6  
try{ PSPmO'C+  
Thread.sleep(nSecond); sgO'wXcoP  
} J,zO2572u  
catch(Exception e) Rr!Y3)f;  
{ z,VD=Hnz  
e.printStackTrace (); u-tQ9ioKC  
} A?`jnRo=\  
} HO[wTB|D]  
?}m']4p  
//日志 TOoQZTI  
public static void log(String sMsg) $d,0=Ci  
{ F35#dIs`&  
System.err.println(sMsg); JqMDqPIQ  
} 'sxNDnGg  
Qu7T[<  
'w14sr%  
public static void log(int sMsg) \TF!S"V  
{ &[At`Nw71  
System.err.println(sMsg); 2hee./F`  
} &m[Qn!>i6  
} -CRraEXf8  
&R$CZU  
i,|0@Vy  
/* HmZ{L +"  
**TestMethod.java 5r?m&28X  
*/ ~u.T-0F  
package NetFox; ki{3IEOr}  
!o>H1#2l  
iR\Hv'|  
public class TestMethod { M{$j  
meCC?YAB  
>/#KI~}'N  
public TestMethod() t#S<iBAZ  
{ ///xx/weblogic60b2_win.exe $z$u{  
try{ 4]/7 )x?R  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); p2N:;lXM  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); I(S)n+E  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Cn_$l>  
fileFetch.start(); Iu{kPyx  
} XTd3|Pm  
catch(Exception e){e.printStackTrace ();} I"1;|`L~:  
@&"Pci+-|  
jM&r{^(  
} i[ $0
a4  
>5wx+n)/)  
fi+R2p~vs  
public static void main(String[] args) ~h"/Tce  
{ 8`b`QtGf  
new TestMethod(); IQ!\w-  
} gaf$uT2  
} @A+RVg*=  
点击下载更多相关资料