http断点续传简单实现（java)

/* .1q4Q\B<  
**SiteFileFetch.java D8O&`!mf  
*/ /ygC_,mx  
package NetFox; S [=l
/3c  
import java.io.*; y88lkV4a  
import java.net.*; 9x]yu6  
qrLE1b 1$  
SO#R5Mu2N  
public class SiteFileFetch extends Thread { R)Y*<Na  
v-MrurQ4  
vK7J;U+cJ  
SiteInfoBean siteInfoBean = null; //文件信息Bean scZSnCrR  
long[] nStartPos; //开始位置 )*m
#RqLQ8  
long[] nEndPos; //结束位置 bpaS(nBy  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~]l T>|X  
long nFileLength; //文件长度 C%ZSsp u  
boolean bFirst = true; //是否第一次取文件 *S?vw'n  
boolean bStop = false; //停止标志 abczW[\  
File tmpFile; //文件下载的临时信息 >&-" X# :  
DataOutputStream output; //输出到文件的输出流 }|-Yd"$  
9C"d7--  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） lDf:~  
public SiteFileFetch(SiteInfoBean bean) throws IOException IV]2#;OO?  
{ %I^y@2A4`  
siteInfoBean = bean; |K11Woii  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y)](j
U%o  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =K`]$Og}8  
if(tmpFile.exists ()) FJC}xEMcN  
{ *D:"I!Ho  
bFirst = false; &`}8Jz=S  
read_nPos(); :OC(93d)0  
} 2`V[Nb  
else `U6bI`l  
{ .8~zgpK  
nStartPos = new long[bean.getNSplitter()]; [}1+=Ub  
nEndPos = new long[bean.getNSplitter()]; ,enU`}9V*  
} '>aj5tZ>R  
vq_v;$9}  
M?3#XQDvD  
7eP3pg#  
} JXNfE,_  
:WM[[LOaC  
ns}"[44C}l  
public void run() bKb}VP  
{ ><r\ 5`  
//获得文件长度 x/]]~@:  
//分割文件  1cvH  
//实例FileSplitterFetch ecqL;_{o  
//启动FileSplitterFetch线程 1^R:[L4R`  
//等待子线程返回 {T(z@0Xu  
try{ 0%OV3`  
if(bFirst) JQdeI+  
{ okSCM#&:[2  
nFileLength = getFileSize(); jv5Os-  
if(nFileLength == -1) jC3)^E@:"  
{ w}:&+B:  
System.err.println("File Length is not known!"); s<`54o ,  
} d2=Z=udd  
else if(nFileLength == -2) TQiDbgFo  
{ dZi?Z  
System.err.println("File is not access!"); !tckE\ h#N  
} 1XD|H_JG<j  
else TxDzG
C  
{ kE*OjywN  
for(int i=0;i<nStartPos.length;i++) MET"s.v
 
{ "U6:z M  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); go[(N6hN  
} X{-[ E^X  
for(int i=0;i<nEndPos.length-1;i++) qR>"r"Fq  
{ f83Tl~  
nEndPos = nStartPos[i+1]; 0X: :<N@  
} ztG!NZL  
nEndPos[nEndPos.length-1] = nFileLength; $=rLs)  
} N8K @ch3=P  
} P{{U  
*E1v  
J[7|Ul1 <  
//启动子线程 {I"`
(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; [pgld9To  
for(int i=0;i<nStartPos.length;i++) mO~A}/je  
{ O%R*1 P9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "<LVA2v;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #fTPo:*t  
nStartPos,nEndPos,i); Ej7>ywlW  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _=d X01  
fileSplitterFetch.start(); S-D=-{@  
} Zyx92z9Y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _WeN\F~^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Rb=8(#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", hq[RU&\  
nEndPos = " + nFileLength); >~)IsQ*%  
// fileSplitterFetch[nPos.length-1].start(); cJQ&#u  
xOgUX6n  
yDn8{uI  
//等待子线程结束 2ij
/!  
//int count = 0; KfkE'_F  
//是否结束while循环 B6hd*f  
boolean breakWhile = false; Ohe*m[  
@*{sj`AS '  
XDM~H  
while(!bStop) ]%8f-_fSy  
{ NIascee  
write_nPos(); 7x ?2((  
Utility.sleep(500); ( /):  
breakWhile = true; A
g#o&Y  
5lp};  
C6P
(86?  
for(int i=0;i<nStartPos.length;i++) 7Rix=*  
{ 1E'/!|  
if(!fileSplitterFetch.bDownOver) e_{!8u.+  
{ gJv;{;%  
breakWhile = false; |Vq&IfP  
break; FA#?+kd  
} R:}u(N  
} _#mo6')j  
if(breakWhile) zC[lPABQ  
break; {#Vck\&  
2*<'=*zaQ  
5/{";k)L+  
//count++; Pa}B0XBWP  
//if(count>4) LtDQgel"  
// siteStop(); pHpHvSI  
} @T6Z3Zj}  
G>q16nS~KP  
:>t^B+  
System.err.println("文件下载结束！"); kk*:S*,  
} >tFv&1iR  
catch(Exception e){e.printStackTrace ();} =e>#oPH  
} X
A%a7Xtni  
EDkxRfY2/  
z%
pD3J?>  
//获得文件长度 6QC=:_M;  
public long getFileSize() 7KzMa%=  
{ ~.,h12  
int nFileLength = -1; rW&#Xw/a  
try{ Z
O!  
URL url = new URL(siteInfoBean.getSSiteURL()); QV@NA@;XZ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B,Gt6cUq  
httpConnection.setRequestProperty("User-Agent","NetFox"); |0jmOcZF  
!^/Mn  
xO<
$xx  
int responseCode=httpConnection.getResponseCode(); (3;dtp>Xx  
if(responseCode>=400)
&K*x[  
{ cx(W{O"Jb  
processErrorCode(responseCode); sivd@7r\Fa  
return -2; //-2 represent access is error mGK-&|gq  
} ra'h\m  
m<cvx3e  
I )LO@  
String sHeader; mm5y'=#  
%488"  
k'd(H5A
 
for(int i=1;;i++) J^G#x}y  
{ 4[eQ5$CB<u  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); s.)nS$  
//Utility.log(in.readLine()); SB3=5"q  
sHeader=httpConnection.getHeaderFieldKey(i); ?<#2raH-  
if(sHeader!=null) UOg4
E  
{ H%*<t}  
if(sHeader.equals("Content-Length")) MGmUgc  
{ E9yBa=#*c  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5}/TB_W7j  
break; |=Mn~`9p  
} 27NhYDo  
} N{$'-[  
else 5
*d  
break; JvZNr?_w%  
} JrkjfoN  
} D3>;X=1  
catch(IOException e){e.printStackTrace ();} j+_pF<$f:  
catch(Exception e){e.printStackTrace ();} Ve1O<i  
T|c9Swur  
rU{E}  
Utility.log(nFileLength); /<Doe SDJ|  
TyCMZsvM,  
d/57;6I_  
return nFileLength; tv+H4/  
} N~%F/`Z<+  
=7Wr  
g`skmHS89  
//保存下载信息（文件指针位置） V|h/a\P  
private void write_nPos() t1I` n(]n  
{ >9S@:?^&q>  
try{ &$vW  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Wy'H4Rg8  
output.writeInt(nStartPos.length); a^*@j:[  
for(int i=0;i<nStartPos.length;i++) #h 4`f  
{ B`/cKfg  
// output.writeLong(nPos); a09]5>*  
output.writeLong(fileSplitterFetch.nStartPos); p$5+^x'(  
output.writeLong(fileSplitterFetch.nEndPos); c 4<~?L  
} K`9ph"(Z  
output.close(); NTHy!y<!h  
} Use`E  
catch(IOException e){e.printStackTrace ();} !*?Ss  
catch(Exception e){e.printStackTrace ();} +U%U3tAvs  
} H@uCbT  
u,d@oF(=  
zaix_mR  
//读取保存的下载信息（文件指针位置） zlh}8Es  
private void read_nPos() r`Qzn" H  
{ `z=I}6){  
try{ Ng6(2
Wt0e  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); \?bp^BrI  
int nCount = input.readInt(); kW#{[,7r  
nStartPos = new long[nCount]; "))G|+tz  
nEndPos = new long[nCount]; \gh`PS-B  
for(int i=0;i<nStartPos.length;i++) WrR97]7t  
{ u= |hRTD=  
nStartPos = input.readLong(); }<EA)se"  
nEndPos = input.readLong(); NC*h7  
} u0md ^  
input.close(); LN8V&'>  
} O
1
.a=O  
catch(IOException e){e.printStackTrace ();} 0aMw  
catch(Exception e){e.printStackTrace ();} /;%[:x  
} '~^3 =[Z  
dnby&-+T  
g2=5IU<  
private void processErrorCode(int nErrorCode) %C]K`=vI-  
{ bBQ1~ R  
System.err.println("Error Code : " + nErrorCode); y:0j$%^  
} T5eXcI0t  
Z7eD+4gD  
kpM5/=f/@  
//停止文件下载 ~ituPrH%<  
public void siteStop() :eK;:p
N  
{ QES[/i +  
bStop = true; C} #:<Jx  
for(int i=0;i<nStartPos.length;i++) u/5I;7cb  
fileSplitterFetch.splitterStop(); p",HF%  
JNzNK.E!m-  
2EubMG  
} }ug|&25D  
} {YCquoF  
//负责部分文件的抓取 hi>sDU<x  
**FileSplitterFetch.java <}c`jN!z.  
*/ W9{>.E?  
package NetFox; F<y5zqGy@  
Z#wmEc.}C  
^/Id!Y7  
import java.io.*; 5Pis0fa  
import java.net.*; ]_S&8F}|  
Z6}B}5@y  
$Nr :YI  
public class FileSplitterFetch extends Thread { {*8'b
NJ  
! K
~PH  
V`KXfY  
String sURL; //File URL =OIxG}*  
long nStartPos; //File Snippet Start Position 4#?OxvH  
long nEndPos; //File Snippet End Position p7Yej(B  
int nThreadID; //Thread's ID E%M~:JuKd?  
boolean bDownOver = false; //Downing is over 3_Su5~^  
boolean bStop = false; //Stop identical yfS`g-j{~  
FileAccessI fileAccessI = null; //File Access interface jXO*_R  
-WIT0F4o;  
1.]Py"@:  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException $/%|0tQ  
{ u-zl-?Ne  
this.sURL = sURL; 2\ /(
!n  
this.nStartPos = nStart; )#9R()n!  
this.nEndPos = nEnd; kfo, PrW`A  
nThreadID = id; &p1Et  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9-DDly [)4  
} $cr
i"G  
}>cQ}6n.
 
.y{qsL^P  
public void run() uj$b/I>.'  
{ f1;Pzr  
while(nStartPos < nEndPos && !bStop) .~0A*a  
{ (( 0%>HJ{~  
xp%,@]p  
mnM#NT5]  
try{ 7d?'~}j  
URL url = new URL(sURL); w!7f*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?]}1FP
 
httpConnection.setRequestProperty("User-Agent","NetFox"); xBhfC!AK}  
String sProperty = "bytes="+nStartPos+"-"; @ oE [!  
httpConnection.setRequestProperty("RANGE",sProperty); 9l?#ZuGXp  
Utility.log(sProperty); I\O<XJO)_  
^$aj,*Aj~  
/>(e.)f  
InputStream input = httpConnection.getInputStream(); 1}mIzrY  
//logResponseHead(httpConnection); oc
,a  
9g#L"T=  
)p7WU?&I  
byte[] b = new byte[1024]; F4i c^F{K  
int nRead; 4r!8_$fN?G  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) RYDV60*O6  
{ _f%Wk>
A4  
nStartPos += fileAccessI.write(b,0,nRead); PNLtpixZ  
//if(nThreadID == 1) ~/J:p5?L  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Mg]q^T.a  
} n83,MV?-  
}E+}\&  
Bry\"V"'g  
Utility.log("Thread " + nThreadID + " is over!"); +(VHnxNQs  
bDownOver = true; 8V%(SV  
//nPos = fileAccessI.write (b,0,nRead); K oPTY^  
} +Sk;  
catch(Exception e){e.printStackTrace ();} \+mc   
} az~4sx$+}  
} XM$r,}B k  
aDuO!?Cm  
UUy|/z%  
//打印回应的头信息 }3cOZd_,t
 
public void logResponseHead(HttpURLConnection con) _"%ef"oPh  
{ yw`xK2(C$  
for(int i=1;;i++) |HXI4MU"  
{ 0jO]+BI1  
String header=con.getHeaderFieldKey(i); F.mS,W]  
if(header!=null) 8moX"w\~_h  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); [)|P-x-<  
Utility.log(header+" : "+con.getHeaderField(header)); |a#4  
else QT/TZ:  
break; p`-`(i=iJo  
} }zi:nSpON  
} M@S6V7  
CF3Z`xD  
JK.lL]<p i  
public void splitterStop() Q*mzfsgr  
{ ;JMd(\+-  
bStop = true; j"*ZS'0  
} ig^9lM'  
$Ml/=\EHOg  
PA;RUe  
} Fn*clx<  
l?v-9l M  
#*;(%\q}  
/* NvWwj%6]  
**FileAccess.java g5/%}8[- 2  
*//文件访问(定位，写) |*"uj  
package NetFox; u1O?
`  
import java.io.*; E~]8>U?V  
-J4?Km  
a9qB8/Gg[  
public class FileAccessI implements Serializable{ "BZ6G`  
RG-pN()  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 $QmP' <  
RandomAccessFile oSavedFile; ]Qe;+p9vU  
long nPos; =1f
O"|L  
g<O*4 ]=  
-Y
%#z'^-  
public FileAccessI() throws IOException {XiBRs e  
{ a?K=  
this("",0); )s(J8J[b*L  
}
,Khhu%$  
N7k<q=r-  
*xXa4HB  
public FileAccessI(String sName,long nPos) throws IOException mV0F^5  
{ nY"9"R\.=  
oSavedFile = new RandomAccessFile(sName,"rw"); @47MJzC  
this.nPos = nPos; w}^z1n  
oSavedFile.seek(nPos); n.p6+^ES  
} AxLnF(eG  
4;WeB   
u&1n~t`  
public synchronized int write(byte[] b,int nStart,int nLen) )e|Cd} 2  
{ 4UmTA_& Io  
int n = -1; 5FcKY_  
try{ rVq=,>M9  
oSavedFile.write(b,nStart,nLen); T1c2J,+}R  
n = nLen; 4A.ZMH  
} C
,+6g/{  
catch(IOException e) nJ |O,*`O  
{ T;X8T  
e.printStackTrace (); X64OX9:YF  
} ]0.? 1se  
X*VHi  
R:kNAtK  
return n; Y15KaoK?  
} fw,ruROqD  
>tXn9'S  
Fy5xIRyI\F  
} ?I&ha-."  
KB!.N[!v  
$/5<f<%u&)  
/* fg"@qE-;  
**SiteInfoBean.java !fr /WxJ  
*/ .g_BKeU  
package NetFox; Lc
(D2=%  
dHc38zp  
~,KAJ7O_  
public class SiteInfoBean { EU.vw0}u8  
j7=I!<w V  
=wH
H
R1e  
private String sSiteURL; //Site's URL 8v"tOa4D7  
private String sFilePath; //Saved File's Path
#=UEx  
private String sFileName; //Saved File's Name -~ytk=  
private int nSplitter; //Count of Splited Downloading File Y%:FawR  
<T{2a\i 4f  
)nU%}Z  
public SiteInfoBean() Fv=7~6~  
{//nSplitter的缺省值为5 q/~U[.C  
//default value of nSplitter is 5 SHS:>V  
this("","","",5); oB;EP  
} eW#U<x%P  
awN{F6@ZE  
S]iM
Z \I/  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \^2%v~  
{ YJ_`[LnL  
sSiteURL= sURL; j|!.K|9B  
sFilePath = sPath; JCZ"#8M3  
sFileName = sName; &x19]?D"+  
this.nSplitter = nSpiltter; /WXy!W30<  
FU/yJy  
",&#9  
} Va,M9)F  
CPc<!CC  
Bi2be$nV  
public String getSSiteURL() ;%P$q9*C  
{ +hL+3`TD#H  
return sSiteURL; "f\2/4EIl  
} zq-"jpZG  
(lF;c<69  
0 (jb19  
public void setSSiteURL(String value) 2)]C'  
{ x"h0Fe?J  
sSiteURL = value; ]^MOFzSz~  
} dk

~h  
0mo^I==J1  
i
aO;i1K5U  
public String getSFilePath() uP/PVoKQ  
{ Vzf{gr?  
return sFilePath; O~
F/{:U  
} R>H*MvN  
'0x`Oh&PK  
&P{  
public void setSFilePath(String value) /l_$1<c  
{ Gs%IZo_  
sFilePath = value; 1><\
3+8  
} j(/Bf m  
xMJF1O?3  
vf(8*}'!Q  
public String getSFileName() Dgh|,LqUB  
{ S@]7   
return sFileName; u38FY@U$  
} JmdXh/X
 
rhY>aj  
d&'z0]mOe  
public void setSFileName(String value) K_j$iHqLF  
{ %:^,7 .H@  
sFileName = value; Ai\"w0  
} 9frP`4<)  
v<iMlOEt  
>ijFQ667>j  
public int getNSplitter() %||}WT-wv  
{ ?z0f5<dL  
return nSplitter; ) ?rJKr[`  
} Ao)hb4ex  
1 Y_e1tgmm  
=$601r  
public void setNSplitter(int nCount) p%e!&:!  
{ RP
'`\||*  
nSplitter = nCount; 0-cqux2U  
} KpBh@S  
} 8;9GM^L  
Knsb`1"E^6  
b9%}<w  
/* Pm; /Ua  
**Utility.java O @fX +W?U  
*/ ,GEMc a,`  
package NetFox; Ti`<,TA54  
3N6U6.Tqb  
7
?j$Lwt  
public class Utility { BX$t |t;!m  
Y W_E,A>h  
<$Q\vCR  
public Utility() 4S|! iOY  
{ Ge$cV}  
;AKtbS;H  
B[7|]"L@  
} G3&ES3L  
*FDz20S  
//线程睡眠 QxvxeK!Y  
public static void sleep(int nSecond) ut%t`Y( ]  
{ p3O%|)yV  
try{ o>#<c @  
Thread.sleep(nSecond); zMb7a_W  
} t$=FcKUV}f  
catch(Exception e) :7%JD.;W  
{ 6"Q/Y[y  
e.printStackTrace (); , RfU1R  
} +(3"XYh  
} ; iQ@wOL]  
0?l|A1I%  
//日志 Y9~;6fg  
public static void log(String sMsg) k9UmTvX  
{ [9UKVnX.V  
System.err.println(sMsg); %lNWaA  
} E }|g3  
(WiA  
VA.jt}YGE  
public static void log(int sMsg) GyJp! xFB  
{ I$0`U;Xd  
System.err.println(sMsg); 5P{dey!  
} I2("p.+R  
} T:x5 ,vpM  
>1:s.[&  
@8C^[fDL  
/* M xj  
**TestMethod.java AoyU1MR(  
*/ pcNVtp'V  
package NetFox; kbBD+*  
VpMpZ9oM<  
xtf]U:c  
public class TestMethod { uxk&5RY  
=]oBBokV  
>JS\H6  
public TestMethod() {y<[1Pms  
{ ///xx/weblogic60b2_win.exe L5%~H?K(  
try{ >`= '~y8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); FOpOS?Cr'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);
PYr#vOH  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {r.#R| 4v  
fileFetch.start(); mJewUc!<5  
} V S2p"0$3D  
catch(Exception e){e.printStackTrace ();} ,HS\(Z  
TveCy&  
H? N!F7s  
} ]7zDdI|  
&q1(v3cOO  
cRz7.9-<  
public static void main(String[] args) z;1tJ  
{ $=iz&{9  
new TestMethod(); UV)[a%/SB&  
} =Y|TShKk  
} 6k"Wy3/  
点击下载更多相关资料