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http断点续传简单实现(java)

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/* uZi.HG{<)  
**SiteFileFetch.java S{K0.<,E  
*/ JO'>oFv_W  
package NetFox; z7-k`(l4  
import java.io.*; _pH{yhA  
import java.net.*; o-cAG{.WC  
K]xa/G(  
wIf {6z{  
public class SiteFileFetch extends Thread { |0z;K:5s  
hwqbi "o  
++Ww88820  
SiteInfoBean siteInfoBean = null; //文件信息Bean s[Ur~Wvn  
long[] nStartPos; //开始位置 \sA*V%n  
long[] nEndPos; //结束位置 R3X{:1{j  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 sFDG)  
long nFileLength; //文件长度 vJ`.iRU|  
boolean bFirst = true; //是否第一次取文件 <*EZ@XoN>  
boolean bStop = false; //停止标志 |([R'Orm  
File tmpFile; //文件下载的临时信息 j( #%tIv  
DataOutputStream output; //输出到文件的输出流 Bg8#qv  
?U7) XvQ  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ,pBh`av  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6/ `.(fL1  
{ pA4*bO+  
siteInfoBean = bean; aJqeD'\>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >ulY7~wUv  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 3CE[(   
if(tmpFile.exists ()) =IKEb#R/  
{ q/1Or;iK  
bFirst = false; 19q{6X`x  
read_nPos(); bY~@}gC**@  
} l =IeJh  
else l?*r5[O>n  
{ /hv#CB>1x  
nStartPos = new long[bean.getNSplitter()]; xdy^ ^3"  
nEndPos = new long[bean.getNSplitter()]; OJb*VtZz5R  
} 23DJV);g8  
Qju`e Eo  
<a le$[  
uENdI2EY8y  
}  Zt E##p  
u2(eaP8d  
SNT5Amz!  
public void run() _w ]4~V9  
{ YW; Hk1  
//获得文件长度 ;,O fJ'q^  
//分割文件 C0x "pO7  
//实例FileSplitterFetch "?.~/@  
//启动FileSplitterFetch线程 P(omfD4  
//等待子线程返回 3,aN8F1;C  
try{ H' J|U|  
if(bFirst) 1QJBb \  
{ sNU}n<J-  
nFileLength = getFileSize(); v@EQ^C2.&  
if(nFileLength == -1) ]qw0V   
{ F#+.>!  
System.err.println("File Length is not known!"); w36(p{#vp  
} }{],GHCjQ  
else if(nFileLength == -2) CL7Nr@  
{ v vE\  
System.err.println("File is not access!"); RHNk%9  
} ?Hy+'sq[  
else $(HjI \%l^  
{ ~S(^T9R  
for(int i=0;i<nStartPos.length;i++) yi!`V.  
{ FEm=w2  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); rj  H`  
} )%JD8;[Jq  
for(int i=0;i<nEndPos.length-1;i++) fUcLfnr  
{ Ttv9" z  
nEndPos = nStartPos[i+1]; LAZVW</  
} w}<^l  
nEndPos[nEndPos.length-1] = nFileLength; MC=G"m:_  
} G?V"SU.  
} >#N[GrJAE  
:%tuNJjj  
yBn_Kd  
//启动子线程 [!?wyv3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; vD=%`G[m  
for(int i=0;i<nStartPos.length;i++) m)f|:MM  
{ g#W_S?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yr4ou  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), (@ ]tG?I=  
nStartPos,nEndPos,i); ?q%b*Ek  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); am:.NG+  
fileSplitterFetch.start(); ~b8a^6:R"  
} ^Rmoz1d  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), v*P[W_.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !A[S6-18%-  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", v.`+I-\.z)  
nEndPos = " + nFileLength); %ejeyc  
// fileSplitterFetch[nPos.length-1].start(); #%cR%Z  
exphe+b  
K}2Npo FS  
//等待子线程结束 sb'p-Mj  
//int count = 0; -2lRia  
//是否结束while循环 (2%>jg0M  
boolean breakWhile = false; K/Jk[29"\  
z~.9@[LG]  
k!13=Gh  
while(!bStop) l10-XU02  
{ $Q4=37H+  
write_nPos(); [.U^Wrd  
Utility.sleep(500); d;g-3Pf  
breakWhile = true; :r39wFi  
0P9Wy!f7  
U_*3>Q  
for(int i=0;i<nStartPos.length;i++) KW>VOW<.  
{ KnFQ)sX^  
if(!fileSplitterFetch.bDownOver) 3M$X:$b  
{ S.]MOB dt  
breakWhile = false; k5s?lWH  
break; bs:QG1*.  
} +:y&{K  
} .Qk{5=l6P  
if(breakWhile) ^^ j/  
break; h60\ Y 8  
\-G5l+!  
M8Juykw  
//count++; TMY{OI8a  
//if(count>4) 8GW ut=D  
// siteStop(); 54wM8'+  
} 6puVw-X  
r\bq[9dX>  
lrn+d$!@  
System.err.println("文件下载结束!"); i^/Di Wdyf  
} (n}%a6M  
catch(Exception e){e.printStackTrace ();} IrUi E q  
} c&A]pLn+x  
Pzptr%{  
7p !zp9|  
//获得文件长度 ' XEK&Yi1  
public long getFileSize() `~|DoSi^d  
{ X,&xhSzg?  
int nFileLength = -1; Q~h6J*  
try{ N[]U%9[=2F  
URL url = new URL(siteInfoBean.getSSiteURL()); `:R-[>5P8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,0FwBK  
httpConnection.setRequestProperty("User-Agent","NetFox"); oX#9RW/ >I  
Z3Gm  
*<?XTs<  
int responseCode=httpConnection.getResponseCode(); n)Hk8)^8  
if(responseCode>=400) sD.6"w7}  
{ Q{8qm<0g  
processErrorCode(responseCode); QWKs[yfdo  
return -2; //-2 represent access is error 0|GpZuGO9  
} i@Vs4E[b  
]|;7R^o3|  
O<bDU0s{M  
String sHeader; xdCs5ko  
GPMrs)J*!  
\N4d_ fPj  
for(int i=1;;i++) N:A3kp  
{ }]tFz}E\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 6/VNuQ_#  
//Utility.log(in.readLine()); Ko]QCLL  
sHeader=httpConnection.getHeaderFieldKey(i); H 'D#s;SlR  
if(sHeader!=null) 2(hvv-  
{ ~NA1SZ{Y+  
if(sHeader.equals("Content-Length")) #`r(zI[  
{ R9bhC9NP  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); w< v1 N  
break; 9=H}yiJz  
} O{Dm;@J-aM  
} lGl[^ 0  
else omNpE_  
break; T4Xtuu1  
} jC#`PA3m=  
} yi sF5`+  
catch(IOException e){e.printStackTrace ();} o?;F.W_  
catch(Exception e){e.printStackTrace ();} b{zAJ`|#[n  
/A0 [_  
Gg'<Q.H  
Utility.log(nFileLength); D!c1;IHZ  
mJSK; @w<O  
n9N#&Q"7m  
return nFileLength; bcUC4g\9N  
} >0kmRVd  
H&~5sEGa  
bl$+8 !~  
//保存下载信息(文件指针位置) 71JM [2  
private void write_nPos() lb-S0plw  
{ ,Le&I9*%  
try{ ~8XX3+]z:X  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .WBI%ci  
output.writeInt(nStartPos.length); m(8jSGV  
for(int i=0;i<nStartPos.length;i++) a v'd%LZP  
{ s"pR+)jf1D  
// output.writeLong(nPos); 6F@zCv"w  
output.writeLong(fileSplitterFetch.nStartPos); SPfD2%jjC  
output.writeLong(fileSplitterFetch.nEndPos); Pz5ebhgq  
} Y1#-^,qg  
output.close(); Pd)K^;em  
} MZ;"J82p  
catch(IOException e){e.printStackTrace ();} b*btkaVue  
catch(Exception e){e.printStackTrace ();} N$N;Sw  
} %bCcsdK  
sN6 0o 7.  
* i=?0M4S  
//读取保存的下载信息(文件指针位置) Qw3a"k-  
private void read_nPos() Z}sG3p  
{ [ c ~LY4:  
try{ 8O"x;3I9  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); "[%;B0J  
int nCount = input.readInt(); >k$[hk*~  
nStartPos = new long[nCount]; ^U-vD[O8  
nEndPos = new long[nCount]; Rel(bA-[N  
for(int i=0;i<nStartPos.length;i++) }9L 40)8  
{ l-DGy#h+z  
nStartPos = input.readLong(); UgF)J  
nEndPos = input.readLong(); !L &=?CX  
} O\|C,Ep m  
input.close(); O!#L#u53  
} 1?/5A|?V4+  
catch(IOException e){e.printStackTrace ();} ,Hik(22  
catch(Exception e){e.printStackTrace ();} ()+jrrK  
} NYSj^k;^(z  
JxX jDYrU  
#Pb7EL#c  
private void processErrorCode(int nErrorCode) LV}UBao5n  
{ 4FfwpO3,Ku  
System.err.println("Error Code : " + nErrorCode); ir?Uw:/f  
} [JX}1%NA  
N:UDbLjw~  
?=/}Ft  
//停止文件下载 qB+:#Yrx/  
public void siteStop() ,xAM[h&  
{ +t7c&td\  
bStop = true; ~|aeKtCs(.  
for(int i=0;i<nStartPos.length;i++) eZ8Y"i\!y  
fileSplitterFetch.splitterStop(); /tId#/Y  
FT|/ WZR  
>.!5M L\  
} vWnHC  
} ~aauW?  
//负责部分文件的抓取 +WV_`Rx#  
**FileSplitterFetch.java dVj'  
*/ [#STR=_f  
package NetFox; :=iM$_tp'  
V'HlAQr  
;y?D1o^r8W  
import java.io.*; -7Aw s)  
import java.net.*; (!XYH@Mz<w  
 rvwl  
'y+bx?3Z  
public class FileSplitterFetch extends Thread { 6g~o3  
.(MbP  
K=!ZI/+ju  
String sURL; //File URL a.Rp#}f  
long nStartPos; //File Snippet Start Position s0`|G|.}  
long nEndPos; //File Snippet End Position aowPji$H  
int nThreadID; //Thread's ID 3IJI5K_  
boolean bDownOver = false; //Downing is over V(' 'p{  
boolean bStop = false; //Stop identical '1kj:Np  
FileAccessI fileAccessI = null; //File Access interface LAK-!!0X  
$8X tI  
U'h[ {ek  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException T ,O<LFv  
{ 7=QC+XSO  
this.sURL = sURL; Vav+$l|j@  
this.nStartPos = nStart; t_zY0{|P  
this.nEndPos = nEnd; ~ ];6hxv  
nThreadID = id; L?D~~Jb  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 02J6Pn3  
} njwR~aL`|  
aoakTi!}  
'^-4{Y^2E  
public void run() giSG 6'WA  
{ qV,$bw  
while(nStartPos < nEndPos && !bStop) ik1L  
{ T^(n+lv  
p^zEfLTU  
 Z@.ol Y  
try{ LO$#DHPt  
URL url = new URL(sURL); ,# jOf{L*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z:B Y*#B  
httpConnection.setRequestProperty("User-Agent","NetFox"); Cs1%g  
String sProperty = "bytes="+nStartPos+"-"; Kz3h]/A.  
httpConnection.setRequestProperty("RANGE",sProperty); UTK.tg  
Utility.log(sProperty); ;FgEE%  
E/L?D  
N5w]2xz!  
InputStream input = httpConnection.getInputStream(); *p#YK|  
//logResponseHead(httpConnection); C!/8e (!N  
iz  GaV[  
HDW\S#  
byte[] b = new byte[1024]; k+Ma_H`  
int nRead; A]SB c2   
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) H'= i  
{ R SWB!-  
nStartPos += fileAccessI.write(b,0,nRead); O'& \-j 1  
//if(nThreadID == 1) _"w!KNX>(~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); e2h k  
} bU4+P A@$  
4qSS<SqY  
Aya;ycsgE  
Utility.log("Thread " + nThreadID + " is over!"); IrwF B  
bDownOver = true; 3d)+44G_)  
//nPos = fileAccessI.write (b,0,nRead); LWb}) #E  
} ]kplb0`  
catch(Exception e){e.printStackTrace ();} wmcp`8w.  
} 7quwc'!  
} l& ^B   
n,Mw# r?y  
8s5ru)  
//打印回应的头信息 M"$RtS|h  
public void logResponseHead(HttpURLConnection con) q!oZ; $  
{ E~g}DKs_5  
for(int i=1;;i++) R?9Plzt5  
{ 8H`l"  
String header=con.getHeaderFieldKey(i); ~z1KD)^   
if(header!=null) (b 2^d  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); VU'l~%ql  
Utility.log(header+" : "+con.getHeaderField(header)); 0!'M#'m  
else  B3+WOf5W  
break; +U/"F|M  
} ?o DfI  
} S| -{wC%  
 { e  
+VW]%6 +  
public void splitterStop() [Z G j7  
{ vls> 6h  
bStop = true; 98}vbl31j  
} =$zr t  
I/-w65J]  
<@j  
} rMFZ#38d  
7<Js'\Z  
(X7yNIPfA  
/* d\Z4?@T<5  
**FileAccess.java [3NV #  
*//文件访问(定位,写) @dKf]&h%%  
package NetFox; 0|Ft0y`+  
import java.io.*; z iGL4c0p  
w>UV\`x  
vHe.+XY  
public class FileAccessI implements Serializable{ 4_:e+ ql  
W2(=m!:U  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 r$eL-jQmn  
RandomAccessFile oSavedFile; zw9ULQ$#  
long nPos; h?tV>x/Fu  
 F%$Ws>l  
daJ-H  
public FileAccessI() throws IOException Ae zXou&  
{ F7Yuky  
this("",0); &'2l_b  
} um;U;%?Q  
Z$K%@q,10+  
4IE#dwZW  
public FileAccessI(String sName,long nPos) throws IOException = |zLr"  
{ DYk->)   
oSavedFile = new RandomAccessFile(sName,"rw"); d }CMX$1  
this.nPos = nPos; Ec/+9H6g  
oSavedFile.seek(nPos); Ds5&5&af  
} -xEg"dY/  
}slEkpk? ]  
ATewdq[C  
public synchronized int write(byte[] b,int nStart,int nLen) 1fp&"K:yR  
{ X KeK;+  
int n = -1; j*\MUR=  
try{ 1:V/['|*g)  
oSavedFile.write(b,nStart,nLen); Y{{,62D  
n = nLen; `b$I)UUm  
} Jq@LZ2^  
catch(IOException e) r2`?Ta  
{ \05C'z3]  
e.printStackTrace (); Gwk@X/q  
} ]qQB+]WN  
>CA1Ub&ls  
z$,hdZ]  
return n; .^W0;ISX  
} duTSU9  
]z@]Fi33Y  
O$\N]#  
} c9K\K~bk  
FpYoCyD}  
u(qpdG||7  
/* s @9#hjv2  
**SiteInfoBean.java ";%1sK  
*/ 7] H4E.(l  
package NetFox; <CdO& xUY  
B W1O1zIh\  
z#ET-[ I  
public class SiteInfoBean { svII =JB  
WocFID:b  
X13bi}O6#  
private String sSiteURL; //Site's URL FL}8h/  
private String sFilePath; //Saved File's Path 83|/sWrvh  
private String sFileName; //Saved File's Name GR9F^Y)K{  
private int nSplitter; //Count of Splited Downloading File =!2   
QX/`s3N  
O5"80z38[  
public SiteInfoBean() 'McVaPav  
{//nSplitter的缺省值为5 qz):YHxT]n  
//default value of nSplitter is 5 C8-q<t#SF  
this("","","",5); dzap]RpB  
} vOU -bF%u  
TlJF{ <E  
Sx7xb]3XI"  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) q9>w3 <  
{ A1@a:P=  
sSiteURL= sURL; [\y>Gv%  
sFilePath = sPath; ?2a gU  
sFileName = sName; Ib C)F> Dq  
this.nSplitter = nSpiltter; auU{I y   
+-i@R%  
o@-cT`HP  
} sP#5l @  
5,3h'\ "!  
2TO1i0  
public String getSSiteURL() N[%IrN3  
{ %\u>%s <9  
return sSiteURL; -b<+Ra  
} ]H*=Z:riu  
3FfS+q*3S  
 K!j2AP3  
public void setSSiteURL(String value) -vQ`}e1  
{ n%}0hVu  
sSiteURL = value; NoT oLt\  
} 6/ )A6Tt  
x :s-\>RcA  
idQr^{  
public String getSFilePath()  }#1g;  
{ YZd4% zF  
return sFilePath; : s35{K  
} fQ@["b   
tBt\&{=|D  
)DW;Gc  
public void setSFilePath(String value) bZ=d!)%P-{  
{ e): &pqA  
sFilePath = value; asb") NfIm  
} QCMF_;aNI  
U3>G9g>^B  
:v+ 39  
public String getSFileName() &e{&<ZVR  
{ 6mZFsB  
return sFileName; K(hf)1q  
} cVU[>gkg_  
MZ.Jkf(  
8Vp"}(Q  
public void setSFileName(String value) }6\p7n  
{ (_D#gr{S=  
sFileName = value; FRr<K^M  
} nX~sVG{Q  
D0~mu{;c$  
s;L7 _.hH@  
public int getNSplitter() *ZRQ4i[+  
{ 9tJiIr8i  
return nSplitter; !,]_tw>R  
} k&^fIz  
y37@4p^@9  
r'j*f"uAm  
public void setNSplitter(int nCount) 9d v+u6)  
{ n/?_]  
nSplitter = nCount; L(iWFy1& T  
} ^z_~e@U  
} ]P-;]*&=  
%@LVoP!@!  
<~]s+"oVc  
/* qT(j%F  
**Utility.java .Sm7na K  
*/ SJL?(S*  
package NetFox; V7.EDE2A3  
P66>w})@  
jZ)1]Q2  
public class Utility { `6'fX[j5  
|]V0sgpoZ  
hW]:CIqk  
public Utility() ~R3@GaL1  
{ |#"<{RS+w  
i0hF9M  
XB2[{XH,  
} [W` _`  
P@)z Nik[  
//线程睡眠 b:oB $E  
public static void sleep(int nSecond) PKk_9Xd  
{ XfharJ_b  
try{ y<MXd,eE  
Thread.sleep(nSecond); nF]lSg&]X  
} =98@MX%P  
catch(Exception e) @#;2P'KL  
{ D >$9(  
e.printStackTrace (); G7 b>r  
} R0vWj9nPh  
} }<m9w\pA  
ar }F^8Ku  
//日志 pxjb^GZ0  
public static void log(String sMsg) r1f##  
{ !{jDZ?z{h  
System.err.println(sMsg); g,*LP  
} N2WQrTA:S+  
[WW3'= e^  
Qt` }$]  
public static void log(int sMsg) cyL"?vR*<  
{ p@0Va  
System.err.println(sMsg); ]hRCB=G  
} ,ir(~g+{g  
} +/E`u|%|\]  
4-1=1)c*  
u[k0z!p_ c  
/* 8Th{(J_  
**TestMethod.java %|Sh|\6A!  
*/ 2N B/&60<  
package NetFox; Gf*|f"O  
2[zFKK  
 UDl[  
public class TestMethod { CEzwI _  
xvU@,bzz  
|L wn<y  
public TestMethod() u)J&3Ah%  
{ ///xx/weblogic60b2_win.exe cHP~J%&L  
try{ 6_}& WjU'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); xO3-I@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?o$ hlX  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ,%Sf,h?"^  
fileFetch.start(); K FMx(fD  
} <l>o6K  
catch(Exception e){e.printStackTrace ();} !'#Y-"=ypk  
,0k3Qi%  
<9Sg,ix't  
} jxeZ,w o  
cug=k  
ol#| .a2O  
public static void main(String[] args) uPh/u!  
{ ebv"`0K$  
new TestMethod(); 2":{3=oW~  
} wB%N}bi!  
} ny++U;qi  
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