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http断点续传简单实现(java)

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/* g>[|/z P  
**SiteFileFetch.java J-W, ^%  
*/ KAg<s}gQJ  
package NetFox; jH*+\:UP-  
import java.io.*; $Xlyc.8YId  
import java.net.*; 5T[9|zJs  
,x+_/kqx  
D&WXa|EOK  
public class SiteFileFetch extends Thread { N_vVEIO9  
NLJD}{8Ot  
zS:89y<  
SiteInfoBean siteInfoBean = null; //文件信息Bean  X7sWu{n  
long[] nStartPos; //开始位置 /~_Cb= 7  
long[] nEndPos; //结束位置 ;+-$=l3[a  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  *it(o  
long nFileLength; //文件长度 Po[u6K2&  
boolean bFirst = true; //是否第一次取文件 mI=^7 'Mk  
boolean bStop = false; //停止标志 ;8~`fK  
File tmpFile; //文件下载的临时信息 #lyvb.;  
DataOutputStream output; //输出到文件的输出流 AJrwl^ lm  
bOCdf"!g  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) {Izg1 N  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?ng?>!  
{ N0c+V["s  
siteInfoBean = bean; fB5Bh;K  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >GiM?*cC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); z[Kxy1,  
if(tmpFile.exists ()) !MB%  
{ RB_7S!qC5  
bFirst = false; 0k5Z l?  
read_nPos(); G'( %8\  
} ( $3j  
else wLD/#Hfi7  
{ a4,bP*H  
nStartPos = new long[bean.getNSplitter()]; r0kA47  
nEndPos = new long[bean.getNSplitter()]; uNnwz%w  
} +a sJV1a  
@2 dp5  
Q8M&nf  
>b-rAO\{}  
} .i/]1X*;r^  
d@"eWvnlZ  
iQ-;0<=G  
public void run() @hm %0L  
{ UTUIL D  
//获得文件长度 %_1~z[Dv  
//分割文件 ~GfcI:Zz&  
//实例FileSplitterFetch mf@YmKbp  
//启动FileSplitterFetch线程 q4 'x'8  
//等待子线程返回 $BE^'5G&4Y  
try{ ,I=Cl mR  
if(bFirst) AnPm5i.  
{ Xr M[8a  
nFileLength = getFileSize(); % @Ks<"9  
if(nFileLength == -1) T] EXm/  
{ SBjtg@:G0n  
System.err.println("File Length is not known!"); 5DyN=[b  
} xbo-~{  
else if(nFileLength == -2) V{Idj\~Jh  
{ $Miii`VS9  
System.err.println("File is not access!"); {L$b$u$7:  
} yL.si)h(p  
else }#<Sq57n  
{ nB,FJJ{kb  
for(int i=0;i<nStartPos.length;i++) >o 3X)  
{ #jr;.;8sQ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); An[*Jx  
} <$Uj ~jN  
for(int i=0;i<nEndPos.length-1;i++) ~uC4>+dk  
{ 9z'</tJ`  
nEndPos = nStartPos[i+1]; ":7cZ1VN2  
} Yc?taL)  
nEndPos[nEndPos.length-1] = nFileLength; /gy;~eB01  
} D{'Na5(  
} 1V+1i)+  
m1F<L  
gyCb\y+\a  
//启动子线程 tO[+O=d  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; CM5A-R90  
for(int i=0;i<nStartPos.length;i++) .[ 1A  
{ i'e^[oZ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Bf'jXM{-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0M8JE9 Kx  
nStartPos,nEndPos,i); '12|:t&7  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0^ E!P>  
fileSplitterFetch.start(); i6`8yw  
} +o'. !sRH  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oN `tZ;a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %m+MEh"b5  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", n"FOCcTIs  
nEndPos = " + nFileLength); n;Iey[7_E`  
// fileSplitterFetch[nPos.length-1].start(); cWRB=`=qz  
lf|^^2'*2<  
huKz["]z[  
//等待子线程结束 :!}zdeRJ  
//int count = 0; "BFW&<1  
//是否结束while循环 qsk71L  
boolean breakWhile = false; 5\4>H6  
r`B+ KQ4  
~-:CN(U  
while(!bStop) 3@"VS_;?  
{ cF(9[8c{  
write_nPos(); A+F-r_]}db  
Utility.sleep(500); <}mT[;:"  
breakWhile = true; *e>:K$r  
ZcWl{e4  
1|. 0]~0  
for(int i=0;i<nStartPos.length;i++) epG;=\f}m`  
{ w`7l ;7[  
if(!fileSplitterFetch.bDownOver) XdS<51 C  
{ GUp51*#XR  
breakWhile = false;  +;!w;t  
break; I9Sh~vTm=u  
} 4Dd9cG,lN  
} S}< <jI-z  
if(breakWhile) GecXMAa:2  
break; y]CJOC)/K  
< Ihn1?  
`nM4kt7  
//count++; Q` s(T  
//if(count>4) ~%}g"|o  
// siteStop(); [`b{eLCFX]  
} (qG$u&  
uf>w*[m5  
W ,U'hk%  
System.err.println("文件下载结束!"); 3PEs$m9e  
} "Jwz.,Y\  
catch(Exception e){e.printStackTrace ();} \bsm#vY,  
} ]e3nnS1*.  
2?ednMoE  
""a8eB 6  
//获得文件长度 DVS7N_cx2o  
public long getFileSize() jFc{$#g-  
{ A^Zs?<C-  
int nFileLength = -1; 2~4C5@SxL  
try{ B)|s.Ez  
URL url = new URL(siteInfoBean.getSSiteURL()); Rq9gtx8,=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Fi`:G}   
httpConnection.setRequestProperty("User-Agent","NetFox"); h P1|l  
*o#`lH  
19vD(KC<  
int responseCode=httpConnection.getResponseCode(); =e+go ]87x  
if(responseCode>=400) {h=Ai[|l4Q  
{ @hvq,[   
processErrorCode(responseCode); "<(~  
return -2; //-2 represent access is error ?`XKaD! f  
} 'YeJGzsJp  
s^ a`=kO  
d]^i1  
String sHeader; # 9t/j`{  
EGt)tI&  
vKt_z@{{L  
for(int i=1;;i++) f,#xicSB*  
{ N#:"X;  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); '$zFGq }}  
//Utility.log(in.readLine()); ep!.kA=\  
sHeader=httpConnection.getHeaderFieldKey(i); smU+:~  
if(sHeader!=null) zyr6Tv61U  
{ R[c_L=  
if(sHeader.equals("Content-Length")) *8p</Q  
{ D4|_?O3 |m  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); e'Pa@]VaC  
break; rU O{-R  
} X@)lPr$a  
} 8{YxUD  
else Xwi&uyvU&  
break; D/WS  
} 2&m7pcls  
} kWd'gftQ  
catch(IOException e){e.printStackTrace ();} A M2M87{t  
catch(Exception e){e.printStackTrace ();} ht |r+v-  
>g&`g}xZQ  
PwW@I~@>  
Utility.log(nFileLength); :dzU]pk%0  
E@Fen CF  
hqPn~Tq  
return nFileLength; @2gMtf?<  
} z@i4dC  
)VT/kIq-U  
<B`V  
//保存下载信息(文件指针位置) b5Pn|5AVj  
private void write_nPos() >gl.(b25C  
{ F 4/Uu"J:  
try{ +$t%L  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7,TWCVap  
output.writeInt(nStartPos.length); }U9jsm  
for(int i=0;i<nStartPos.length;i++) ' T]oV~H  
{ L|LTsRIq  
// output.writeLong(nPos); kdC OcJB  
output.writeLong(fileSplitterFetch.nStartPos); I8?[@kg5b'  
output.writeLong(fileSplitterFetch.nEndPos); dI-5%Um  
} YkX=n{^  
output.close(); d]E vC>  
} 0K ?(xB  
catch(IOException e){e.printStackTrace ();} _GqE'VX  
catch(Exception e){e.printStackTrace ();} }=a4uCE  
} "N]o5d   
mx~sxYa  
P~e$iBH'  
//读取保存的下载信息(文件指针位置) Wi^rnr'S s  
private void read_nPos() 4&e@>  
{ Wg^cj:&`u  
try{ s.'\&B[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); x[UO1% _o-  
int nCount = input.readInt(); Nl`ry2"<  
nStartPos = new long[nCount]; 070IBAk}_  
nEndPos = new long[nCount]; GDp p`'\  
for(int i=0;i<nStartPos.length;i++) Q/)ok$A&  
{ OPW"AB J  
nStartPos = input.readLong(); `aL|qyrq#  
nEndPos = input.readLong(); ~uadivli  
} 493i*j5r)l  
input.close(); nM-SDVFM  
} "R@N|Qx'  
catch(IOException e){e.printStackTrace ();} l-}5@D[  
catch(Exception e){e.printStackTrace ();} AijTT%  
} /v4S@SQ+  
xc.D!Iav  
h;qy5KS  
private void processErrorCode(int nErrorCode) BWdc^  
{ Wx$q:$h@q  
System.err.println("Error Code : " + nErrorCode); Fx5d@WNa>  
} '<< ~wt  
v9m;vWp  
ir:~*|  
//停止文件下载 @B[Cc`IN"  
public void siteStop() ]^jdO##M  
{ 9,f<Nb(\  
bStop = true; 9+ l3 $  
for(int i=0;i<nStartPos.length;i++) > ' 0 ][~  
fileSplitterFetch.splitterStop(); <3=qLm  
#0hNk%X=  
fGf-fh;s  
} .#55u+d,  
} exO#>th1  
//负责部分文件的抓取 )S};k=kG  
**FileSplitterFetch.java $n Sh[ {  
*/ HJaw\zbL  
package NetFox; {lTxB'W@d  
i4zV(  
bro  
import java.io.*; H9VXsFTW  
import java.net.*; lI_Yb:  
>q@Sd  
S=H_9io  
public class FileSplitterFetch extends Thread { 7X{bB  
w zqd g  
BBR" HMa4  
String sURL; //File URL 4 %)N(%u  
long nStartPos; //File Snippet Start Position pq[X)]z|  
long nEndPos; //File Snippet End Position Afy .3T @)  
int nThreadID; //Thread's ID (y~laW!  
boolean bDownOver = false; //Downing is over H >:4MY  
boolean bStop = false; //Stop identical 7e c0Xh1  
FileAccessI fileAccessI = null; //File Access interface /ggkb8<3  
^+%tlX_+.  
 S2&9# 6  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException yw.~trF&%  
{ twtkH~`"Q  
this.sURL = sURL; 3g0u#t{  
this.nStartPos = nStart; l{6` k<J(  
this.nEndPos = nEnd; ZEj!jWP2m  
nThreadID = id; $xA J9_2P  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _2m[(P9d  
} w3<"g&n|  
slge+xq\J  
NSS4v tA  
public void run() xaWGa1V'z  
{ ,rZn`9  
while(nStartPos < nEndPos && !bStop) m0|Ae@g~3  
{ g=xv+e  
,](v?v.[4  
=_8 UZk.  
try{ df4sOqU  
URL url = new URL(sURL); lI4J=8O0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); tE]5@b,R  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6Z(*cf/s  
String sProperty = "bytes="+nStartPos+"-"; \D,M2vC~G  
httpConnection.setRequestProperty("RANGE",sProperty); 0R@g(  
Utility.log(sProperty); (_w %  
G@!_ZM8h  
?7yQ&p  
InputStream input = httpConnection.getInputStream(); N7*CP|?E  
//logResponseHead(httpConnection); 'Aj(i/CM  
_%wK}eH+sy  
~$4]HDg  
byte[] b = new byte[1024]; psIkG0 &  
int nRead; # 0GGc.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -F"d0a,  
{ vpm ]9>1[  
nStartPos += fileAccessI.write(b,0,nRead); (Sth:{;  
//if(nThreadID == 1) vWU%ST  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _0,"vFdj  
} ytjK++(T5  
oGm1d{_-O  
-3.UE^W2  
Utility.log("Thread " + nThreadID + " is over!"); uAu( +zV2  
bDownOver = true; ]alh_U  
//nPos = fileAccessI.write (b,0,nRead); cMDRWh  
} b fp,zs  
catch(Exception e){e.printStackTrace ();} umQi  
} bh6d./  
} lPY@{1W  
\ V6   
CI,lkO|C  
//打印回应的头信息 =~J"kC  
public void logResponseHead(HttpURLConnection con) $ !v}xY  
{ p?Ed- S  
for(int i=1;;i++) $^}[g9]1  
{ Yeqvv  
String header=con.getHeaderFieldKey(i); }>V/H]B  
if(header!=null) 5k69F   
//responseHeaders.put(header,httpConnection.getHeaderField(header)); i{8]'fM  
Utility.log(header+" : "+con.getHeaderField(header)); E;6~R M:  
else Sv7 i! j  
break; 9C_*3?6  
} \e<mSR  
} Iz#yQ`  
t)9]<pN%  
SD?BM-&~  
public void splitterStop() &vCeLh:s  
{ 2\VAmPG.Zs  
bStop = true; V1<ow'^i  
} h40'@u^W  
8O6_iGTBh  
U^[<  
} R'SBd}1  
u?F (1iN =  
Y+g,pX  
/* 9`B0fv Q&  
**FileAccess.java eOt%xTx  
*//文件访问(定位,写) SB TPTb  
package NetFox; D9.`hs0  
import java.io.*; vQ 4}WtvA  
Bz+.Qa+  
q +R*Hi  
public class FileAccessI implements Serializable{ 7rcA[)<'  
-/>9c-F  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 OUzR@$  
RandomAccessFile oSavedFile; }taLk@T  
long nPos; n#BvW,6J  
ic E|.[  
,h^r:g  
public FileAccessI() throws IOException o@9+mM"B)  
{ :\b|dvI<  
this("",0); O|I+],  
} /Pvk),ca  
f2yq8/J8.  
gfde#T)S  
public FileAccessI(String sName,long nPos) throws IOException =q+R   
{ jH>8bXQqZ  
oSavedFile = new RandomAccessFile(sName,"rw"); Q(Gyq:L=>  
this.nPos = nPos; URA0ey`  
oSavedFile.seek(nPos); Z~p!C/B  
} qZ*f%L(  
;F5"}x  
?^9BMQ+  
public synchronized int write(byte[] b,int nStart,int nLen) IkDiT63]I  
{ x7dEo%j  
int n = -1; /[ K_ &  
try{ XA<ozq'  
oSavedFile.write(b,nStart,nLen); ZyI$M3{J  
n = nLen; rkDi+D6`q  
} T#EFXHPr  
catch(IOException e) (}smW_ `5  
{ mnjs(x<m  
e.printStackTrace (); E!J=8C.:  
} ,%[4j9#!_  
J;}3t!  
7Xg?U'X  
return n;  D!F 2l_  
} (ChD]PWQ  
<*(^{a. O  
n2f6 p<8A  
} h2~4G)J  
HYCuK48F[_  
tfYB_N  
/* 6w| J -{2  
**SiteInfoBean.java =\};it{u  
*/ wL}l`fRB  
package NetFox; mwC=o5O  
epg#HNP7^Y  
g/~XCC^F?  
public class SiteInfoBean { sOBu7!G%  
CMW,slC_3  
Lrd[O v  
private String sSiteURL; //Site's URL +f|BiW  
private String sFilePath; //Saved File's Path =*Z5!W'd  
private String sFileName; //Saved File's Name z6*<V5<7  
private int nSplitter; //Count of Splited Downloading File 2`?!+")  
V}WB*bE  
-e*ZCwQ  
public SiteInfoBean() y<:<$22O  
{//nSplitter的缺省值为5 (MLwQiop  
//default value of nSplitter is 5 i-" p)2d=#  
this("","","",5); #%lo;W~IY  
} m GjN_  
O|kOI?f  
=(HeF.!  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *L4`$@l8  
{ 0Ua%DyJ  
sSiteURL= sURL; #V,R >0"  
sFilePath = sPath; c;2#,m^  
sFileName = sName; KNLnn;l  
this.nSplitter = nSpiltter; !C4!LZ0A  
R?o$Y6}5  
5=|hC3h  
} r!PpUwod  
dG7OqA:9  
P!G858V(  
public String getSSiteURL() G fEX>  
{ cy yVg!+  
return sSiteURL; )3Z ^h<"j  
} Z;/$niY  
<r#eL39I  
4)|8Eu[p7  
public void setSSiteURL(String value) >TkE~7?l  
{ 4%nE*H%  
sSiteURL = value; a`[uNgDO  
} Qv,"($n\  
%h?x!,q Y  
1 i[\T  
public String getSFilePath() #9-P%%kQ  
{ li~d?>  
return sFilePath; FKNMtp[`  
} CHrFM@CM  
$6OkIP.  
~T&<CTh  
public void setSFilePath(String value) (q+)'H%iK  
{ "#[!/\=?:  
sFilePath = value; =  C4  
} )OiT{-m  
C{gyj}5  
x=ul&|^7D  
public String getSFileName() wr[,  
{ X.hm s?]  
return sFileName; 3;S, 3  
} CC#;c1t  
\jOA+FU [  
8GvJ0Jq}U  
public void setSFileName(String value) `c<;DhNO  
{ ZovW0Q)m  
sFileName = value; {&jb5-*f  
} N[<\>Ps|u  
+L7n<U3  
b0lq\9  
public int getNSplitter() q Y#n'&  
{ S H!  
return nSplitter; "jG}B.l=,  
} N[s}qmPha  
^$b Y,CE  
{q"OM*L(  
public void setNSplitter(int nCount) G1vNt7  
{ N<~t3/Nm  
nSplitter = nCount; e" St_z(  
} SHe49!RA'{  
} _lamn }(x0  
ILGMMA_2  
|Y?H A&  
/* "wNJ  
**Utility.java N@t|7~  
*/ Wk)OkIFR  
package NetFox; 0*f)=Q'  
~_/(t'9  
G"h'_7  
public class Utility { wne,e's}   
!@}wDt  
uG,5BV.M  
public Utility() ML|FQ  
{ k?+?v?I =  
)h7<?@wv&  
%5(I/zB  
} U|jSa,}  
P GqQ@6B  
//线程睡眠 \W~ N  
public static void sleep(int nSecond) ,J+}rPe"sf  
{ 1*\o.  
try{ 8WXQ Oo8  
Thread.sleep(nSecond); M/b Sud?@%  
} 8Vr%n2M  
catch(Exception e) 6 (]Dh;gC  
{ l3)} qu  
e.printStackTrace (); "&Y`+0S8  
} V<GHpFi0  
} h`^jyoF"(  
!|^|,"A)  
//日志 Mk"^?%PxT  
public static void log(String sMsg) |-:()yxs  
{ p{r}?a  
System.err.println(sMsg); Hj^1or3R]  
} C5o#i*|  
(A9Fhun  
d; boIP`M;  
public static void log(int sMsg) @>,^":`#  
{ Fs9!S a7v  
System.err.println(sMsg); 01t1Z}!y  
} |d{PA.@33  
} p`olCp'  
cr7 }^s  
5_GYrR2  
/* rV` #[d  
**TestMethod.java 11 Q1AN  
*/ dqU~`b9  
package NetFox; fK>L!=Q  
?WGA?J %2  
rBQ_iB_  
public class TestMethod { R0KPZv-  
<sb~ ^B  
Yl Zso2  
public TestMethod() - YEZ]:"  
{ ///xx/weblogic60b2_win.exe W!Gq.M  
try{ n@<YI  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); D+rxT: d  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ^UP`%egR  
SiteFileFetch fileFetch = new SiteFileFetch(bean); LBw1g<&  
fileFetch.start(); cN/6SGHK  
} Wf+cDpK  
catch(Exception e){e.printStackTrace ();} [_BP)e  
G30-^Tr   
qU \w=  
} zVViLUwG  
is?{MJZ_  
(~p< P+  
public static void main(String[] args) {:/#Nc$5  
{ j`{?OYD  
new TestMethod(); yuh *  
} E^ B'4  
} x+\`gK5  
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