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http断点续传简单实现(java)

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/* tW5 \Ktjno  
**SiteFileFetch.java UwtOlV:G{  
*/ Bp\io$(%  
package NetFox; C>cc!+n%H  
import java.io.*; R#~}ZUk2  
import java.net.*; o^~6RZ  
Gb 61X6  
O%9Cq}*  
public class SiteFileFetch extends Thread { 'R*gSqx~  
($(6]?J(?7  
T(+F6d=1  
SiteInfoBean siteInfoBean = null; //文件信息Bean V5rnI\:7  
long[] nStartPos; //开始位置 ~ C5iyXR  
long[] nEndPos; //结束位置 $gDp-7  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 n ! qm  
long nFileLength; //文件长度 X@+:O-$  
boolean bFirst = true; //是否第一次取文件 &n<jpMB  
boolean bStop = false; //停止标志 |Ix6D  
File tmpFile; //文件下载的临时信息 HY#7Ctn3  
DataOutputStream output; //输出到文件的输出流 zc J]US  
qt]QO1pAd  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) `.a L>hf  
public SiteFileFetch(SiteInfoBean bean) throws IOException 567ot|cc  
{ 7^sU/3z  
siteInfoBean = bean; WA Y<X:|We  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); &ukNzV}VW  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); GQqw(2Ub}  
if(tmpFile.exists ()) !N$4.slr<p  
{ q`1t*<sk  
bFirst = false; 7qE V5!  
read_nPos(); qNHS 1  
} 7tAWPSwf  
else ]wne2WXE  
{ mXc/sh")X  
nStartPos = new long[bean.getNSplitter()]; &o"Hb=k<  
nEndPos = new long[bean.getNSplitter()]; }=A6Jv(j  
} 7i{Rn K6*  
rQ}4\PTi  
+azPpGZ=  
PB>p"[ap4  
} ~b\7 qx_a9  
JoW*)3Z  
_zh}%#6L  
public void run() UShn)3F  
{ '5ky<  
//获得文件长度 XyS#6D  
//分割文件 u4VQx,,  
//实例FileSplitterFetch H[@}ri<  
//启动FileSplitterFetch线程 R'dF<&Kj|  
//等待子线程返回 3JW9G04.  
try{ CcY.8|HT  
if(bFirst) md$[Bs9  
{ !P@u4FCs  
nFileLength = getFileSize(); QX%m4K/a  
if(nFileLength == -1) n_Um)GI>  
{ u;J=g  
System.err.println("File Length is not known!"); EfDo%H^!j  
} ?; )(O2p  
else if(nFileLength == -2) vCH>Fj"7  
{ ^e@c Ozt  
System.err.println("File is not access!"); gEKJrAA  
} }/c.>U  
else S-2xe?sb  
{ ?Tuh22J{Q  
for(int i=0;i<nStartPos.length;i++) ) 2S0OY.  
{ ""pJO 6bI  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 4n3QW%#  
} 2IjqT L  
for(int i=0;i<nEndPos.length-1;i++) hN\E8"To  
{ tB(Q-c  
nEndPos = nStartPos[i+1]; !c6 lP'U  
} VPN@q<BV  
nEndPos[nEndPos.length-1] = nFileLength; 7/Lbs  
} [-6j4D  
} qgZ(o@\  
!YJdi~q  
] (MXP,R  
//启动子线程 @Jm$<E  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; fvit+  
for(int i=0;i<nStartPos.length;i++) dUO~dV1  
{ *qOo,e  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ix:aHl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8.k"kXU@n  
nStartPos,nEndPos,i); IR/0gP  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0@AK  
fileSplitterFetch.start(); (59<Zo  
} yv3my aS  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &)s A(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 1pzU=!R?-O  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", D%^EG8i n.  
nEndPos = " + nFileLength); Q|5wz]!5Y(  
// fileSplitterFetch[nPos.length-1].start(); (|U+(~PJ  
Y}1|/6eJ  
&OI=r vDmo  
//等待子线程结束 ][G<CO`k  
//int count = 0; _"WQi}Mm  
//是否结束while循环 `n^jU92  
boolean breakWhile = false; Kq{s^G  
f7s]:n*Ih  
P\2QH@p@t  
while(!bStop) q,:\i+>K*  
{ 9,y&?GLP  
write_nPos(); 42m`7uQ  
Utility.sleep(500); 8 6L&u:o:  
breakWhile = true; *EV]8  
_^a.kF  
 h@W}xT  
for(int i=0;i<nStartPos.length;i++) |d%Dw^  
{ ;7m>40W  
if(!fileSplitterFetch.bDownOver) =z=Guvcn`  
{ kOtC(\]5  
breakWhile = false; tOspDPSXX  
break; gVG :z_6  
} hJd#Gc~*M  
} ~Zj?%4  
if(breakWhile) h+Q ==  
break; k.lnG5e  
Q;aZpi-E"  
J=\Y4- "  
//count++; %{HqF>=~  
//if(count>4) /@wm?ft6Gk  
// siteStop(); wh*OD  
} q1?2 U<  
~(%G; fZ?x  
pM#:OlqC  
System.err.println("文件下载结束!"); W1: o2 C7  
} ,Y`C7Px  
catch(Exception e){e.printStackTrace ();} &UzZE17R  
} {g @ *jo&  
dvL'>'g  
<|2_1[,sl  
//获得文件长度 Kjf#uU.7  
public long getFileSize() Np/[MC  
{ iOJgZuP  
int nFileLength = -1; pnqjAT GU  
try{ &rNXn?>b  
URL url = new URL(siteInfoBean.getSSiteURL()); I) Y$?"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |Zt=8}di  
httpConnection.setRequestProperty("User-Agent","NetFox"); jM7}LV1Ck  
W B!$qie\  
(yXVp2k  
int responseCode=httpConnection.getResponseCode(); !4 hs9b  
if(responseCode>=400) @x=CMF15  
{ "n8_Ag@r  
processErrorCode(responseCode); ;l`8w3fDt  
return -2; //-2 represent access is error ~Yr.0i.W  
} (> 8fcQUBb  
N@A#e/8  
F8=6!Qj  
String sHeader; G4RsH/  
Ko%rB+d  
o&CvjE  
for(int i=1;;i++) Wc]Fg9E  
{ ~Snw':  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); qy-BZ%3  
//Utility.log(in.readLine()); `nizGg~1  
sHeader=httpConnection.getHeaderFieldKey(i); mYy3KqYu  
if(sHeader!=null) d->b9  
{ UWusSi3+LG  
if(sHeader.equals("Content-Length")) O! j@8~='  
{ p[/n[@<8=  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); XBr>K> (  
break; z?gJHN<  
} Zv-6H*zM6  
} k,@1rOf  
else N9*$'  
break; tP:xx2N_  
} DX!$k[  
} k[zf`x^  
catch(IOException e){e.printStackTrace ();} ?.Kl/8ml  
catch(Exception e){e.printStackTrace ();} >eEf|tKO  
4o=G) KO{  
X'u`\<&W  
Utility.log(nFileLength); |BW956fBU  
}YSH8d  
Qy$QOtrv  
return nFileLength; PAc~p8S  
} MRC5c:(  
-!}1{   
1u` Z?S(  
//保存下载信息(文件指针位置) S\X_!|  
private void write_nPos() @ =,J6  
{ $"UAJ-  
try{ H{}6`;W  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]':C~-RV{  
output.writeInt(nStartPos.length); jxoEOEA  
for(int i=0;i<nStartPos.length;i++) 9z-"JnM  
{ pTN_6=Y"  
// output.writeLong(nPos); zCQv:.0L  
output.writeLong(fileSplitterFetch.nStartPos); TxiJ?sDh*  
output.writeLong(fileSplitterFetch.nEndPos); DBv5Og  
} Th8Q ~*v  
output.close(); pE`( kD  
} \UC4ai2MK  
catch(IOException e){e.printStackTrace ();} 1rKR=To  
catch(Exception e){e.printStackTrace ();} .DX#:?@4@Y  
} +amvQ];?Q8  
awawq9)Y  
O@$hG8:  
//读取保存的下载信息(文件指针位置) 3gM{lS}h#  
private void read_nPos()  qJK^i.e  
{ vd ;wQ  
try{ 49#-\=<gt  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~q4y'dBy*  
int nCount = input.readInt(); dqkkA/1  
nStartPos = new long[nCount]; |/s.PNP2  
nEndPos = new long[nCount]; Mfz5:'  
for(int i=0;i<nStartPos.length;i++) $wN.~"T  
{ )N=wJN1  
nStartPos = input.readLong(); ?y '.sQ  
nEndPos = input.readLong(); vbFAS:Y:+  
} |'J3"am'  
input.close(); i3GvTg-X  
} iIT<{m&`  
catch(IOException e){e.printStackTrace ();} "2h#i nS  
catch(Exception e){e.printStackTrace ();} lfKknp#B/O  
} ! of7]s  
jab]!eY  
K4rr.f6  
private void processErrorCode(int nErrorCode) t.zSJ|T_&O  
{ fg9sZ%67]\  
System.err.println("Error Code : " + nErrorCode); _I!Xr!!)a0  
} 2Fh_  
& p%,+|  
jmb\eOq+~V  
//停止文件下载 63f/-64?7  
public void siteStop() 2ReulL8j  
{ d}G?iX;c}  
bStop = true; U!'lc} 5  
for(int i=0;i<nStartPos.length;i++) %MIu;u FR  
fileSplitterFetch.splitterStop(); /}VQzF  
she`_'?5  
+-Dd*yD6<  
} c`>\R<Z ]  
} nqH^%/7)A@  
//负责部分文件的抓取 dOhV`8l  
**FileSplitterFetch.java M{S7ia"s  
*/ OBZ|W**N"  
package NetFox; /X:lt^?%I  
@U)'UrNr~  
6M6QMg^  
import java.io.*; JC#@sJ4az)  
import java.net.*; Dux`BKl  
U %4g:s  
-Z Z$ 1E  
public class FileSplitterFetch extends Thread { X1-s,[j'  
?yz%r`;r  
\w:u&6,0O  
String sURL; //File URL (kHR$8GFM  
long nStartPos; //File Snippet Start Position j@ "`!uPz  
long nEndPos; //File Snippet End Position bXW)n<y  
int nThreadID; //Thread's ID J.&q[  
boolean bDownOver = false; //Downing is over sH]AB =_  
boolean bStop = false; //Stop identical *HC8kD a%$  
FileAccessI fileAccessI = null; //File Access interface e%P;Jj476  
{, |"Rpd  
H )}WWXK  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException bDkE*4SRX  
{ 8N`$7^^  
this.sURL = sURL; U VLcR  
this.nStartPos = nStart; =?lT&|"  
this.nEndPos = nEnd; 5B2,=?+o  
nThreadID = id; Yyo|W;a]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 zbR.Lb  
} d3$<|mG$  
4Rm3'Ch  
W>~%6K>p  
public void run() 7L]?)2=  
{ $7r wara  
while(nStartPos < nEndPos && !bStop) `SW " RLS3  
{ KCFwO'  
mx[^LaR>v  
qh'BrYu*  
try{ JA}'d7yEa  
URL url = new URL(sURL); [E^X=+Jnz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); g-^m\>B  
httpConnection.setRequestProperty("User-Agent","NetFox"); jysV%q 3  
String sProperty = "bytes="+nStartPos+"-"; Dmi;# WY  
httpConnection.setRequestProperty("RANGE",sProperty); ;Y '\:  
Utility.log(sProperty); </Id';|v  
n96gDH*  
s`J=:>9*  
InputStream input = httpConnection.getInputStream(); e^GW[lT  
//logResponseHead(httpConnection); \,EPsQV0?  
VqrMi *W6  
]Yu+M3Fq  
byte[] b = new byte[1024]; _HK& KY  
int nRead; acZHb[w  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) l!  y _P  
{ M;Rw]M  
nStartPos += fileAccessI.write(b,0,nRead); ]*@$%iCPE  
//if(nThreadID == 1) 9O Q4\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ib\G{$r  
} =QfKDA  
aX%Zuyny  
?>8zU;Aj  
Utility.log("Thread " + nThreadID + " is over!"); I`TD*D  
bDownOver = true; !S!03|  
//nPos = fileAccessI.write (b,0,nRead); EAB+kY  
} K)+l6Q  
catch(Exception e){e.printStackTrace ();} ?GarD3#A  
} #<PdZl R  
} 5Nb_K`Vp*  
ehusI-q  
5)7mjyo%  
//打印回应的头信息 /vDF<HVzm  
public void logResponseHead(HttpURLConnection con) S7/v ,E  
{ 1hyah.i]Y  
for(int i=1;;i++) Q/n.T0Z ^  
{ I 6YT|R  
String header=con.getHeaderFieldKey(i); )T5h\ZO`;  
if(header!=null)  ;"^9L  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); .^S78hr]n  
Utility.log(header+" : "+con.getHeaderField(header)); F\R}no5C  
else mv?H]i`N  
break; y7-:l u$9  
} J\+gd%  
} b6Hk20+B;  
B9DxV>mr\r  
;cn.s,  
public void splitterStop() GKhwn&qCKb  
{ ^6oqq[$  
bStop = true; s~ZFVi-i  
} . b`P!  
 &n.uNe  
5{0>7c|.  
} eKz~viM'  
'F?Znd2L  
!s*''v*  
/* 0r ; nz]'  
**FileAccess.java FqxOHovE  
*//文件访问(定位,写) 1GE%5  
package NetFox; nj0AO0  
import java.io.*; k3 [h'.ps  
6xIYg^  
SzlfA%4+GR  
public class FileAccessI implements Serializable{ 64']F1p0  
!TL}~D:J  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 o;>3z*9?3  
RandomAccessFile oSavedFile; 0,$-)SkT  
long nPos; rY?F6'}  
>MWpYp  
K_|~3g  
public FileAccessI() throws IOException yLO &(Mb  
{ :@`(}5F4  
this("",0); s|j<b#<xQ  
} &9_\E{o%]  
';\gR/L  
<GgtP55  
public FileAccessI(String sName,long nPos) throws IOException u?3NBc$~A  
{ AJ` v  
oSavedFile = new RandomAccessFile(sName,"rw"); AV 5\W}  
this.nPos = nPos; '#i]SU&*  
oSavedFile.seek(nPos); AOx3QgC^NO  
} FT/5 _1i  
o-=d|dWG  
_#D\*0J  
public synchronized int write(byte[] b,int nStart,int nLen) d<Q+D1  
{ iynS4]`U  
int n = -1; EKd3$(^   
try{ hJo^Wo  
oSavedFile.write(b,nStart,nLen); VUC <0WV  
n = nLen; ^GrkIh0nL  
} E'^]zW=9  
catch(IOException e) #O9*$eMw  
{ + lB+|yJ+  
e.printStackTrace (); +#uNQ`1v  
} )*K<;WI WH  
+:]Aqyc\  
EPe]-C`  
return n; NVc! g  
} X ' #$e{  
B.mbKntK)R  
aDl, K;GL  
} g{W6a2  
ZE8/ m")  
&[ u6oAR  
/* R=amKLD?  
**SiteInfoBean.java 4-+ozC{  
*/ #A/]Vs$  
package NetFox; t&9as}  
RCh$j&Tn  
=,d* {m~A  
public class SiteInfoBean { Y%)h)El  
|J<pLz  
XiRT|%j  
private String sSiteURL; //Site's URL C9mzg  
private String sFilePath; //Saved File's Path ;o)=XEh8P  
private String sFileName; //Saved File's Name ]]uzl0LH  
private int nSplitter; //Count of Splited Downloading File (~7m"?  
Z<N&UFw7QJ  
P~\a)Szy  
public SiteInfoBean() ].-J.  
{//nSplitter的缺省值为5 up &NCX  
//default value of nSplitter is 5 G/fP(o-Wd  
this("","","",5); c+8>EU AW  
} Oj"pj:fB  
 !u53 3  
1<W4>~,wj  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,qe]fo >  
{ 5BU%%fBJ.  
sSiteURL= sURL; Ig02M_  
sFilePath = sPath; \,l.p_<  
sFileName = sName; 8|5Gv  
this.nSplitter = nSpiltter; oEenm\ZI  
Txt%nzIu  
)l#%.Z9  
}  :Hzz{'  
(:?5 i`  
t+3   
public String getSSiteURL() nIyROhZ  
{ lrs0^@.+  
return sSiteURL; ;]gsJ9FK<  
} :F^$"~(,  
~KAp\!,  
d; mmM\3]  
public void setSSiteURL(String value) 8! H8[J  
{ @ ],6SKbG6  
sSiteURL = value; :BL'>V   
} <JL\?)}n  
s- ,=e  
`Di ^6UK(  
public String getSFilePath() C#U< k0R  
{ z^gQ\\,4  
return sFilePath; `1fJ:b/M  
} {PODisl>\D  
W;Ud<7<;Z  
j-lSFTo  
public void setSFilePath(String value) Rwc[:6;fn  
{ I&TTr7  
sFilePath = value; JrCf,?L^  
} L_THU4^j  
mL:m;>JJ n  
DKy >]Hca  
public String getSFileName() c*x J=Gz6d  
{ QKp+;$SE'  
return sFileName; +cz"`T`X 2  
} .cg=  
r5MxjuOB1  
3>-[B`dD(  
public void setSFileName(String value) y|q@;*rGNa  
{ Rk($lW)  
sFileName = value; zmrQf/y{R  
} Js\-['`  
9J~:m$.  
5^/,aI  
public int getNSplitter() E4sn[DO  
{ J)9 AnGWe  
return nSplitter; "/ tUA\=j  
} 9W{,=.%MX$  
CfPXn0I  
V";mWws+?#  
public void setNSplitter(int nCount) )KSisEL  
{ :/o C:z\h  
nSplitter = nCount; { 1+Cw?1d  
} K0tV'Ml#"  
} i\t753<Ys  
xS= _yO9-  
<8u>_o6  
/* 0JmFQ ^g(  
**Utility.java R%>jJ[4\[  
*/ b8rp8'M)  
package NetFox; W|)GV0YM  
oN *SRaAp  
kQ@gO[hS  
public class Utility { 9@:BK;Fi  
QCeMKjCmY  
H@K#|A=a  
public Utility() 'e}uvbK  
{ =yl4zQmg$  
F(#haJ$>  
z%OuI 8"'  
} R=!kbBK>\  
Q;4}gUmI$  
//线程睡眠 fv|]= e  
public static void sleep(int nSecond) :]vA 2  
{ K@B" ]6  
try{ <^d!Vzr]  
Thread.sleep(nSecond); cNe0x2Z$?  
} h,^BC^VU9-  
catch(Exception e) u3U4UK  
{ 30D: ZmlY  
e.printStackTrace (); !n|#|.0m  
} EJ1Bq>u7  
} ARPKzF`Wq  
10mK}HT>4B  
//日志 }7K@e;YUg  
public static void log(String sMsg) k/%#>  
{ 59V#FWe-  
System.err.println(sMsg); OkLz^R?d  
} 3)}(M  
W%TQYR  
+wipfL~&S  
public static void log(int sMsg) 538fK9[  
{ 2b5#PcKa  
System.err.println(sMsg); +a|"{  
} zJ5hvDmC  
} vkJ)FEar  
M)L/d_4ka  
BWWq4mdb{  
/* hw;0t,1  
**TestMethod.java 'iJDWxCD  
*/ =/[ltUKs:a  
package NetFox; JjQ8|En  
T'E ] i!$  
2+z1h^)W  
public class TestMethod { )B6# A0  
1!vPc93 $$  
R,%_deV\(  
public TestMethod() YydA6IK4  
{ ///xx/weblogic60b2_win.exe ?]^zD k@~  
try{ @<2d8ed  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); R~)ybf{  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); u#1%P5r&X  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ]Kv q |}=  
fileFetch.start(); k}GjD2m  
} Y,C=@t@_  
catch(Exception e){e.printStackTrace ();} Q $]YD pCM  
y,Jh@n';|  
k0L] R5W  
} %Uy%kN_&  
Y(_KizBY  
P|N2R5(>T  
public static void main(String[] args) Jy]Id*u9  
{ 6JhMkB^h  
new TestMethod(); @D)Z{=>{=5  
} L7]]ZAH!1  
} pE2QnNr'  
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