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http断点续传简单实现(java)

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/* o @(.4+2m  
**SiteFileFetch.java i$jzn ga  
*/ *Me&> "N"  
package NetFox; #DkdFy %`  
import java.io.*; qo!6)Z  
import java.net.*; ^$x1~}D  
ur| vh5  
3'xmq  
public class SiteFileFetch extends Thread { qbq.r&F&  
 8\Uy  
>^bSjE  
SiteInfoBean siteInfoBean = null; //文件信息Bean ,(v=ZeI  
long[] nStartPos; //开始位置 z>A;|iL  
long[] nEndPos; //结束位置 pp1kcrE\M  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +8Q5[lh2]j  
long nFileLength; //文件长度 =DsFR9IB  
boolean bFirst = true; //是否第一次取文件 ?atHZLF  
boolean bStop = false; //停止标志 z`2Ais@ao  
File tmpFile; //文件下载的临时信息 kj]m@mS[  
DataOutputStream output; //输出到文件的输出流 NhRKP"<CO  
,UATT]>  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) D`hg+64}  
public SiteFileFetch(SiteInfoBean bean) throws IOException n^2'O:V s  
{ nPg,(8Tt  
siteInfoBean = bean; |TQa=  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); X(qs]:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \o<&s{ 6L  
if(tmpFile.exists ()) (3  ]!ZV  
{ w1:%P36H  
bFirst = false; dCO7"/IHW  
read_nPos(); n<3{QqF  
} Ji e=/:&  
else 3!Cab/T  
{ (P|k$S?m  
nStartPos = new long[bean.getNSplitter()]; E, ;'n  
nEndPos = new long[bean.getNSplitter()]; ur JR[$p  
} / 0y5/  
KF}_|~~T  
,nGZ( EBD  
miEf<<L#z  
} _[{oK G^u  
dhmrh5Uf  
iL;{]A'0  
public void run() 9RmdQ]1n4  
{ T&u25"QOf  
//获得文件长度 TSKR~3D#  
//分割文件 WF`  
//实例FileSplitterFetch `XK#sCC  
//启动FileSplitterFetch线程 =g<Yi2  
//等待子线程返回 G&@vTcF  
try{ U{ ZKxE  
if(bFirst) ucX!6)Op  
{ TykY>cl   
nFileLength = getFileSize(); A}MF>.!}C  
if(nFileLength == -1) ,Lr}P  
{ H':0  
System.err.println("File Length is not known!"); 2,e>gP\]  
} 17S<6j#H5  
else if(nFileLength == -2) VNHt ]Ewj  
{ .( X!*J]G  
System.err.println("File is not access!"); cW?~]E'<  
} ](SqLTB+?  
else "fWm{;  
{ ldNWdz  
for(int i=0;i<nStartPos.length;i++) ?RU_SCp-  
{ 3 , nr*R!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;;<[_gp,E  
} "= >8UR  
for(int i=0;i<nEndPos.length-1;i++) Z8q*XpUH  
{ Xf*}V+&WN  
nEndPos = nStartPos[i+1]; p0@l581  
} Yy4l -}"  
nEndPos[nEndPos.length-1] = nFileLength; 0JX/@LNg0  
} 7 ^n{BsN  
} &OP =O*B  
"-A@d&5.  
U?(+ {4l  
//启动子线程 EV|L~^Q  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; a 8.Xy])!  
for(int i=0;i<nStartPos.length;i++) ( Y)a`[B  
{ ^9 {r2d&c  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), k{ibD5B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), .R{+Pz D  
nStartPos,nEndPos,i); n%I9l]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C5&+1VrP  
fileSplitterFetch.start(); *D;VZs0O  
} hnnPi  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), VDC"tSQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); n8 e4`-cY  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", b@yFqgJ_  
nEndPos = " + nFileLength); ]-tAgNzl%  
// fileSplitterFetch[nPos.length-1].start(); V SUz+W  
8,YxCm ie  
@d_;p<\l  
//等待子线程结束 {uji7TB  
//int count = 0; C 8q VYrw  
//是否结束while循环 q<!Kt I4  
boolean breakWhile = false; jG~UyzWH;  
~#V1Gunq  
O!.mc=Gx7  
while(!bStop) jN^09T49  
{ qD/FxR-!  
write_nPos(); NZ?|#5 3  
Utility.sleep(500); B(U0 ~{7a  
breakWhile = true; +Y|HO[  
:z}  
c0W4<(  
for(int i=0;i<nStartPos.length;i++) rkC6 -9V  
{ &yQM 8J~  
if(!fileSplitterFetch.bDownOver) >m&r,z  
{ 4E.K6=k|=a  
breakWhile = false; y6 !Zt}m  
break; XG_Iq ,  
} NK0hT,_  
} (8/Qt\3jv  
if(breakWhile) k7ODQ(*v  
break; Pw_[{LL  
l\Or.I7n  
:i_k A'dl&  
//count++; {|Pz9a- :  
//if(count>4) smt6).o  
// siteStop(); 9Ucn 6[W  
} Q&Ox\*sMK  
m+/-SG  
$6]7>:8mz  
System.err.println("文件下载结束!"); C5jR||  
} YOHYXhc{S  
catch(Exception e){e.printStackTrace ();} KU}HVM{  
} 1@Zjv>jy[  
)!``P?3?  
\PB~ 6  
//获得文件长度 'ehJr/0&g  
public long getFileSize() #e:*]A'I  
{ $&|*v1rH  
int nFileLength = -1; ?>p<!:E!r  
try{ ZP& "[_  
URL url = new URL(siteInfoBean.getSSiteURL()); $N#f)8v  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @Pc]qu  
httpConnection.setRequestProperty("User-Agent","NetFox"); \KaWR  
O/(qi8En  
K"sfN~@rT[  
int responseCode=httpConnection.getResponseCode(); `[;b#.  
if(responseCode>=400) r4~Bn7j2  
{ ?wR;"  
processErrorCode(responseCode); d&p]O  
return -2; //-2 represent access is error &!{wbm@  
} m$xyUv1  
:fr 2K  
 |Aw(v6  
String sHeader;  OT9\K_  
Yp`6305f  
_ID2yJ   
for(int i=1;;i++) $+<X 1  
{ 9Osjh G  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A`7uw|uO$  
//Utility.log(in.readLine()); MO :##C  
sHeader=httpConnection.getHeaderFieldKey(i); QY2!.a^q  
if(sHeader!=null) ~$f+]7  
{ \>j._#t$h  
if(sHeader.equals("Content-Length")) '?5=j1  
{ j$#pG  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }}?L'Vby  
break; 1{%EQhNd  
} r6Z&i^cMe  
} &G@*/2A  
else r+;C}[E  
break; M"K$81  
} 0gVylQ  
} :x97^.eW~  
catch(IOException e){e.printStackTrace ();} 0K, *FdA  
catch(Exception e){e.printStackTrace ();} $.(>Sj1  
pN&Dpz^  
Nora<  
Utility.log(nFileLength);  :XF;v  
.*D~ .!  
_"J-P={=  
return nFileLength; -) $$4<L  
} K(Otgp+zb  
!5 %c`4  
r M'snW)  
//保存下载信息(文件指针位置) K|Std)6  
private void write_nPos() Cdiu*#f  
{ ro6peUL*2`  
try{ Gy 'l;2  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Hbx=vLQ6  
output.writeInt(nStartPos.length); J}KATpHs  
for(int i=0;i<nStartPos.length;i++) bR49(K$~  
{ A;w,m{9<  
// output.writeLong(nPos); >t?;*K\x"  
output.writeLong(fileSplitterFetch.nStartPos); tp_*U,  
output.writeLong(fileSplitterFetch.nEndPos); uFb&WIo1  
} 9pStArF?F0  
output.close(); {DBgW},  
} WU{G_Fqaz  
catch(IOException e){e.printStackTrace ();}  HlPf   
catch(Exception e){e.printStackTrace ();} bKmR &  
} I 8`@Srw8  
znFa4  
!u~( \ Rb;  
//读取保存的下载信息(文件指针位置) zhKb|SV  
private void read_nPos() 1>4'YMdZi  
{ : UD<1fh  
try{ CP'?Om2  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); jUZ84Gm{  
int nCount = input.readInt(); ?H0 #{!s  
nStartPos = new long[nCount]; `K~300-hOb  
nEndPos = new long[nCount]; m /JpYv~  
for(int i=0;i<nStartPos.length;i++) %gJf&A  
{ 3rTYe6q$U  
nStartPos = input.readLong(); eL#pS=  
nEndPos = input.readLong(); ;a XcGa  
} d5\w'@Di  
input.close(); W'-B)li   
} BE:HO^-.1  
catch(IOException e){e.printStackTrace ();} d11~ mU\  
catch(Exception e){e.printStackTrace ();} C\j|+s  
} :7<spd(%"  
votv rZ=  
=" #O1$  
private void processErrorCode(int nErrorCode) YbND2 i  
{ 8{8J(~  
System.err.println("Error Code : " + nErrorCode); BYyR-m  
} sikG}p0mx<  
>pbO\=j]X  
^0R.'XL  
//停止文件下载 vtKQvQ  
public void siteStop() i!LEA/"V  
{ vXAO#'4tm%  
bStop = true; 8Sd<!  
for(int i=0;i<nStartPos.length;i++) (g`G(K_  
fileSplitterFetch.splitterStop(); HbX>::J8  
c]v $C&FX  
>_jT.d  
} h<f_Eo z-a  
} $5jQm,V$K  
//负责部分文件的抓取 |`1lCyV\tE  
**FileSplitterFetch.java <xKer<D %  
*/ a"EX<6"  
package NetFox; 7;jwKA;k  
NGOc:>}k>  
<La$'lG4J  
import java.io.*; 0D+[W5TB  
import java.net.*; 3s<~}&"  
R?b3G4~  
Z,^`R] 9  
public class FileSplitterFetch extends Thread { { Iy<iV  
7xTgG!>v  
?n)d: )Ud"  
String sURL; //File URL ~1]4 J(+  
long nStartPos; //File Snippet Start Position ijEMS1$=7  
long nEndPos; //File Snippet End Position _CO?HX5ek  
int nThreadID; //Thread's ID hCVe05  
boolean bDownOver = false; //Downing is over %4|*  
boolean bStop = false; //Stop identical gHpA@jdC*  
FileAccessI fileAccessI = null; //File Access interface 0}C> e`<'  
[nZf4KN  
 S<#>g s4  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException tgSl (.  
{ Anr''J&9`H  
this.sURL = sURL; 1O]'iS"  
this.nStartPos = nStart; epuN~T  
this.nEndPos = nEnd;  +:k Iq  
nThreadID = id; @/FE!6 |O  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?f f!(U  
} n}/?nP\%  
:,Z'/e0&  
bnHQvCO3$  
public void run() `2-6Qv  
{ wCw-EGLR  
while(nStartPos < nEndPos && !bStop) tj$&89  
{ {9:[nqX  
;,2i1m0"  
v;m`d{(i2  
try{ o81RD#>E)  
URL url = new URL(sURL); 1W3+ng  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )r2$!(NQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); /e5' YVP  
String sProperty = "bytes="+nStartPos+"-"; cq:<,Ke  
httpConnection.setRequestProperty("RANGE",sProperty); #gn{X!;-;  
Utility.log(sProperty); ;e Iqxe>  
&O8vI ,M  
r9MS,KG8  
InputStream input = httpConnection.getInputStream(); do,ZCn  
//logResponseHead(httpConnection); H4RqOI  
qLC_p)  
&! i'Q;q  
byte[] b = new byte[1024]; [bM$n m  
int nRead; ,w-=8>5lrj  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^u2unZ9BK!  
{ pRR1k?  
nStartPos += fileAccessI.write(b,0,nRead); m8M2ka  
//if(nThreadID == 1) = VIU  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); stGk*\>U'  
} ?R-4uG[(  
bd|ZhRsL  
N;Hoi8W  
Utility.log("Thread " + nThreadID + " is over!"); >A&D/k MO  
bDownOver = true; @}9*rWJIE  
//nPos = fileAccessI.write (b,0,nRead); 3DjlX*  
} W5i{W'  
catch(Exception e){e.printStackTrace ();} RJ}%pA4I  
} hA=.${uIO  
} ul(pp+%S  
/Ne;Kdp  
wFbw3>'a9  
//打印回应的头信息 iA.:{^_)09  
public void logResponseHead(HttpURLConnection con) C2e.RTxc  
{ z`]sWi F0  
for(int i=1;;i++) T-MC|>pv  
{ \B/!}Tn;  
String header=con.getHeaderFieldKey(i); q,;8Ka )  
if(header!=null) hW<TP'Zm*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); uuaoBf  
Utility.log(header+" : "+con.getHeaderField(header)); jJ.isr|`  
else 7a0T]  
break; 3M^s EaUI  
} \9t/*%:  
} xg(* j[ff3  
=w!>/#U  
P>U7RX e  
public void splitterStop() \wR;N/tg  
{ JnE\z*NB  
bStop = true; (e"\%p`  
} \d)HwO  
>mAi/TZC  
!8Y $}  
} * lo0T93B  
6N\f>c  
99GK6}~TGm  
/* }'`iJ b\  
**FileAccess.java 2#81oz&K  
*//文件访问(定位,写) Au10]b  
package NetFox; a&z$4!wQB  
import java.io.*; mXwDB)O{)  
2}uSrA7n]  
Ir6(EIwx0  
public class FileAccessI implements Serializable{ 'ZFbyt Q2  
P. Kfoos  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 d_1uv_P  
RandomAccessFile oSavedFile; d-{1>\-_  
long nPos; dy.U;  
!sVW0JSh  
b QgtZHO  
public FileAccessI() throws IOException 3D-VePM=`  
{ *{!E`),FX  
this("",0); 4^GIQEjx  
} bLsN?_jy  
(`"87Xomnn  
G  L-Pir  
public FileAccessI(String sName,long nPos) throws IOException WRqpQEY  
{ =m-nvXD  
oSavedFile = new RandomAccessFile(sName,"rw"); yvCX is  
this.nPos = nPos; h$)4%Fy  
oSavedFile.seek(nPos); "Z]z9(  
} :h8-y&;  
T@R2H&L  
LI9 Uc\  
public synchronized int write(byte[] b,int nStart,int nLen) |wM<n  
{ a}g <<{  
int n = -1; :Aa5,{v _  
try{ R4%}IT^%P  
oSavedFile.write(b,nStart,nLen); av"dJm  
n = nLen; LMRq.wxbbB  
} UT%?3}*u"  
catch(IOException e) x31Jl{x8\?  
{ |xFSGrC  
e.printStackTrace (); avb'dx*q>  
} rm%MQmF  
a8 .x=j<  
\:jJ{bl^A  
return n; 4W<8 u(  
} ~\OZEEI  
oAF#bj_f  
om{aws;  
} RG6U~o1  
UIo jXR<  
8Z>=sUMQ  
/* O4oI&i 7  
**SiteInfoBean.java 9+!"[  
*/ $ S]l%  
package NetFox; +:&|]$8<  
&Fh#otH_  
C/ENJ&  
public class SiteInfoBean { <_#a%+5d  
H|z:j35\  
m`xzvg  
private String sSiteURL; //Site's URL !Q=xIS  
private String sFilePath; //Saved File's Path UF;iw  
private String sFileName; //Saved File's Name 2`pg0ciX (  
private int nSplitter; //Count of Splited Downloading File [&+5E1%L  
wZb7 7  
)|B3TjH C  
public SiteInfoBean() cIg+^Tl  
{//nSplitter的缺省值为5 lr9s`>9  
//default value of nSplitter is 5 bj_oA i  
this("","","",5); -5GRit1q?  
} Z`x*Igf8  
wY*tq{7  
<CN+VXF  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) C/YjMYwKgv  
{ c52S2f7  
sSiteURL= sURL; li&&[=6A  
sFilePath = sPath; x%%OgO +>  
sFileName = sName; tjbI*Pw7(  
this.nSplitter = nSpiltter; _e$T'*q  
nZ/pi$7  
.NT9dX  
} F~x>\?iN  
E&>=  
f~{4hVA  
public String getSSiteURL() M5c~-}Ay  
{ 2-_d~~O1N  
return sSiteURL; ,Kwtp)EX  
} h.)o4(bO  
'L8B"5|>  
ok(dCAKP  
public void setSSiteURL(String value) Mc<O ~  
{ A3Oe=rB  
sSiteURL = value; ~JG\b?s  
} %>E M ^Z  
L(DDyA{bA  
!+T29QYK8  
public String getSFilePath() OpFm:j3  
{ @h!nVf%fe  
return sFilePath; #GOL%2X  
} L<Q>:U.@\  
zaG1  
MhZ\]CAs9  
public void setSFilePath(String value) %IK[d#HO  
{ cCO2w2A[*  
sFilePath = value; ##BfI`FJ  
} Q<T+t0G\O-  
`} S; _g!  
h Nx#x  
public String getSFileName() WnL7 A:sZ  
{ =_Ip0FfK!  
return sFileName; ;%!]C0 ?  
} 2JL\1=k;  
tFu"h1  
6D/K=-   
public void setSFileName(String value) Cnv?0to2l  
{ ]?lUe5F  
sFileName = value; _:~I(c6   
} dzs(sM=  
{P'^X+B0*  
[^0 S#,L  
public int getNSplitter() &*# Obv  
{ b E6bx6=u  
return nSplitter; U o[\1)  
} v/x~L$[  
D+"+m%^>C  
|OBh:d_B]  
public void setNSplitter(int nCount) uYCWsw/  
{ 7& 'p"hF  
nSplitter = nCount; xl ,(=L]  
} 1C+d&U  
} >>%E?'9A  
`l0"4 [?  
A.cNOous|  
/* JS^!XB' !  
**Utility.java PnZY%+[I  
*/ 8c%_R23  
package NetFox; 7'.]fs:  
#:s*Hy=  
*AJYSa,z  
public class Utility { IsiBn(1Z  
>hO9b;F}  
$7*@TMX  
public Utility() c' Q4Fzj0'  
{ eS/Au[wS  
ffR<G&"n~b  
e#!p6+#"  
} @1s 2# )l(  
t&Jrchk  
//线程睡眠 LC})aV|  
public static void sleep(int nSecond) O96%U$W  
{ s9,Z}]Th  
try{ ',]^Qu`a  
Thread.sleep(nSecond); p4vX3?&1W  
} <Yn-sH  
catch(Exception e) GDYFhH7H  
{ 5xhYOwQBo  
e.printStackTrace (); R5=M{  
} 6"yIk4u:  
} Y2$xlqQd"  
EbnV"]1  
//日志 ),XDY_9K  
public static void log(String sMsg) rmeGk&*R8  
{ v9"03 =h  
System.err.println(sMsg); +LF`ZXe8l  
} @T%8EiV  
xwojjiV  
oZ>2Tt%  
public static void log(int sMsg) Rw^X5ByJE  
{ (} wMU]!_  
System.err.println(sMsg); X*t2h3 "}  
} -nqq;|%  
} <3laNk  
]/7#[  
> 1=].  
/* t'[`"pp=  
**TestMethod.java ~z'Y(qG  
*/ H` h]y  
package NetFox; S|]\q-qA&  
gP`CQ0t  
d "25e"(~F  
public class TestMethod { S5[}kfe  
7A^L$TY  
w d6+,B  
public TestMethod() 4e?MthJ>  
{ ///xx/weblogic60b2_win.exe Qn}M  
try{ ?hKpJA'%  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^*b11 /7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5=Il2  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 7`tJ/xtMy;  
fileFetch.start(); EzU3'x  
} vf-8DB  
catch(Exception e){e.printStackTrace ();} 4wPP/`  
{J-Ojw|Y b  
H^+Znmo  
} e17]{6y  
3x)jab  
D!mx&O9  
public static void main(String[] args) f1q0*)fk  
{ \7G.anY  
new TestMethod(); 5% w08  
} E.G]T#wt0  
} |a=7P  
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