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http断点续传简单实现(java)

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/* {;^GKb+  
**SiteFileFetch.java Dwa.ZY}-  
*/ h{/lW#[  
package NetFox; R\Of ,  
import java.io.*; j9g0k<eg  
import java.net.*; 4V7=VZ, @3  
9?Q0O\&uP  
:7L[v9'  
public class SiteFileFetch extends Thread { {osadXd C  
]uZaj?%J<  
\}EJtux q  
SiteInfoBean siteInfoBean = null; //文件信息Bean ^tRy6zG  
long[] nStartPos; //开始位置 O3En+m~3n)  
long[] nEndPos; //结束位置 F [S'l  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Sh;Z\nj  
long nFileLength; //文件长度 |h%0)_  
boolean bFirst = true; //是否第一次取文件 W@p27Tiq  
boolean bStop = false; //停止标志 V:h3F7  
File tmpFile; //文件下载的临时信息 d8N4@3CkL  
DataOutputStream output; //输出到文件的输出流 c-`izn]  
9w}_CCj3  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) `6FH@" |I  
public SiteFileFetch(SiteInfoBean bean) throws IOException _M)J{ {?:  
{ * amZ  
siteInfoBean = bean; wCw_aXqq  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); z *~rd2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5{\;7(  
if(tmpFile.exists ()) >goG\y  
{ yo]8QO]97  
bFirst = false; Zd~Q@+sH  
read_nPos(); UYkuz  
} `(&GLv[i^2  
else  E-L>.tD  
{ r [4dGt  
nStartPos = new long[bean.getNSplitter()]; <qjolMO`  
nEndPos = new long[bean.getNSplitter()]; iXD=_^^o .  
} :IRQouTf:,  
G`R_kg9$  
mt]50}eK  
XEb+Z7L1  
} :~LOw}N!aQ  
nna boD  
y;ymyy&  
public void run() )vy_m_f&  
{ #)z7&nD  
//获得文件长度 I!Uj~jV  
//分割文件 M6:$ 0(r  
//实例FileSplitterFetch aB)G!Rm&  
//启动FileSplitterFetch线程 ucX!6)Op  
//等待子线程返回 TykY>cl   
try{ A}MF>.!}C  
if(bFirst) ,Lr}P  
{ H':0  
nFileLength = getFileSize(); pL`)^BJ  
if(nFileLength == -1) n+w$'l  
{ ]:Sb#=,!&!  
System.err.println("File Length is not known!"); .( X!*J]G  
} cW?~]E'<  
else if(nFileLength == -2) z]n&,q,5g  
{ "fWm{;  
System.err.println("File is not access!"); BBHoD:l  
} k?`Q\  
else ?jH u,  
{ ]X<L~s_*  
for(int i=0;i<nStartPos.length;i++) >IEc4  
{ i$dF0.}Q  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); %)PQomn?  
} KK41I 8Mw  
for(int i=0;i<nEndPos.length-1;i++) ?oulQR6:  
{ 7U`8W\-  
nEndPos = nStartPos[i+1]; u!9bhL`  
} N7}y U~j^  
nEndPos[nEndPos.length-1] = nFileLength; A}z1~Z+  
} [K#pU:lTH  
} t2#zQ[~X!  
Fu"@)xw/-q  
ErY-`8U"  
//启动子线程 {14sI*b16  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0=c:O  
for(int i=0;i<nStartPos.length;i++) ^9 {r2d&c  
{ ^ Mw=!n[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), A]AM|2 D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #u$ Z/,  
nStartPos,nEndPos,i); x qLIs:*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?PDrj/: *  
fileSplitterFetch.start(); &E$:^a4d  
} /<it2=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), u,),kj<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `]m/za%7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", HQtUNtZ  
nEndPos = " + nFileLength); 8b:\@]g$  
// fileSplitterFetch[nPos.length-1].start(); O:Ob{k  
kq=tL@W`0}  
0/0rWqg /  
//等待子线程结束 qwDoYy yu  
//int count = 0; \X0wr%I  
//是否结束while循环 k ks ?S',  
boolean breakWhile = false; `%Uz0hF  
?KtvXTy{m  
OCYC Dn  
while(!bStop) ~n`G>Oe3  
{ ,Z p9,nf  
write_nPos(); X]AbBzy  
Utility.sleep(500); TM1J1GU  
breakWhile = true; }Q%fY&#(bp  
*r]Mn~3  
M}W};~V2ng  
for(int i=0;i<nStartPos.length;i++) TLiA>`r=  
{ 3+| {O  
if(!fileSplitterFetch.bDownOver) I0]"o#Lj T  
{ PmT,*C`/X  
breakWhile = false; Il,^/qvIY  
break; txW<r8  
} 'P5|[du+  
} )./.rtP|4  
if(breakWhile) ?{M!syD<  
break; aok,qn'j  
w=S7zzL)  
*,=WaODO%  
//count++; B)`^/^7  
//if(count>4) ewb/ Z[4  
// siteStop(); x#s=eeP1  
} IRW%*W#  
,"!P{c  
Z/@%MEU[zl  
System.err.println("文件下载结束!"); 9AROvq|#  
} WxF rqUz  
catch(Exception e){e.printStackTrace ();} %<Q?|}  
} a>{b'X^LV  
2 !^[x~t  
q$=EUB"C  
//获得文件长度 }uE8o"q  
public long getFileSize() uY;2tZldf=  
{ ,3{z_Rax-  
int nFileLength = -1; wbaXRvg  
try{ .h8%zB#|i  
URL url = new URL(siteInfoBean.getSSiteURL()); L('G1J}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Sh_=dzM  
httpConnection.setRequestProperty("User-Agent","NetFox"); SEc3`y;j%  
2eBA&t  
$LF  
int responseCode=httpConnection.getResponseCode(); Y+#e| x  
if(responseCode>=400) >Rbgg1^]5  
{ Svmyg]  
processErrorCode(responseCode); [[PUK{P0  
return -2; //-2 represent access is error G'<J8;B* t  
} |WB<yA1  
rwlV\BU  
1;l&ck-Gg/  
String sHeader; .wD>0Ig  
,Jf)A/_  
!j)H !|R  
for(int i=1;;i++) }V3p <  
{ @awaN  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ,0#5kc*X  
//Utility.log(in.readLine());  S< <xlW  
sHeader=httpConnection.getHeaderFieldKey(i); ~7!J/LHg  
if(sHeader!=null) )T:{(v7 d`  
{ B(mxW8y  
if(sHeader.equals("Content-Length")) ! G%LYHx  
{ W9?Yzl  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); SPIYB/C  
break; ~$f+]7  
} hltH{4  
} buRXzSR  
else \K)"@gdW  
break; 8 F'i5i  
} :YB:)wV,P  
} &tKs t,UR8  
catch(IOException e){e.printStackTrace ();} n]x4twZ  
catch(Exception e){e.printStackTrace ();} M%:ACLYP  
cW,wN~  
F]W'spF,  
Utility.log(nFileLength); >#R<*?*D}  
$6:j3ZTXrt  
A~-e?.  
return nFileLength; Q/iaxY#  
} S,vrz!'>A  
Y.@ vdW  
!wvP 24"y  
//保存下载信息(文件指针位置) m4ovppC  
private void write_nPos() sRo%=7Z  
{ =4yME  
try{ #HB]qa  
output = new DataOutputStream(new FileOutputStream(tmpFile)); SMgf(N3]  
output.writeInt(nStartPos.length); FgRlxz  
for(int i=0;i<nStartPos.length;i++) GFx >xQk  
{ p0uQ>[NV0  
// output.writeLong(nPos); f6^H Q1SSt  
output.writeLong(fileSplitterFetch.nStartPos); Ol"p^sqwj  
output.writeLong(fileSplitterFetch.nEndPos); ,a< !d  
} PR~ho&!  
output.close(); 1d|+7  
} %|o4 U0c  
catch(IOException e){e.printStackTrace ();} Z KnEg2a  
catch(Exception e){e.printStackTrace ();} " 9 h]P^  
} ]gkI:scPA  
_i:yI-jA  
_7]* 5Pxo  
//读取保存的下载信息(文件指针位置) . 5|wy<  
private void read_nPos() $~50M5&K#  
{ >&e|ins^N  
try{ jRXByi=9  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Fc7mAV=  
int nCount = input.readInt(); Am!$\T%2  
nStartPos = new long[nCount]; ` *8p T  
nEndPos = new long[nCount]; xgL*O>l)  
for(int i=0;i<nStartPos.length;i++) UbJ_'>hK6  
{ G*mk 19Z  
nStartPos = input.readLong(); }Hrm/Ni  
nEndPos = input.readLong(); E*.D_F  
} XJC|6"n  
input.close(); mE%H5&VSI  
} lycY1lK  
catch(IOException e){e.printStackTrace ();} $=TFTSO  
catch(Exception e){e.printStackTrace ();} <:2El9l!  
} L/"XIMI*Xg  
H{E223  
/'u-Fr(Q+  
private void processErrorCode(int nErrorCode) tqAh &TW3+  
{ 41^+T<+  
System.err.println("Error Code : " + nErrorCode); ((N<2G)  
} pz6fL=Xd  
TV#pUQ3K  
cMsm[D{b  
//停止文件下载 V?t^ J7{'  
public void siteStop() a"0Xam  
{ PiMh]  0  
bStop = true; OSK 3X Qc  
for(int i=0;i<nStartPos.length;i++) weU'3nNN  
fileSplitterFetch.splitterStop(); ,Za!  
mMS%O]m,|  
.v9#|d d+  
} Z[R E|l{  
} ZC@ 33Q(  
//负责部分文件的抓取 !0CC&8C`  
**FileSplitterFetch.java c]v $C&FX  
*/ Cz-eiPlq  
package NetFox; U ]`SM6  
M^AwOR7<  
oa?bOm  
import java.io.*; 9i*t3W71]  
import java.net.*; WId"2W3M  
L%}k.)yev  
aJ}y|+Cj  
public class FileSplitterFetch extends Thread { KaNi'=nW  
P hs4]!  
?{NP3  
String sURL; //File URL R?b3G4~  
long nStartPos; //File Snippet Start Position 'c*Q/C;  
long nEndPos; //File Snippet End Position { Iy<iV  
int nThreadID; //Thread's ID LuM:dJ  
boolean bDownOver = false; //Downing is over RSC^R}a5  
boolean bStop = false; //Stop identical w=Ac/ 12  
FileAccessI fileAccessI = null; //File Access interface 9E5Ec~l  
N DZ :`D  
umhg O.!  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0+L:+S  
{ sG[v vm  
this.sURL = sURL; {}kE=L5  
this.nStartPos = nStart; SR)G!9z_/  
this.nEndPos = nEnd; }^U7NZn<"  
nThreadID = id; I(tMw6C$:  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -c|dTZ8D)8  
} _&)^a)Nu  
I .jB^  
vikA  
public void run() "HX,RJ @^K  
{ E w#UlA:"v  
while(nStartPos < nEndPos && !bStop) wCw-EGLR  
{ ecaEWIOG  
"Zm**h.t  
`G7LM55  
try{ +a1Or  
URL url = new URL(sURL); TgMa! Vz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U4)x"s[CP  
httpConnection.setRequestProperty("User-Agent","NetFox"); VBnD:w"z  
String sProperty = "bytes="+nStartPos+"-"; W%&t[ _21  
httpConnection.setRequestProperty("RANGE",sProperty); }p,#rOX:A  
Utility.log(sProperty); r&  
S:2M9nC  
r9MS,KG8  
InputStream input = httpConnection.getInputStream(); cHo@F!{o=  
//logResponseHead(httpConnection); &U*MLf83`  
-KV)1kET  
"/H B#  
byte[] b = new byte[1024]; X!H[/b:1O  
int nRead; 8xf]zM"Q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^97u0K3$  
{ t&|M@Ouet  
nStartPos += fileAccessI.write(b,0,nRead); 5rp,xk!  
//if(nThreadID == 1) zplAH!s5''  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ByyvRc,v  
} m\*;Fx  
@M( hyS&on  
M2Q*#U>6r  
Utility.log("Thread " + nThreadID + " is over!"); Pgug!![  
bDownOver = true; !s^[|2D_U  
//nPos = fileAccessI.write (b,0,nRead); B:mtl?69g  
} Dh+<|6mx  
catch(Exception e){e.printStackTrace ();} kPRG^Ox8e  
} .+3~ w  
} >wSrllmj@  
(JMk0H3u  
MS5X#B  
//打印回应的头信息 ,I|3.4z  
public void logResponseHead(HttpURLConnection con) ATRB9  
{ 9U]3B)h%m  
for(int i=1;;i++) cQzUR^oq,  
{ . E8Gj'yO  
String header=con.getHeaderFieldKey(i); x*'2%3C~  
if(header!=null) g9~QNA  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +HDfEo T  
Utility.log(header+" : "+con.getHeaderField(header)); .@KI,_X6,  
else kR0/jEz C  
break; } "QL"%  
} "J(T?|t  
} %ztv.K(8  
U{C& R&z  
Q]1s*P  
public void splitterStop() F+<e9[  
{ 99GK6}~TGm  
bStop = true; MV.&GUez{  
} fK/|0@B8  
%\f<N1~*  
A)9F_;BY  
} >PS`;S!(  
zI7iZ"2a  
gmUX 2x(  
/* 'ZFbyt Q2  
**FileAccess.java P. Kfoos  
*//文件访问(定位,写) A$jf#,  
package NetFox; [QDM_n  
import java.io.*; 6s.>5}M!  
_aP 2gH  
aY8QYK ;?^  
public class FileAccessI implements Serializable{ >F5E^DY  
' e:rL.  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 GZ1c~uAu  
RandomAccessFile oSavedFile; ZH)thd9^b  
long nPos; O77^.B  
U|~IJU3-  
6f*QUw~  
public FileAccessI() throws IOException ' OXL'_Xl  
{ %CV.xDE8  
this("",0); uskJ(!  
} /k.?x]Ab  
Gp0yRT.  
!j%#7  
public FileAccessI(String sName,long nPos) throws IOException @(CJT-Ak  
{ 6<o2 0(?  
oSavedFile = new RandomAccessFile(sName,"rw"); #BW:*$>}  
this.nPos = nPos; $O^"O Q_@  
oSavedFile.seek(nPos); ==npFjB  
} -\&b&;_  
)v+\1  
CwaW>(`v  
public synchronized int write(byte[] b,int nStart,int nLen) 3Ct)5J  
{ :yFmCLZaQ  
int n = -1; n{"e8vQx  
try{ =`g@6S  
oSavedFile.write(b,nStart,nLen); ]$)U~)T iW  
n = nLen; bL2b^UB~%  
} H`OJN .  
catch(IOException e) `s8!zy+  
{ hQ}y(2A.XI  
e.printStackTrace (); \hD jZ  
} 5Ve T8/7Q  
;Dp<|n  
^=arKp,?5  
return n; 4tlLh`-8  
} @DuSii#.S  
}K|40oO5  
+:&|]$8<  
} &Fh#otH_  
C/ENJ&  
{YIf rM  
/* lbm ,#  
**SiteInfoBean.java g|<$ \}  
*/ <KrfM  
package NetFox; HFW8x9Cc  
7gQ 2dp  
;v m$F251  
public class SiteInfoBean { bG/[mZpRT  
.&rL>A2U  
; mwU>l,4  
private String sSiteURL; //Site's URL ~IQw?a.E  
private String sFilePath; //Saved File's Path B qcFbY  
private String sFileName; //Saved File's Name yZY.B {  
private int nSplitter; //Count of Splited Downloading File QygbfW6u  
Jj7he(!_1  
]] 50c  
public SiteInfoBean() <CN+VXF  
{//nSplitter的缺省值为5 B8NMo5a  
//default value of nSplitter is 5 G$E+qk nJL  
this("","","",5); 6$ ag<  
} VH6J @m  
6MmkEU z  
6.k>J{GG  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) lH"4"r  
{ JQH>{OB  
sSiteURL= sURL; 7 |Q;E|=-Y  
sFilePath = sPath; !1xX)XD4y  
sFileName = sName; T*qSk!  
this.nSplitter = nSpiltter; !c;BOCqa  
,m1F<Pdts  
L]{1@~E:q  
} -}9>#<v  
DGO\&^GT^  
L[O.]2  
public String getSSiteURL() @]@6(To  
{ tVhf1TH#  
return sSiteURL; hYSf;cG}A  
} >rid3~  
y28 e=i  
MT{ovDA].  
public void setSSiteURL(String value) hv#|dI=kZR  
{ lFbf9s:$B  
sSiteURL = value; ' ;3#t(J;  
} s}bv o  
48RSuH  
agj_l}=gO  
public String getSFilePath() 67A g.f6-  
{ maVfLVx-  
return sFilePath; ;Miag'7  
} -;j ' =?  
i2X%xYv ^  
1 i/&t[  
public void setSFilePath(String value) h Nx#x  
{ MP$9W)  
sFilePath = value; NM4b]>   
} CZw]@2/JuQ  
k%%0"+y#a  
zy'cf5k2  
public String getSFileName() $$e"[g  
{ Q|(G -  
return sFileName; ]? % *3I  
} 5aJd:36I  
#}S<O_  
!z2KQ 4C  
public void setSFileName(String value) q}cm"lO$  
{ GGez!?E%  
sFileName = value; cjwc:3 CM  
} T7?cnK"  
S(PU"}vZy  
*u]aWx  
public int getNSplitter() u#nM_UJe  
{ X ;Cl8  
return nSplitter; 'q\[aKEX=  
} h?P- :E  
1"f)\FPGe  
|syvtS{  
public void setNSplitter(int nCount) GD0Q`gWNe  
{ OBL2W\{  
nSplitter = nCount; 8c%_R23  
} yR1v3D4E  
} ]h%~'8g,  
_B7+n"t\r  
7mA:~-.u  
/* ?,w9e|  
**Utility.java FK~*X3'  
*/ om2)Cd9~7  
package NetFox; ZKt`>KZ  
vP'#x  
-+y3~^EYm,  
public class Utility { S|r,RBeZ  
cYz|Ux  
a/xnf<(H  
public Utility() .4[M7)  
{ eI1C0Uz1  
KJ cuZ."wX  
jIck!  
} 6"yIk4u:  
6 #k mV  
//线程睡眠 1*?L>@Wdy  
public static void sleep(int nSecond) q9(Z9$a(\  
{ ht2J, 1t  
try{ xM?tdQ~VHY  
Thread.sleep(nSecond); <Aqo[']  
} ny1Dg$u i2  
catch(Exception e) rPK1#  
{ -nqq;|%  
e.printStackTrace (); v;(k7  
} {_ {zs!r  
} Y%^qt]u.8  
S|]\q-qA&  
//日志 dH)\zCt  
public static void log(String sMsg) *iJ>@ vew  
{ 6*:U1{Gl)  
System.err.println(sMsg); HjY! ]!4p  
} p8MN>pLP%  
f@0Km^aUc  
kOQ!]-;  
public static void log(int sMsg) |eK^Yhym  
{ U% OlYP$g  
System.err.println(sMsg); =g$%jM>35  
} 2E0oLl[  
} iN1_ T  
/L=Y8tDt  
s#FX2r3=Fg  
/* o,'Fz?[T%  
**TestMethod.java p. KT=dZT  
*/ JZ/T:Hsh4  
package NetFox; QObHW[:F  
L=&}s[5  
3x>Y  
public class TestMethod { 1cD  
D&1(qi=x&  
1ezBn ZJg  
public TestMethod() meZZQ:eSl  
{ ///xx/weblogic60b2_win.exe ,,;vG6^a  
try{ | CPyCM$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ne%(`XY{Q]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 7=a e^GKo  
SiteFileFetch fileFetch = new SiteFileFetch(bean); XO}SPf-  
fileFetch.start(); Wm/0Pi  
} p5J!j I=  
catch(Exception e){e.printStackTrace ();} sLf~o" yb  
y<PQ$D)  
[= Xb*~  
} s?PB ]Tr  
_+}f@&"  
vJ e c+a  
public static void main(String[] args) _z>%h>L|g  
{ DS;.)P"  
new TestMethod(); &U\//   
} fvj  
} pW_mS|  
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