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http断点续传简单实现(java)

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/* ^].jH+7i*  
**SiteFileFetch.java .@q-B+Eg  
*/ ?, r~=  
package NetFox; X-LA}YH=tS  
import java.io.*; 8.J( r(;>  
import java.net.*; bx4'en#  
v``-F(i$  
>EsziRm  
public class SiteFileFetch extends Thread { 5yZTcS z  
lbdTQ6R  
%+>s#Q2d  
SiteInfoBean siteInfoBean = null; //文件信息Bean %xZG*2vc!B  
long[] nStartPos; //开始位置 gi/@ j  
long[] nEndPos; //结束位置 $2^`Uca  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +  @9.$6N  
long nFileLength; //文件长度 |{r$jZeE  
boolean bFirst = true; //是否第一次取文件 j%u-dr  
boolean bStop = false; //停止标志 N,dT3we  
File tmpFile; //文件下载的临时信息 M 3 '$[  
DataOutputStream output; //输出到文件的输出流 '_\;jFAM  
$''?HjB}T  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) }9HmTr|  
public SiteFileFetch(SiteInfoBean bean) throws IOException j(:I7%3&(*  
{ h^9"i3H  
siteInfoBean = bean; cJo\#cr  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %@a8P  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); K;hh&sTB  
if(tmpFile.exists ()) 1=sXdcy;  
{ ?3ig)J,e[  
bFirst = false; w]b,7QuNz  
read_nPos(); '^BV_QQ  
} '>$EOg"  
else X,aYK;q%z  
{ \0l>q ,  
nStartPos = new long[bean.getNSplitter()]; PNF?;*`-{7  
nEndPos = new long[bean.getNSplitter()];  VGHWNMT  
} s>k Uh  
7|\@zQ h   
I:bD~F b3  
vu!d)Fy  
} QxuhGA  
p.I.iAk%G^  
7(M(7}EKA  
public void run() eI.2`)>  
{ RIu~ @  
//获得文件长度 f4-a?bp  
//分割文件 XC 7?VE  
//实例FileSplitterFetch TD[EQ  
//启动FileSplitterFetch线程 \!IMaB]  
//等待子线程返回 BqDKT  
try{ M.-"U+#aD  
if(bFirst) ;6@r-r  
{ 09A X-JP  
nFileLength = getFileSize(); %75xr9yOP  
if(nFileLength == -1) I? THa<  
{ c_aZ{S  
System.err.println("File Length is not known!"); $aHAv/&(5  
} du$|lxC  
else if(nFileLength == -2) Mb3}7@/[  
{ vZ/6\Cz  
System.err.println("File is not access!"); *k"|i*{  
} 43?^7_l-  
else JN^ &S  
{ 5@*'2rO&!  
for(int i=0;i<nStartPos.length;i++) yC 77c=  
{ (-]r~Ol^  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); x21dku<6K[  
} V f-a'K&  
for(int i=0;i<nEndPos.length-1;i++) eh1Q7 ~  
{ %WqNiF0-  
nEndPos = nStartPos[i+1]; 1qV@qz  
} ThPE 0V  
nEndPos[nEndPos.length-1] = nFileLength; S'oGt&Z<  
} =rdY @  
} 7t,t`  
+,~z Wv1v  
r=yK,d/1  
//启动子线程 .jy]8S8[|%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *'Z B*>  
for(int i=0;i<nStartPos.length;i++) .NtbL./=|  
{ *6xgctk  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .]aF 1}AI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), OL_{_K(w  
nStartPos,nEndPos,i); uKgZ$-'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5[j`6l  
fileSplitterFetch.start(); T~h5B(J;  
} "c}@V*cO<d  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5*[2yKsTi  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7ugZE93!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", O;7)Hjwt  
nEndPos = " + nFileLength); &uC@|dbC5  
// fileSplitterFetch[nPos.length-1].start(); [AV4m   
eNiaM6(J  
jA#/Z  
//等待子线程结束 ?\8?%Qk  
//int count = 0; j~j\\Y  
//是否结束while循环 hHqh{:q{v  
boolean breakWhile = false; Kx_h1{  
EyY.KxCB  
wP,JjPUt  
while(!bStop) fDx9iHGv  
{ nx0K$ Ptq  
write_nPos(); +cU>k}  
Utility.sleep(500); qRbf2;  
breakWhile = true; h*u`X>!!  
;gC|  
fwzb!"!.@  
for(int i=0;i<nStartPos.length;i++) AkOO )0  
{ \.mI  
if(!fileSplitterFetch.bDownOver) $%VuSrZ&  
{ Qp`gswvE  
breakWhile = false; Xl74@wq   
break; 9'hv%A:\3  
} };'\~g,1  
} nC{%quwh{  
if(breakWhile) Zw wqSyuGf  
break; #97h6m?  
Fs[aa#v4B  
Vb BPB5 $q  
//count++; &~CY]PN.  
//if(count>4) B c2p(z4  
// siteStop(); >vo=]c w  
} l7De6A"  
Fd*8N8Pi  
M:5b4$Qh<  
System.err.println("文件下载结束!"); C* nB  
} }MUn/ [x  
catch(Exception e){e.printStackTrace ();} If%/3UJ@  
} Z4IgBn(Z_}  
'=P7""mN5  
%,ngRYxT#  
//获得文件长度 Le%Z V%,  
public long getFileSize() F:mq'<Q  
{ 0Ia($.1mY  
int nFileLength = -1; q\H[am  
try{ ,]b~t0|B  
URL url = new URL(siteInfoBean.getSSiteURL()); k%^lF?_0I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +VQ\mA59  
httpConnection.setRequestProperty("User-Agent","NetFox"); )& u5IA(  
-(K9s!C!.  
~)(\6^&=|  
int responseCode=httpConnection.getResponseCode(); QNDHOo>v  
if(responseCode>=400) Hr$QLtr  
{ "Ky; a?Y  
processErrorCode(responseCode); h,"4SSL  
return -2; //-2 represent access is error 1{P'7IEj  
} tnLAJ+ -M  
F`9]=T0  
$ /nY5[  
String sHeader; |^@dFOz  
ul*Qt}  
)Pv9_XKJ  
for(int i=1;;i++) }pJwj  
{ P (S>=,Y&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); YtO|D  
//Utility.log(in.readLine()); 'fPdpnJ<  
sHeader=httpConnection.getHeaderFieldKey(i); r [ K5w  
if(sHeader!=null) MX+ Z ?  
{ |\n_OS 7  
if(sHeader.equals("Content-Length")) w|Nz_3tI  
{ In[Cr/&/Y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #h/Mbj~S  
break; )XWP\ h  
} Zkf0p9h\  
} DfKr[cqLM  
else `7H4Y&E  
break; yeHDa+}  
} VWO9=A*Y|  
} o: ;"w"G  
catch(IOException e){e.printStackTrace ();} ;,]P=Ey  
catch(Exception e){e.printStackTrace ();} zz& ?{vJ  
)Y)pmjZaG  
xp Og8u5  
Utility.log(nFileLength);  }K3x  
>a}f{\Q  
<vwkjCA`  
return nFileLength; Onwp-!!.  
}  @Pt="*g  
GH[wv<  
]7e =fM9V;  
//保存下载信息(文件指针位置) hqRw^2F  
private void write_nPos() 6"}?.E$  
{ be +4junf  
try{ +a*tO@HG  
output = new DataOutputStream(new FileOutputStream(tmpFile)); "Y\_TtY  
output.writeInt(nStartPos.length); #UbF9})q  
for(int i=0;i<nStartPos.length;i++) cH>%r^G\  
{ R+CM`4CD  
// output.writeLong(nPos); O|w J)  
output.writeLong(fileSplitterFetch.nStartPos); KIWe@e  
output.writeLong(fileSplitterFetch.nEndPos); %dY<=x#b  
} xNbPsoK  
output.close(); &iV,W4  
} o^ XtU5SVq  
catch(IOException e){e.printStackTrace ();} []D@Q+1  
catch(Exception e){e.printStackTrace ();} [p<w._b i  
} ^yOZArc'r  
4R\ Hpt  
\eFR(gO+  
//读取保存的下载信息(文件指针位置) [Jv@J\  
private void read_nPos() _8E/) M  
{ N ,z6y5Lu  
try{ >vA2A1WhW  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Jkek-m  
int nCount = input.readInt(); pxa(  
nStartPos = new long[nCount]; 4]E3c AJ  
nEndPos = new long[nCount]; F >rH^F  
for(int i=0;i<nStartPos.length;i++) e2A-;4?_  
{ ,2W8=ON  
nStartPos = input.readLong(); rvw)-=qR[  
nEndPos = input.readLong(); hvaSH69*m  
} 5;HH4?]p  
input.close(); Gy(=706  
} |vw"[7_aS  
catch(IOException e){e.printStackTrace ();} /gG"v5]  
catch(Exception e){e.printStackTrace ();} )-. _FOZ6  
} O<V4HUW  
^ (FdXGs[  
15sp|$&`  
private void processErrorCode(int nErrorCode) /~<@*-'  
{ |)*fRL,  
System.err.println("Error Code : " + nErrorCode); q*9!,!e  
} aca=yDs2  
o !U 6?  
}B1!gz$YNO  
//停止文件下载 ,l)^Ft`5  
public void siteStop() Ct>GYk$  
{ UNBH  
bStop = true; mrjswF27$o  
for(int i=0;i<nStartPos.length;i++) g?ULWeZg5  
fileSplitterFetch.splitterStop(); _D+J!f^  
X93!bB  
d}4Y(   
} ZEx}$<)_  
} % S os  
//负责部分文件的抓取 <q@a~'Ai?!  
**FileSplitterFetch.java sL$:"=  
*/ )<tI!I][j  
package NetFox; S@/IQR  
H7DJ~z~J  
mV pMh#zw  
import java.io.*; Sb82}$sO  
import java.net.*; {.INnFGP@)  
Qr{E[6  
@nCd  
public class FileSplitterFetch extends Thread { +csi[c)3E  
:w^Ed%>y7  
#e$5d>j(  
String sURL; //File URL *vwbgJG! *  
long nStartPos; //File Snippet Start Position W}mn}gTQ  
long nEndPos; //File Snippet End Position >: g3k  
int nThreadID; //Thread's ID R)m'lMi|  
boolean bDownOver = false; //Downing is over \r+8qC[,  
boolean bStop = false; //Stop identical +O?KNZ  
FileAccessI fileAccessI = null; //File Access interface 7](KV"%V  
Xx>X5Fy  
pW J Fz-  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException V: TM]  
{ L bmawi^  
this.sURL = sURL; JVSA&c%3  
this.nStartPos = nStart; VG ;kPzze  
this.nEndPos = nEnd; W~7A+=&  
nThreadID = id; XLrwxj0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 }*S `qW;B  
} yvO{:B8%  
|M, iM]  
#6HA\dE  
public void run() t,+nQ9  
{ ) u`[6,d  
while(nStartPos < nEndPos && !bStop) 85Otss/mM  
{ y1+*6|  
z?*w8kU&>  
N@Uy=?)ZJ  
try{ ?b>,9A.Z  
URL url = new URL(sURL); IHv[v*4:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9^#c| 0T  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7%|~>  
String sProperty = "bytes="+nStartPos+"-"; Eu@huN*/  
httpConnection.setRequestProperty("RANGE",sProperty); Oagsoik  
Utility.log(sProperty); c2'Lfgx4  
&keR~~/  
2Tp1n8FV  
InputStream input = httpConnection.getInputStream(); M:[ %[+6  
//logResponseHead(httpConnection); I7n"&{s"*  
(<xfCH F5  
+{f:cea (1  
byte[] b = new byte[1024]; @a0DT=>dT  
int nRead; p o2!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &&8IU;J  
{ ,NyY>~+  
nStartPos += fileAccessI.write(b,0,nRead); Gsq00j &<Z  
//if(nThreadID == 1) 2Ay* kmW  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); tnN.:%mZ  
} nz=G lO'[  
wc}5m Hs  
E%,^Yvh/  
Utility.log("Thread " + nThreadID + " is over!"); FE (ev 9@  
bDownOver = true; i/`m`qdg  
//nPos = fileAccessI.write (b,0,nRead); # Oc] @  
} j2StXq3  
catch(Exception e){e.printStackTrace ();} keX,d#  
} ?IqQ-C)6D  
} OuID%p"O  
ogHCt{'  
fPR1f~r  
//打印回应的头信息 `tA" }1;ka  
public void logResponseHead(HttpURLConnection con) "8x8UgG  
{ iXVe.n  
for(int i=1;;i++) 1AM!8VR2  
{ $!-c-0ub  
String header=con.getHeaderFieldKey(i); R6kD=JY/!  
if(header!=null) r")`Ph@yp  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "!ug_'VW  
Utility.log(header+" : "+con.getHeaderField(header)); [6%VRqY  
else ^cP!\E-^  
break; ;Q OBBF3HG  
} g"p%C:NN  
} 4~Vx3gEV:  
=JK@z  
g9}DnCT*.  
public void splitterStop() /_AnP  
{ 4C61GB?Vy  
bStop = true; NV72  
} z<U-#k7nz  
ORHp$Un~)  
?mFv0_!O  
} "4+ &-ms  
"/3'XOK|  
@s ?  
/* 5HkKurab  
**FileAccess.java 5 ZGNz1)?V  
*//文件访问(定位,写) jjw`Dto&  
package NetFox; }@'$b<!B  
import java.io.*; ]6(N@RC  
.f%fHj  
bpJ(XN}E  
public class FileAccessI implements Serializable{ ;g5m0l5  
-:Da&V  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 0WZ_7C?  
RandomAccessFile oSavedFile; -Ta9 pxZk  
long nPos; Xqg@ e:g  
Ce9|=Jx!  
hV8[@&Sx3  
public FileAccessI() throws IOException B%)%  
{ O`x;,6Vr  
this("",0); 1PVtxL?1P  
} xW)2<m6C&  
;qafT@ }C  
.h@rLorm>  
public FileAccessI(String sName,long nPos) throws IOException "7'J &^|  
{ R_W+Ylob  
oSavedFile = new RandomAccessFile(sName,"rw"); n'wU;!W9  
this.nPos = nPos; =n5zM._S-  
oSavedFile.seek(nPos); 8_BV:o9kL  
} J>wt (] y  
NO "xL,  
F\JM\{&F  
public synchronized int write(byte[] b,int nStart,int nLen) #>b3"[ |  
{ Neq+16*u  
int n = -1; I5 o)_nc  
try{ TJ_$vI  
oSavedFile.write(b,nStart,nLen); X^}I-M%{m  
n = nLen; ,<n}W+3  
} @r/#-?W  
catch(IOException e) :)wy.r;N  
{ bf ]f=;.+  
e.printStackTrace (); #^l L5=  
} QUq_:t+Dv  
L[oui,}_  
D.B.7-_8  
return n; s @&`f{  
} rdl;M>0@  
y I HXg#  
AK,J7  
} Su 586;\  
c]x1HvPE  
#|Y5,a ,{  
/* Ygm`ZA y  
**SiteInfoBean.java a,@]8r-"  
*/ >:AARx%  
package NetFox; XX7{-Y y  
{@H6HqD  
.*@;@06?  
public class SiteInfoBean { FOv=!'S o  
*W4m3Lq  
9_# >aOqL  
private String sSiteURL; //Site's URL 7`- Zuf  
private String sFilePath; //Saved File's Path J`peX0Stl  
private String sFileName; //Saved File's Name 3 R=,1<  
private int nSplitter; //Count of Splited Downloading File `YFtL  
4x {0iav  
~bM4[*Q7  
public SiteInfoBean() oRm L {UDZ  
{//nSplitter的缺省值为5 0LPig[  
//default value of nSplitter is 5 9oyE$S h]  
this("","","",5); ?J%1#1L"/  
} %q/62f7?  
V/%>4GYnC  
oibsh(J3  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) oI0M%/aM  
{ [>+4^&  
sSiteURL= sURL; s`M9    
sFilePath = sPath; aXQnZ+2e^R  
sFileName = sName; d?s<2RkPT  
this.nSplitter = nSpiltter; ~ZmN44?R  
-E^vLB)O  
bx#>BK!  
} o1-m1<ft  
3B1XZm  
#ZJ _T`l  
public String getSSiteURL() h%o%fH&F!  
{ 3AHlSX  
return sSiteURL; G! ]k#.^A,  
} K#%&0D!  
sd,J3  
$h2){*5E{  
public void setSSiteURL(String value) mPOGidxix  
{ K{x\4  
sSiteURL = value; ~xA-V4.  
} o9|nJ;  
X^T:8npxt  
;9[fonk  
public String getSFilePath() jlkmLcpf  
{ o>).Cj  
return sFilePath; zjJ *n8l  
} 9E zj"  
6TQoqH8@U  
UR%/MV  
public void setSFilePath(String value) ?+_Gs;DGVE  
{ txJr;  
sFilePath = value; 8e*,jH3  
} ,p4&g)o  
2"0es40;0  
7F zA*  
public String getSFileName() t|H^`Cv6  
{ x^HGVWw_  
return sFileName; SFB~ ->db  
} hU(umL<  
:V1W/c  
"8c@sHk(w  
public void setSFileName(String value) "w^!/  
{ #D<C )Q  
sFileName = value; bP8Sj16q  
} O;z,qo X  
~rlB'8j(  
~?D4[D|sB  
public int getNSplitter() 9)y/:sO<P  
{ _76PIR{an  
return nSplitter; Ozw;(fDaU  
} t`WB;o!  
NhfJ30~  
rx $mk  
public void setNSplitter(int nCount) r#+d&.|  
{ zAK+8{,  
nSplitter = nCount; {!.(7wV\  
} 4zASMu  
} 2>|dF~"  
L; T8?+x  
o 4`hY/<t  
/* ,oN8HpGs  
**Utility.java N96jJk  
*/ )i~cr2Hk  
package NetFox; <A<{,:5C  
tkVbo.[8K  
wmk *h-  
public class Utility { O#x*iI%  
l\BVS)  
8yRJD[/S  
public Utility() 3t`P@nL0;  
{ P::TO-C  
CEXyrs<  
/,1D)0  
} =CK4.   
<DMl<KZ  
//线程睡眠 *7*lE"$p  
public static void sleep(int nSecond) *n; !G8\  
{ kv8Fko  
try{ 9)0D~oUi  
Thread.sleep(nSecond); `k OD[*  
} Yb:\a/ y  
catch(Exception e) @_U;9)  
{ ~oI1 zNz/  
e.printStackTrace (); bIGHGd  
} {xwm^p(f  
} Uh.oErHQD  
[!!o-9b  
//日志 |w_7_J2  
public static void log(String sMsg)  i7]4W  
{ Ol1e/Wv  
System.err.println(sMsg); 9w"h  
} #@^t;)|  
h lkn%  
W;_nK4$%'  
public static void log(int sMsg) q/4YS0CqE  
{ I*LknU@  
System.err.println(sMsg); k:*S&$S!E  
} -9"['-WH,  
} 'I_Qb$  
0zo?eI  
9dFy"yxYa  
/* +cIUGF p}  
**TestMethod.java k9)jjR*XxG  
*/ 6Pnk5ps }h  
package NetFox; < XP9@t&  
'pm2n0  
P9=?zh 6G.  
public class TestMethod { W)9K`hM6  
d_4T}% q  
Vm%1> '&  
public TestMethod() $P>`m$(8  
{ ///xx/weblogic60b2_win.exe ${+ @gJ+S  
try{ 7#@cz5Su  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 9[1`jtm  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 3mYiQ2  
SiteFileFetch fileFetch = new SiteFileFetch(bean); gfsI6/Y  
fileFetch.start(); EG0WoUX|  
} u1t% (_h  
catch(Exception e){e.printStackTrace ();} L~(_x"uXd  
Ae69>bkE0  
r;>*_Oc7g  
} $}lbT15a  
t>1Z\lE\"  
=3q/F7-  
public static void main(String[] args) jZh';M8"  
{ R16'?,  
new TestMethod(); XpmS{nb  
} bA= |_Wt  
} (:._"jp]  
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