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http断点续传简单实现(java)

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/* * b>W  
**SiteFileFetch.java {@g3AG%  
*/ I%%\;Dy  
package NetFox; x*5' 6  
import java.io.*; u(02{V  
import java.net.*; lT$Vv= M  
tr7FV1p  
z_!P0`  
public class SiteFileFetch extends Thread { 8<3J!X+  
_Pa(5-S'KR  
yXY8 o E  
SiteInfoBean siteInfoBean = null; //文件信息Bean }r`!p5\$K0  
long[] nStartPos; //开始位置 l#%Y]1 *  
long[] nEndPos; //结束位置 }txHuq1Q.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 K"eR 6_ k  
long nFileLength; //文件长度 $;7?w-.  
boolean bFirst = true; //是否第一次取文件 aGNt?)8WPZ  
boolean bStop = false; //停止标志 *j><a  
File tmpFile; //文件下载的临时信息 S+|aCRS  
DataOutputStream output; //输出到文件的输出流 k]Y+C@g  
>!A&@1[M  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) !l~tBJr*sB  
public SiteFileFetch(SiteInfoBean bean) throws IOException &bh?jW  
{ K>Fo+f  
siteInfoBean = bean; En+4@BC  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); gd.P%KC!g  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @z$V(}(O^  
if(tmpFile.exists ()) ) !3XM  
{ Cst\_j  
bFirst = false; `kyr\+hp  
read_nPos(); =Xm [  
} eznw05U  
else 8U\;N  
{ u%a2"G|  
nStartPos = new long[bean.getNSplitter()]; xBG&ZM4"^f  
nEndPos = new long[bean.getNSplitter()]; /#9O{)  
} HoymGU`w  
w|>:mQnU  
?A(=%c|,g  
|^Try2@  
}  ]N-K`c]  
//Ioh (N  
F0bmGDp@-  
public void run() (Z)  
{ k<"ZNQm$.  
//获得文件长度 Ha$|9li`  
//分割文件 Y1{6lhxgE  
//实例FileSplitterFetch +%eMm.(  
//启动FileSplitterFetch线程 M^r1b1tR  
//等待子线程返回 HCb7 `(@  
try{ 6;dB   
if(bFirst) gTW(2?xYf  
{ x_v pds  
nFileLength = getFileSize(); #$K\:V+ 4  
if(nFileLength == -1) P`[6IS#\S  
{ $b\Gl=YX^  
System.err.println("File Length is not known!"); S#!PDg  
} j!&g:{ e  
else if(nFileLength == -2) +;`Cm.Iu  
{ Mz40([{  
System.err.println("File is not access!"); D!J ("~[3  
} 9g J`H'  
else ?.|qRzWL  
{ vrGRZa  
for(int i=0;i<nStartPos.length;i++) iK(n'X5i  
{ Mh>^~;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); r&0v,WSp&S  
} ," :ADO-  
for(int i=0;i<nEndPos.length-1;i++) eXnMS!g%Z  
{ 7 -gt V#  
nEndPos = nStartPos[i+1]; S`K8e^]  
} =B*,S#r  
nEndPos[nEndPos.length-1] = nFileLength; jFw?Ky2  
} M ,e_=aq  
} >8t3a-/  
DB:Ia5|*i  
.cQwj L  
//启动子线程 kxWf1hIz0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "J, ErnM  
for(int i=0;i<nStartPos.length;i++) $oq&uL  
{ #p*{p)]HiA  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z^{VqC*o+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), H1 n`A#6?  
nStartPos,nEndPos,i); MCe =RR  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); KSqWq:W+  
fileSplitterFetch.start(); Z)|*mJ  
} E$4\Yc)(AL  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F_zs"ex/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); w80g) 4V+  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", +aEE(u6%E@  
nEndPos = " + nFileLength); $}aLFb  
// fileSplitterFetch[nPos.length-1].start(); ZR6KE_  
P`Anf_  
j?g{*M  
//等待子线程结束 r?\hZ*|M  
//int count = 0; ,X+mXtg.  
//是否结束while循环 [US.n +G6  
boolean breakWhile = false; !R[o6V5T  
HMS9_#[kE  
jToA"udW/  
while(!bStop) PD:" SfV,G  
{ $vTU|o>|  
write_nPos(); or]8;eQ?  
Utility.sleep(500); bMxzJRrNg  
breakWhile = true; CcLP/  
d; oaG (e  
tl CgW)<?  
for(int i=0;i<nStartPos.length;i++) fN?HF'7V  
{ y_Bmd   
if(!fileSplitterFetch.bDownOver) w~;1R\?|  
{ %=]~5a9  
breakWhile = false; Cc]t*;nU_  
break; g.s~Ph-G  
} o D*h@yL  
} 71@V|$Dy  
if(breakWhile) +smPR  
break; ^$6EO) <  
teg LGp@_  
RnIL>Akp  
//count++; n>+M4Zb  
//if(count>4) *t 3fbD  
// siteStop(); 2J|Wbey  
} _Sosw|A  
}Rt?p8p  
=sG  C  
System.err.println("文件下载结束!"); B7fURL Rqr  
} Qg%B<3 <  
catch(Exception e){e.printStackTrace ();} Mf<P ms\F  
} |jU/R  
egYJ.ZzF0  
b=wc-n A  
//获得文件长度 rMH\;\ I|U  
public long getFileSize() -Z-|49I/mN  
{ &+xNR2";  
int nFileLength = -1; va:5pvt2&  
try{ ss-{l+Z5  
URL url = new URL(siteInfoBean.getSSiteURL()); "/S-+Ufn  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2pQ zT  
httpConnection.setRequestProperty("User-Agent","NetFox"); 38 tRb"3zP  
dK#:io[Nz  
HKP<=<8/O  
int responseCode=httpConnection.getResponseCode(); xeIt7b?#  
if(responseCode>=400) Elo m_   
{ ~Z=Q+'Hu0  
processErrorCode(responseCode); Z7V 1e<E  
return -2; //-2 represent access is error %S. _3`A  
} <2fZYt vt  
%{Kp#R5E  
.Qyq*6T3&  
String sHeader; :Z- = 1b~  
uv%T0JA/  
7s4G|N[wR\  
for(int i=1;;i++) ?rKewdGY  
{ ,j:`yB]4,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0/6f9A  
//Utility.log(in.readLine()); yrSmI)&%  
sHeader=httpConnection.getHeaderFieldKey(i); Q=)$  
if(sHeader!=null) fk<0~ tE  
{ 9G[!"eZ}  
if(sHeader.equals("Content-Length")) U6t>UE6k  
{ {dH87 nt  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); u<!8dQ8  
break; 4[44Eku\  
} 9f\Lon4lX  
} _U?   
else DJdW$S7  
break; yTm/P!1S  
} 2`9e20  
} 7v]>ID  
catch(IOException e){e.printStackTrace ();} %c<e`P;  
catch(Exception e){e.printStackTrace ();} h8&VaJ  
\uQ yp*P1s  
)[C]1N=tK  
Utility.log(nFileLength); FO<PMK   
H9?(5  
J /mLmSx  
return nFileLength; b}HL uX  
} )\s{\u \  
-|bnvPmE  
M4w,J2_8MK  
//保存下载信息(文件指针位置) F{WV}o=MY  
private void write_nPos() r5M {*  
{ }^ +E S^~  
try{ <~@}r\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); LUc!a4i"fO  
output.writeInt(nStartPos.length); Za_w@o  
for(int i=0;i<nStartPos.length;i++) CBN,~wzP*  
{ ,bzE`6  
// output.writeLong(nPos); 84j6.\,  
output.writeLong(fileSplitterFetch.nStartPos); pX8TzmIB0  
output.writeLong(fileSplitterFetch.nEndPos); H*51GxK  
} RZoSP(6  
output.close(); aZn]8jC%  
} K~$A2b95  
catch(IOException e){e.printStackTrace ();} mM0VUSy  
catch(Exception e){e.printStackTrace ();} -+?ZJ^A   
} OyH>N/  
G8z.JX-7g  
"m,)3zND3  
//读取保存的下载信息(文件指针位置) R&KFF'%  
private void read_nPos() |(u6xPs;P  
{ L{1MyR7`I+  
try{ :d}I`)&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); v7gs $'Q  
int nCount = input.readInt(); /*Iq,"kGz  
nStartPos = new long[nCount]; c|RTP  
nEndPos = new long[nCount]; Of0(.-Q w  
for(int i=0;i<nStartPos.length;i++)  vX1 8 ]  
{ B6ee\23  
nStartPos = input.readLong(); h*d1G9%Q1  
nEndPos = input.readLong(); K G<. s<  
} =hFIH\x  
input.close(); S9RH&/^H  
} xl2;DFiYt  
catch(IOException e){e.printStackTrace ();} 3w!8PPl  
catch(Exception e){e.printStackTrace ();} 'tvX.aX2  
} cQ}3? v  
1i3;P/  
v+d} _rCT  
private void processErrorCode(int nErrorCode) 7" Qj(N  
{ ZDny=&>#  
System.err.println("Error Code : " + nErrorCode); K93L-K^J  
} %4'<0  
qJ(XW N H  
yUnNf 2i  
//停止文件下载 ?, B4  
public void siteStop() K Q^CiX  
{ F3nYMf  
bStop = true; =sZ58xA  
for(int i=0;i<nStartPos.length;i++) )hG4,0hv&  
fileSplitterFetch.splitterStop(); .ni<'  
!aQb Kp  
AS4mJ UU9  
} 4}4cA\B:n  
} 8]h~jNku  
//负责部分文件的抓取 5tx!LGOK  
**FileSplitterFetch.java ":@\kw  
*/ ~'1gX`o:  
package NetFox; *!oV?N[eA'  
Yo%ph%e  
HpP82X xj  
import java.io.*; &?g!)O  
import java.net.*; ;P *`v  
E<RPMd @a  
fofYe0z  
public class FileSplitterFetch extends Thread { ,="hI:*<  
  6a}  
GHNw.<`l?  
String sURL; //File URL }fO+b5U  
long nStartPos; //File Snippet Start Position 2ieyU5q7#  
long nEndPos; //File Snippet End Position @cB7tY*Ski  
int nThreadID; //Thread's ID w.VjGPp  
boolean bDownOver = false; //Downing is over QL]e<2oPJ  
boolean bStop = false; //Stop identical jQBL 8<  
FileAccessI fileAccessI = null; //File Access interface d! {]CZ"@  
=xw+cs1,x  
=j~BAS*"  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >piVi[`  
{ -\<\OV:c*  
this.sURL = sURL; CS'LW;#[  
this.nStartPos = nStart; 'VgEf:BS  
this.nEndPos = nEnd; 2OVN9_D%  
nThreadID = id; j+9;Rvt2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 'uC=xG.*}  
} W{m_yEOf  
mF:Pplf<  
=U7P\s w2  
public void run() %u}#|+8}  
{ 60TM!\  
while(nStartPos < nEndPos && !bStop) <$(y6+lY  
{ }1 ,\ *)5  
]sTbEw.[  
\&_pI2X  
try{ po\(O8#5U  
URL url = new URL(sURL); `=V p 0tPI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k?Kt*T  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7Q^p|;~a  
String sProperty = "bytes="+nStartPos+"-"; D%}rQ,*  
httpConnection.setRequestProperty("RANGE",sProperty); t!-\:8n  
Utility.log(sProperty); {o SdVRI  
Nj;5iy  
nuH=pIq6x  
InputStream input = httpConnection.getInputStream(); 6(=B`Z}a  
//logResponseHead(httpConnection); fUMjLA|*I<  
}W)b  
Jxf>!\:AZu  
byte[] b = new byte[1024]; Vy=P*  
int nRead; 3n,jrX75u  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) cO$xT;kK  
{ |k$6"dXSO  
nStartPos += fileAccessI.write(b,0,nRead); P!Brw72  
//if(nThreadID == 1) )SZzA'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QLH!>9Ch  
} !RP0W  
en>n\;U  
> ^=n|%  
Utility.log("Thread " + nThreadID + " is over!"); ~R&rQJJeJ  
bDownOver = true; q68CU~i*  
//nPos = fileAccessI.write (b,0,nRead); JC0#pU;  
} {]bmecz  
catch(Exception e){e.printStackTrace ();} Y'{}L@"t  
} tD*k   
} )T6:@n^]h  
%QG3~b% h  
uK] -m  
//打印回应的头信息 5dGfO:Dy_  
public void logResponseHead(HttpURLConnection con) <2d)4@B=  
{ Pbd[gKX_  
for(int i=1;;i++) _@i-?Q  
{ *I!R0;HT  
String header=con.getHeaderFieldKey(i); }uNj#Uf  
if(header!=null) mqHcD8X  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); wPEK5=\4Ob  
Utility.log(header+" : "+con.getHeaderField(header)); mv>0j<C91  
else mPU}]1*p  
break; Zs(BViTb|  
} IsmZEVuC  
} hraR:l D  
eR4ib-nS  
:zX^H9'E<(  
public void splitterStop() A!,c@Kv 3  
{ zMRa <G7  
bStop = true; N5{v;~Cm}V  
} tm/=Oc1p  
Td ade+  
veuX />!  
} Ni8%K6]z  
(/At+MF3E  
^vxx]Hji  
/* BTD_j&+(  
**FileAccess.java EnGh&]  
*//文件访问(定位,写) &\I<j\F2/  
package NetFox; m.rV1#AI  
import java.io.*; i}:hmy'  
'<3h8\"  
Z^]jy>dj  
public class FileAccessI implements Serializable{ 'z^'+}iyv  
#8sy QWlG  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 >|, <9z`D  
RandomAccessFile oSavedFile; ~;jgl_5?b  
long nPos; vp2w^/])u  
}]H7uC!t   
~r?tFE* +  
public FileAccessI() throws IOException KTt+}-vP^  
{ !zt>& t  
this("",0); r&Nh>6<&/  
} (V&8 WN  
k>F!S`a&m  
2Y%7.YX"  
public FileAccessI(String sName,long nPos) throws IOException lX%-oRQ/os  
{ sVr|kvn2  
oSavedFile = new RandomAccessFile(sName,"rw"); KAXjvZN1  
this.nPos = nPos; t #Kucde  
oSavedFile.seek(nPos); KB^8Z@(+  
} F53 .g/[  
g0"xG}d  
iZ>P>x\  
public synchronized int write(byte[] b,int nStart,int nLen) n-2!<`UFX  
{ U# [T!E  
int n = -1; [<5/s$,i  
try{ yZ 7)|j  
oSavedFile.write(b,nStart,nLen); Vpp$yM&?  
n = nLen; dH.Fb/7f  
} G62;p#  
catch(IOException e) >?OUs>}3y2  
{ T u%XhXl:j  
e.printStackTrace (); &"W gO!pzD  
} >]anTF`d  
nBd]rak'  
w>\oz  
return n; j94~c YV  
} O'B3sy  
+,,dsL  
xOPQ~J|z  
} ;~DrsQb  
y\j[\UZKO  
G~DHNO6  
/* ~Er0$+q=Y;  
**SiteInfoBean.java [T4{K &  
*/ JBA{i45x  
package NetFox; xv Xci W  
8\9W:D@"x  
kssRwe%>;  
public class SiteInfoBean { u$[&'D6  
lAA&#-#YG  
Ip`1Wv_  
private String sSiteURL; //Site's URL 5x|$q kI  
private String sFilePath; //Saved File's Path ?]bx]Y;  
private String sFileName; //Saved File's Name /s%-c!o^  
private int nSplitter; //Count of Splited Downloading File )X," NJG  
-W.-m2:1  
3 ^x&G?)  
public SiteInfoBean() ern\QAhXX  
{//nSplitter的缺省值为5 sVFX(yx0  
//default value of nSplitter is 5 Xs|d#WbX  
this("","","",5); L~e0^X?  
} \D' mo  
</ "Wh4>C  
N%'(8%;  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [kpQ:'P3  
{ >r C*.  
sSiteURL= sURL;  6W  
sFilePath = sPath; 88<d<)7t  
sFileName = sName; yPT o,,ca=  
this.nSplitter = nSpiltter; 5D=U.UdR  
]@cI_n  
ZvQZD=,F  
} %).I &)i  
AX&Emz-  
GIkeZV{4}  
public String getSSiteURL() Ct?xTFb  
{ >Ik%_:CC`  
return sSiteURL; _-H,S)kI`  
} ]K8G}|Wy6  
-hfkF+=U'  
suIYfjh  
public void setSSiteURL(String value) o<p4r}*AVJ  
{ %-fS:~$  
sSiteURL = value; p %.Adxx  
} p<h(  
bC"h7$3  
Ac{TqiIv  
public String getSFilePath() ^b~ZOg[p  
{ )(yaX  
return sFilePath; -IVWkA)7  
} _1O .{O  
mJd8?d  
^fsC]9NS  
public void setSFilePath(String value) nv+miyvvm  
{ 9@lG{9id?  
sFilePath = value; nj00g>:>  
} b?cO+PY01  
G9xO>Xp^Al  
ZwY mR=  
public String getSFileName() yK9EHJ$  
{ E_$nsM8?  
return sFileName; ~ArRD-_t  
} a%a0/!U[  
>dgq2ok!u  
zsd<0^ p\{  
public void setSFileName(String value) 7&HcrkP]  
{ Wl=yxJu_(  
sFileName = value; TG8U=9qt  
} vfj{j= G  
<h+@;/v:  
jA2%kX\6//  
public int getNSplitter() tI^[|@,  
{ pRxVsOb  
return nSplitter; ~*\ *8U@7  
} "Xwsu8~  
G(shZ=fq  
3G 5xIr6   
public void setNSplitter(int nCount) (RrC<5"  
{ D+ .vg?8  
nSplitter = nCount; ?IS[2 v$   
} +_vf=d  
} =zrfh-lwH  
@c"s6h&  
{*g{9`   
/* P_mP ^L  
**Utility.java @p/"]zf  
*/ 3}3b@:<  
package NetFox; 4bdCbI  
EBk-qd a}  
B<Cg_C  
public class Utility { y4 ]5z/  
Y=_*Ai  
v@2@9/  
public Utility() $_eJ@L#  
{ 9C Ki$L  
yA*U^:%  
Wlq3r#  
} :i {; 81V  
_akjgwu  
//线程睡眠 `D=d!!1eUi  
public static void sleep(int nSecond) L:?Ew9Lf  
{ *}Gys/\!S  
try{ +O8zVWr  
Thread.sleep(nSecond); c3c3T`B  
} cH:&S=>h  
catch(Exception e) 'L9hM.+  
{ #4"eQ*.*"  
e.printStackTrace (); SD8>,  
} 1g t 7My  
}  xI#rnx*  
D^p)`*  
//日志 Ly2!(,FB.  
public static void log(String sMsg) 0yMHU[):~  
{ FzCXA=m  
System.err.println(sMsg); }y J,&N'p  
} p0l.f`B  
7i02M~*uS  
S5Pn6'w  
public static void log(int sMsg) hcYqiM@8>  
{ ''!j:49  
System.err.println(sMsg); 4f ~q$Sf]<  
} saQo]6#  
} !Z{7X ^  
dNqj|Vu  
*u,xBC2C  
/* -'WR9M?fq  
**TestMethod.java [TqX"@4NS  
*/ ,VUOsNN4\  
package NetFox; -?{g{6  
xdaq` ^Bbt  
QG L~??  
public class TestMethod { x{So  
$$Ibr]$5  
T?jN/}qg  
public TestMethod() v6! `H  
{ ///xx/weblogic60b2_win.exe 9asA-'fZ  
try{ d>#X+;-k  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); s,/C^E  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `jhbKgR[  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~+Cl9:4T  
fileFetch.start(); rTJqw@]#WH  
} H+gB|  
catch(Exception e){e.printStackTrace ();} T-7( 3#&  
k{lXK\zN  
j':<7n/A  
} Pd `~#!  
xH,e$t#@@~  
0lOan  
public static void main(String[] args) Y<N#{)Q  
{ Kg /,  
new TestMethod(); IC$"\7 @  
}  _PwPLSg  
} 9q&~!>lt  
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