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http断点续传简单实现(java)

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/* 4Cn% h)w  
**SiteFileFetch.java q+}KAk|]V  
*/ ^w(~gQ6|mP  
package NetFox; okv`+VeA  
import java.io.*; <yq kJ  
import java.net.*; 4' MmT'  
i`hr'}x  
SWpvbs.'so  
public class SiteFileFetch extends Thread { ]#*S.  r]  
2\/,X CQV  
 5gZ6H/.  
SiteInfoBean siteInfoBean = null; //文件信息Bean G!L(K  
long[] nStartPos; //开始位置 Tb@r@j:V  
long[] nEndPos; //结束位置 IqW4Q1>f  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *~>} *  
long nFileLength; //文件长度 zA g.,dA  
boolean bFirst = true; //是否第一次取文件 dr~6}S#  
boolean bStop = false; //停止标志 9z0G0QW[  
File tmpFile; //文件下载的临时信息 ~aZy52H_#.  
DataOutputStream output; //输出到文件的输出流 ooW;s<6  
h]{V/  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) `z)q/;}fC  
public SiteFileFetch(SiteInfoBean bean) throws IOException ZD(VH6<g%  
{ C ks;f6G  
siteInfoBean = bean; psaPrE  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;)'@kzi  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); :U!@  
if(tmpFile.exists ()) B2/d%B  
{ Q2(K+!Oe  
bFirst = false; yJRqX]MLA  
read_nPos(); 6#SUfK;  
} E@(nKe&6T_  
else q<Sb>M/\,  
{ NZW)$c'  
nStartPos = new long[bean.getNSplitter()]; .%x%b6EI  
nEndPos = new long[bean.getNSplitter()]; CNkI9>L=W`  
} (<ZpT%2  
KyQd6 1  
4J9VdEKk  
)4tOTi[  
} d(X/N2~g  
HkL`- c0  
"z6 xS;  
public void run() |3{"ANmm'  
{ ;if PqL kO  
//获得文件长度 N R0"yJV>  
//分割文件 nd4Z5=X  
//实例FileSplitterFetch r\."=l  
//启动FileSplitterFetch线程 ZCC T  
//等待子线程返回 618k-  
try{ #q mv(VB4  
if(bFirst) =lOdg3#\a  
{ 9(AY7]6  
nFileLength = getFileSize(); `Hp=1a  
if(nFileLength == -1)  gmW-#.  
{ 3[Xc:;+/  
System.err.println("File Length is not known!"); 7]`l"=/z  
} JV`"kk/  
else if(nFileLength == -2) uG){0%nX  
{ qOs'Ljx6l  
System.err.println("File is not access!"); nd #owjB  
} o6Jhl8  
else dMlJ2\ ]u  
{ &)ED||r,  
for(int i=0;i<nStartPos.length;i++) E gD$A!6N8  
{ F>lM[Lu#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); :6[G;F7s  
} 5 !Ho[  
for(int i=0;i<nEndPos.length-1;i++) !+V."*]l  
{ D_)N!,i  
nEndPos = nStartPos[i+1]; !(8) '<t9  
} IDK~ (t  
nEndPos[nEndPos.length-1] = nFileLength; Xf%vfAf  
} $No^\.mV  
} >*]dB|2  
N# <X"&-_#  
)zv"<>Q 6  
//启动子线程 VYw<8AEFY  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; k((kx:  
for(int i=0;i<nStartPos.length;i++) m>{I>:sq  
{ 1/tyne=m  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <Eu/f`8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), JH+uBZh6  
nStartPos,nEndPos,i); w/, A@fLL  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8I]rC<O6:  
fileSplitterFetch.start(); VoC|z Rd_  
} 6c[Slq!KA  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ZU68\cL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Q79WGW  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8JojKH  
nEndPos = " + nFileLength); 9l<}`/@}W  
// fileSplitterFetch[nPos.length-1].start(); k!0vpps  
fJK;[*&Y  
;;}}uW=  
//等待子线程结束 #B6$ r/%  
//int count = 0; 8'-E>+L   
//是否结束while循环 KSve_CBOh  
boolean breakWhile = false; 6ee1^>  
rKkFflOVO  
Xk?Y  
while(!bStop) XYze*8xUb  
{ qNX+!Y}y  
write_nPos(); qoAJcr2uN  
Utility.sleep(500); RHu4cK!5  
breakWhile = true; RH^; M-'  
WiqkC#N  
Fgw$;W  
for(int i=0;i<nStartPos.length;i++) 5 D[`nU}  
{ nU23D@l  
if(!fileSplitterFetch.bDownOver) ?6V U4nK/*  
{ /}Ct2w&<k  
breakWhile = false; PnJA'@x  
break; !N74y%=M  
} #SR )tU  
} 8E|FFHNK<2  
if(breakWhile) Bp/ k{7  
break; TeHxqWx  
4hWFgk  
Exz(t'  
//count++; "P!zu(h4  
//if(count>4) xgJyG.?  
// siteStop(); p?#xd!tc2N  
} +HF*X~},i  
Eyh(257  
4Ix~Feuph  
System.err.println("文件下载结束!"); {k)H.zwe  
} I3A xK A  
catch(Exception e){e.printStackTrace ();} V>"N VRY  
} d(q2gd@  
L"'L@ A|U  
EASN#VG  
//获得文件长度 @N6KZn |R  
public long getFileSize() nnuJY$O;M  
{ b8h6fB:2  
int nFileLength = -1; ~EO=;a_  
try{ ge[&og/$  
URL url = new URL(siteInfoBean.getSSiteURL()); "Xj>dB1~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); = /kT|  
httpConnection.setRequestProperty("User-Agent","NetFox"); CA3`Ee+rD  
6#Bg99c  
uiq;{!dop  
int responseCode=httpConnection.getResponseCode(); 7 aN}l QM  
if(responseCode>=400) 1Ba.'~:  
{ ;5:3 =F>ao  
processErrorCode(responseCode); l<p6zD$l  
return -2; //-2 represent access is error t<yOTVah  
} n:[LsbTk  
rp!>rM] s  
V&R_A~<T  
String sHeader; fvM|Jb  
vqRW^>~-B  
,a\pdEPj  
for(int i=1;;i++) ee*E:Ltz\  
{ f/pr  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); WO+_ |*&  
//Utility.log(in.readLine()); 4p]hY!7  
sHeader=httpConnection.getHeaderFieldKey(i); 7Yly^  
if(sHeader!=null) /S`d?AV  
{ e[%g'}D:-  
if(sHeader.equals("Content-Length")) ktiC*|fd  
{ K~ VUD(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ~c|{PZ9U  
break; AUwIF/>F(]  
} fHacVj J  
} iYz!:TxP  
else p} i5z_tS  
break; t**o<p#)f  
} 9 [wR/8Xm  
} F2Co Xe7  
catch(IOException e){e.printStackTrace ();} NplkhgSj  
catch(Exception e){e.printStackTrace ();} jHpFl4VPz  
7_]Bu<{f  
?&"!,  
Utility.log(nFileLength); pd oCV  
J}s)#va9R  
*_tJ;  
return nFileLength; k1_ 3\JO"6  
} #3((f[  
h7[PU^m  
nX-%qc"  
//保存下载信息(文件指针位置) &+7G|4!y  
private void write_nPos() J@Qw6J  
{ psAdYEGk!  
try{ yWZ%|K~$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); qb$f,E[  
output.writeInt(nStartPos.length); P*6&0\af|  
for(int i=0;i<nStartPos.length;i++) M UqV$#4@I  
{ (C!33s1  
// output.writeLong(nPos); -,} ppTG  
output.writeLong(fileSplitterFetch.nStartPos); 'E~[I"0  
output.writeLong(fileSplitterFetch.nEndPos); 2Ls  
} \7A6+[ `fa  
output.close(); m'ykDK\B  
} *m`KY)b=l  
catch(IOException e){e.printStackTrace ();} Auf2JH~  
catch(Exception e){e.printStackTrace ();} L }&$5KiwV  
} wEJ?Y8  
/]"2;e-s+  
y w>T1  
//读取保存的下载信息(文件指针位置) "ju0S&  
private void read_nPos() Dv[ 35[Yh  
{ t"]~e"  
try{ %2TjG  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));  XV*uu "F  
int nCount = input.readInt(); tS&rR0<OW  
nStartPos = new long[nCount]; mLL?n)   
nEndPos = new long[nCount]; +)l6%QKcW  
for(int i=0;i<nStartPos.length;i++) V-%Am  
{ gTwxmp.,  
nStartPos = input.readLong(); >$p|W~x  
nEndPos = input.readLong(); cQldBc  
} l]v>PIh~N  
input.close(); |HMpVT-;j  
} >s+*D=k  
catch(IOException e){e.printStackTrace ();} $r87]y!  
catch(Exception e){e.printStackTrace ();} E0a &1j  
} s6J`i&uu  
8^%Nl `_2B  
isR|K9qf^  
private void processErrorCode(int nErrorCode) '{xPdN  
{ #iAEcC0k5  
System.err.println("Error Code : " + nErrorCode); Wf>scl `s  
} a'2^kds  
$C8nPl' 7  
Wa+q[E  
//停止文件下载 V_Oj?MMp n  
public void siteStop() >gFEA0-  
{ =g+Rk+jn  
bStop = true; ]EZiPW-uy  
for(int i=0;i<nStartPos.length;i++) MUfhk)"  
fileSplitterFetch.splitterStop(); @>sZ'M2mq  
JM-+p  
Yx{qVU  
} 9akIu.H  
} _r&,n\ T  
//负责部分文件的抓取 !*@sX7H  
**FileSplitterFetch.java xf]_@T;  
*/ a@&P\"k  
package NetFox; O#962\  
y}t1r |p  
oWo/QNw9  
import java.io.*; &KS*rHgt?  
import java.net.*; H~Fb=.h]U  
kKP<K+hH  
xLmgr72D  
public class FileSplitterFetch extends Thread { 5g(`U+ ,*(  
o)pso\;  
>l3iAy!sZ  
String sURL; //File URL <|MF\D'  
long nStartPos; //File Snippet Start Position QZs ]'*=#  
long nEndPos; //File Snippet End Position aEW sru  
int nThreadID; //Thread's ID =~f\m:Y  
boolean bDownOver = false; //Downing is over 1||\3L/  
boolean bStop = false; //Stop identical mjtmN0^SR  
FileAccessI fileAccessI = null; //File Access interface e7^B3FOx  
kg^VzNX  
qu:nV"~_  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException F+3}Gkn  
{ Lradyo44u\  
this.sURL = sURL; |kXx9vGq@  
this.nStartPos = nStart; c/Ykk7T9--  
this.nEndPos = nEnd; z[`O YwsW  
nThreadID = id; -]K9sy)I  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 FELDz7DYya  
} Btgxzf  
~l@ h  
NP#:} )  
public void run() kED1s's  
{ 7} 2Aq  
while(nStartPos < nEndPos && !bStop) B<" `<oG@|  
{ BrO" _  
_^5OoE"}!  
gx',~  
try{ p2/Pj)2  
URL url = new URL(sURL); TC+L\7   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R ]! [h  
httpConnection.setRequestProperty("User-Agent","NetFox"); -)p S\$GC  
String sProperty = "bytes="+nStartPos+"-"; hmQ;!9  
httpConnection.setRequestProperty("RANGE",sProperty); L H8iHB  
Utility.log(sProperty); ;0c -+,  
NM{/rvM  
iUua!uC  
InputStream input = httpConnection.getInputStream(); (Iz$_(  
//logResponseHead(httpConnection); =h Lw 1~  
/eO :1c  
r$ 8 ^K\oF  
byte[] b = new byte[1024]; >{HQ"{Q  
int nRead; 3\B 28m  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Y%1 94fY$  
{ -0>gq$/N=^  
nStartPos += fileAccessI.write(b,0,nRead); KW1b #g%Z  
//if(nThreadID == 1) }@XokRk  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); JE<w7:R&  
} [<,i}z  
+M=`3jioL  
<lo\7p$A  
Utility.log("Thread " + nThreadID + " is over!"); #@3& 1 }J/  
bDownOver = true; n,_q6/!  
//nPos = fileAccessI.write (b,0,nRead); OkV*,n  
} 3Hd~mfO\  
catch(Exception e){e.printStackTrace ();} &{uj3s&C   
} U7do,jCoa  
} hRwj-N%C  
r&/M')}?Lw  
9{KL^O?g  
//打印回应的头信息 \~!!h.xR  
public void logResponseHead(HttpURLConnection con) TF1,7Qd  
{ ]~K&b96(  
for(int i=1;;i++) ~EL3I  
{ MOia] 5  
String header=con.getHeaderFieldKey(i); rijavZS6  
if(header!=null) V*< `!w  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); fFYfb4o  
Utility.log(header+" : "+con.getHeaderField(header)); y<5RV>"Vg  
else $~+(si2  
break; a-bj! Rs  
} Pb`Uxv  
}  B8~JUGD  
X;&Iu{&=  
<c77GimD?  
public void splitterStop() QB.QG!@  
{ W2Ik!wEe&  
bStop = true; "\k| Z  
} JuKG#F#,  
|W#(+m  
6Lc{SR  
} [2$mo;E?  
?`lD|~  
\5iMr[s  
/* RH}i=  
**FileAccess.java mfqnRPZ  
*//文件访问(定位,写) ;0vCZaEF  
package NetFox; L~+/LV  
import java.io.*; \}Al85  
hl]q6ZK!6  
9]Fi2M  
public class FileAccessI implements Serializable{ 'CMbq Lk#  
U #C@&2  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \_]X+o;  
RandomAccessFile oSavedFile; SNJSRqWL/  
long nPos; dM=45$\q  
J6I:UML  
jP{&U&!i  
public FileAccessI() throws IOException yiw4<]{IX  
{ `+m:@0&L  
this("",0); y '[VZ$^i  
} Gl"|t't(  
N<PDQ  
0MI4"<  
public FileAccessI(String sName,long nPos) throws IOException .0Kc|b=w  
{ YSh@+AN  
oSavedFile = new RandomAccessFile(sName,"rw"); D"V(A\sZ  
this.nPos = nPos; s(Bcw`'#  
oSavedFile.seek(nPos); )Yu  
} uc>":V  
jNvDE}'  
w *M&@+3I  
public synchronized int write(byte[] b,int nStart,int nLen) %E\zR/  
{ $<QrV,T  
int n = -1; d%za6=M  
try{ bFIM07  
oSavedFile.write(b,nStart,nLen); [=BccT:b  
n = nLen; ,gpZz$Ef(  
} _ a#k3r  
catch(IOException e) 4_`(c1oA  
{ u4h0s1iI  
e.printStackTrace (); ^)y8X.iO  
} AP1&TQ,&  
rQxiG[0  
"<"m}rE?Q  
return n; e }Mf  
} r7,}"Pl  
^) (-7H  
B<Q)z5KK  
} 0NeIQr1N_  
^TtL-|I  
3vs{*T"  
/* 0|Xz-Y  
**SiteInfoBean.java  W,|+Dl  
*/ FUarI5#fwF  
package NetFox; h 8xcq#  
{h=gnR-9  
84WX I#BH  
public class SiteInfoBean { >%ovL8F  
c: r25  
RfOJUz  
private String sSiteURL; //Site's URL 6O <UW.  
private String sFilePath; //Saved File's Path 1<Sg@  
private String sFileName; //Saved File's Name f14^VTzP/#  
private int nSplitter; //Count of Splited Downloading File aeISb83Y|  
}T0O~c{$i  
8t3m$<7  
public SiteInfoBean() Khb Ku0Z  
{//nSplitter的缺省值为5 AhD C5ue=  
//default value of nSplitter is 5 jU $G<G  
this("","","",5); sH.=Faos  
} _jc_(;KPF  
O%3Hp.|!  
<PVwf`W.  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) | UlG@Mn  
{ o@BV&|  
sSiteURL= sURL; !> =ybRe  
sFilePath = sPath; 64mg:ed&  
sFileName = sName; 8IA1@0n&  
this.nSplitter = nSpiltter; /)T~(o|i  
Cs_&BSs  
}jUsv8`}8R  
} M.K^W`  
D<m0G]Ht*  
J\Hv42  
public String getSSiteURL() *i}X(sfe  
{ qi B~  
return sSiteURL; D#G%WT/"  
} >{N}UNZ$}  
CxTmW5l  
oNtoqYwH  
public void setSSiteURL(String value) fd4C8>*7G  
{ #1/~eIEY  
sSiteURL = value; V^,eW!  
} gfs;?vP  
zGFD71=#  
@zC6`  
public String getSFilePath() d\ 8v VZ  
{ F~8'3!<9  
return sFilePath; R0}1:1}$Sn  
} WFiX=@SS  
s(nT7x+W  
b,^Gj]7  
public void setSFilePath(String value) 0|RofL&o  
{ ?+))J~@t  
sFilePath = value; D3 yTN"  
} +rJ6DZ  
."H;bfcL_  
bx(@ fl:m  
public String getSFileName() 8[KKi~A  
{ ] \M+ju  
return sFileName; @uH!n~QV  
} y-db CYMc  
c7jmzo  
>;^/B R=  
public void setSFileName(String value) (Kwqa"Hk4{  
{ ~g\~x  
sFileName = value; aknIrblS\  
} &yvvea]  
F)(^c  
0eNdKE  
public int getNSplitter() %W"u4 NT7  
{ u MEM7$o  
return nSplitter; ? Bpnnwx  
} a$ "nNmD?  
g5|~ i{"0  
oGRk/@  
public void setNSplitter(int nCount) )Cl>%9  
{ %+H_V1F  
nSplitter = nCount; 3l~+VBR_  
} lcie6'<  
} `UTPX'Vz  
d/bimQ  
4LKpEl.=  
/* x-m*p^}  
**Utility.java T@tsM|pI  
*/ (T_-`N|  
package NetFox; ~=*o  
3uocAmY  
z.Ic?Wz7  
public class Utility { bGCC?}\  
1EXT^2!D  
>jX "  
public Utility() &t^*0/~  
{ c|k_[8L  
2n,z`(=  
&{V|%u}v  
} `Pvi+:6\Y  
8f9wUPr  
//线程睡眠 Hw o _;fV  
public static void sleep(int nSecond) [(heE  
{ %dzt'uz  
try{ TP rq:"K  
Thread.sleep(nSecond); NX& dJ 6a  
} uQIPnd(V  
catch(Exception e) ?> }p'{I  
{ Nvgi&iBh8  
e.printStackTrace (); YGJ!!(~r  
} hSm?Z!+  
} Hz.i$L0}  
t1Fqq4wRi  
//日志 xoKK{&J  
public static void log(String sMsg) 7GOBb|  
{ -G.N  
System.err.println(sMsg); ]p`y  
} l8FJ\5'M  
G*I    
s<zN`&t  
public static void log(int sMsg) lxyTh'  
{ )8A.Wg4S;c  
System.err.println(sMsg); &DWSf`:Hx  
} N4vcd=uG#  
} EB}B75)x  
CP J21^  
;k!.ey $S  
/* `;j1H<L  
**TestMethod.java uO]D=Z\S(  
*/ ~#E&E%sJ  
package NetFox; q[\3,Y  
,^([aK  
,<U= 7<NU  
public class TestMethod { 98Vv K?  
p(n0(}eVC'  
~6f/jCluR%  
public TestMethod() G'\[dwD,u  
{ ///xx/weblogic60b2_win.exe yv4x.cfI2W  
try{ \6|y~5Hw{r  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 1eD#-tzV  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); pTCD1)  
SiteFileFetch fileFetch = new SiteFileFetch(bean); K=N&kda   
fileFetch.start(); dHDtY$/_  
} nK;d\DO  
catch(Exception e){e.printStackTrace ();} y|| n9  
9i\RdJv.  
6\.g,>   
} 3+Lwtb}XPF  
Gd 4S7JE  
f6Y?),`  
public static void main(String[] args) I6^y` 2X  
{ |HycBTN#E  
new TestMethod(); OkciL]  
} =3035{\  
} nX (bVT4i  
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