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http断点续传简单实现(java)

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/* Eei"baw/  
**SiteFileFetch.java %LeQpbyOR  
*/ ' `0kW_'  
package NetFox; Vej [wY-c  
import java.io.*; pwg$% lv  
import java.net.*; #cB=] (N  
VO _! +  
!.(Kpcrg  
public class SiteFileFetch extends Thread { uSZCJ#'G  
axJuJ`+Y  
6S#Y$2 P  
SiteInfoBean siteInfoBean = null; //文件信息Bean 8@Zg@>,  
long[] nStartPos; //开始位置 +mM=`[Z`??  
long[] nEndPos; //结束位置 gB4&pPN  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 iV h^;  
long nFileLength; //文件长度 "m*.kB)e7  
boolean bFirst = true; //是否第一次取文件 \#LkzN8  
boolean bStop = false; //停止标志 cL31g_u  
File tmpFile; //文件下载的临时信息 -__RFxG  
DataOutputStream output; //输出到文件的输出流 9`83cL  
>FO4]  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 3\x@G)1  
public SiteFileFetch(SiteInfoBean bean) throws IOException =o N(1k^  
{ 2K^D%U  
siteInfoBean = bean; sVk+E'q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); W[pOLc-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); I r8,=  
if(tmpFile.exists ()) ]_Cm 5Z7  
{ Y7W xV>E  
bFirst = false; 'r&az BO  
read_nPos(); G,tJ\xMw8  
} @J`o pR  
else (IlHg^"  
{ do {E39  
nStartPos = new long[bean.getNSplitter()]; #nK38W#  
nEndPos = new long[bean.getNSplitter()]; F.zx]][JV  
} _|f1q  
qOA+ao  
K U 2LJ_~Y  
s}2TJa  
} D{-h2=V  
RMinZ}/  
s)Gnj;  
public void run() IM.sW'E  
{ nkI+"$Rz0  
//获得文件长度 p`/"e<TP  
//分割文件 !n;0%"(FH  
//实例FileSplitterFetch  HaJs)j  
//启动FileSplitterFetch线程 Gv ';  
//等待子线程返回 xC3h m  
try{ w %4SNR  
if(bFirst) p>4tPI}bf  
{ Rm@#GP`  
nFileLength = getFileSize(); *QKxrg  
if(nFileLength == -1) ]!7 %)  
{ 4Zz%vY  
System.err.println("File Length is not known!"); 06ndW9>wD)  
} L]wWJL  
else if(nFileLength == -2) W''%{A/'  
{ ~ m/nV81  
System.err.println("File is not access!"); Xk9mJ]31LC  
} lk.]!K$}  
else wM$N#K@  
{ w=NM==cLj  
for(int i=0;i<nStartPos.length;i++) OQlmzg  
{ u|;?FQ$M  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0ge"ISK  
} [&_7w\m  
for(int i=0;i<nEndPos.length-1;i++) YmrrZ&]q  
{ d=` a-R0  
nEndPos = nStartPos[i+1]; 968<yO]  
} z7vc|Z|  
nEndPos[nEndPos.length-1] = nFileLength; 5j8aMnvs  
} / .wO<l=  
} @nC][gNv  
b 7XTOB_HO  
PK C}!>2  
//启动子线程 rJjNoY  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; UL{+mp  
for(int i=0;i<nStartPos.length;i++) 0+-"9pED>E  
{ 1c5+X Cr  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +3>)r{#k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), OC?a[^hB^)  
nStartPos,nEndPos,i); FUt{-H!<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \d'>Ky;GD  
fileSplitterFetch.start(); x;^DlyyYU  
} Y ~TR`y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `w&A;fR! H  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <{ER#}b:O  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", lEZODc+%Y  
nEndPos = " + nFileLength); P O*;V<^  
// fileSplitterFetch[nPos.length-1].start(); k.."_ 4  
@AB}r1E2  
CpE LLA<  
//等待子线程结束 M]Kx g;  
//int count = 0; tPp9=e2[s  
//是否结束while循环 :VkuK@Th`  
boolean breakWhile = false; ;[qA?<GJ  
8+* 1s7{  
v}cTS@0  
while(!bStop) ?\Bm>p% +  
{ p*NKM} ]I  
write_nPos(); c-`'`L^J  
Utility.sleep(500); 0 ~a9gBG  
breakWhile = true; k)3b0T@b  
{4F=].!  
g=gM}`X%  
for(int i=0;i<nStartPos.length;i++) Exb?eHO  
{ (]@yDb4  
if(!fileSplitterFetch.bDownOver) @u>:(9bp  
{ (DIMt-wz  
breakWhile = false; +vr|J:  
break; .OM^@V~T  
} 4)Bk:K  
} We`6# \Z X  
if(breakWhile) 7DZZdH$Fm  
break; EXF|; @-"  
]lqe,>  
ixvF `S9  
//count++; g`Kh&|GU  
//if(count>4) ` t6|09e  
// siteStop(); [mcER4]}  
} 0Yk$f1g  
yC:C  
^KF%Z2:$  
System.err.println("文件下载结束!"); @e#{Sm  
} tqFE>ojlI  
catch(Exception e){e.printStackTrace ();} r}\m%(i  
} 3/{,}F$  
oypF0?!m  
 NZu2D  
//获得文件长度 H3xMoSs  
public long getFileSize() u2E}DhV  
{  vWH)W?2  
int nFileLength = -1; D_Zt:tzO  
try{ Yn_v'Os2  
URL url = new URL(siteInfoBean.getSSiteURL()); jtv<{7a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); X:>,3[hx|  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1YtbV3  
f q&(&(|  
yog(  
int responseCode=httpConnection.getResponseCode(); J $^"cCMr  
if(responseCode>=400) h( DmSW  
{ N|2PW ~,  
processErrorCode(responseCode); &5y|Q?  
return -2; //-2 represent access is error adn2&7H  
} `'E(L&  
zHX7%x,Cq  
h]vu BHJ}  
String sHeader; "oT&KW   
mVd%sWD  
K2qKkV@  
for(int i=1;;i++) 8b:GyC5L  
{ n`X}&(O  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); `]I p`_{  
//Utility.log(in.readLine()); r>lo@e0G  
sHeader=httpConnection.getHeaderFieldKey(i); Ew )1O9f  
if(sHeader!=null) *5KDu$'(e  
{ Rd;^ fBx  
if(sHeader.equals("Content-Length")) B'-n ^';  
{ 8\S$iGd  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =/ +f3  
break; 8dLK5"_3  
} Ez+8B|0P  
} NydF'N_1  
else yIu_DFq%  
break; Q"s]<MtdS  
} Y#zHw< <E  
} RZ0+Uu/J  
catch(IOException e){e.printStackTrace ();} XD%GNZ  
catch(Exception e){e.printStackTrace ();} Q%QIr  
bMB@${i}  
?$6(@>`f&t  
Utility.log(nFileLength); ] 1s6=  
Xd@ d$  
YJF|J2u  
return nFileLength; /^9=2~b  
} ,: Ij@u>)  
6Zx)L|B  
)@],0yL  
//保存下载信息(文件指针位置) f<;eNN  
private void write_nPos() >{{0odBF  
{ !8I80 :e_~  
try{ Hy b_> n  
output = new DataOutputStream(new FileOutputStream(tmpFile)); fp?/Dg"49.  
output.writeInt(nStartPos.length); R9-Uoc/  
for(int i=0;i<nStartPos.length;i++) 9*S9~  
{ 5i-VnG  
// output.writeLong(nPos); IOY<'t+  
output.writeLong(fileSplitterFetch.nStartPos); *&~(>gNF,  
output.writeLong(fileSplitterFetch.nEndPos); K2gF;(  
} pwVaSnre`  
output.close(); 39bw,lRPV  
} @2~;)*  
catch(IOException e){e.printStackTrace ();} M Al4g+es  
catch(Exception e){e.printStackTrace ();} Eih6?Lpu  
} PU-L,]K  
! Q8y]9O  
L5 wR4Ue)  
//读取保存的下载信息(文件指针位置) P@0J!  
private void read_nPos() GK[9Cm"v  
{ pB0 SCS*  
try{ OCu/w1 bc  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); EGzlRSgO  
int nCount = input.readInt(); fLZ99?J  
nStartPos = new long[nCount]; n^Q-K}!T/  
nEndPos = new long[nCount]; >J_(~{-sNG  
for(int i=0;i<nStartPos.length;i++) s;#,c(   
{ S])*LUi  
nStartPos = input.readLong(); K$wxiGg8P  
nEndPos = input.readLong(); 6GoQJ  
} @CS%=tE}U  
input.close(); #kgLdd"  
} 0lU pil  
catch(IOException e){e.printStackTrace ();} \s6 VOR/  
catch(Exception e){e.printStackTrace ();} *-&+;|mM  
} ~!P&LZ  
F{E`MK~f_  
JvF0s}#4  
private void processErrorCode(int nErrorCode)  = Atyy  
{ _FkH;MGWS  
System.err.println("Error Code : " + nErrorCode); IM_SZs  
} pp+z5  
_adW>-wQ!d  
$mxl&Qr>Q;  
//停止文件下载 $ncP#6  
public void siteStop() _FCg5F2U  
{ 2>g!+p Ox  
bStop = true; MaZVGrcC  
for(int i=0;i<nStartPos.length;i++) d wku6lCk  
fileSplitterFetch.splitterStop();  Q!(qb  
Q"K`~QF"  
Fr#QM0--B  
} C3KAQ U  
} n2Y a'YF  
//负责部分文件的抓取 y>c Yw!  
**FileSplitterFetch.java Qx8O&C?Ti  
*/ H-3*},9  
package NetFox; l)f 2T@bHl  
bZ}T;!U?I  
jxZ_-1  
import java.io.*; }Vfc;2  
import java.net.*; @xr}(.  
jP.dQj^j&  
=3=8oFx8  
public class FileSplitterFetch extends Thread { C_&ZQlgQ  
tlgg~MViS  
^*F'[!. p  
String sURL; //File URL 71Y3.1+  
long nStartPos; //File Snippet Start Position _ Gkb[H&RZ  
long nEndPos; //File Snippet End Position ;Q<2Y#  
int nThreadID; //Thread's ID v!#koqd1y.  
boolean bDownOver = false; //Downing is over D2f~*!vEnA  
boolean bStop = false; //Stop identical bp'\nso/  
FileAccessI fileAccessI = null; //File Access interface QwLSL<.  
|P-kyY34  
cA~bH 6  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException FAq9G-\B  
{ MADt$_  
this.sURL = sURL; {d%hkbN+{  
this.nStartPos = nStart; \*Z:w3;r  
this.nEndPos = nEnd; 5k;}I|rg%  
nThreadID = id; n`D-?]*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 m,Mg  
} _pkmHj(  
A27!I+M  
7)BK&kpVr  
public void run() c1<jY~U  
{ Sc:)H2k`$  
while(nStartPos < nEndPos && !bStop) 1cV0TUrz  
{ :H/Rhx=  
$PMD$c  
REPI >-|  
try{ =<Ss&p>  
URL url = new URL(sURL); EQX?Zs?C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q& esI  
httpConnection.setRequestProperty("User-Agent","NetFox"); >fp_$bjd  
String sProperty = "bytes="+nStartPos+"-"; VqS1n  
httpConnection.setRequestProperty("RANGE",sProperty); 6%&DJBU!  
Utility.log(sProperty); awSi0*d~  
J!H)[~2/  
_xM3c&VeG  
InputStream input = httpConnection.getInputStream(); 4{%-r[C9k  
//logResponseHead(httpConnection); o`nJJ:Cxq-  
]3 76F7  
X]s="^  
byte[] b = new byte[1024]; :` S\p[5  
int nRead; 1_> w|6;e  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 7|<-rjz^  
{ o),@I#fM  
nStartPos += fileAccessI.write(b,0,nRead); X(Lz&fkd  
//if(nThreadID == 1) 1%7zCM0s  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ODKS6E1{  
} :JK+V2B$H  
Q@rlqWgU ~  
!*}E  
Utility.log("Thread " + nThreadID + " is over!"); >[g.8'hI  
bDownOver = true; ,<;.'r  
//nPos = fileAccessI.write (b,0,nRead); Ll`nO;h  
} \F<C$cys\  
catch(Exception e){e.printStackTrace ();} Wv30;7~  
} nbBox,zW  
} y 27MG  
+u3vKzD  
70Ei<  
//打印回应的头信息 @1V?94T1  
public void logResponseHead(HttpURLConnection con) v>5TTL~?  
{ ~zFwSF  
for(int i=1;;i++) c1 1?Kq  
{ \7Fp@ .S3  
String header=con.getHeaderFieldKey(i); 5Z[HlN|-!  
if(header!=null) $S U<KNMZ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 64SRW8AH  
Utility.log(header+" : "+con.getHeaderField(header)); E#\'$@8j  
else NYPjN9L  
break; &7KX`%K"D  
} ~uuM0POo  
} ZSn6JV'g  
z=TuUl@  
v&xhS yZ  
public void splitterStop() zI_pP?4;.q  
{ SA~oGgk=P  
bStop = true; L/,M@1@R  
} Kk>va->R  
#^w8Y'{?  
vZIx>  
} :~~\{fm  
=9A!5  
4qyPjAG  
/* QLZ%m$Z  
**FileAccess.java N._^\FRyn  
*//文件访问(定位,写) "S psSQ  
package NetFox; [L?WM>]%  
import java.io.*; VQbKrnX  
/Mw0<#  
Gk)6ljL  
public class FileAccessI implements Serializable{ g?>   
Olr'n% }  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 KXcE@q9  
RandomAccessFile oSavedFile; !{XVaQ?x  
long nPos; cB2~W%H  
F#|mN0op  
Pa/2])w  
public FileAccessI() throws IOException Zrq\:KxX  
{ nDXy$f8  
this("",0); Suk;##I  
} |q 0iX2W  
qO>A 6  
rM20Y(|  
public FileAccessI(String sName,long nPos) throws IOException }5y ]kn  
{ =l%|W[OO  
oSavedFile = new RandomAccessFile(sName,"rw"); D/tFN+|P  
this.nPos = nPos; cFoeyI#v  
oSavedFile.seek(nPos); bJL,pe+u  
} /%P,y+<}iG  
\m+;^_;5GW  
hD7Lgi-N)W  
public synchronized int write(byte[] b,int nStart,int nLen) f1I/aRV:+  
{ da$ErN '{  
int n = -1; u7 {R; QKw  
try{ KvlLcE~`o  
oSavedFile.write(b,nStart,nLen); !8o;~PPVl  
n = nLen; 1P/4,D@  
} +P=I4-?eX  
catch(IOException e) qhNYQ/uS  
{ /z4n?&tM  
e.printStackTrace (); 8[u$CTl7a  
} m"vWu0/#  
uD4$<rSHb  
l6-%)6u>  
return n; _@sSVh$+  
} xUDXg*  
<X]dR 6FT  
oTf^-29d  
} A )xfO-  
Uy$?B"Z  
0lpUn74F  
/* s5oU  
**SiteInfoBean.java yu=(m~KX   
*/ f6%7:B d  
package NetFox; )IGx3+I ,  
S{JBV@@tC  
-nk0Q_7N  
public class SiteInfoBean { Og"\@n  
:JzJ(q/  
''B}^yKEW  
private String sSiteURL; //Site's URL kDWvjT  
private String sFilePath; //Saved File's Path n<MreKixE  
private String sFileName; //Saved File's Name ,/..f!bp  
private int nSplitter; //Count of Splited Downloading File sT>l ?L  
%>,Kd6bdg  
rq^VOK|L  
public SiteInfoBean() s@|TQ9e |j  
{//nSplitter的缺省值为5 HeM-  
//default value of nSplitter is 5 'dcO-A:>  
this("","","",5); 01o,9_|FL  
} |3 v+&eVi  
3NgyF[c  
3!u:*ibt  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 6g'+1%O  
{ ]}BT'fky#  
sSiteURL= sURL; t+n+_X  
sFilePath = sPath; .q9i10C  
sFileName = sName; F vHd `  
this.nSplitter = nSpiltter; H)i%\7F5  
PYW>  
q%MLj./?[  
} $(;0;!t.  
,%,.c^-  
-\}Ix>  
public String getSSiteURL() i,y7R?-K  
{ KgEfhO$W  
return sSiteURL; ;Y`k-R:E6A  
} X8(WsN  
mjbV^^>  
f=nVK4DuZ  
public void setSSiteURL(String value) ~9dAoILrl  
{ a9TKp$LP`  
sSiteURL = value; sQ%gf  
} BY??X=  
n; *W#c  
3+iQct[  
public String getSFilePath() S$i3/t  
{ w-?Cg8bq<  
return sFilePath; x-@6U  
} ZVz`-h B  
f}+8m .g2  
 ~b LhI  
public void setSFilePath(String value) `r.  
{ Mt+gg F.  
sFilePath = value; XnV$}T:?X  
} 3ypf_]<  
firiYL"=44  
Be2yS]U  
public String getSFileName() BI 0 A0  
{ Qb&gKQtt@  
return sFileName; VHTr;(]hk  
} +v"%@lC};  
q<w Q/m  
1<3!   
public void setSFileName(String value) v6+<F;G3y>  
{ wM&WR2  
sFileName = value; ?K^~(D8(  
} 2^=.jML[  
$nW^Gqwj]1  
pN7 v7rs  
public int getNSplitter() 1U~yu&  
{ ~QE-$;  
return nSplitter; ;n=A245W\  
} ob"yz}  
_ hs\"W  
Y!lc/[8  
public void setNSplitter(int nCount) 5 _ a-nWQ  
{ j-wz7B  
nSplitter = nCount; JM Ikr9/$  
} -XARew  
} + +G %~)S:  
/a:L"7z  
XpibI3:<  
/* xzTF| Z\  
**Utility.java qn|~z@"  
*/ nV&v@g4Tt  
package NetFox; rty&\u@}  
vP{;'R  
txXt<]N  
public class Utility { b#E!wMClS  
+K03yphZr  
`d. 4 L.],  
public Utility() LjMhPzCp  
{ mY,t]#^m7  
#~`]eM5`J  
keL!;q|r-)  
} ,7|Wf %X  
I 6Mr[#*  
//线程睡眠 UIi`bbJ  
public static void sleep(int nSecond) >PMLjXK  
{ * IBCThj  
try{ k>q}: J9V  
Thread.sleep(nSecond);  F5FzT^  
} qI#ow_lL#  
catch(Exception e) uV+.(sjH  
{ %t<ba[9F  
e.printStackTrace (); UV8K$n<  
} ZMI vzQYI  
} N"rZK/@}  
dt|f4 XWF  
//日志 ~ 6-6aYhe  
public static void log(String sMsg) qb1[-H  
{ {kp^@  
System.err.println(sMsg); %e'Z.vm  
} , 1` -u$  
![a~y`<K,  
rYwUD7ip  
public static void log(int sMsg) '`fz|.|cbB  
{ JypXQC}~  
System.err.println(sMsg); j: /cJt  
} N"q C-h  
} e3b|z.^8  
dw]wQ\4B  
l9X\\uG&  
/* T&PLvyBL  
**TestMethod.java |8YP8o  
*/ 1xE*quhrh  
package NetFox; 8'6$t@oT9w  
Jh)K0>R  
aj)?P  
public class TestMethod { a#o6Nv  
N"wp2w  
%1jApCJ  
public TestMethod() fK{[=xMr@  
{ ///xx/weblogic60b2_win.exe JDy;Jb  
try{ I~.d/!>Z  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); <OC|z3na_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .&Ok53]b  
SiteFileFetch fileFetch = new SiteFileFetch(bean); xRU ~h Q  
fileFetch.start(); 4%L-3Ij  
} KGoHn6jM  
catch(Exception e){e.printStackTrace ();} l`A4)8Y@  
Lb} cjI:  
1-bQ ( -  
} Jf{ M[ z  
@*rED6zH  
b[_${in:  
public static void main(String[] args) 5};$>47m  
{ .A2u7*h&  
new TestMethod(); \<R.F  
} _cW6H B^j  
} -d8||X[  
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