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http断点续传简单实现(java)

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/* 'J+Vw9 s7  
**SiteFileFetch.java 5jkW@  
*/ ;J2=6np  
package NetFox; ^'[Rb!Q8  
import java.io.*; `P"-9Ue=  
import java.net.*; @;Yb6&I;  
Fy^!*M-  
o^_z+JFwb  
public class SiteFileFetch extends Thread { KJJ8P`Kx  
DKYrh-MN  
,I'Y)SLx  
SiteInfoBean siteInfoBean = null; //文件信息Bean \y#gh95  
long[] nStartPos; //开始位置 kXv -B-wOj  
long[] nEndPos; //结束位置 Qz[~{-<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 %p@A8'b  
long nFileLength; //文件长度 1+Ja4`o,iS  
boolean bFirst = true; //是否第一次取文件 RIb< 7  
boolean bStop = false; //停止标志 Xg#Dbf4  
File tmpFile; //文件下载的临时信息 &vd9\Pp  
DataOutputStream output; //输出到文件的输出流 .2Gn)dZU  
Nqewtn9n  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 42 8kC,  
public SiteFileFetch(SiteInfoBean bean) throws IOException =<R77rnY&  
{ V=.lpj9m  
siteInfoBean = bean; naM4X@jl  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "7iHTV  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); e2Ba@e-  
if(tmpFile.exists ()) JrS/"QSA  
{ q<.^DO~$L  
bFirst = false; prhFA3 rW.  
read_nPos(); y7$e7~}/  
} pO GVD  
else ($[pCdY  
{ Vz51=?75  
nStartPos = new long[bean.getNSplitter()]; GP[;+xMBh  
nEndPos = new long[bean.getNSplitter()]; 0.bmVN<  
} 4?1Ac7bE  
HFvhrG  
); 7csh%  
XOVZ'V  
} pA"pt~6  
Q->'e-\E<"  
Oa CkU  
public void run() 4- N>#  
{ A\.k['!  
//获得文件长度 X7Cou6r  
//分割文件 DTAEfs!ZW  
//实例FileSplitterFetch LHR%dt|M  
//启动FileSplitterFetch线程 G2 xYa$&][  
//等待子线程返回 6(<AuhFu  
try{ nu4GK}xI  
if(bFirst) W~Eq_J?I  
{ BY32)8SH  
nFileLength = getFileSize(); FV!  
if(nFileLength == -1) RR*z3i`PP  
{ ,`S"nq  
System.err.println("File Length is not known!"); `61VP-r  
} (E\7Ui0 Q  
else if(nFileLength == -2) N;;!ObVHnP  
{ /N{xFt/?  
System.err.println("File is not access!"); J[RQF54qA{  
} FwmE1,  
else b6R0za  
{ Bn-%).-ED  
for(int i=0;i<nStartPos.length;i++) a~:'OW:Q  
{ :X,1KR  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); )I$_wB!UV  
} #eR*|W7o  
for(int i=0;i<nEndPos.length-1;i++) htkn#s~=  
{ ~^KemwogPN  
nEndPos = nStartPos[i+1]; b"/P  
} wNcf7/ky  
nEndPos[nEndPos.length-1] = nFileLength; 6 @'v6 1'  
} .' 3;Z'%"g  
} \ Lrg:  
i[T!{<  
OI::0KOv  
//启动子线程 0waQw7 E  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^Me__Y  
for(int i=0;i<nStartPos.length;i++) n)^B0DnIk  
{ W 29@`93  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bUU_NqUf*3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <eQS16  
nStartPos,nEndPos,i); KZsSTB6J  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3' mQ=tKa  
fileSplitterFetch.start(); ]* ':  
} `:R8~>p  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), svHs&v  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @0-<|,^]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", J XbG|L  
nEndPos = " + nFileLength); qIuY2b`6  
// fileSplitterFetch[nPos.length-1].start(); s{'r'`z.  
sMs 0*B-[  
bt-y6,> +E  
//等待子线程结束 <vhlT#p   
//int count = 0; 'HH[[9Q  
//是否结束while循环 zxT&K|  
boolean breakWhile = false; u\Tq5PYXt  
D)K/zh)  
'\[GquK;P  
while(!bStop) `G@]\)-!  
{ WVir[Kv%  
write_nPos(); o~*% g.  
Utility.sleep(500); mj{TqF  
breakWhile = true; Vj2]-]Cm  
(wo.OH  
j1_CA5V  
for(int i=0;i<nStartPos.length;i++) >#)^4-e  
{ !QSL8v@c  
if(!fileSplitterFetch.bDownOver) Jx.Jx~  
{ "tn]s>iAd=  
breakWhile = false; ZZX|MA!  
break; 1<Qb"FN!2  
} l]uF!']f  
} 5)AMl)  
if(breakWhile) &Plc  
break; [yW0U:m  
xbvZ7g^  
?FA} ;?v  
//count++; #JWW ;M6F  
//if(count>4) Nw/4z$].J  
// siteStop(); ~]O~a}]g(  
} Cevl#c5p>  
g-bHf]'  
F $^RM3  
System.err.println("文件下载结束!"); es6!p 7p?  
} }[ld=9p(  
catch(Exception e){e.printStackTrace ();} {M )Y6\v  
} sV%<U-X  
7:)=  
to|O]h2*U2  
//获得文件长度 z)#I"$!d  
public long getFileSize() Vof[yL `  
{ [h {zT)[  
int nFileLength = -1; V<*PaS..  
try{ |~Z.l  
URL url = new URL(siteInfoBean.getSSiteURL()); RplLU7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .!/DM-C  
httpConnection.setRequestProperty("User-Agent","NetFox"); X6)-1.T&  
;%0$3a  
x&@. [FJhO  
int responseCode=httpConnection.getResponseCode(); zgI!S6q  
if(responseCode>=400) 6k|o<`~,  
{ *%=BcV+,  
processErrorCode(responseCode); |a*VoMZ  
return -2; //-2 represent access is error bqWo*>l  
} LPc)-t|p"  
@!"w.@ Y  
{P&{+`sov  
String sHeader; "3(""0Q  
 iVu  
KLBU8%  
for(int i=1;;i++) nD@/,kw"  
{ 3"NO"+Q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ZX'q-JUv f  
//Utility.log(in.readLine()); |-a5|3  
sHeader=httpConnection.getHeaderFieldKey(i); k Pi%RvuQ  
if(sHeader!=null) U0 nSI  
{ ;wK;  
if(sHeader.equals("Content-Length")) >E;kM B  
{  Tvqq#;I  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); WYSqnmi  
break; opU=49 b  
} |r>+\" X  
} 7 XE&[o  
else NvW`x   
break; 6<u =hhL  
} [uU"=H|  
} kVz9}Xp"  
catch(IOException e){e.printStackTrace ();} Yd'Fhvo8  
catch(Exception e){e.printStackTrace ();} j)xRzImu  
lqe|1vN  
Y3=5J\d!a  
Utility.log(nFileLength); n("Xa#mY[  
lR5[UKr  
X6)%2TwO  
return nFileLength; U6cpj  
} 1 j"G~TM  
P{fT5K|  
~" |MwR!0  
//保存下载信息(文件指针位置) `?E|frz[  
private void write_nPos() M(8dKj1+  
{ n_QSuh/Wn  
try{ )O\w'|$G  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 10R#} ~D  
output.writeInt(nStartPos.length); .);~H#  
for(int i=0;i<nStartPos.length;i++) SQ'\Kd=  
{ ~tx|C3A`d  
// output.writeLong(nPos); E)sC:oO  
output.writeLong(fileSplitterFetch.nStartPos); D+m#_'ocL  
output.writeLong(fileSplitterFetch.nEndPos); <` [o|>A Z  
} i<@"+~n~GK  
output.close(); X .,Lmh  
} W>TG!R 5  
catch(IOException e){e.printStackTrace ();} JYbsta  
catch(Exception e){e.printStackTrace ();} ,Ei!\U^)  
} +q n[F70}  
Cm@rX A/  
}?G([s56  
//读取保存的下载信息(文件指针位置) nVB.sab  
private void read_nPos() :j^IXZW  
{ 2qd5iOhX+  
try{ [x{z}rYH  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,+2!&"zD  
int nCount = input.readInt(); PWciD '!  
nStartPos = new long[nCount]; 6`Hd)T5{w  
nEndPos = new long[nCount]; gxnIur)  
for(int i=0;i<nStartPos.length;i++) }a O6%  
{ 8u8-:c%{  
nStartPos = input.readLong(); k_;g-r,  
nEndPos = input.readLong(); q)j b9e   
} m.F}9HI%hN  
input.close(); GdN9bA&,  
} E? lK(C  
catch(IOException e){e.printStackTrace ();} {g9*t}l4  
catch(Exception e){e.printStackTrace ();} {E=BFs  
} $, hHR:  
zUuOX5-6x  
gGZ-B<  
private void processErrorCode(int nErrorCode) ;k ?Z,M:  
{ 'Em3;`/C*+  
System.err.println("Error Code : " + nErrorCode); 7N:3  
} TOT#l6yqdd  
M( w'TE@  
O06 2c)vIY  
//停止文件下载 /U$5'BoS  
public void siteStop() ,3XlX(P  
{ 6v"WI@b4  
bStop = true; =/5^/vwgY  
for(int i=0;i<nStartPos.length;i++) hY5GNYDh  
fileSplitterFetch.splitterStop(); 5Ve`j,`=<  
hGU  m7  
*kY JwO^  
} TWSqn'<E  
} cMs8D  
//负责部分文件的抓取 ygK@\JHn  
**FileSplitterFetch.java 3vXa#f>P<  
*/ kB` @M>[  
package NetFox; e"#QUc(  
niA>afo  
($nQmr;t  
import java.io.*; `T\_Wje(  
import java.net.*; bv^wE,+?o  
f9K+o-P.h  
7 D(Eo{ue  
public class FileSplitterFetch extends Thread { CdZ. T/x  
m!5MGq~  
gV}c4>v(  
String sURL; //File URL !78P+i  
long nStartPos; //File Snippet Start Position o75l&`  
long nEndPos; //File Snippet End Position _V`F_C\\#  
int nThreadID; //Thread's ID E "%d O  
boolean bDownOver = false; //Downing is over Ec9%RAxl  
boolean bStop = false; //Stop identical t:x"]K  
FileAccessI fileAccessI = null; //File Access interface C/?x`2'  
FuC#w 9_  
mzf~qV^T  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException mE\)j*Nnv  
{ mzRH:HgN?  
this.sURL = sURL; 63E)RR_Lh  
this.nStartPos = nStart; #V{!|Y'  
this.nEndPos = nEnd; M!YGv   
nThreadID = id; bMq)[8,N  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 E- jJ!>&K  
} jl>jy6T  
0fGt7 "Q  
xX?9e3(  
public void run() d>gQgQ;g  
{ r>#4Sr  
while(nStartPos < nEndPos && !bStop) frokl5L@  
{ 2BKiA[ ;;  
kyi"U A82  
+iqzj-e&e[  
try{ 1B#iJZ}  
URL url = new URL(sURL); `@xnpA]l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f AY(ro9Q(  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7@R^B=pb  
String sProperty = "bytes="+nStartPos+"-"; LC7%Bfn!  
httpConnection.setRequestProperty("RANGE",sProperty); o2D;EUsNX  
Utility.log(sProperty); ,|g&v/WlC%  
aX,6y1  
KV8Ok  
InputStream input = httpConnection.getInputStream(); w5 #;Lm  
//logResponseHead(httpConnection); NR,R.N^[  
:d6]rOpX  
j.!5&^;u4  
byte[] b = new byte[1024]; SoWMP2/  
int nRead; n-9a 0_{k  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) uZTbJ3$$  
{ 2KlVj]!7  
nStartPos += fileAccessI.write(b,0,nRead); &^`[$LtYd  
//if(nThreadID == 1) shD4";8*@  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); : q>)c]  
} Quwq_.DU  
J`4V\D}n  
?bH`  
Utility.log("Thread " + nThreadID + " is over!"); Mp QsM-iW  
bDownOver = true; Dz,|sHCmk  
//nPos = fileAccessI.write (b,0,nRead); j0^1BVcj  
} #kk5{*`  
catch(Exception e){e.printStackTrace ();} ]u^ybW"  
} 7z_ZD0PxPc  
} YSzC's[  
rB-R(2 CCN  
N1}r%!jk/  
//打印回应的头信息 )(OGo`4Qz  
public void logResponseHead(HttpURLConnection con) T/0cPn0>  
{ L&KL]n  
for(int i=1;;i++) ]UkqPtG;  
{ ^M1jv(  
String header=con.getHeaderFieldKey(i); D9  Mst6  
if(header!=null) O2":)zU.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); z6Fl$FFP  
Utility.log(header+" : "+con.getHeaderField(header)); ZA&bp{}D  
else mBEMwJ}O`  
break; ~|[i64V<^  
} U'^ G-@  
} l, 9r d[  
R|k:8v{V=  
<isU D6TC  
public void splitterStop() ._]*Y`5)d  
{ xU2i&il^!  
bStop = true; Jz4;7/  
} D9H%jDv  
S}VN(g  
fRxn,HyV  
} 7|"l/s9,  
Y3#8]Z_"}O  
W9{i~.zo  
/* qu.AJ*  
**FileAccess.java M+M  ;@3  
*//文件访问(定位,写) uGn BlR$}  
package NetFox; aTfc>A;  
import java.io.*; .:XXc  
~1XC5.*-  
# F6<N]i  
public class FileAccessI implements Serializable{ mE;^B%v  
!u:Fn)j  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 7yJE+o'  
RandomAccessFile oSavedFile; l*(L"]  
long nPos; RD0*]4>]  
KMG}VG   
0}YadNb7  
public FileAccessI() throws IOException +U<.MVOo.  
{ ([|^3tM  
this("",0); ~;-2eKw  
} 0eKLp8;Lh  
@NiLKcL#  
\Unawv~  
public FileAccessI(String sName,long nPos) throws IOException Xg l %2'  
{ mhM;`dl  
oSavedFile = new RandomAccessFile(sName,"rw"); Y O|hwhe_  
this.nPos = nPos; M?Fv'YE  
oSavedFile.seek(nPos); Lp3pJE  
} A k~|r#@  
t\]kVo)  
'SXLnoeTa  
public synchronized int write(byte[] b,int nStart,int nLen) ;1s;"  
{ I FvigDj?  
int n = -1; T*S) U ;  
try{ .76Z  
oSavedFile.write(b,nStart,nLen); lfG',hlI;  
n = nLen; O$x +>^  
} xnJ#}-.7  
catch(IOException e) z:N?T0b(  
{ K47.zu  
e.printStackTrace (); ,<C~DSAyZ  
} [vz2< genn  
?)[=>Kp  
l: kW|  
return n; B qINU  
} w11L@t[5W8  
CKSs(-hkJ  
<IBUl}|\  
} *y(UI/c  
dQFUQ  
Pf;RJeD  
/* `Ba?4_>k  
**SiteInfoBean.java )iVuac]E++  
*/ TwF.UL@G%  
package NetFox; [,;O$j}  
|MN2v[y  
qG2P?DR  
public class SiteInfoBean { e|>@ >F]K  
QxuU3#l  
\F\xZ.r  
private String sSiteURL; //Site's URL AFeFH.G6Jr  
private String sFilePath; //Saved File's Path o.Bbb=*rZ  
private String sFileName; //Saved File's Name D(&Zq7]n  
private int nSplitter; //Count of Splited Downloading File T!pA$eE  
:o87<) _F  
+;*4.}  
public SiteInfoBean() ^jcVJpyT@R  
{//nSplitter的缺省值为5 oA:`=f%\  
//default value of nSplitter is 5 . Y$xNLoP[  
this("","","",5); a[,p1}!_  
} L^PBcfg  
#)i+'L8  
' QjJ^3A  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #s#BYbF  
{ *5\'$;Rg  
sSiteURL= sURL; HX,i{aWWy  
sFilePath = sPath; ~0o>B$xJ  
sFileName = sName; Q \S Sv;3_  
this.nSplitter = nSpiltter; +VJyGbOcC  
W<TfDEEa  
fN21[Jv3  
} c>! ^\  
G)f!AuN=  
bYX.4(R  
public String getSSiteURL() <u1`o`|-  
{ ]3 Ibl^J  
return sSiteURL; t0?t Xe.B  
} E70o nR!i  
b_u; `^  
bA'N2~.,  
public void setSSiteURL(String value) >5TXLOYZ  
{ )4hA Fy6l  
sSiteURL = value; .81 ~ K[  
} ~]9EhC'l  
cXr_,>k  
I"Q U{]|J  
public String getSFilePath() ``@e7~F{  
{ &m]jYvRc  
return sFilePath; Q4Qf/q;U  
} k'sPA_|  
_EP~PW#J  
T.B7QAI. H  
public void setSFilePath(String value) wbk$(P'gN  
{ obv_?i1  
sFilePath = value; (yeWArQ  
} ]US!3R^  
AM#s2.@  
*o!#5c  
public String getSFileName() p;D {?H/  
{ OB^j b8  
return sFileName; MUCes3YJH  
} (\wV)c9  
[M:<!QXw  
ytV[x  
public void setSFileName(String value) Bt1v7M  
{ 7 9k+R9m  
sFileName = value; P?jI:'u!R.  
} {Q`Q2'@  
QF22_D<.}J  
0HQTe>!  
public int getNSplitter() b&d4(dk  
{ *iyc,f^w  
return nSplitter; jR+k x:+  
} NSR][h_  
#BgiDLh  
Adfnd  
public void setNSplitter(int nCount) r;>.*60AT  
{ 10GU2a$0"$  
nSplitter = nCount; =.) :tGDp  
} }^b  
} RXu` DWN  
9C!b f \  
<^942y-=  
/* 9T1 - {s R  
**Utility.java 3;!!`R>e  
*/ MOi1+`kwh  
package NetFox; :2XX~|  
sv#b5,>9  
T&:~=  
public class Utility { Um*&S.y  
S0LaQ<9.  
-3m!970  
public Utility() t8.3  
{ |eJR3o  
I SdB5Va  
Im]6-#(9\|  
} @~&^1%37)  
&]A0=h2{P*  
//线程睡眠 MlW*Tugg  
public static void sleep(int nSecond) g; 7u-nP  
{ tDMNpl  
try{ )M"xCO3a  
Thread.sleep(nSecond); >LPIvmT4D?  
} ~8-xj6^  
catch(Exception e) $' ::51  
{ 4AF.KX7  
e.printStackTrace (); P{: 5i%qC  
} k%aJ%(  
} UA*Kuad  
<,U$Y>  
//日志 mHH>qW{`  
public static void log(String sMsg) .*J /F$  
{ l|;]"&|_]c  
System.err.println(sMsg); %J9+`uSl  
} .S* sGauM  
C9,Uwz<!]  
M~+DxnJ=  
public static void log(int sMsg) ][YC.J  
{ CW.T`F  
System.err.println(sMsg); !;${2Q  
} ocZ^rqo2w  
} ;Sp/N4+  
}'n]C|gZ  
2R;#XmKS  
/* x,fL656t  
**TestMethod.java WSGho(\  
*/ k<NxI\s8]  
package NetFox; QiJ  
lnF{5zc  
LyL(~Jc|  
public class TestMethod { ktp<o.f[  
8PWEQ<ev7>  
HK%W7i/k@  
public TestMethod() j[dgY1yE:  
{ ///xx/weblogic60b2_win.exe >&^jKfY  
try{ @3S:W2k  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); e_cK#9+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); BKgCuz:y  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *9EW &Ek  
fileFetch.start(); "98 j-L=F+  
} dyohs_  
catch(Exception e){e.printStackTrace ();} %8d]JQ  
r @ !  
H?V b   
} Q\btl/?  
Wr'1Y7z  
y! QYdf?  
public static void main(String[] args) ,R-aO= %  
{ Wv ~&Qh}  
new TestMethod(); x@[6u  
} 7<Y aw,G  
} =F %lx[9Ye  
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