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http断点续传简单实现(java)

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/* DGfQo5#  
**SiteFileFetch.java 46?F+,Rzl  
*/ U#]eN[  
package NetFox; r5qx! >  
import java.io.*; IOSoc 7+"  
import java.net.*; $}nUK~$GSv  
=5=Vm[  
y>cmKE  
public class SiteFileFetch extends Thread { *I1W+W`G  
e %v4,8  
jUR #  
SiteInfoBean siteInfoBean = null; //文件信息Bean Z2j*%/  
long[] nStartPos; //开始位置 A"3&EuvU  
long[] nEndPos; //结束位置 llG#nDe  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 g Wv+i/,  
long nFileLength; //文件长度 >=W#z  
boolean bFirst = true; //是否第一次取文件 JO^ [@  
boolean bStop = false; //停止标志 ^Er`{|o6u  
File tmpFile; //文件下载的临时信息 oY6|h3T=Q$  
DataOutputStream output; //输出到文件的输出流 >dm._*M  
'%RK KA  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) I~ ]mX;  
public SiteFileFetch(SiteInfoBean bean) throws IOException MbFe1U]B  
{ #|_UA}Y  
siteInfoBean = bean; ~$ qJw?r  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); '>mb@m  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); WKJL< D ]:  
if(tmpFile.exists ()) }nY^T&?`  
{ f]A6Mx6  
bFirst = false; `rdfROKv  
read_nPos(); ?G>TaTiK#  
}  aC }1]7  
else I \%Lb z  
{ >h( rd1  
nStartPos = new long[bean.getNSplitter()]; 8*PAgPj a  
nEndPos = new long[bean.getNSplitter()]; hSKH#NS  
} ?uX6X'-  
U9[A(  
=bg&CZV T  
Fx:en|g  
} tKsM}+fq  
/FV6lR!0^  
0#{]!>R  
public void run() "XsY~  
{ 1@z@  
//获得文件长度 A-Pwi.$  
//分割文件 2 Yd~v|  
//实例FileSplitterFetch qVe6RpS  
//启动FileSplitterFetch线程 4NR5?s  
//等待子线程返回 Lz{T8yvZ  
try{ 2&K|~~  
if(bFirst) Wk6&TrWlY  
{ 7Z~szD  
nFileLength = getFileSize(); :h^UC~[h 3  
if(nFileLength == -1) '*;eFnmvs:  
{ |{IU<o x  
System.err.println("File Length is not known!"); @wgGnb)  
} AG\ 852`1m  
else if(nFileLength == -2) wR+`("2{r  
{ BOQV X&g%  
System.err.println("File is not access!"); s i.a]k/f  
} $5CY<,f  
else 9x^ /kAB  
{ AbI*/ |sY  
for(int i=0;i<nStartPos.length;i++) 4x?u5L 9o  
{ 9.#R?YP$  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); L\b_,'I  
} A'-YwbY  
for(int i=0;i<nEndPos.length-1;i++) `[:1!I.}-  
{ YIUmCx0a  
nEndPos = nStartPos[i+1]; d*(Bs $De  
} i{[H3p8  
nEndPos[nEndPos.length-1] = nFileLength; E/P53CD  
} r_sl~^* :  
} U105u.#7  
u,SZ-2K!7~  
xWb?i6)z&  
//启动子线程 by<@Zwtf  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; .LcE^y[V  
for(int i=0;i<nStartPos.length;i++) '<D}5u7 2  
{ n >PM_W  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), poFjhq /#(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 'wlP`7&Tn  
nStartPos,nEndPos,i); 7.rZ%1N  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J3S+| x h~  
fileSplitterFetch.start(); ayz1i:Q|  
} |/\1nWD  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f_2^PF>?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5nqdY*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", PlRs- %d  
nEndPos = " + nFileLength); D c.WvUM  
// fileSplitterFetch[nPos.length-1].start(); j =%-b]  
k#NMD4(%O  
cD@lor j  
//等待子线程结束 pdqa)>$  
//int count = 0; aMg f6veM  
//是否结束while循环 J$*["y`+  
boolean breakWhile = false; `2,_"9Z(  
?o5#Ve$-X  
@@mW+16  
while(!bStop) \#7%%>p=O'  
{ Riuv@i^6K  
write_nPos(); TFNU+  
Utility.sleep(500); y/VmjsN}  
breakWhile = true; q ? TI,  
M|=$~@9#X  
;OqLNfU3y  
for(int i=0;i<nStartPos.length;i++) .T w F] v  
{ b=\3N3OX  
if(!fileSplitterFetch.bDownOver) n7.lF  
{ Cy'W!qH  
breakWhile = false; <%uZwk>#  
break; rWKLxK4oU  
} k\Tm?^L)  
} `9{C/qB  
if(breakWhile) .h^Ld,Chj  
break; I19F\ L`4  
&?sjeC_  
usf(U>  
//count++; =C1Qo#QQ%  
//if(count>4) ([o:_5/8I  
// siteStop(); Y,}43a0A  
} e ;r-}U  
D|3QLG  
D ,^ U%<`  
System.err.println("文件下载结束!"); ys6"Q[B  
} cty#@?"e  
catch(Exception e){e.printStackTrace ();} xmd$Jol^  
} {\Y,UANZ  
oioN0EuDk  
Ps4A B#3  
//获得文件长度 v~QZO4[ '  
public long getFileSize() d}J#wT  
{ wk/U"@lq  
int nFileLength = -1; Q 5TyS8  
try{ :u93yH6~8  
URL url = new URL(siteInfoBean.getSSiteURL()); 0LuY"(LR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -z1o~~  
httpConnection.setRequestProperty("User-Agent","NetFox"); V t;&2v  
>m{-&1Tx  
\9Zfu4WR  
int responseCode=httpConnection.getResponseCode(); 7O :Gi*MA  
if(responseCode>=400) Z9bPj8d  
{ S]@iS[|?  
processErrorCode(responseCode); K%_JQ0`  
return -2; //-2 represent access is error ,{t!->K  
} ?IO/zkeXg  
3_-m>J**  
hmk5 1  
String sHeader;  :Xr3 3  
vtjG&0GSK  
,kuOaaV7K  
for(int i=1;;i++) >g=:01z9  
{ sOenR6J<$  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); .gg0:  
//Utility.log(in.readLine()); KO$8lMm$  
sHeader=httpConnection.getHeaderFieldKey(i); @cNI|T  
if(sHeader!=null) @},k\Is  
{ L6qA=b~iz  
if(sHeader.equals("Content-Length")) ;yrcH+I$_  
{  ]^%3Y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); NPabM(<`  
break; X~!?t }  
} -W vAmi  
} |8ZAE%/d  
else ?"Q6;np*  
break; lph_cY3p  
} ?q`mr_x%?  
} .1M>KRSr,  
catch(IOException e){e.printStackTrace ();} "<b84?V5  
catch(Exception e){e.printStackTrace ();} gRSG[GMV  
H-lRgJdc  
\/zS@fz  
Utility.log(nFileLength); B)*%d7=x  
NYRNop( N#  
Os+ =}  
return nFileLength; 1-<Xi-=^{t  
} qILr+zH  
#}?$mxME*  
F@3,>~[%I  
//保存下载信息(文件指针位置) f}3bYF  
private void write_nPos() (avaTUMOqy  
{ GrIdQi^8  
try{ FA,CBn5%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); e&nw&9vo  
output.writeInt(nStartPos.length); ),|bP`V  
for(int i=0;i<nStartPos.length;i++) IC~D?c0H:  
{ ${3OQG  
// output.writeLong(nPos); L.[2l Q  
output.writeLong(fileSplitterFetch.nStartPos); hw2Hn   
output.writeLong(fileSplitterFetch.nEndPos); r?*?iw2g  
} d~%Rnic6*  
output.close(); E ..[F<5  
} g`8|jg0]`I  
catch(IOException e){e.printStackTrace ();} SNFz#*  
catch(Exception e){e.printStackTrace ();} $!lxVZ>  
} &*~ WK  
"zc!QHpSd  
Rwk|cqr  
//读取保存的下载信息(文件指针位置) v-qS 'N 4  
private void read_nPos() dRmTE  
{ *z~Y*Q0  
try{ p6*D^-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); xa:P(x3[  
int nCount = input.readInt(); >[U$n.  
nStartPos = new long[nCount]; Oylw,*%  
nEndPos = new long[nCount]; %yVZ|d*Q  
for(int i=0;i<nStartPos.length;i++) I+SL0  
{ ;2}Gqh)Yr  
nStartPos = input.readLong(); iV=#'yY  
nEndPos = input.readLong(); L3\{{QOA  
} n\4+xZr  
input.close(); AS;{{^mM(  
} x&wUPo{  
catch(IOException e){e.printStackTrace ();} d=XhOC$  
catch(Exception e){e.printStackTrace ();} Qzv_|U  
} wVTo7o%U  
7Ll(,i<,C  
?a}~yz#B(  
private void processErrorCode(int nErrorCode) :OM>z4mQ  
{ 2o;M:+KQ)  
System.err.println("Error Code : " + nErrorCode); +tF,E^  
} Oh: -Y]m=  
_{aVm&^kA  
gg9W7%t/  
//停止文件下载 }sZ]SE  
public void siteStop() -XBNtM_ "  
{ l=yO]a\QZ  
bStop = true; A(B2XBS!?  
for(int i=0;i<nStartPos.length;i++) as8<c4:v  
fileSplitterFetch.splitterStop(); 2},}R'aR  
H#D=vx'  
I{ $|Ed1  
} <LE>WfmC  
} o2L/8q.  
//负责部分文件的抓取 QX4I+x~oo\  
**FileSplitterFetch.java f$L5=V  
*/ &nYmVwi?"Q  
package NetFox; y[vjqfdmU  
?/~1z*XUW  
_)Ms9RN  
import java.io.*; {+MMqJCa  
import java.net.*; \BDNF< _  
]_h"2|  
Q=[&~^ Y)  
public class FileSplitterFetch extends Thread { FP$]D~DMo  
`i-&Z`  
]iPdAwc.1  
String sURL; //File URL j:#[voo7  
long nStartPos; //File Snippet Start Position uIu0"pv`x  
long nEndPos; //File Snippet End Position @`{UiTN X`  
int nThreadID; //Thread's ID >jcNo3S  
boolean bDownOver = false; //Downing is over wJ}8y4O!N  
boolean bStop = false; //Stop identical bCsQWsj^NW  
FileAccessI fileAccessI = null; //File Access interface s`{O-  
|@ + x9|'W  
:;EzvRy  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Nuj%8om6  
{ J_,y?}.e3  
this.sURL = sURL; 8K qv)FjB  
this.nStartPos = nStart; Vy biuP  
this.nEndPos = nEnd; @ 9uwcM1F  
nThreadID = id; 0|cQx VJb  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 83h6>D b  
} 3yQ(,k#  
t|/ /oEY  
~b+>o  
public void run() _%x|,vo`(  
{ {5*5tCIt  
while(nStartPos < nEndPos && !bStop) ;Wr$hDt^  
{ 5ZPl`[He  
84k;d;  
Y9C]-zEv  
try{ ~7*HZ:.  
URL url = new URL(sURL); nV<YwqK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Gr_I/+<  
httpConnection.setRequestProperty("User-Agent","NetFox"); QeK~A@|F&  
String sProperty = "bytes="+nStartPos+"-"; jooh`| `P  
httpConnection.setRequestProperty("RANGE",sProperty); X,p&S^  
Utility.log(sProperty); 4):\,>%pK  
Uc&0>_Z  
49CMRO,T  
InputStream input = httpConnection.getInputStream(); sx9 N8T3n  
//logResponseHead(httpConnection); q>Y_I<;'g  
?#W>^Za=  
kn! J`"b  
byte[] b = new byte[1024]; OIN]u{S  
int nRead; (GZm+?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) u3q!te  
{ 7 >.^GD  
nStartPos += fileAccessI.write(b,0,nRead);  tW,<Pe  
//if(nThreadID == 1) TGg*(6'z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =U:iR  
} 6Cibc .vt  
}MoCUN)I  
4m~\S)ad  
Utility.log("Thread " + nThreadID + " is over!"); Axr 'zc  
bDownOver = true; !nu#r$K(  
//nPos = fileAccessI.write (b,0,nRead); 6A%Y/oU+2  
} '?QZ7A  
catch(Exception e){e.printStackTrace ();} ]xuq2MU,l  
} @sVBG']p  
} -V9Cx_]y  
v^e[`]u(  
I%%$O' S  
//打印回应的头信息 Z*JZ Ubo-Q  
public void logResponseHead(HttpURLConnection con) U_w)*)F  
{ bo]k9FC  
for(int i=1;;i++) Dgdh3q;  
{ qoEOM%dAqV  
String header=con.getHeaderFieldKey(i); VRD2e ,K  
if(header!=null) zj8;ENhEI  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); \PL92HV  
Utility.log(header+" : "+con.getHeaderField(header)); ;Eck7nRA)  
else #ujcT%1G  
break; B64%| S  
} #x'C  
} Bs^W0K$uBO  
4p F%G  
9!o:)99U  
public void splitterStop() O^LzS&I*  
{ @%RDw*L(  
bStop = true; wLW!_D,/R  
} 6MZfoR  
1,4kw~tA  
olh|.9Kdj}  
} 55hJRm3  
[j&>dE  
%uQ^mK  
/* #B54p@.}  
**FileAccess.java +&JF|#FQ`  
*//文件访问(定位,写) puDy&T  
package NetFox; rGx1>xd(k  
import java.io.*; (R.k.,z  
sjztT<{Q^-  
o6'`W2P  
public class FileAccessI implements Serializable{ @UD6qA  
xJ,V !N  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {<&x9<f9  
RandomAccessFile oSavedFile; T?Gi;ld7  
long nPos; U%2pbGU  
^M8\ 3G  
>:8GU f*  
public FileAccessI() throws IOException ^8B#-9Ph b  
{ KWM.b"WnXr  
this("",0); nJrV  
} oU67<jq  
AM\`v'I*6  
1Hzj-u&N/  
public FileAccessI(String sName,long nPos) throws IOException <` HLG2  
{ 'j>Q7M7q{  
oSavedFile = new RandomAccessFile(sName,"rw"); )0!hw|0|  
this.nPos = nPos; %$S.4#G2  
oSavedFile.seek(nPos); i |cSO2O+  
} XYf;72*  
?f:FmgQk  
_^Rf*G!  
public synchronized int write(byte[] b,int nStart,int nLen) vfmKYiLp  
{ E+csK*A7  
int n = -1; Ws'3*HAce  
try{ i $#bg^  
oSavedFile.write(b,nStart,nLen); 9CW .xX8  
n = nLen; .DIHd/wA  
} I9TOBn|6   
catch(IOException e) `2 Z  
{ Q_]O[Kx  
e.printStackTrace (); jg' 'T1)  
} 0lY.z$V  
iw<+rh*C  
J$@3,=L6V  
return n; -&%#R_RV  
} {'EQ%H $q  
0t'WM=W<!8  
n`;=^^B  
} "m(HQ5e)*  
=[3I#s?V  
kznmA`#jn  
/* Tj@s\@hv  
**SiteInfoBean.java B!yAam#^  
*/ NkA|T1w7  
package NetFox; O~Pb u[C  
?tg(X[h{S  
7l%O:M(\  
public class SiteInfoBean { (?;Fnq  
x~Y]c"'D  
,accw}G  
private String sSiteURL; //Site's URL tBp dKJn##  
private String sFilePath; //Saved File's Path %Gh!h4Pv  
private String sFileName; //Saved File's Name ut fD$8UI  
private int nSplitter; //Count of Splited Downloading File H~Hh $-z  
u6$fF=  
>@` D@_v  
public SiteInfoBean() ]t(;bD hT  
{//nSplitter的缺省值为5 \k;*Ej~.  
//default value of nSplitter is 5 rt^<=|Z  
this("","","",5); !ku5P+y$  
} [r<lAS{ .  
ldO6W7 G|h  
c"H*9u:  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) gfR B  
{ WfL5. &  
sSiteURL= sURL; u#ag|b/C:  
sFilePath = sPath; d*4fl.  
sFileName = sName; {?$-p%CF`8  
this.nSplitter = nSpiltter; Vd1.g{yPV  
?1JS*LQ$  
DgGGrV`  
} now\-XrS  
3mIVNT@S9  
T&j_7Q\;vI  
public String getSSiteURL() "at*G>+  
{ %n SLe~b  
return sSiteURL; S{XV{o  
} &>XIK8*  
eZ8~t/8  
^~E?7{BL  
public void setSSiteURL(String value) !/[/w39D0o  
{ Mnn\y Tblp  
sSiteURL = value; ckHHD|  
} h}nceH0s3d  
mhv{6v  
2zZ" }Zr#  
public String getSFilePath() Wz`MEyj  
{ Hw-,sze j"  
return sFilePath; |W[BqQIf  
} 3){ /u$iH.  
Xb@lKX5Re  
"u@)   
public void setSFilePath(String value) 82O#Fe q  
{ /4}{SE  
sFilePath = value; 07:CcT  
} oj/,vO:QT  
_VFl.U,   
0O5(\8jM  
public String getSFileName() $DuX1T  
{ 4 Z.G  
return sFileName; tF}Vs}  
} IV]s!  
EZ15  
]2`PS<a2  
public void setSFileName(String value) X~(%Y#6  
{ 3C=ON.1eg  
sFileName = value; ~G+o;N,V  
} qv>?xKSm  
wxYB-Wh<  
$[x2L s~  
public int getNSplitter() zZ@]Kq;.s  
{ 2y s'q !  
return nSplitter; aY&He~  
} @8a1a3_F  
|1iCt1~U  
z~i=\/~tZ  
public void setNSplitter(int nCount) Yx>y(Whu.  
{ 16Ym*kWIps  
nSplitter = nCount; {x$jGiag+8  
} ;-Fr^|do y  
} C]59@z;+bN  
E2+x?Sc+  
)4q0(O)d  
/* I CCmE#n  
**Utility.java E`]lr[  
*/ KV v0bE  
package NetFox; c'ExZ)RJ  
J\VG/)E  
^LO=&Cq  
public class Utility { {y-7xg~}  
f_y+B]?'M  
G9"2h \  
public Utility() x;w&JS1 V  
{ *8y kE  
XaOq&7  
ig(dGKD\=9  
} /G[; kR"  
j5QS/3  
//线程睡眠 ZU\TA|  
public static void sleep(int nSecond) mVUDPMyZ  
{ VbQ9o  
try{ }g6:9%ZMu  
Thread.sleep(nSecond); A& u"NgJ  
} l8rBp87Q  
catch(Exception e) 'Pyeb`AXE9  
{ z'FD{xdf  
e.printStackTrace (); s2s}5b3  
} `hJSo?G>  
} WPLM*]6  
=I. b2e 1z  
//日志 OY$P8y3MY  
public static void log(String sMsg) ?fF{M%i-%  
{ 0tV"X  
System.err.println(sMsg); doM}vh)6  
} `uK_}Vy_  
~Mu=,OT  
;/.ZjTRw  
public static void log(int sMsg) LU "e9  
{ 9*wS}A&Jh  
System.err.println(sMsg); pI*/ - !I  
} c}(fmJB&(  
} ,2hZtJ<A  
mNUc g{ +/  
(5AgI7I,  
/* Ewg5s?2|  
**TestMethod.java A#t#c*  
*/ e+J|se4L5  
package NetFox; cu&tdg^q  
--Dd'  
T 9lk&7W  
public class TestMethod { A'(v]w  
U-+%e:v  
uEp v l  
public TestMethod() /Hxz@=LC1  
{ ///xx/weblogic60b2_win.exe v"x{oD$R  
try{ ;533;(d* o  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); j(JUOief  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); +Ja9p  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 38(Cj~u=3  
fileFetch.start(); 0>PO4WFVJ  
} &Z Ja}5k!r  
catch(Exception e){e.printStackTrace ();} ?Uz7($}  
'J*)o<%  
QvB]?D#h  
} tTa" JXG  
,1>ABz  
L\p@1N?K  
public static void main(String[] args) uYk4qorA  
{ doJ\7c5uU  
new TestMethod(); MN|8(f5Gs  
} z>_jC+  
} P8#;a  
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