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http断点续传简单实现(java)

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/* Y,w'Op  
**SiteFileFetch.java 29("gB  
*/ jfP2n5X83  
package NetFox; L.ScC  
import java.io.*; b`){f\#t  
import java.net.*; K1>X%f^  
5\gL+ qM0  
GqMa|8j  
public class SiteFileFetch extends Thread { e/Wrm^]y  
H .*:+  
f!%G{G^`  
SiteInfoBean siteInfoBean = null; //文件信息Bean AFE6@/'  
long[] nStartPos; //开始位置 F0:|uC4  
long[] nEndPos; //结束位置 $\M<gW6  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  J@sH(S  
long nFileLength; //文件长度 6_]-&&Nr  
boolean bFirst = true; //是否第一次取文件 4Vl_vTz{i  
boolean bStop = false; //停止标志 eG&\b-%  
File tmpFile; //文件下载的临时信息 d3-F?i 5d  
DataOutputStream output; //输出到文件的输出流 *`2.WF@E)  
=lT~  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) HK&Ul=^VN|  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,cZhkXd  
{ l/1u>'  
siteInfoBean = bean; GKT2x '(e  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); eRU0gvgLu"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }<R,)ZV^G  
if(tmpFile.exists ()) 8XJg  
{ O AJGwm  
bFirst = false; mN^w?R41m  
read_nPos(); jz,Mm,Gi  
} 7k,pUC-w7c  
else ,;;7+|`  
{ NwAvxN<R(f  
nStartPos = new long[bean.getNSplitter()]; jf&B5>-x  
nEndPos = new long[bean.getNSplitter()]; e_RLKFv7  
} DrI"YX  
nhV\<  
KuBN_bd  
4'3do>!  
} loRT+u$&  
H<_BnT #  
dbn9t7'{  
public void run() L\0;)eJ#M  
{  N>ncv  
//获得文件长度 w>#{Nl7gz  
//分割文件 w`BY>Xft0  
//实例FileSplitterFetch yP$@~L[!  
//启动FileSplitterFetch线程 ~8 >Tb  
//等待子线程返回 :j(e+A1@  
try{ R[_Q}W'HG  
if(bFirst) (~>uFH  
{ =MR.*m{  
nFileLength = getFileSize(); MoAie|MKe  
if(nFileLength == -1) jr/  
{ #(@!:f1  
System.err.println("File Length is not known!"); z$g cK>@l  
} X0:V5 e  
else if(nFileLength == -2) sX8d8d`}  
{ Xir ERc.e  
System.err.println("File is not access!"); 8;PS>9<  
} rA+UftC:p6  
else SEfRU`  
{ r]q;>\T'  
for(int i=0;i<nStartPos.length;i++) f^JiaU4 [  
{ 5(wmy-x\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @!p bR(8  
} Ibf~gr(j  
for(int i=0;i<nEndPos.length-1;i++) 8y:/!rRN  
{ ;x<5F+b  
nEndPos = nStartPos[i+1]; mJxr"cwHl  
} (vX) <Z !  
nEndPos[nEndPos.length-1] = nFileLength; Zv]'9,cbk  
} / esdtH$=  
} 6=cfr; BH2  
k8KRVXgx  
yMG(FAyu  
//启动子线程 z*V 8l*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; su$IXI#R-&  
for(int i=0;i<nStartPos.length;i++) .7 K)'  
{ &9Y ^/W  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), < `$svM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), @h&:xA56  
nStartPos,nEndPos,i); rn$G.SMgz  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Cn"_x  
fileSplitterFetch.start(); 1Kjqs)p^  
} ]I,(^Xq3a(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V0)bPcS/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ^C=dq(i=[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Vc[aNpE  
nEndPos = " + nFileLength); r'J="^k{  
// fileSplitterFetch[nPos.length-1].start(); O]4v\~@-j  
X<%`  
K}t=Y  
//等待子线程结束 Vu`5/QDq  
//int count = 0; 1Clid\T,o  
//是否结束while循环 uTShz3  
boolean breakWhile = false; Z";&1cK  
` 0$i^,}  
/0Jf/-}ovn  
while(!bStop) eA{ nwtN  
{ ^4b;rLfk@  
write_nPos(); -9] ucmN  
Utility.sleep(500); zq6)jHfq.  
breakWhile = true; 9^L{)t>  
lRk_<A  
mEm=SpO[$o  
for(int i=0;i<nStartPos.length;i++) t[e]AU[}  
{ LR "=(  
if(!fileSplitterFetch.bDownOver) ZZ>"LH  
{ `@q\R-`  
breakWhile = false; z!M #   
break; <4LW.q  
} F?z:[1(:  
} vfd<qdi3p(  
if(breakWhile) /0swrt.  
break; ~6"=d  
{q/;G!ON.S  
A"B#t"  
//count++; l4gF.-.GYF  
//if(count>4) 4#Xz-5v  
// siteStop(); !/ a![Ne  
} vbD""  
"S]G+/I|iw  
gSa!zQN6  
System.err.println("文件下载结束!"); f, '*f:(  
} w%?Zb[!&  
catch(Exception e){e.printStackTrace ();} Z%Pv,h'Q  
} zfD@/kU  
&cWC&Ws"  
GlHP`&;UH  
//获得文件长度 mm9uhlV8  
public long getFileSize() =F2`X#x_j  
{ { 2%'=v  
int nFileLength = -1; 4Q!|fn0Sv  
try{ p[O\}MAd#  
URL url = new URL(siteInfoBean.getSSiteURL()); 86pA+c+U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); g~ii^[W  
httpConnection.setRequestProperty("User-Agent","NetFox"); d,b]#fj  
1COSbi]  
ih|;H:"^  
int responseCode=httpConnection.getResponseCode(); SiYH@Wma  
if(responseCode>=400) P L7(0b%  
{ QuP)j1"X  
processErrorCode(responseCode); i[?VF\Y(  
return -2; //-2 represent access is error d8uDSy  
} K'}I?H~P_  
2,Aw 6h;  
m-6&-G#  
String sHeader; ~ulcLvm:i  
Q:j~ kutS|  
i&1rf|  
for(int i=1;;i++) C B`7KK  
{ [8<0Q_?,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Qgf\"s  
//Utility.log(in.readLine()); Ge @qvP_  
sHeader=httpConnection.getHeaderFieldKey(i); ^AShy`o^X  
if(sHeader!=null) Z l;TS%$  
{ 1:iB1TclP  
if(sHeader.equals("Content-Length")) *8J 0yv  
{ id588Y78  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); >=d 5Scix  
break; !PA><F  
} '`YZJ  
} ]WzeJ"r {3  
else ^9`|QF  
break; joDqv,iW8  
} `M*jrkM]x  
} `T+w5ONn  
catch(IOException e){e.printStackTrace ();} qw*) R#=  
catch(Exception e){e.printStackTrace ();} P:_bF>r ?  
0K6My4d{  
r7sA;Y\  
Utility.log(nFileLength); Q_Br{ `c  
M KX+'p\w  
LzJ`@0RrX  
return nFileLength; s q;!5qK  
} S[gACEZ =  
3~Lsa"/  
c5|sda{  
//保存下载信息(文件指针位置) Vo6+|ztk|  
private void write_nPos() vsyg u  
{ n=PfV3B  
try{ u(fZ^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); u|Oc+qA(  
output.writeInt(nStartPos.length); Yg?BcY\  
for(int i=0;i<nStartPos.length;i++) tUuARo7#  
{ ${E^OE  
// output.writeLong(nPos); A|,qjiEJCc  
output.writeLong(fileSplitterFetch.nStartPos); +~BP~  
output.writeLong(fileSplitterFetch.nEndPos); 7x=4P|(\}  
} @)x*62r+  
output.close(); ,a?oGi  
} 3;FV^V'  
catch(IOException e){e.printStackTrace ();} Fc8 0HK5R  
catch(Exception e){e.printStackTrace ();} dF09_nw  
} J2 /19'QE  
]kXW eY<  
a'`?kBK7`U  
//读取保存的下载信息(文件指针位置) Ch3MwM5]  
private void read_nPos() :h |]j[2p  
{ q2r$j\L%  
try{ o ^ \+Ua  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .P`QCH;Ih  
int nCount = input.readInt(); $}r.fji,c  
nStartPos = new long[nCount]; jV9oTH-  
nEndPos = new long[nCount]; qp)Wt6 k?  
for(int i=0;i<nStartPos.length;i++) BVj(Q}f8  
{ liG|#ny{  
nStartPos = input.readLong();  sa&`CEa  
nEndPos = input.readLong(); O_ZYm{T[7  
} : 8j7}'  
input.close(); &PH:J*?C}  
} 4xq|  
catch(IOException e){e.printStackTrace ();} HzKY2F(,  
catch(Exception e){e.printStackTrace ();} :fwtPvLo  
} UKZ )Boo  
z6l'v~\  
s3nO"~tM  
private void processErrorCode(int nErrorCode) ;Vc|3  
{ :b(W&iBWhI  
System.err.println("Error Code : " + nErrorCode); {:("oK6w  
} b=1E87i@W  
\lm]G7h  
^r.CUhx)  
//停止文件下载 L'S,=NYXY  
public void siteStop() OA=~ i/n~  
{ qljsoDG  
bStop = true; 2_)UHTwsK  
for(int i=0;i<nStartPos.length;i++) 9M3"'^ {$  
fileSplitterFetch.splitterStop(); Osm))Ua(  
Eyjsbj8  
%7}j|eS)G  
} 9]w?mHslE  
} NU?<bIQ  
//负责部分文件的抓取 K)wWqC.  
**FileSplitterFetch.java TEY~E*=}$  
*/ hm d3W`8D  
package NetFox; CYQ)'v  
G%: 3.:E"  
(YYg-@IO  
import java.io.*; GVJ||0D  
import java.net.*; OR!W3 @  
![_0GFbT  
+)WU:aKI  
public class FileSplitterFetch extends Thread { J ffaT_"\  
^d{5GK'  
-,b+tC<V)0  
String sURL; //File URL =#[oi3k  
long nStartPos; //File Snippet Start Position ;m#4Q6k)V?  
long nEndPos; //File Snippet End Position V`#2jDz  
int nThreadID; //Thread's ID q)Nw$dW<  
boolean bDownOver = false; //Downing is over b^C27s  
boolean bStop = false; //Stop identical Ze8.+Ee  
FileAccessI fileAccessI = null; //File Access interface x51R:x(p  
vi UJ4Pn  
1w(3!Ps+  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException T:Nk9t$W7@  
{ 1S!}su,uH  
this.sURL = sURL; >@Ht*h{~  
this.nStartPos = nStart; 4F G0'J&hw  
this.nEndPos = nEnd; o.A:29KoU  
nThreadID = id; ?YS>_ MN  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 pKy4***I3  
} &=jPt%7#M  
6Q [  
>FwK_Zd'  
public void run() |r Aot2  
{ QwWd"Of  
while(nStartPos < nEndPos && !bStop) &`v?oN9$  
{ {~&Q"8 }G  
Vez8 ~r3  
WIf.;B)L  
try{ EG3,TuDH8  
URL url = new URL(sURL); <6Gs0\JB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >h;]rMD!|  
httpConnection.setRequestProperty("User-Agent","NetFox"); r4X}U|s!0  
String sProperty = "bytes="+nStartPos+"-"; 4k@n5JNa  
httpConnection.setRequestProperty("RANGE",sProperty); > B@c74  
Utility.log(sProperty); >bze0`}Z  
s. A}ydtt  
EUuSN| a  
InputStream input = httpConnection.getInputStream(); %eg+ .  
//logResponseHead(httpConnection); IJGw<cB]+  
M=uT8JB  
b;UDgq8v  
byte[] b = new byte[1024]; pN5kcvQ  
int nRead; 2.niB>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ,GYQ,9:  
{ } #H,oy;Dz  
nStartPos += fileAccessI.write(b,0,nRead); >lUPOc  
//if(nThreadID == 1) Vn sV&cx  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mXp#6'a  
} X'PZCg W  
}u O YF  
vJ65F6=G  
Utility.log("Thread " + nThreadID + " is over!"); I@ue eDY  
bDownOver = true; )8W! |  
//nPos = fileAccessI.write (b,0,nRead); }^Q:Q\  
} Mt-r`W3 q  
catch(Exception e){e.printStackTrace ();} 1l#46?]~  
} j@z IJ  
} HbA/~7  
F5 ]<=i  
M@.S Q@E  
//打印回应的头信息 } jJKE  
public void logResponseHead(HttpURLConnection con) l EFd^@t  
{ H575W"53  
for(int i=1;;i++) ?<!q F:r:  
{ 1$vGQ  
String header=con.getHeaderFieldKey(i); OA3J(4!"W  
if(header!=null) MZ,1mR  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); b`#YJpA  
Utility.log(header+" : "+con.getHeaderField(header)); ,7&\jET5^0  
else (V6bX]<  
break; I!Z`'1"  
} ~hvj3zC5xz  
} ~k?rP}>0  
05FGfnq.8  
S"h;u=5it  
public void splitterStop() r$={_M$  
{ JFm@jc  
bStop = true; AuXUD9 -  
} z.cDbkf}  
H1kI+YJ@  
B&a{,.m&q6  
} FFcCoPX_  
Z2$_9.  
`;6M|5G  
/* ?CQE6ch  
**FileAccess.java _ f%s]  
*//文件访问(定位,写) V@`b7GM  
package NetFox; 5Z!$?J4Rl  
import java.io.*; X#&5?oq`  
!+PrgIp>  
y5j:+2|I  
public class FileAccessI implements Serializable{ Qjj }k)  
M#'7hm6  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Og7yT{h_  
RandomAccessFile oSavedFile; gLv+L]BnhH  
long nPos; jV sH  
;\0|1Eem`  
FLMiW]?x  
public FileAccessI() throws IOException =Q_1Mr4O  
{ gFTU9k<  
this("",0); $#h U_vr  
} oDA'$]UL  
qIZ+%ZOu  
.jQx2 O  
public FileAccessI(String sName,long nPos) throws IOException s1 >8uW  
{ e`4mrBtz|  
oSavedFile = new RandomAccessFile(sName,"rw"); =T[P  
this.nPos = nPos; K]m#~J3d>  
oSavedFile.seek(nPos); ?_gvI  
} fxcE1=a  
B9"o Ru^}  
; pBLmm*F  
public synchronized int write(byte[] b,int nStart,int nLen) #a}w&O";  
{ h2zSOY{su  
int n = -1; ~%*l>GkP*  
try{ )jL@GW  
oSavedFile.write(b,nStart,nLen); `C>h]H(  
n = nLen; @sn:%/x_  
} SdlO]y9E  
catch(IOException e) Wmd@%K  
{ 4xW~@m eNB  
e.printStackTrace (); mHMsK}=~  
} q<E7q Y+  
/1LN\Eu  
.$-;`&0cZ  
return n; F[\T'{  
} !6|_`l>G,  
Jzf+"%lv  
;b [>{Q;  
} c_qox  
X{#^O/  
ph6/+[:  
/* l^R:W#*+U  
**SiteInfoBean.java -J63'bb7oi  
*/ &pI\VIx ?  
package NetFox; (Yj6 |`  
g=D]=&H  
|h $Gs2  
public class SiteInfoBean { yam'LF  
)b nGZ8h99  
i-0 :Fs  
private String sSiteURL; //Site's URL &H# l*  
private String sFilePath; //Saved File's Path jF6Q:`k  
private String sFileName; //Saved File's Name 1R-0b{w[  
private int nSplitter; //Count of Splited Downloading File 1<@lM8&.kO  
JL_(%._J  
<6]Hj2  
public SiteInfoBean() .n IGs'P  
{//nSplitter的缺省值为5 ,Z|O y|+'  
//default value of nSplitter is 5 jR1^e$  
this("","","",5); #p=+RTZ<  
} 0 F8xS8vK+  
j\KOKvY)  
<8%+-[(  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) k7:ISj J  
{ t#M[w|5?  
sSiteURL= sURL; 8Ie0L3d-  
sFilePath = sPath; 7202N?a {  
sFileName = sName; u@Gum|_=N  
this.nSplitter = nSpiltter; ,^4"e (  
t`&mszd~T  
d+P<ce2 G  
} .))k  
m?Jnb\0  
7g8\q@',  
public String getSSiteURL() jY9tq[~/  
{ 56."&0  
return sSiteURL; ([JFX@  
} %\v  
r_ 9"^Er  
#@Tm5z  
public void setSSiteURL(String value) 6UN{Vjr%`  
{ WZA1nzRc  
sSiteURL = value; y54RD/`-  
} !N:w?zsp  
#I ,c'Vj  
%,N-M]Jf  
public String getSFilePath() Qc9[/4R>  
{ YS9)%F=X  
return sFilePath; ]w)uo4<^J  
} UWCm:eRQ  
h9A=20fj  
|%Y=]@f  
public void setSFilePath(String value) kad$Fp39  
{ %AgCE"!  
sFilePath = value; BH^cR<<j  
} A?ESjMy(R  
W.7u6F`  
{yBd{x<>/  
public String getSFileName() 48GaZ@v  
{ iQh:y:Jo1&  
return sFileName; D1fUEHB}A8  
} ]w8h#p  
s;[64ca]Q  
Wu?[1L:x  
public void setSFileName(String value) ,l)AYu!q4F  
{ e+MsFXnB8  
sFileName = value; -fz(]d  
} H#`&!p  
\ ]h$8JwV  
(n{!~'3  
public int getNSplitter() 7sJGB^vM  
{ p_sqw~)^%  
return nSplitter; BI6`@}%7>  
} 'Ya-;5Y]  
,Hc,]TPC4  
P6ugbq[x#e  
public void setNSplitter(int nCount) 0[OlJMVf  
{ TP/bPZY  
nSplitter = nCount; +Kg3qS"  
} %t-}dC&  
} *5'l"YQ@1  
w >#.id[k  
y{qKb:~wv  
/* 1b"3]?  
**Utility.java BG@[m  
*/ ^t)alNGos  
package NetFox; v.]W{~PI2V  
C'0=eel[  
9O#?r82  
public class Utility { ML_[Z_Q<z  
w 259':  
2W`<P2IA  
public Utility() :sb+jk  
{ 2k""/xMF'  
)pt#Pu  
A v%'#1w<"  
} h`p9H2}0  
c:z<8#A}  
//线程睡眠 [kg*BaG:  
public static void sleep(int nSecond) p[gq^5WuC  
{ '4d+!%2t  
try{ q1o)l  
Thread.sleep(nSecond); \wo'XF3:  
} ID v|i.q3  
catch(Exception e) r*s)T`T}}  
{ |h1 Y3  
e.printStackTrace (); syLpnNx=  
} E?P:!V=_  
} !_UBw7Zm  
<</ Le%  
//日志 I!-5 #bxD  
public static void log(String sMsg) 5oI gxy  
{ HvVS<Ke  
System.err.println(sMsg); @8 GW?R  
} 'uA$$~1  
mq~L1< f  
J#& C&S 2  
public static void log(int sMsg) p^QB^HEV  
{ IGtqY8  
System.err.println(sMsg); (!`]S>_w9  
} .9;wJ9Bw[  
} 5%Q[X  
rN^P//  
7Cj6Kw5k  
/* Tn8GLn  
**TestMethod.java q!zsGf {  
*/ J deGQ  
package NetFox; O:,Fif?;  
LK[%}2me  
X>y6-%@  
public class TestMethod { b}#ay2AR  
u0& dDZ  
oVSq#I4  
public TestMethod() :.M"M$MRp8  
{ ///xx/weblogic60b2_win.exe @z)_m!yV1  
try{ ${%*O}$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~'l.g^p bv  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); (Q09$  
SiteFileFetch fileFetch = new SiteFileFetch(bean); FO5'<G-  
fileFetch.start(); 5 5T c  
} c,I|O' &k  
catch(Exception e){e.printStackTrace ();} cU'^ Ja?%  
Lcyj, R  
 $VCWc#  
} $w$4RQk3n  
7EAkY`Op  
[8QE}TFic  
public static void main(String[] args) lE?F Wt  
{ Eo }mSd  
new TestMethod(); xc+h Fx  
} F$Q@UVA  
} U0:tE>3`  
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