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http断点续传简单实现(java)

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/* Iz^lED  
**SiteFileFetch.java >U%:Nfo3  
*/ $t1XoL  
package NetFox; =o<iBbK#|  
import java.io.*; - C  
import java.net.*; s\Zp/-Q  
:)PAj  
L2N O_N  
public class SiteFileFetch extends Thread { +^@;J?O  
cW|M4`  
cD!y d^QE  
SiteInfoBean siteInfoBean = null; //文件信息Bean [0lu&ak[&  
long[] nStartPos; //开始位置 @/DHfs4O  
long[] nEndPos; //结束位置 @a[Y[F S  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .5ItH^  
long nFileLength; //文件长度 eG F{.]  
boolean bFirst = true; //是否第一次取文件 0}:wM':G  
boolean bStop = false; //停止标志 |K7zN\ Wq  
File tmpFile; //文件下载的临时信息 8B|qNf `Yi  
DataOutputStream output; //输出到文件的输出流 sy s6 V?  
O=A(x m#  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) %XU V[L}  
public SiteFileFetch(SiteInfoBean bean) throws IOException Y, ?- []  
{ 0=,vdT  
siteInfoBean = bean; 3%J7_e'  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); DX H"`1[-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); a YC[15?'  
if(tmpFile.exists ()) wv6rjg:7  
{ CSBk  
bFirst = false; < gtqwH]   
read_nPos(); G\I DgPj`  
} N8-!}\,  
else bq}hj Cy  
{ piy_9nk  
nStartPos = new long[bean.getNSplitter()]; ;FI"N@z  
nEndPos = new long[bean.getNSplitter()]; kCuIEv@  
} LY? `+/  
Kx@Papn|6  
n}T;q1  
=Eimbk  
} O0i)Iu(J7;  
FFvF4]|L  
3u tJlD  
public void run() xi!CZNz  
{ AlH\IP  
//获得文件长度 b5Sgf'B^  
//分割文件 L6jD4ec8  
//实例FileSplitterFetch 2y"|l  
//启动FileSplitterFetch线程 BPH-g\q  
//等待子线程返回 =Ll:Ba Q  
try{ ]a ,H!0i  
if(bFirst) ;t_'87h$y  
{ vnrP;T=^  
nFileLength = getFileSize(); );~JyoDo  
if(nFileLength == -1) m%[Ul@!V  
{ :I)WSXP9h  
System.err.println("File Length is not known!"); = ;!$Qw4  
} jJ B+UF=  
else if(nFileLength == -2) .8I\=+Zi  
{ EU0b>2n4  
System.err.println("File is not access!"); FkS$x'~2$  
} F79!B  
else 7/:C[J4GTN  
{ >0kZ-M5  
for(int i=0;i<nStartPos.length;i++) q7!$-  
{ Oosr`e@S  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); foi@z9  
} "PI]k  
for(int i=0;i<nEndPos.length-1;i++)  6[{|'  
{ q!sazVaDp  
nEndPos = nStartPos[i+1]; Fhr5)Z  
} SCUsDr+.  
nEndPos[nEndPos.length-1] = nFileLength; :hA=(iz  
} |hlc#t ?  
} <691pk X  
6n  
(C=.&',P  
//启动子线程 ohod)8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; h\@\*Xz<v  
for(int i=0;i<nStartPos.length;i++) /%P|<[< [  
{ x_yQoae  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $^ wqoW%t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {okx*]PIc  
nStartPos,nEndPos,i); qVpV ZH!  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); , '_y@9?I  
fileSplitterFetch.start(); Xc!0'P0T  
} R}S@u@mOE  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M zWVsV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); lebwGW,!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ?df*Y5I2  
nEndPos = " + nFileLength); @'Y^A  
// fileSplitterFetch[nPos.length-1].start(); X5V8w4NN  
X:c k  
eMDO;q  
//等待子线程结束 <x^Ab#K"  
//int count = 0; , Ac gsC  
//是否结束while循环 )nI}KQJ<  
boolean breakWhile = false; Qel2OI`b  
+5>*$L%8T`  
Yr\pgK,  
while(!bStop) WLB@]JvTBY  
{ :7&-<ae2  
write_nPos(); f7mN,_Lt  
Utility.sleep(500); V2&O]bR  
breakWhile = true; zK5/0zMZ  
ZYi."^l  
+;ILj<!Z7  
for(int i=0;i<nStartPos.length;i++) C1V@\mRi  
{ _(R1En1  
if(!fileSplitterFetch.bDownOver) p#yq'kY  
{ L93PDp4v  
breakWhile = false; "Q>gQKgL  
break; ]rpU3 3  
} }#0i1]n$D  
} \m\E*c ):  
if(breakWhile) PqhR^re0.  
break; 6hW ~Q  
WaaF;| ,(  
2EU((Q`>=(  
//count++;  3 )bC,  
//if(count>4) [i&EUvo  
// siteStop(); lHTW e'  
} Pa8E.<>  
8`0/?MZ)   
rQuozbBb  
System.err.println("文件下载结束!");  ./iC  
} \fk%^1XY  
catch(Exception e){e.printStackTrace ();} 91Fx0(  
} ;E!(W=]*F  
Rfk8trD B  
_ yu d  
//获得文件长度 =tS1|_  
public long getFileSize() \E!a=cL!  
{ #jc+2F,+{  
int nFileLength = -1; qt.G_fOz  
try{ ]WO0v`xh  
URL url = new URL(siteInfoBean.getSSiteURL()); ,bLHkBK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S-4C >gM  
httpConnection.setRequestProperty("User-Agent","NetFox"); s.zfiJ  
nz?jNdyz  
x3`b5^  
int responseCode=httpConnection.getResponseCode();  wh A  
if(responseCode>=400) +bGj(T%+'  
{ *i=+["A  
processErrorCode(responseCode); vZ rE9C }  
return -2; //-2 represent access is error h8ikM&fl  
} Ci}v+  
+i@r-OL   
74h[YyVi  
String sHeader; P_[A  
-Tzp;o  
m,u5S=3A{!  
for(int i=1;;i++) S m%\,/3  
{ t=K;/ 1  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); } ^}fx [  
//Utility.log(in.readLine()); m$bX;F}T  
sHeader=httpConnection.getHeaderFieldKey(i); v}Gpw6   
if(sHeader!=null) sM4Qu./  
{ {1<XOp#b  
if(sHeader.equals("Content-Length")) #lf3$Tm D  
{ w6PKr^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &7}\mnhB  
break; G<5i %@  
} x=/`W^t2  
} l\?HeVk^  
else e13{G @  
break; Zgw;AY.R>  
} ':mw(`  
} T~238C{vh  
catch(IOException e){e.printStackTrace ();} AB.gVw| 4  
catch(Exception e){e.printStackTrace ();}  /z0X  
L,m'/}$  
Y/3CB  
Utility.log(nFileLength); tfSY(cXg'T  
NB["U"1[^E  
M<AjtDF%  
return nFileLength; ;T9u$4 <  
} tR! !Q  
|<Cz#| ,q  
3k#?E]'  
//保存下载信息(文件指针位置) <;O -N=  
private void write_nPos() 9i&(VzY[=  
{ 6 aE:v R2  
try{ udEJo~u  
output = new DataOutputStream(new FileOutputStream(tmpFile)); j[^(<R8  
output.writeInt(nStartPos.length); a-A>A_.  
for(int i=0;i<nStartPos.length;i++) ']bpsn  
{ !zu YO3:  
// output.writeLong(nPos); s!vvAD;\  
output.writeLong(fileSplitterFetch.nStartPos); \NiW(!Z}  
output.writeLong(fileSplitterFetch.nEndPos);  ?^8CD.|  
} Ve]ufn6  
output.close(); e(5 :XHe  
} .tg2HKD_lW  
catch(IOException e){e.printStackTrace ();}  .IO_&^  
catch(Exception e){e.printStackTrace ();} k2"DFXsv  
} c]eDTbXd  
{.D^2mj |  
zq:+e5YT?T  
//读取保存的下载信息(文件指针位置) n]15 ~GO.  
private void read_nPos() n!Ic.T3PA  
{ Xscm>.di  
try{ WDM^rjA|j  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); g!#M0  
int nCount = input.readInt(); 4*)a3jI?  
nStartPos = new long[nCount]; MRI`h.  
nEndPos = new long[nCount]; s_/a1o  
for(int i=0;i<nStartPos.length;i++) ]uikE2nn  
{ jHU5>Gt-}  
nStartPos = input.readLong(); bv NXA*0  
nEndPos = input.readLong(); V!|:rwG2  
} k\ 2.\Lwb  
input.close(); n^a&@?(+  
} ;fdROI  
catch(IOException e){e.printStackTrace ();} !LG 5q/}&  
catch(Exception e){e.printStackTrace ();} 6> fQe8Y  
} IbC8DDTD  
 d*Wg>8|  
&D/@H1fBe  
private void processErrorCode(int nErrorCode)  3ih3O  
{ ]12ypcf  
System.err.println("Error Code : " + nErrorCode); DE$HF*WY  
} Pl>BTo>p'  
aX)k (*|  
LNA5!E  
//停止文件下载 _3pME9l  
public void siteStop() l{2Y[&%  
{ RF#S=X6  
bStop = true; T[?toqkD>z  
for(int i=0;i<nStartPos.length;i++) P 2j"L#%  
fileSplitterFetch.splitterStop(); 8Hdm(>  
AjW5H*  
y<h~jz#hkq  
} -MCDX^ >P  
} dr54 D  
//负责部分文件的抓取 K [.*8  
**FileSplitterFetch.java o>#ue<Bc6  
*/ Fm|h3.`V  
package NetFox; q JdC5z\[  
VJ8 " Q  
]1^F  
import java.io.*; _#SCjFz  
import java.net.*; M<%g)jn_  
MnQ4,+ji-  
k|r+/gIV  
public class FileSplitterFetch extends Thread { -;i vBR  
0bcbH9) 1q  
LdPA`oI3j  
String sURL; //File URL 5Nt40)E}sN  
long nStartPos; //File Snippet Start Position BDO]-y  
long nEndPos; //File Snippet End Position \qo}}I>e  
int nThreadID; //Thread's ID RqONVytx  
boolean bDownOver = false; //Downing is over iB1+4wa  
boolean bStop = false; //Stop identical "u H VX|`  
FileAccessI fileAccessI = null; //File Access interface :/.SrkN(A7  
~8j4IO(  
.#4;em%7  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException =B/Ac0Y  
{ )R- e^Cb  
this.sURL = sURL; kdam]L:9  
this.nStartPos = nStart; L] syD n  
this.nEndPos = nEnd; cD6T4  
nThreadID = id; S, *  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 TTfU(w%&P  
} Yu`KHvur  
Hy*_4r  
o)M=; !  
public void run() 3jJd)C R  
{ ` 465 H  
while(nStartPos < nEndPos && !bStop) 2JMMNpya  
{ -Y{=bZS u  
pSPVY2qKX  
hd'JXKMy  
try{ Za>0&Fnf  
URL url = new URL(sURL); T\ cJn>kCn  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -!ARVf *  
httpConnection.setRequestProperty("User-Agent","NetFox"); v)!C Dpw  
String sProperty = "bytes="+nStartPos+"-"; ^&Re-{ES]  
httpConnection.setRequestProperty("RANGE",sProperty); Wifr%&t{J  
Utility.log(sProperty); 2H]~X9,z2  
HTa]T'  
PdkS3Hz  
InputStream input = httpConnection.getInputStream(); iVQ)hs W/  
//logResponseHead(httpConnection); 0o>l+c  
G|LJOq7QB  
hk7kg/"  
byte[] b = new byte[1024]; pAm L  
int nRead; E[nJ'h<h  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) j@98UZ{g\  
{ mZgYR~  
nStartPos += fileAccessI.write(b,0,nRead); bo]= *  
//if(nThreadID == 1) "A>/m"c]*  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m0 a<~  
} Or2J  
Ibbpy++d[  
Z7G l^4zn  
Utility.log("Thread " + nThreadID + " is over!"); d$;1%rRj8  
bDownOver = true; v< Ozr:lL  
//nPos = fileAccessI.write (b,0,nRead); |#Q4e51H  
} #% 1|$V*:  
catch(Exception e){e.printStackTrace ();} /ll2lyS+  
} o=}vK[0u  
}  yf/c  
 Bm\OH#  
sT;:V  
//打印回应的头信息 !ot$Q  
public void logResponseHead(HttpURLConnection con) ?%]?#4bkc  
{ mD]^a;U[X  
for(int i=1;;i++) Cbq|<p# #o  
{ Z4ZR]eD  
String header=con.getHeaderFieldKey(i); #n5D K{e  
if(header!=null) -IP3I  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); o(|fapK.  
Utility.log(header+" : "+con.getHeaderField(header)); w<o#/J9  
else _]/&NSk  
break; M6MtE_E  
} f:K3 P[|  
} IW&.JNcN  
"x"y3v'  
h{BO\^6x  
public void splitterStop() _ITA$ #  
{ _XP3|E;I/  
bStop = true; pRTdP/(OQ  
} .o"FT~}z  
b- FJMY  
wvu h   
} B+pJWl8u  
Kd%>:E*  
l4LowV7  
/* U*R  
**FileAccess.java }w%W A&"W  
*//文件访问(定位,写) sP` k{xG  
package NetFox; ->0OqVQA  
import java.io.*; Ozo)}  
B*,Qw_3dG  
sO;]l"{<  
public class FileAccessI implements Serializable{ }8\"oA6  
=JK# "'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8ba*:sb  
RandomAccessFile oSavedFile; 6Y-sc*5  
long nPos; SaA9)s  
LqOjVQxz  
rjJ-ZRs\  
public FileAccessI() throws IOException v."0igMO  
{ P?Fm<s:  
this("",0); s(3iGuT  
} {W5D)  
l*0`{R  
YYiT,Xp<A  
public FileAccessI(String sName,long nPos) throws IOException P:3%#d~q  
{ [ ]LiL;A&  
oSavedFile = new RandomAccessFile(sName,"rw"); :87HXz6]jS  
this.nPos = nPos; ,2y " \_  
oSavedFile.seek(nPos); UB7H`)C}  
} I$#)k^Q  
UN"U#Si)  
IY=CTFQ8lm  
public synchronized int write(byte[] b,int nStart,int nLen) ~l@-gAyw  
{  @U;U0  
int n = -1; ~?x `f +  
try{ RE?j)$y?`  
oSavedFile.write(b,nStart,nLen); 4t<l9Ilp  
n = nLen; G"'[dL)N>  
} HsQ\xQ"k!  
catch(IOException e) d mj T$a|  
{ ?xgrr7  
e.printStackTrace (); N`Q[OFe  
} 0 3/ <A^  
iO?Sf8yJ:  
*?Pbk+}%  
return n; TM1D|H  
} $!-a)U,w$B  
ktMUTL(B  
4qc 0QA%  
} 3"pl="[*  
w' gKE'c  
~l=Jx*  
/* |##rs  
**SiteInfoBean.java _?IP}}jA:  
*/ ?7:?OX  
package NetFox; 8pQ:B/3=  
i H^Gv*  
HR> X@g<c  
public class SiteInfoBean { ^^{gn3xJ  
,svj(HP$  
ZGHh!Ds;  
private String sSiteURL; //Site's URL RlH~<|XK  
private String sFilePath; //Saved File's Path XJ.ERLR.  
private String sFileName; //Saved File's Name .bT|:Q~@{  
private int nSplitter; //Count of Splited Downloading File \XUG-\$p  
~_YU%y  
YhzDi>hob  
public SiteInfoBean() w=txSF&Qr  
{//nSplitter的缺省值为5 '/@] V  
//default value of nSplitter is 5 t;~H6  
this("","","",5); =rrbS8To=  
} fcC?1M[BP~  
>[U.P)7;  
*k7vm%#ns  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) NIQX?|;b{  
{ D#~S< >u@  
sSiteURL= sURL; <g^!xX<r?  
sFilePath = sPath; Owa]ax5  
sFileName = sName; 3?"JFfYU,'  
this.nSplitter = nSpiltter; NP {O  
\~YyY'J  
@fVCGV?'  
} {m&8Viq1  
ezOZHY>|#  
w?+v+k\  
public String getSSiteURL() 96&Y  
{ i7m=V T  
return sSiteURL; R4R SXV  
} VgSk\:t  
#1v>3H(  
N]k(8K  
public void setSSiteURL(String value) 8#S}.|"?F  
{ jC)lWD  
sSiteURL = value; xTJ-v/t3<  
} kr_!AW<.tz  
njk1x  
y.LJ 5K$&a  
public String getSFilePath() xGzp}   
{ ;8G( l   
return sFilePath; LD~s@}yH>  
} #0+`dI_5/  
PUdJ>U  
NB z3j  
public void setSFilePath(String value) P0En&g+~  
{ Zy -&g:  
sFilePath = value; ZL-YoMHc+_  
} '|\et aD  
R`RLq1WA  
&y}nd 7o  
public String getSFileName() g8_C|lVZi  
{ E[FRx1^R9  
return sFileName; f.o,VVYi  
} a s{^~8B  
1xJc[q  
\I"UW1)B  
public void setSFileName(String value) 5nGDt~a  
{ ]vPa A  
sFileName = value; Au6*hv3:  
} 4[S0~O{r  
WG{mg/\2(C  
]J t8]w  
public int getNSplitter() 4<['%7U_[  
{ yvgn}F{}  
return nSplitter; jQKlJi2xu  
} \xH#X=J  
"\'g2|A  
^Fl6-|^~  
public void setNSplitter(int nCount) \qrSJ=}t  
{ 1D0_k  
nSplitter = nCount; +b7}R7:AFH  
} 8"M*,?.]  
} K$H>/*&'~  
,=9e]pQ  
Dm=Em-ST6  
/* G n_AXN  
**Utility.java da[u@eNrnX  
*/ uh~/ybR  
package NetFox; q>~\w1%}a\  
}@ *Me+  
GnE%C2L -  
public class Utility { `>1"v9eF  
idC4yH42  
)TceNH  
public Utility() .oJs"=h:m  
{ cm8-L[>E  
7-oH >OF^  
rpgr5>  
} 5dV Sir  
?/_8zpW  
//线程睡眠 0,T'z,  
public static void sleep(int nSecond) |EJ&s393&  
{ ?Jlz{msI  
try{ 3&D;V;ON}_  
Thread.sleep(nSecond); &=sVq^d@qe  
} s<I[)FQVr  
catch(Exception e) XIu3n9g^#  
{ TU&t 1_6  
e.printStackTrace (); l_lm)'ag  
} sOJH$G3O  
} zFjG20w%3g  
w$9aTL7  
//日志 ) 0x* >;"o  
public static void log(String sMsg) No)v&P%  
{ Tr1#=&N0  
System.err.println(sMsg); 9})!~r;|  
} zfE;)K^"  
aW8Bx\q  
`  L(AvSR  
public static void log(int sMsg) y)W.xR  
{ Ge+&C RhyX  
System.err.println(sMsg); ZDZPJp,  
} lD!o4ZAo  
} ()}B]?  
1n! Jfs U  
APT'2 -I_  
/* AW8"@  
**TestMethod.java P!C!E/Jf5  
*/ ny5 = =C{9  
package NetFox; |H.(?!nTb  
8k$iz@e  
,Ty>sZ#/fz  
public class TestMethod { )* @Oz  
D<[4}og&]  
*M_.>".P  
public TestMethod() P-L<D!25  
{ ///xx/weblogic60b2_win.exe >Au]S `  
try{ IKM=Q. 7j  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4-`C !q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =|n NC  
SiteFileFetch fileFetch = new SiteFileFetch(bean); DT #1*&-  
fileFetch.start(); Dg]ua5jk  
} W"fdK_F\  
catch(Exception e){e.printStackTrace ();} )-824?Nl:  
W:uIG-y~  
J!,5HJh1  
} ]6{G;f$  
29g("(}TK  
(=${@=!z  
public static void main(String[] args) Sd.i1w &  
{ WigC'  
new TestMethod(); >JFAE5tj&2  
} ^f{+p*i}:  
} tvptaw A.  
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