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http断点续传简单实现(java)

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/* &Y{F? c^  
**SiteFileFetch.java V!mWn|lf  
*/ S45'j(S=  
package NetFox; OthG7+eF  
import java.io.*; 61G|?Aax  
import java.net.*; -H4PRCDH  
{d8^@UL  
k@7kNMl  
public class SiteFileFetch extends Thread { 8:~b &>   
miPmpu!  
se!g4XEWD  
SiteInfoBean siteInfoBean = null; //文件信息Bean YRXK@'[=  
long[] nStartPos; //开始位置 {798=pC<.  
long[] nEndPos; //结束位置 4yhcK&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 b"^\)|*4;  
long nFileLength; //文件长度 R3cg2H  
boolean bFirst = true; //是否第一次取文件 +9TV:T  
boolean bStop = false; //停止标志 .6LS+[  
File tmpFile; //文件下载的临时信息 $kv@tzO  
DataOutputStream output; //输出到文件的输出流 :r\xkHg/f  
So?m?,!W  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) "8FSA`>=  
public SiteFileFetch(SiteInfoBean bean) throws IOException :|=- (z  
{ f]c <9Q>*  
siteInfoBean = bean; 3=IG#6)~C  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); iEe#aO"D!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); <H!O:Mf_p  
if(tmpFile.exists ()) ~bWhth2*  
{ JXL'\De ;  
bFirst = false; m!;G/s*  
read_nPos(); >n(F4C-pl  
} TFYw  
else KLW&bJ$|j  
{ S3QaYq"v  
nStartPos = new long[bean.getNSplitter()]; R#D#{ cC(  
nEndPos = new long[bean.getNSplitter()]; Y!F!@`%G  
} Q~8y4=|#CY  
ZxI]I1)  
&eU3(F`.  
JfSdUWxT  
} {b[tA, >  
~C0 Pu.{o  
L -YNz0A  
public void run()  Ll?g.z"  
{ vABXXB  
//获得文件长度 >C:If0S4X  
//分割文件 4Q$!c{Y r  
//实例FileSplitterFetch gXF.on4B  
//启动FileSplitterFetch线程 9]Lo  
//等待子线程返回 `wf|uM  
try{ 6vF/e#},  
if(bFirst) $Vsy%gA<  
{ 4'` C1a  
nFileLength = getFileSize(); 4? v,wq  
if(nFileLength == -1) ,! hnm  
{ :1*zr  
System.err.println("File Length is not known!"); ]r!QmWw~V  
} 8sH50jeP  
else if(nFileLength == -2) BO]=vH  
{ v"/TmiZ  
System.err.println("File is not access!"); ZOC#i i`:  
} F'rt>YvF  
else T30Zk*V  
{ ",T` \8&@e  
for(int i=0;i<nStartPos.length;i++) d[S#Duz<&  
{ ETe-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); oCbpK  
} I ld7}R  
for(int i=0;i<nEndPos.length-1;i++) g1ytT%]  
{ dGU8+)2cn  
nEndPos = nStartPos[i+1]; Qne0kB5m  
} (U_wp's  
nEndPos[nEndPos.length-1] = nFileLength; qv$!\T  
} h mds(lv7  
} y #69|G  
Ox~ 9_d  
l0. FiO@_Q  
//启动子线程 # 3.\j"b  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; z(rK^RT  
for(int i=0;i<nStartPos.length;i++) rpSr^slr  
{ JCNk\@0i*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :pb67Al29  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), i+1Qf  
nStartPos,nEndPos,i); &>g~-s  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jFG5)t<D  
fileSplitterFetch.start(); 0d";Hh:  
}   Y<aO  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Li]k7w?H  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); HS7_MGU  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", G0pBR]_5z$  
nEndPos = " + nFileLength); dqxd3,Z  
// fileSplitterFetch[nPos.length-1].start(); gvGi %gq  
W_%W%i|  
r ^ Y~mq  
//等待子线程结束 F3Dt7q  
//int count = 0; ogJ<e_ m  
//是否结束while循环 ewym 1}o  
boolean breakWhile = false; ||XIWKF<n2  
P.h.M A]  
p/3BD&6  
while(!bStop) kZv*rWAm  
{ pqH4w(;  
write_nPos(); f1J %]g!  
Utility.sleep(500); R^6Zafp  
breakWhile = true; R1/q3x  
S/fW/W*/}  
-bm,:Iy!  
for(int i=0;i<nStartPos.length;i++) B4^`Sw  
{ ssA7Dx:  
if(!fileSplitterFetch.bDownOver) {_(+>v"eJ  
{ p-Pz=Cx-  
breakWhile = false; lJ&y&N<O  
break; nj  
} !k-` eJ|  
} ~&KX-AC@  
if(breakWhile) `m, Ki69.  
break; `kPc!I7Y  
nE7JLtbH  
(6clq:c7j  
//count++; ;'^, ,{  
//if(count>4) )2V@p~k?  
// siteStop(); iadkH]w  
} Z2bUs!0  
'hF@><sqk  
v?)SA];  
System.err.println("文件下载结束!"); #w*"qn#2Uz  
} :,^>d3k  
catch(Exception e){e.printStackTrace ();} /PW&$P1.]"  
} Egf^H>,.M  
e9:P9Di(b  
!F$R+A+L  
//获得文件长度 ^yJ:+m;6K  
public long getFileSize() vI|As+`$d  
{ Hk9U&j$  
int nFileLength = -1; T>F9Hs  W  
try{ /AR]dcL@76  
URL url = new URL(siteInfoBean.getSSiteURL());  D%gGRA  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); OpQ8\[X+  
httpConnection.setRequestProperty("User-Agent","NetFox"); KuXkI;63J>  
H`el#tt_  
NnOI:X {  
int responseCode=httpConnection.getResponseCode(); vYdlSe=6G  
if(responseCode>=400) L {qJ-ln:  
{ H;y}-=J+  
processErrorCode(responseCode); !.-.#<<_a  
return -2; //-2 represent access is error )8'jxiGs  
} 4| f}F  
kc Y,vl  
PU Cx]5  
String sHeader; ~K` 1  
IT&i,`cJ~F  
&D*8l?A/1f  
for(int i=1;;i++) jyQVSQ s  
{ J3IRP/*z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L;yEz[#xaT  
//Utility.log(in.readLine()); g`3H(PVg  
sHeader=httpConnection.getHeaderFieldKey(i); ]! )xr  
if(sHeader!=null) LM6]kll  
{ p:tN642  
if(sHeader.equals("Content-Length")) ,]q%/yxi  
{ L[]BzsIv  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *~;8N|4<  
break; x8/us  
} >qpqQ; bm  
} ^*>n4U  
else ANb"oX c  
break; u>o<tw%Y  
} a.,i.2  
} Wj OH/$(  
catch(IOException e){e.printStackTrace ();} Pb4q`!  
catch(Exception e){e.printStackTrace ();} RH~sbnZ)F  
o(Kcs-W2  
=YHt9fb$c  
Utility.log(nFileLength); Kj!Y K~~  
TPK@*9rI  
EneAX&SG  
return nFileLength; )eq}MaW+j  
} "K ?#,_  
r<|nwFJ  
]1}h8/  
//保存下载信息(文件指针位置) (: OHyeNt  
private void write_nPos() O<`,,^4w/  
{ -l JYr/MSL  
try{ xFwXW )  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 27iy4(4  
output.writeInt(nStartPos.length); @h(!<Ux_  
for(int i=0;i<nStartPos.length;i++) c'rd$  
{ kwF]TO S  
// output.writeLong(nPos); 7E(%9W6P  
output.writeLong(fileSplitterFetch.nStartPos); 4>_d3_1sn  
output.writeLong(fileSplitterFetch.nEndPos); waQtr,m)  
} PkJcd->  
output.close(); x.\XUJ4x  
} lY,/ W  
catch(IOException e){e.printStackTrace ();} +5-fk>o  
catch(Exception e){e.printStackTrace ();} ZpWu,1  
} .[,6JU%  
6|oWaA\gI  
<I 1y  
//读取保存的下载信息(文件指针位置) 045\i[l=  
private void read_nPos() :l`i4kx  
{ I.9o`Q[8&  
try{ h!Y?SO.b  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Fx5ZwT t  
int nCount = input.readInt(); bg1un@%!l  
nStartPos = new long[nCount]; ph#efY`a:  
nEndPos = new long[nCount]; nuxd S ,  
for(int i=0;i<nStartPos.length;i++) I%i:)6Un-y  
{ j6og3.H-  
nStartPos = input.readLong(); PY -+Bf  
nEndPos = input.readLong(); 1LyT7h  
} +f|6AeE  
input.close(); [Auc*@  
} m>YWxa   
catch(IOException e){e.printStackTrace ();} %A2`&:ip  
catch(Exception e){e.printStackTrace ();} x< S\D&  
} AsAFUuI  
n.Vtc-yZU  
((cb4IX  
private void processErrorCode(int nErrorCode) 6Hn)pD#U  
{ lC2?sD$  
System.err.println("Error Code : " + nErrorCode); P}l#VJWp  
} 7V 'Le2T'  
6V P)$h8  
h>|u:]I>  
//停止文件下载 M5 `m.n<  
public void siteStop() Qg>0G%cXU  
{ ]?&H^"=  
bStop = true; _NT[ ~M_Q  
for(int i=0;i<nStartPos.length;i++) ~lk@6{`l|1  
fileSplitterFetch.splitterStop(); ALAL( f`  
6g|#ho1Bbs  
@p6@a6N%  
} %yvA   
} J&_3VKrN  
//负责部分文件的抓取 6qDfcs  
**FileSplitterFetch.java [-]A^?yBM  
*/ _25d%Ne0  
package NetFox; e{JVXc[D  
6WO7+M;z  
~$*`cO  
import java.io.*; 6e/7'TYwT  
import java.net.*; RF!'K ko  
ZYDW v/u  
[ t$AavU.  
public class FileSplitterFetch extends Thread { 4(8<w cL  
FW5}oD( H  
/W0E(8:C)  
String sURL; //File URL {wv&t R;  
long nStartPos; //File Snippet Start Position }1F6?do3&  
long nEndPos; //File Snippet End Position &M= 3{[  
int nThreadID; //Thread's ID EIPnm%{1  
boolean bDownOver = false; //Downing is over Ph Ttx(!  
boolean bStop = false; //Stop identical %Gu][_.L  
FileAccessI fileAccessI = null; //File Access interface jiq2x\\!  
7$#rNYa,z  
ke^d8Z.  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %i3{TL  
{ h(|;\~  
this.sURL = sURL; wB 2}uk7  
this.nStartPos = nStart; =+4 _j  
this.nEndPos = nEnd; w#<p^CS  
nThreadID = id; egWx9xX  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 o"\{OX  
} :~i+tD  
i3d y  
KD=bkZ&  
public void run() iU XM( ]  
{ N|$5/bV  
while(nStartPos < nEndPos && !bStop) 9 R  
{ EP(Eq  
CdNih8uG  
Pr2;Kp  
try{ I5Q~T5Ar  
URL url = new URL(sURL); !%V*UR9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); DiR'p`b~  
httpConnection.setRequestProperty("User-Agent","NetFox"); <uC<GDO  
String sProperty = "bytes="+nStartPos+"-"; E$R_rX4x  
httpConnection.setRequestProperty("RANGE",sProperty); pkW5D  
Utility.log(sProperty); VW~Xbyf  
,0h3x$l)   
{Y^c*Iqn  
InputStream input = httpConnection.getInputStream(); +NT:<(;|i5  
//logResponseHead(httpConnection); fQ1 0O(`g,  
4ODX 5If  
cPJ7E  
byte[] b = new byte[1024]; 4M7^ [G  
int nRead; Op90NZI#K  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) G\):2Qz!|  
{  qJURPK  
nStartPos += fileAccessI.write(b,0,nRead); Z7oaQ\fR  
//if(nThreadID == 1) @f%wd2  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )lOji7&e  
} xh`Du|jvm  
_\!0t  
NU(^6  
Utility.log("Thread " + nThreadID + " is over!"); !YIb  
bDownOver = true; Q<C@KBiVE  
//nPos = fileAccessI.write (b,0,nRead); VT Vm7l  
} 9GaL0OWo  
catch(Exception e){e.printStackTrace ();} ff[C'  
} j 37:  
} C-&#r."L  
5/k)\`  
Q Y@nE  
//打印回应的头信息 K: 4P ;ApI  
public void logResponseHead(HttpURLConnection con) uZ-`fcCjD  
{ dhs#D:/{9  
for(int i=1;;i++) 8>m1UONr  
{ bYK]G+Ww  
String header=con.getHeaderFieldKey(i); M{G$Pk8[  
if(header!=null) 6z PV'~q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); K/~Y!?:J r  
Utility.log(header+" : "+con.getHeaderField(header)); C_C$5[~-:  
else 9X.gg$P  
break; C5cFw/',  
} ')rD?Z9 ^  
} VGfD;8]z  
e`vUK.UoW  
{;\%!I  
public void splitterStop() <e[!3,%L  
{ 3JTU^-S<  
bStop = true; 9W$m D w6f  
} E $<;@  
??q!jm-m  
FDl,Ey^r/  
} A7.JFf>  
O-?z' @5cI  
f x%z| K  
/* 3b,=  
**FileAccess.java 1 iquHn  
*//文件访问(定位,写) JtThkh'-"  
package NetFox; {rs6"X^  
import java.io.*; JE/l#Q!  
O3!Ouh&  
j\nE8WH  
public class FileAccessI implements Serializable{  Pb*q;9  
s8{-c^G:R  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节  on6<l  
RandomAccessFile oSavedFile; .0?ss0~  
long nPos; >\RDQ%z  
Vvx a.B  
'T6B_9GQ8  
public FileAccessI() throws IOException Feh"!k <6k  
{ </8be=e7p  
this("",0); B #;s(O  
}  xh=FkY&d  
gD,A9a(3  
 \\y}DNh  
public FileAccessI(String sName,long nPos) throws IOException SIj6.RK  
{ >t2]Ssi(  
oSavedFile = new RandomAccessFile(sName,"rw"); XryQ)x(  
this.nPos = nPos; h 3eGq:!9  
oSavedFile.seek(nPos); e=0l<Rj  
} >N :|Km\  
Jii?r*"d  
u XaL  
public synchronized int write(byte[] b,int nStart,int nLen) uPM8GIvZX.  
{ W dei`u[  
int n = -1; iH($rSE  
try{ K]*g, s+  
oSavedFile.write(b,nStart,nLen); *Pa2bY3:  
n = nLen; p)K9 ZI  
} _G_ &Me0  
catch(IOException e) 2O}s*C$Xav  
{ c _R)P,P  
e.printStackTrace (); L3-<Kop  
} 50}.Xm@,BO  
Q=)"om  
^yzo!`)fso  
return n; ;5,`Jpca  
} g}\U, (  
olUqBQ&ol  
Ak<IHp^Q  
} GGFar\ EzW  
7I@9v=xV  
XhJP87A  
/* D5o+ 0R  
**SiteInfoBean.java M6@'9E]|>  
*/ V{7lltu  
package NetFox; LAu+{'O\  
~v{C6)  
H]T2$'U6  
public class SiteInfoBean { <lg"M;&Ht  
{9m!UlTtw  
o O{|C&A  
private String sSiteURL; //Site's URL M]%!n3Fb  
private String sFilePath; //Saved File's Path Bd N{[2  
private String sFileName; //Saved File's Name ,6cbD  
private int nSplitter; //Count of Splited Downloading File /ze_{{o  
OuYE-x2]x"  
;T"m [D  
public SiteInfoBean() \'}/&PCkr  
{//nSplitter的缺省值为5 #XYLVee,  
//default value of nSplitter is 5 Jq$6$A,f  
this("","","",5); 5VoOJ_hq  
} yNb#Ia  
+Y.uZJ6+  
iuH8g  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Z!s>AgH9u  
{ Uy_}@50"l  
sSiteURL= sURL; Wf+Cc?/4  
sFilePath = sPath; V5(tf'  
sFileName = sName; 3^iQe"P%a@  
this.nSplitter = nSpiltter; D x >1y  
#h #mOJ5  
y(wqcDok|n  
} !4b; >y=m  
1o5Y9#7  
t?#vb}_  
public String getSSiteURL() 21)-:rS  
{ hq&  
return sSiteURL; 99+/W*C  
} YiQeI|{oN  
|=h)efo}  
e{rHO,#A>  
public void setSSiteURL(String value) 4E>/*F!  
{ k_|v)\4B  
sSiteURL = value; B1i!te}*  
} Ep,0Z*j  
bTo@gJk n  
J:TI>*tn  
public String getSFilePath() '#An+;x{  
{ ,N@Icl  
return sFilePath; YVg}q#  
} !Z0rTC3d  
-<}>YtB Q  
OV@h$fg  
public void setSFilePath(String value) MTFVnoZMQ_  
{ ~jRk10T(B  
sFilePath = value; mSfkyw.  
} PE6u8ZAb"  
l_q>(FoqA  
r #6l?+W ;  
public String getSFileName() coP$7Q .  
{ g]PLW3  
return sFileName; /cg]wG!n8  
} 2Ws/0c  
ph&H*Mc  
R82Zr@_  
public void setSFileName(String value) e5/ DCz  
{ x#e\ H F  
sFileName = value; ]JCB^)tM  
} V.a]IkK'K  
VOF:+o@.  
YQ8x6AJ  
public int getNSplitter() Gp3t?7S{T  
{ %_J/&{6G  
return nSplitter; YT%SCaU  
} \$\(9!=  
<+1w'-  
ZD] '$  
public void setNSplitter(int nCount) q$2taG}  
{ *,*:6^t  
nSplitter = nCount; !)*T  
} fz?Wr: I  
} /wRK[i  
;KZ2L~ THG  
kc(b;EA  
/* PG~m-W+  
**Utility.java {arjW3~M:  
*/ o-i.'L)X  
package NetFox; %?G.lej,x  
s8I77._s  
@j8L{FGnN  
public class Utility { &7kSLat+9{  
sbiDnRf  
3SB7)8Id1  
public Utility() /z-C :k\  
{ HE<%d  
r-"`Abev  
#?d>S;)+  
} Ywb)h^{!  
{ZYCnS&?CL  
//线程睡眠 (i~%4w=  
public static void sleep(int nSecond) D '_#?%3^  
{ eMd1%/[  
try{ ~~E=E;9  
Thread.sleep(nSecond); 8; N}d)*O  
} owVUL~  
catch(Exception e) 6!=9V0G~  
{ |0 pBBDw  
e.printStackTrace (); UY& W]  
} xu pdjT%4  
} ?[fl$EG  
S5 oHe4#89  
//日志 Hx/Vm`pRyX  
public static void log(String sMsg) g_!xO2LH,8  
{ }8KL]11b  
System.err.println(sMsg); !-o||rt  
} &CsBG?@Z|  
&aht K}u  
lukRFN>c"  
public static void log(int sMsg) G uI sM  
{ /OtQk -E  
System.err.println(sMsg); iQR})=Q  
} ?#y<^oNM  
} [5#/& k{  
{7szo`U2  
x};g!FYfkB  
/* sOHAW*+  
**TestMethod.java 6Kc7@oO~  
*/ NOr*+N\  
package NetFox; -Z& {$J  
2%%U)|39mB  
aRKG)0=  
public class TestMethod { 1{glRY'  
,<WykeC  
lMf5F8  
public TestMethod() , &f20o  
{ ///xx/weblogic60b2_win.exe )8>f  
try{ vK>^#b3  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {8Nd-WJ{  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); XD>@EYN<X  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 1pr_d"#4  
fileFetch.start(); KT?s\w  
} qq{N; C  
catch(Exception e){e.printStackTrace ();} qk"=nAJX  
jJnBwHp  
bL[W.O0  
} W8rn8Rh  
.`=PE&xq  
JEkVj']?  
public static void main(String[] args) 9r*T3=u.S  
{ a8U2c;  
new TestMethod(); F!t13%yeu?  
} 5Rp2O4Z  
} 6$.Xj\zl  
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