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http断点续传简单实现(java)

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/* f 0H.$UAL  
**SiteFileFetch.java x#`p.sfVo  
*/ N)"8CvQL  
package NetFox; n0lOq  
import java.io.*; bh@CtnO  
import java.net.*; I#2$CSJ  
4z(~)#'^  
i3 eF_  
public class SiteFileFetch extends Thread { TX=894{nGh  
qGA|.I9,  
S a +Y/  
SiteInfoBean siteInfoBean = null; //文件信息Bean 3JGrJ!x  
long[] nStartPos; //开始位置 *>a=ku:?  
long[] nEndPos; //结束位置 8r(a wp  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 B{)#A?Rh.  
long nFileLength; //文件长度 >UCg3uFj  
boolean bFirst = true; //是否第一次取文件 nriSVGi  
boolean bStop = false; //停止标志 w(V%EEk  
File tmpFile; //文件下载的临时信息 )vO"S  
DataOutputStream output; //输出到文件的输出流 ,y]-z8J  
2"G9?)d9  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) R%szN.cI  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~ L4NK#  
{ :6(\:  
siteInfoBean = bean; W+a/>U  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )!-gT  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 2L&c91=wE  
if(tmpFile.exists ()) vSHPN|*  
{ )IcSdS0@M  
bFirst = false; LY0f`RX*&  
read_nPos(); wKpBH}  
} O(I^:_eH  
else MU$tX  
{ T!,5dt8L  
nStartPos = new long[bean.getNSplitter()]; r{.pXf  
nEndPos = new long[bean.getNSplitter()];  lPZ>#  
} OpaRQ=  
1|{s8[;8  
T!]rdN!  
48 wt  
} >fYcr#i0[  
^>E>\uz0v  
D\5+2 G  
public void run() HK :K~h  
{ kFE9}0-   
//获得文件长度 (xW+* %  
//分割文件  7V5c`:"  
//实例FileSplitterFetch d2eXN3"  
//启动FileSplitterFetch线程 R|*0_!O:[  
//等待子线程返回 aUNA` L  
try{ vQCb?+X&  
if(bFirst) /4(HVua  
{ 6MM\nIU)/  
nFileLength = getFileSize(); *jhgCm  
if(nFileLength == -1) C')KZ|JIC  
{ L|WrdT D;  
System.err.println("File Length is not known!"); 9^DAlY,x.  
} t#(=$  
else if(nFileLength == -2) e'uC:O.u  
{ 9]+zZP_#  
System.err.println("File is not access!"); |a03S Zx  
} &S xF"pYV  
else j~Pw t9G  
{ i ZPNss  
for(int i=0;i<nStartPos.length;i++) G0!6rDu2,  
{ Eb~vNdPo  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); tW~kn9glZ  
} gpyio1V>  
for(int i=0;i<nEndPos.length-1;i++) dBA&NW07  
{ FR6 W-L  
nEndPos = nStartPos[i+1]; d1_kw A2y  
} (hOD  
nEndPos[nEndPos.length-1] = nFileLength; J>#hu3&UOQ  
} 4G:~|N.{p  
} 'y!qrmMRr  
Q\s+w){f%  
&I=o1F2B)  
//启动子线程 oU,8?( }'~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 5uG^`H@X  
for(int i=0;i<nStartPos.length;i++) e46`"}r  
{ Zgh~7Z/  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xO:h[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {,uSDI Oj$  
nStartPos,nEndPos,i); #Pk{emYW  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Jc?zX8>Ae:  
fileSplitterFetch.start(); nygGI_[l  
} l8(9?!C  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), DqY"N ]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6<@+J  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", C3^3<  
nEndPos = " + nFileLength); ShVR{gIs  
// fileSplitterFetch[nPos.length-1].start(); Q3& ?28  
):4)8@]5M  
}~&0<8m  
//等待子线程结束 \C~6 '  
//int count = 0; ^L.I9a#]  
//是否结束while循环 O[$X36z  
boolean breakWhile = false; z-K};l9y  
GIYdI#0RC  
8IL5 :7H8  
while(!bStop) :9L}jz  
{ ; Yc\O:Qq  
write_nPos(); ^m D$#  
Utility.sleep(500); xe6V7Wi/Tt  
breakWhile = true; nm\f$K>Pg  
/|NyO+Io  
A #SO}c  
for(int i=0;i<nStartPos.length;i++) B!`.,3  
{ 'HfI~wN  
if(!fileSplitterFetch.bDownOver) ":T"Y;  
{ "Ltp]nCR  
breakWhile = false; xzz@Wc^_  
break; Ie Chz d  
} \Qv:7;?  
} tMU10=d  
if(breakWhile) 0Z((cI\J  
break; tculG|/  
uCW}q.@4  
Q$'\_zV  
//count++; JSh'iYJ .  
//if(count>4) b; ;y|H  
// siteStop(); S=< ]u  
} p+Bvfn  
 ;1,#rTs  
y&4im;X0  
System.err.println("文件下载结束!"); &SZAe/3+  
} |%X_<Cpk  
catch(Exception e){e.printStackTrace ();} xXV15%&  
} 1Ogtzf  
|`wJ {-  
[A!=Hv_$  
//获得文件长度 @ *T8>  
public long getFileSize() xU.Ymq& 5  
{ \q-["W34  
int nFileLength = -1; J{EK}'  
try{ _cfAJ)8=  
URL url = new URL(siteInfoBean.getSSiteURL()); ]%Whtj.,x7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); L(`q3>iC4.  
httpConnection.setRequestProperty("User-Agent","NetFox"); CS"k0V44}  
|@>Zc5MY$  
\gZjq]3  
int responseCode=httpConnection.getResponseCode(); -Xgup,}?  
if(responseCode>=400) _{i- .;K  
{ g;3<oI/P  
processErrorCode(responseCode); q*J-ii  
return -2; //-2 represent access is error t&bE/i_T  
} | qf8y  
uUG&At  
6ozBU^n  
String sHeader; TU8K\;l]  
/z,+W9`  
v[ y|E;B  
for(int i=1;;i++) W.b?~  
{ Lr(wS {  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >\!>CuU  
//Utility.log(in.readLine()); $0E_4#kwB  
sHeader=httpConnection.getHeaderFieldKey(i); PmE2T\{s!  
if(sHeader!=null) fm%-wUgj  
{ RE:$c!E!  
if(sHeader.equals("Content-Length")) _RzcMX  
{ Ed~2Qr\65  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); EabZ7zFoN  
break; fL1EQ)  
} bPdbKi{j@  
} 5/{gY{  
else cvf#^Cu   
break; vV9q5Bj:  
} }h)[>I(  
} Q|}Pc>ae  
catch(IOException e){e.printStackTrace ();} AU +2'  
catch(Exception e){e.printStackTrace ();} w,FOq?j^k  
r5?qz<WW~  
 %sLij*  
Utility.log(nFileLength); $r=Ud >  
$.@)4Nu!_  
8.Ty ,7Z  
return nFileLength; rx#\Dc}  
} ~FV Z0%+,  
C[O \aW  
='cr@[~i  
//保存下载信息(文件指针位置) Et+N4w  
private void write_nPos() x~tG[Y2F?  
{ <4Jo1  
try{ yVM 1W"Q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); [sY>ac  
output.writeInt(nStartPos.length); ATU 2\Y  
for(int i=0;i<nStartPos.length;i++) 8W"~>7/>D  
{ ` 0k  
// output.writeLong(nPos); `?VB)  
output.writeLong(fileSplitterFetch.nStartPos); n'JwT! A  
output.writeLong(fileSplitterFetch.nEndPos); 9c1n  
} )S|}de/a2  
output.close(); 'N0/;k0ax  
} *Gm%Dn  
catch(IOException e){e.printStackTrace ();} /tf}8d  
catch(Exception e){e.printStackTrace ();} Ee##:I[z  
} :R<n{%~  
#$Z|)i]w  
P~:W+!@5v  
//读取保存的下载信息(文件指针位置) fV_(P_C  
private void read_nPos() l 49)Cv/  
{ %97IXrE  
try{ U&/Jh^Yy  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -~ `5kO~  
int nCount = input.readInt(); GjA;o3(  
nStartPos = new long[nCount]; VWG#v #o  
nEndPos = new long[nCount]; K{HRjNda#  
for(int i=0;i<nStartPos.length;i++) 81/Bn!  
{ l\*}  
nStartPos = input.readLong(); W]n%$a  
nEndPos = input.readLong(); %u43Pj  
} .Lp0_R@  
input.close(); t_WNEZW7f  
} >'8.>f  
catch(IOException e){e.printStackTrace ();} lBL;aTzo  
catch(Exception e){e.printStackTrace ();} h8O[xca/~  
} -rlxxLT+  
Y'Jb@l`$-  
6pQ#Zg()vp  
private void processErrorCode(int nErrorCode) ' d1E~A  
{ 9+SeG\Th  
System.err.println("Error Code : " + nErrorCode); `96:Z-!}  
} z8= Gc$w!  
U\ y?P:yy  
HH2*12e  
//停止文件下载 +?(2-RBd  
public void siteStop() yc4mWB~gyU  
{ oWo"` "P  
bStop = true; M0x5s@  
for(int i=0;i<nStartPos.length;i++) xK0VWi  
fileSplitterFetch.splitterStop(); gV!Eotq  
Hv<%_t_/  
f| 3`8JU  
} VE6T&fz`  
} _d]w)YMO  
//负责部分文件的抓取 jfS?#;T)  
**FileSplitterFetch.java <2ffcBv  
*/ 7~eo^/Pb S  
package NetFox;  #d*mG =  
r[ ' T.yo  
\%E Zg  
import java.io.*; o]}b#U8S  
import java.net.*; 4G@vO {$  
%7O`]ik:  
=1^Ru*G  
public class FileSplitterFetch extends Thread { r1-?mMSU&  
. %tc7`k8  
.ymR%X_k  
String sURL; //File URL <jw`"L[D  
long nStartPos; //File Snippet Start Position Vs8os+  
long nEndPos; //File Snippet End Position X&^t 8  
int nThreadID; //Thread's ID k^]+I% ?Q  
boolean bDownOver = false; //Downing is over _xAdvr' W  
boolean bStop = false; //Stop identical =a?l@dI]  
FileAccessI fileAccessI = null; //File Access interface vp4!p~C{  
X||o iqbY  
.+ai dWd  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException EZIMp8^  
{ 2*Z~J M  
this.sURL = sURL; 8_Y{7;<ey  
this.nStartPos = nStart; VV?+q)  
this.nEndPos = nEnd; \0(QO8.  
nThreadID = id; tV*g1)'zX  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 5^GUuFt5m  
} `8xe2=Ub  
WsJ3zZc  
Bu>srX9f  
public void run() #?!)-Q%  
{ lx U}HM  
while(nStartPos < nEndPos && !bStop) e0j*e7$  
{ g?^o++  
1-r1hZ-  
7,j}]  
try{ qK.8^{b  
URL url = new URL(sURL);  7I^(v Q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %OfaBv&  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2!7wGXm~U  
String sProperty = "bytes="+nStartPos+"-"; _s|C0Pt  
httpConnection.setRequestProperty("RANGE",sProperty); tE3!;  
Utility.log(sProperty); E:&=A 4 %  
_D$|lk-  
BGLJ>zkq  
InputStream input = httpConnection.getInputStream(); 4 FGcCE3  
//logResponseHead(httpConnection); r<UZ\d -  
V. =!^0'A  
&=<x&4H+  
byte[] b = new byte[1024]; IObGmc  
int nRead; Q;)[~p  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) T.`EDluG  
{ c:>&Bg&,6T  
nStartPos += fileAccessI.write(b,0,nRead); LUHj3H  
//if(nThreadID == 1) ,l&Dt,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dE.R$SM  
} &h`s:Y  
!-U5d9!  
3RXq/E  
Utility.log("Thread " + nThreadID + " is over!"); k9 .@S  
bDownOver = true; FU;Tv).  
//nPos = fileAccessI.write (b,0,nRead); Eu l,1yR  
} r[q-O&2&  
catch(Exception e){e.printStackTrace ();} :+bQPzL  
} vfK^^S  
} HIk5Q'ek  
pBL,kqYNA>  
r0+lH:G*q  
//打印回应的头信息 vCb3Ra~L`  
public void logResponseHead(HttpURLConnection con) 8uP,#D<wZ  
{ Cf91#% :cN  
for(int i=1;;i++) r.lH@}i%n  
{ `J'xVq#O  
String header=con.getHeaderFieldKey(i); FWq+'Gk SV  
if(header!=null) I+ rHb< P%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); P%8 Gaa=  
Utility.log(header+" : "+con.getHeaderField(header)); :rk=(=@8`  
else 3%bCv_6B  
break; cV\(Z6u  
} =ps3=D  
} 9E'fM  
(+`pEDD{X  
` .|JTm[  
public void splitterStop() Oh3AbpTT  
{ 3k.{gAZKh  
bStop = true; qjFz}6  
} Dt%G v0  
i,r O3J n  
{_&'tXL  
} )r3}9J  
[=7=zV;}4  
ELfcZfJ  
/* &_Ze@Ir-  
**FileAccess.java >Akrbmh5  
*//文件访问(定位,写) -^LUa]"E  
package NetFox; ` Fnl<C<  
import java.io.*; a8ya5EO  
U_i%@{  
7#d>a=$h  
public class FileAccessI implements Serializable{ d` %8qLIW  
r<VZE bm)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 XtY!fo *  
RandomAccessFile oSavedFile; +Ysm6n '  
long nPos; cq lA"Eof  
yHhx- `  
H'KCIqo  
public FileAccessI() throws IOException mApn[)?tv  
{ I@Cq<:+(3  
this("",0); G"k.sRKu  
} p]h;M  
@Wgd(Ezd  
^*s DJ #  
public FileAccessI(String sName,long nPos) throws IOException YnM&t ;TX  
{ X$*MxMNs  
oSavedFile = new RandomAccessFile(sName,"rw"); `9;0Y  
this.nPos = nPos; A*+pGQ  
oSavedFile.seek(nPos); mJ+M|#Ox  
} +cH,2^&  
y8*MNw  
d}D%%noIu  
public synchronized int write(byte[] b,int nStart,int nLen) (=A61]yB  
{ LR:PSgy  
int n = -1; $Lj~ge3#  
try{ 6HroKu  
oSavedFile.write(b,nStart,nLen); w8=&rzr8  
n = nLen; r]q;>\T'  
} o<h2]TN  
catch(IOException e) ^}SP,lg'  
{ SjosbdD  
e.printStackTrace (); Wd`*<+t]  
} 6=cfr; BH2  
v~8Cp C  
}K .Rv(m  
return n; $>JfLSyC  
} 7MWd(n-  
[}Q_T.4)E  
1Kjqs)p^  
} QhhL_vP  
ai7R@~O:_k  
w"`Zf7a{/  
/* r` B(ucE  
**SiteInfoBean.java HNJR&U t  
*/ uTShz3  
package NetFox; LC1WVK/  
K`=9"v'f+  
4s s 4O  
public class SiteInfoBean { a(J@]X>'  
^h$^j  
6"Ze%:AZZ  
private String sSiteURL; //Site's URL ZZ>"LH  
private String sFilePath; //Saved File's Path E2xK GK   
private String sFileName; //Saved File's Name hW!2C6  
private int nSplitter; //Count of Splited Downloading File /0swrt.  
 Vp7d  
2Z-[x9t  
public SiteInfoBean() u`.3\Geh  
{//nSplitter的缺省值为5 Y{Ff I+  
//default value of nSplitter is 5 3'Hz,qP  
this("","","",5); Dm@h'*  
} XU`ly3!  
1{ H=The  
zviTGhA  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) iT;Ld $!{f  
{ VFrp7;z43  
sSiteURL= sURL; p,V%wGM  
sFilePath = sPath; '3w%K+eJY  
sFileName = sName; #bJp)&LO  
this.nSplitter = nSpiltter; ~,_@|,)  
eslvg#Q  
r$1b=m,0d  
} =r)LG,w212  
Q:j~ kutS|  
C B`7KK  
public String getSSiteURL() EJP]E)  
{ E/hT/BOPK  
return sSiteURL; x=Aq5*A0  
} g[R4/]K^$  
UGlHe7  
1 0zw}1x  
public void setSSiteURL(String value) (Hmm^MV)  
{ 3GNcnb  
sSiteURL = value; jXVvVv  
} M}j[{wW3  
q9H\ $  
=W;e9 6#  
public String getSFilePath() ,N _/J4Us  
{ U{KnjoS  
return sFilePath; Y]=k"]:%  
} &qK:LHhj  
F\hVunPVx  
mlCBstt{  
public void setSFilePath(String value) }OhSCH'o6  
{  H2oxD$s  
sFilePath = value; J>k 6`gw  
} Fc8 0HK5R  
x N7sFSV@  
AN6Q~%,  
public String getSFileName() 2X[oge0@  
{ AAs&P+;  
return sFileName; S*>T%#F6Uo  
} wx[m-\  
8MI8~  
)#8g<]q  
public void setSFileName(String value) Bu&9J(J1  
{ @tPr\F  
sFileName = value; DRR)mQBb  
} 4;W{#jk  
Cl9rJ oT  
~ +>e hU  
public int getNSplitter() ?pfr^ !@$  
{ ;2\6U;  
return nSplitter; "/RMIS K[;  
} TTFs|T6`q  
GB^`A  
9P ACXW0  
public void setNSplitter(int nCount) +t%2V?  
{ W7b m}JHn  
nSplitter = nCount; p}h.2)PO  
} +&S6se4  
} ;1PJS_@rX  
|6b~c{bt  
zRD-[Z/-  
/* uSRhIKy  
**Utility.java ,OubKcNg  
*/ r8eJ&-Yi{Z  
package NetFox; &Jb\}c}  
=EMB~i  
[:#K_EI5%  
public class Utility { hm d3W`8D  
G%: 3.:E"  
GVJ||0D  
public Utility() Fz,jnV9=j  
{  >(ip-R  
Q8AAu&te7  
~=iH*AQR  
} <{bxOr+  
(g/A uL  
//线程睡眠 N'9T*&o+  
public static void sleep(int nSecond) ;*<R~HJt  
{ vg[3\!8z[  
try{ cPuXy e  
Thread.sleep(nSecond); ) c\Y!vS  
} +llb{~ZN  
catch(Exception e) T\bP8D  
{ :,aY|2si  
e.printStackTrace (); !|xB>d q?  
} `3i>e<m~  
} ;]Q6K9.d8  
(~zu4^9w  
//日志 :M6v<Kg{;  
public static void log(String sMsg) j\~,Gtn>Z  
{ qc @cd i  
System.err.println(sMsg); wCNn/%C  
} r5S/lp+Y+N  
mLZ1u\ 7W  
pN5kcvQ  
public static void log(int sMsg) ,GYQ,9:  
{ >lUPOc  
System.err.println(sMsg); Lo!hyQ)  
} 3;BIwb_  
} N~8H\  
^_Hf}8H7]  
2@6@|jRG  
/* }`<&l  
**TestMethod.java D/."0 #q  
*/ "x=\mA#`  
package NetFox; w/nohZF6H  
_P qq*  
1$vGQ  
public class TestMethod { 6(`N!]e*L  
yqq1a o  
JpfA+r  
public TestMethod() F*PhV|XU  
{ ///xx/weblogic60b2_win.exe M<w.q|P  
try{ W7!gD  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); J#Hh4Kc  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); V )<>W_g  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [G|.  
fileFetch.start(); n]IF`kYQV  
} ?CQE6ch  
catch(Exception e){e.printStackTrace ();} 3s!6rT_=)d  
bu _ @>`S  
>6 o <Q  
} Z\IM~-  
lw9jk`7^  
'lZlfS:Z8  
public static void main(String[] args) D j9aTO  
{ 8/aJ4w[A  
new TestMethod(); / (BS<A  
} #Zm`*s`  
} TRi#  
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