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http断点续传简单实现(java)

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/* #P- S.b  
**SiteFileFetch.java (eN\s98)/  
*/ .8l\;/o|  
package NetFox; \Btv76*,  
import java.io.*; &D uvy#J  
import java.net.*; IyYC).wU}  
T<DQi  
by& #g  
public class SiteFileFetch extends Thread { 1Af~6jz  
C2,,+* v  
cxrUk$f  
SiteInfoBean siteInfoBean = null; //文件信息Bean 3t(nV4uDF  
long[] nStartPos; //开始位置 ./)A6O*#  
long[] nEndPos; //结束位置 Xf9<kbRw/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 KQ xKU?b1  
long nFileLength; //文件长度 Uw5z]Jck  
boolean bFirst = true; //是否第一次取文件 bQb> S<PT  
boolean bStop = false; //停止标志 _;{n+i[  
File tmpFile; //文件下载的临时信息 (D{Fln\  
DataOutputStream output; //输出到文件的输出流 J(h=@cw  
9~<HTH  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) d> `9!)  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?I`']|I  
{ kh 1 7  
siteInfoBean = bean; ~ DVAk|fc  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); g% #" 5Kr  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !SD?  
if(tmpFile.exists ()) >.SU= HG;  
{ w:Tz&$&Y$  
bFirst = false; WtFv"$V  
read_nPos(); $Dd IY}  
} s<xD$K~rM  
else Wj/.rG&tE  
{ $k V^[  
nStartPos = new long[bean.getNSplitter()]; KDuM;  
nEndPos = new long[bean.getNSplitter()]; "N"9PTX  
} S-npJh 6  
sE-E\+  
[(5;jUmF@  
!t{3IE  
}  ]k_@F6 A  
//\ORJd  
^~0\d;l_  
public void run() v1QE|@  
{ fnG&29x  
//获得文件长度 UC;_}>  
//分割文件 b"t!nfgo  
//实例FileSplitterFetch $VhUZGuG>  
//启动FileSplitterFetch线程 ,;'9PsIS^  
//等待子线程返回 v}IkY  
try{ R>To L  
if(bFirst) jtV{Lf3<  
{ j>+x|!k  
nFileLength = getFileSize(); +T+f``RcK  
if(nFileLength == -1) =E8lpN'  
{ g9H~\w  
System.err.println("File Length is not known!"); vdYd~>w  
} {%'(IJ|5z  
else if(nFileLength == -2) ]YQlCx`  
{ r Ka7[/  
System.err.println("File is not access!"); x1]^].#Eo  
} cV_nYcLkz  
else C#`eN{%.YT  
{ uR|Jn)/m(  
for(int i=0;i<nStartPos.length;i++) Y{B|*[xM  
{ @ O5-w  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `ux U H#  
} D:U:( pg  
for(int i=0;i<nEndPos.length-1;i++) n@mWB UM  
{ }>=k!l{  
nEndPos = nStartPos[i+1]; 3205gI,  
} K~5QL/=1  
nEndPos[nEndPos.length-1] = nFileLength; p}hOkx4R\  
} 3aQWzEnh  
} :t8(w>oW  
=M>1;Qr<Z/  
D%N^iJC,9  
//启动子线程 =2BGS\$#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; j#"?Oe{_1  
for(int i=0;i<nStartPos.length;i++) t(-noy)  
{ GN /]^{D  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), YBN@{P$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),   _p\  
nStartPos,nEndPos,i); qg vg MWj  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L@2T  
fileSplitterFetch.start(); }a,j1r_Hl&  
} 5*xk8*  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r ioNP(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); mEmznA  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", fmXA;^%  
nEndPos = " + nFileLength); &/d;4Eu  
// fileSplitterFetch[nPos.length-1].start(); 1D&Q{?RM  
'^'vafs-/@  
".O+";wk  
//等待子线程结束 x1W<r)A )r  
//int count = 0; y5 $h  
//是否结束while循环 ZMy0iQ@  
boolean breakWhile = false; d_BECx <\  
YgNt>4K  
^]3Y11sI  
while(!bStop) sWP5=t(i+9  
{ 5m!FtHvm1  
write_nPos(); Cb7f-Eag  
Utility.sleep(500); tI|?k(D  
breakWhile = true; K4YpE}]u  
'due'|#^  
 $J>GCY  
for(int i=0;i<nStartPos.length;i++) dkt'~  
{ ;t{Ew+s  
if(!fileSplitterFetch.bDownOver) dFFJw[$8w  
{ Q<3=s6@T  
breakWhile = false; XZLo*C!MG  
break; @tWyc%t  
} ME7jF9d  
} bYGK}:T8U  
if(breakWhile) 1T a48  
break; `9n%Dy<  
9}Ud'#E  
oA%8k51>~K  
//count++; m!3b.2/h  
//if(count>4) BoE;,s>]NW  
// siteStop(); "rOe J~4 X  
} $@"o BCc  
,4zwd@&O  
3`S|I_$(T"  
System.err.println("文件下载结束!"); 9"Oz-!Y4  
} >j5) MF{"  
catch(Exception e){e.printStackTrace ();} G.OAzA13!t  
} eVyXh>b*  
1{i)7 :Y  
9>\P]:  
//获得文件长度 CpNnywDRwU  
public long getFileSize() o?$kcI4  
{ ]ppi962Z  
int nFileLength = -1; y.AVH`_u  
try{ \Z-T)7S  
URL url = new URL(siteInfoBean.getSSiteURL()); r63_|~JVB<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 55MrsiW  
httpConnection.setRequestProperty("User-Agent","NetFox"); _\hZX|:]  
")'o5V  
YhYcqE8  
int responseCode=httpConnection.getResponseCode();  17AJT  
if(responseCode>=400) Dj}n!M`2I  
{ .[%em9u  
processErrorCode(responseCode); +b"RZ:tKp  
return -2; //-2 represent access is error bwR_ uF  
} Q?-HU,RBO  
+ntrp='7O7  
aG.j0`)%  
String sHeader; 7p%W)=v  
qq" &Bc>  
6FNs4|(d  
for(int i=1;;i++) 9 ?a-1  
{ dznHR6x  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ,#3u. =IR[  
//Utility.log(in.readLine()); {WQH  
sHeader=httpConnection.getHeaderFieldKey(i); 20750G  
if(sHeader!=null) Oa~|a7`o  
{ MG)wVS<d_  
if(sHeader.equals("Content-Length")) M>W-lp^3  
{ ,3l=44*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); J0CEZ  
break; fmyyQ|]O"  
} ~WXT0-,  
} FjF:Eh  
else }_93}e  
break; B?`n@/  
} dR~4*59Bg  
} qplz !=  
catch(IOException e){e.printStackTrace ();} N=FU>qbz  
catch(Exception e){e.printStackTrace ();} qu- !XC0p  
l*_%K}%?V  
2 g5Ft  
Utility.log(nFileLength); ^HYmi\`  
Seh[".l  
tZ,vt7  
return nFileLength; [~03Z[_"/  
} K dY3  
4+%;eY.A  
8}9|hT;  
//保存下载信息(文件指针位置) RzCC>-  
private void write_nPos() S-V)!6\cK  
{ I{Hl2?CnI,  
try{ y3l3XLI*b  
output = new DataOutputStream(new FileOutputStream(tmpFile)); eFDhJ  
output.writeInt(nStartPos.length); ?O(KmDH  
for(int i=0;i<nStartPos.length;i++) 4|*b{Ni  
{ #RAez:BI  
// output.writeLong(nPos); ?w6zq|  
output.writeLong(fileSplitterFetch.nStartPos); 7KIOI,qb6  
output.writeLong(fileSplitterFetch.nEndPos); L".Qf|b*  
} -;pZC}Nd3  
output.close(); ,,1H#;j  
} #v!(uuq,  
catch(IOException e){e.printStackTrace ();} EOJk7  
catch(Exception e){e.printStackTrace ();} "{>I5<:t  
} %"tLs%"7=P  
?w'a^+H  
E*VUP 5E  
//读取保存的下载信息(文件指针位置) qjcy{@ j  
private void read_nPos() 2,,zN-9mt  
{ 9Fb|B  
try{ YI05?J}  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); T \%{zz_(  
int nCount = input.readInt(); s`"o-w\$>  
nStartPos = new long[nCount]; [P,YW|:n  
nEndPos = new long[nCount]; C@+"d3  
for(int i=0;i<nStartPos.length;i++) 3GVE/GtU  
{ @y:mj \J9  
nStartPos = input.readLong(); %-ih$ZY  
nEndPos = input.readLong(); l%"[857  
} k^3 ?Z2a  
input.close(); |O0=Q,<m  
} *?jU$&Qpj*  
catch(IOException e){e.printStackTrace ();} 46(Vq|  
catch(Exception e){e.printStackTrace ();} 0tbximmDb  
} i*3 4/  
#hL<9j  
{Ic~}>w  
private void processErrorCode(int nErrorCode) $nN`K*%  
{ )o!y7MTl  
System.err.println("Error Code : " + nErrorCode); 0{ M=^96  
} }#~@HM>6Z  
U-.?+ `  
`L<f15][  
//停止文件下载 7oY}=281  
public void siteStop() @ k+Z?Hp  
{ 4T#B7wVoM  
bStop = true; P(?i>F7s  
for(int i=0;i<nStartPos.length;i++) g7*cwu  
fileSplitterFetch.splitterStop(); q~*3Bk~  
Mf0!-bu  
e='bc7$  
} XVXiiQ^  
} BLx tS  
//负责部分文件的抓取 !(\OT  
**FileSplitterFetch.java 'VA\dpa{J  
*/ "=)i'x"0"  
package NetFox; W[S4s/)mg  
_r!''@B  
o6f^DG3*  
import java.io.*; ]{0R0Gr94  
import java.net.*; 0Yz &aH  
{l&6= z  
,EPs>#d  
public class FileSplitterFetch extends Thread { sO7$b@"u.  
ca>6r`  
c +Pg[1-  
String sURL; //File URL l!Q |]-.@  
long nStartPos; //File Snippet Start Position [s?H3yQ.  
long nEndPos; //File Snippet End Position $ijWwrh  
int nThreadID; //Thread's ID C6Qnn@waYb  
boolean bDownOver = false; //Downing is over I"awvUP]a[  
boolean bStop = false; //Stop identical TTjj.fq6  
FileAccessI fileAccessI = null; //File Access interface Y9F78=Q  
SI_{%~k*B  
a<+Qw'  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException $<^4G  
{ C~o6]'+F_  
this.sURL = sURL; y- S]\tu  
this.nStartPos = nStart; vn;_|NeSf  
this.nEndPos = nEnd; F 7+Gt Ed  
nThreadID = id; |a@$KF$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 p"^^9'`=  
} "B`yk/GM]  
e6s-;  
>o{(f  
public void run() F5Ce:+h  
{ YpQ/ )fSEV  
while(nStartPos < nEndPos && !bStop) zjd]65P  
{ =IBdnEz:M  
dP0!?J Y  
0Eq.l<  
try{ r1:S8RT;H5  
URL url = new URL(sURL); Ko%&~C_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T xRa&1  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]X4 A)4y  
String sProperty = "bytes="+nStartPos+"-"; b6=.6?H@4f  
httpConnection.setRequestProperty("RANGE",sProperty); k#k!AcC  
Utility.log(sProperty); IQ$l!)  
Nx4_Oc^hY  
PN0l#[{EN  
InputStream input = httpConnection.getInputStream(); }vBk ,ED  
//logResponseHead(httpConnection); .Ajs0 T2  
eK\ O>  
\ ?['pB  
byte[] b = new byte[1024]; (mXV5IM  
int nRead; kQlXcR  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ~ ar8e  
{ DmAMr=p  
nStartPos += fileAccessI.write(b,0,nRead); *,1^{mb  
//if(nThreadID == 1) #p~tkQ:'1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); k!E`Xeob  
} SPA_a\6_  
A S;ra,x  
?}^e,.M0?s  
Utility.log("Thread " + nThreadID + " is over!"); mJb>)bO l  
bDownOver = true; pLMki=.Ld  
//nPos = fileAccessI.write (b,0,nRead); '3=[xVnv  
} Uxx=$&#  
catch(Exception e){e.printStackTrace ();} ]t_AXKd  
} (_-<3)q4  
} 'LIJpk3J  
oPRvd_~  
reLYtv  
//打印回应的头信息 m<00 5_Z0Q  
public void logResponseHead(HttpURLConnection con) [ >#?C*s  
{ 04NI.Jv  
for(int i=1;;i++) &s_O6cqgh  
{ `9b/Q  
String header=con.getHeaderFieldKey(i); k{Yj!C> #  
if(header!=null) 4VLrl8$K  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); cF_`m  
Utility.log(header+" : "+con.getHeaderField(header)); 5{qFKo"g@,  
else w'ZL'/d  
break; m *8[I  
} O?NAbxkp  
} lwPK^)|}  
I"*g-ji0  
/HH5Mn*  
public void splitterStop() (qHI>3tpY  
{ n5"rSgUtE  
bStop = true; 2-nL2f!a{p  
} cX"[#Em#  
(i>VJr  
_m0H gLS~  
} rFZB6A<(]  
5~4I.+~8  
dsqqq,>Q  
/* jy{T=Nb  
**FileAccess.java x, a[ p\1  
*//文件访问(定位,写) 95^w" [}4Q  
package NetFox; h";G vjy  
import java.io.*; ("o <D{A  
Y>Q9?>}Q  
laqKP+G  
public class FileAccessI implements Serializable{ {'G@-+K  
h;f5@#F  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 iyrUY  
RandomAccessFile oSavedFile; orf21N+[  
long nPos; RvV4SlZz  
9 a2Ga   
N8 }R<3/  
public FileAccessI() throws IOException fHYEK~!C04  
{ K,%H*1YKK  
this("",0); IJO`"da  
} "QACQ-  
Fgxh?Wd9  
h J#U;GL  
public FileAccessI(String sName,long nPos) throws IOException ~\DC )  
{ Sj(uc#  
oSavedFile = new RandomAccessFile(sName,"rw"); sIdo(`8$  
this.nPos = nPos; l*("[?>I  
oSavedFile.seek(nPos); N:[m,U9a  
} 3Gf^IV-  
A_T-]YQ  
qdm5dQ (c  
public synchronized int write(byte[] b,int nStart,int nLen) U*, 8 ,C  
{ J]nb;4w  
int n = -1; EnA) Rz  
try{ O[y.3>l[s  
oSavedFile.write(b,nStart,nLen);  IPa08/  
n = nLen; LslQZ]3MY  
} `R0>;TdT  
catch(IOException e) L7_Mg{  
{ U2/H,D  
e.printStackTrace (); 5.F.mUO  
} @no]*?Gpa  
%m!o#y(hD`  
hE-`N,i }  
return n; $&nF1HBI4  
} =#n05*^  
e"hm|'  
Yi&;4vC  
} V\%;S  
IV;juFw}G  
:ZL;wtT  
/* \`jFy[(Pa'  
**SiteInfoBean.java #nX0xV5=  
*/ _)p@;vGV  
package NetFox; n99:2r_  
yEtI5Qk  
ygS*))7 r  
public class SiteInfoBean { $$<9tqA  
SG |!wH^  
t*zve,?}  
private String sSiteURL; //Site's URL _s (0P*  
private String sFilePath; //Saved File's Path 9c9-1iS  
private String sFileName; //Saved File's Name vLD Ma>  
private int nSplitter; //Count of Splited Downloading File 2V/ A%  
;gy_Qf2U  
.}kUD]pW  
public SiteInfoBean()  kOETx  
{//nSplitter的缺省值为5 a+)Yk8%KY  
//default value of nSplitter is 5 f'TjR#w  
this("","","",5); sn2SDHY  
} ?`AzgM[I  
?*K;+@EH  
f'\I52;FB  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {}N*e"<O  
{ wJ1qJ!s@  
sSiteURL= sURL; lg&"=VXx51  
sFilePath = sPath; %;^[WT`,  
sFileName = sName; g$ZgR)q  
this.nSplitter = nSpiltter; b:\I*WJ  
LpaY M d;  
a36n}R4Q  
} k^z)Vu|f.  
d"Y9go"Z  
!sEI|47{  
public String getSSiteURL() fW!~*Q  
{ . Uv7{(  
return sSiteURL; ss T o?WL|  
} /],:sS7  
P9:7_Vc  
!w]!\H  
public void setSSiteURL(String value) y1c Aw   
{ 6=Kl[U0Y  
sSiteURL = value; RZjTUMAz4  
} [WXtR  
_D1bR7  
,[,+ _A  
public String getSFilePath() yx3M0Qo  
{ g~h`wv'  
return sFilePath; '`T.K<  
} v+znKpE  
YN n,{Xi  
y mY,*Rb  
public void setSFilePath(String value) hZY+dHa]  
{ kWjCSC>jA  
sFilePath = value; Au#(guvm  
} 0?BT*  
Ooc,R(  
Zla5$GM  
public String getSFileName() Ag }hyIl  
{ ?qAX *j  
return sFileName; zu(/ c  
} Ec8Y}C,{7<  
cInzwdh7  
BqvOi~ l  
public void setSFileName(String value) gmLGK1  
{ FgE6j;   
sFileName = value; D *Siy;  
} \! Os!s  
=y,_FFoS  
7`6n]4e  
public int getNSplitter() D2E~ c? V  
{ D`3}j  
return nSplitter; vpv PRwJ  
} aN ). G1  
L; Nz\sJ  
#?}k0Y  
public void setNSplitter(int nCount) +I/7eIG?|  
{ ~d/Doi  
nSplitter = nCount;  v#IW;Rj8  
} %g5weiFM  
} E+dr\Xhv  
@,CCwiF'q  
QJTGeJ Y  
/* }=^YLu=  
**Utility.java $EN A$  
*/ F&lWO!4  
package NetFox; ORs<<H.d  
LV0g *ng  
ZWG$MFEjl  
public class Utility { ]d9;YVAU  
r|fJ~0z  
&w*.S@  ;  
public Utility() 6f?5/hq  
{ !a[ voUS  
'dQ2"x?4  
:o*{.  
} Fb*^GH)J  
UB|Nx(V s  
//线程睡眠 y,DK@X  
public static void sleep(int nSecond) 4sSQ nK  
{ !Lb9KDk  
try{ Kk!D|NKLC  
Thread.sleep(nSecond); r444s8Y  
} J *.Nf)i  
catch(Exception e) tU!"CX  
{ Dgc[WsCEW  
e.printStackTrace (); ``1#^ `  
} P{)&#HXUVb  
} 5f=e JDo=x  
FxKH?Rl  
//日志 7xVI,\qV  
public static void log(String sMsg) bo$xonV@y  
{ b}9K"GT  
System.err.println(sMsg); Xleoh2&M  
} :)q/8 0@  
r*>XkM& M  
4^w>An6  
public static void log(int sMsg) RB\>$D  
{ bG^E]a/D  
System.err.println(sMsg); Cm JI"   
} G- Sw`HHo  
} e3F)FTG&  
#fG!dD42  
H[*.Jd  
/* . m7iXd{  
**TestMethod.java *Y9"-C+  
*/ <gZC78}E  
package NetFox; AQbbIngo  
c<A@Op"A  
"h_n/}r=  
public class TestMethod { s+yBxgQ/  
A0oC*/  
6}L[7~1  
public TestMethod() W7l/{a @  
{ ///xx/weblogic60b2_win.exe *VIM!/YW  
try{ e l'^9K  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6y%BJU.I  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); s)375jCga  
SiteFileFetch fileFetch = new SiteFileFetch(bean); hs2f3;)  
fileFetch.start(); (vz)GrH>  
} d7It}7@9  
catch(Exception e){e.printStackTrace ();} W2%(a0p  
5;>M&qmN  
Z&s+*& TM  
} ;T"}dJel#  
 _"%d9B  
^KF  
public static void main(String[] args) $*xnq%A  
{ Z #w1,n88  
new TestMethod(); I = qd\  
} W5 fO1F  
} R|$=Pfg~4  
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