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http断点续传简单实现(java)

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/* <0h,{28  
**SiteFileFetch.java HB0DG<c-  
*/ x o{y9VS  
package NetFox; nQm (UN  
import java.io.*; UzKB"Q  
import java.net.*; *~%QXNn`  
+YFAZv7`  
/h v2=A  
public class SiteFileFetch extends Thread { ]*&`J4i  
l2h1CtAU  
e&\+o}S  
SiteInfoBean siteInfoBean = null; //文件信息Bean yBYZ?gc  
long[] nStartPos; //开始位置 z[?&bF<|  
long[] nEndPos; //结束位置 dm~Uj  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 gK_#R]  
long nFileLength; //文件长度 k )=Gyv<  
boolean bFirst = true; //是否第一次取文件 i[O{ M`Z%  
boolean bStop = false; //停止标志 \T:*tgU  
File tmpFile; //文件下载的临时信息 ]dd TH l  
DataOutputStream output; //输出到文件的输出流 87p tab@  
.*~t2 :  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) KfkU_0R+~v  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6BY(Y(z  
{ hx$b Y  
siteInfoBean = bean; ?Hrj}K27  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); QZ2a1f'G  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ]z#9)i_l3  
if(tmpFile.exists ()) R\Of ,  
{ j9g0k<eg  
bFirst = false; 4V7=VZ, @3  
read_nPos(); 9?Q0O\&uP  
} |FP@NUX\  
else ~(P\'H&(h  
{ _(J4  
nStartPos = new long[bean.getNSplitter()]; K]H [A,  
nEndPos = new long[bean.getNSplitter()]; /`+ubFXc  
} iVZ X  
w%uM=YmuT  
SG{&2G  
)tp;2rJ/  
} 1`F25DhhY  
X 3(CY`HH[  
g..&x]aS(  
public void run() N@3&e;y  
{ |TQa=  
//获得文件长度 X(qs]:  
//分割文件 +T8]R7b9  
//实例FileSplitterFetch (3  ]!ZV  
//启动FileSplitterFetch线程 4Pkl()\c  
//等待子线程返回 byN4?3 F  
try{ HbMD5(  
if(bFirst) fIii  
{ 7f]O /  
nFileLength = getFileSize(); V1 {'d[E*  
if(nFileLength == -1) 6e4A| <  
{ 5$%CRm  
System.err.println("File Length is not known!"); q?=_{oH9  
} 7i0;Ss*  
else if(nFileLength == -2) &]jCoBj+_  
{ evro]&N{  
System.err.println("File is not access!"); 3bZ:*6W.6  
} <hB~|a<#  
else .s`7n *xz  
{ JVq`v#8  
for(int i=0;i<nStartPos.length;i++) M <c cfU!  
{ 6T-iBJT  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); JTdcL mL  
} WF`  
for(int i=0;i<nEndPos.length-1;i++) `XK#sCC  
{ =g<Yi2  
nEndPos = nStartPos[i+1]; G&@vTcF  
} U{ ZKxE  
nEndPos[nEndPos.length-1] = nFileLength; a~A"uLBR  
} Z1sRLkR^  
} 2O " ~k  
8c'5P  
<59G  
//启动子线程 1)!?,O\ey  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; c'uDK>  
for(int i=0;i<nStartPos.length;i++) ~5 e 1&  
{ 6;p"xC-  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yCZ[z A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %40+si3c  
nStartPos,nEndPos,i); )mE67{YJh~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4]m?8j) 6b  
fileSplitterFetch.start(); 'aJm4W&j  
} o{xA{ @<  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B5MEE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); f\c%G=y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", AN4(]_ ]  
nEndPos = " + nFileLength); Jk,}3Cr/  
// fileSplitterFetch[nPos.length-1].start(); Qvm[2mb  
cPg$*,]  
mmBZ}V+&=  
//等待子线程结束 +YnQOh%v0s  
//int count = 0; 7!('+x(>  
//是否结束while循环 jU_#-<'r  
boolean breakWhile = false; E9#.!re|^  
YA*E93J0  
W24n%Ps  
while(!bStop) A =l1_8,`h  
{ ;1L7+.A  
write_nPos(); 8e}8@[h  
Utility.sleep(500); %\?Gzc_  
breakWhile = true; &~sk7iGi  
ZY-mUg  
'~OKt`SfIo  
for(int i=0;i<nStartPos.length;i++) &T[BS;  
{  Sn-D|Z  
if(!fileSplitterFetch.bDownOver) D0@d}N  
{ !)h?2#V8;  
breakWhile = false; of>}fJ_p  
break; <PTi>C8;r  
} Y"'k $jS-  
} F>co#  
if(breakWhile) g0"KC X  
break; YV"LM6`  
q.69<Rs  
["XS|"DM  
//count++; iYl$25k/1  
//if(count>4)  9Li.B1j  
// siteStop(); {uji7TB  
} 4&'_~qU  
77o&$l,A|  
v9+1[Y";  
System.err.println("文件下载结束!"); s&~.";b  
} aFVd}RO0  
catch(Exception e){e.printStackTrace ();} kU$M 8J.  
} /7-qb^V  
DU.[Sp  
/dt'iai~l  
//获得文件长度 *r]Mn~3  
public long getFileSize() M}W};~V2ng  
{ z]F4Z'(e.  
int nFileLength = -1; V0'_PR@;  
try{ {;j@-=pV  
URL url = new URL(siteInfoBean.getSSiteURL()); x:WxEw>R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _HkB+D0v  
httpConnection.setRequestProperty("User-Agent","NetFox"); C*fSPdg?  
x8wal[6  
RXU#.=xvy  
int responseCode=httpConnection.getResponseCode(); bLpGrGJs  
if(responseCode>=400) -(YdK8  
{ 1O]27"9  
processErrorCode(responseCode); #3o]Qo[Sc  
return -2; //-2 represent access is error 8ncgTCH:  
} Nd.Tda!Kg  
.4-I^W"1  
x#s=eeP1  
String sHeader; smt6).o  
Uv"GG: K_  
6X.lncE@p  
for(int i=1;;i++) m+/-SG  
{ Ug|o ($CY  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L?5OWVX!v  
//Utility.log(in.readLine()); !.ot&EbE  
sHeader=httpConnection.getHeaderFieldKey(i); $@blP<I  
if(sHeader!=null)  ^"d!(npw  
{ Aa;s.:?  
if(sHeader.equals("Content-Length")) ii :h E=  
{ jW-j+ WGSM  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \Ow-o0  
break; HLy}ta\  
} L('G1J}  
} "wPFQXU  
else $*{$90 Q  
break; )2 P4EEs[  
} {m/\AG)1I  
} $I7/FZP  
catch(IOException e){e.printStackTrace ();} hC.7Z]  
catch(Exception e){e.printStackTrace ();} %q@eCN  
t;@VsQ8  
@:~O  
Utility.log(nFileLength); M_2[Wypw  
m$xyUv1  
y^gazr"  
return nFileLength; .wD>0Ig  
} $e|G#mMd-  
%&yD^ q_  
n NI V(  
//保存下载信息(文件指针位置) ]8q5k5~  
private void write_nPos() 1a)NM#  
{ SrN;S kS  
try{ B(mxW8y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?'K}bmdt}.  
output.writeInt(nStartPos.length); m%$z&<!  
for(int i=0;i<nStartPos.length;i++) 'A,&9E{%1  
{ @\_ tS H  
// output.writeLong(nPos); ih?_ fW  
output.writeLong(fileSplitterFetch.nStartPos); 8kih81tx"U  
output.writeLong(fileSplitterFetch.nEndPos); vL13~q*F  
} 9jiZtwRpk  
output.close(); r6Z&i^cMe  
} <}%>a@  
catch(IOException e){e.printStackTrace ();} 2F3IC  
catch(Exception e){e.printStackTrace ();} Y$EqBN  
} ,{7wvXP  
w?.0r6j  
.bvB8VOrW  
//读取保存的下载信息(文件指针位置) Xt /T0.I  
private void read_nPos() A0M)*9 f  
{ pCA(>(  
try{ uj&^W[s  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Nm<3bd  
int nCount = input.readInt(); N40.GL0s  
nStartPos = new long[nCount]; 'oHtg @  
nEndPos = new long[nCount]; lMp)T**  
for(int i=0;i<nStartPos.length;i++) !l_ 1r$  
{ :SSe0ZZ_6b  
nStartPos = input.readLong(); %Md;=,a:6  
nEndPos = input.readLong(); _C"W;n'  
} V_!hrKkL  
input.close(); c3!d4mC:  
} Hbx=vLQ6  
catch(IOException e){e.printStackTrace ();} 9wC q  
catch(Exception e){e.printStackTrace ();} bR49(K$~  
} A;w,m{9<  
bWwc2##7jo  
s9qr;}U.`  
private void processErrorCode(int nErrorCode) 9<P1?Q  
{ 9pStArF?F0  
System.err.println("Error Code : " + nErrorCode); {DBgW},  
} GKtG#jZ&  
3yDa5q{  
#+QwRmJdT!  
//停止文件下载 ,S:LhgSP  
public void siteStop() EdE,K1gD  
{ 2>.B*P  
bStop = true; 4&r^mGs,  
for(int i=0;i<nStartPos.length;i++) @1gX>!  
fileSplitterFetch.splitterStop(); }!(cm;XA"  
yu<sd}@  
_%;$y5]v  
} AlIFTNg:"  
} {*`qL0u]^  
//负责部分文件的抓取 5)2lZ(5.A#  
**FileSplitterFetch.java |9jeOV}/  
*/ 4rc4}Yu,JI  
package NetFox; y!."FoQ  
/'u-Fr(Q+  
tqAh &TW3+  
import java.io.*; O]~cv^  
import java.net.*; GG5wiN*2S  
!GURn1vcAe  
D^]7/w:$-  
public class FileSplitterFetch extends Thread { ]P<u^ `{*  
k!>MZ  
U{} bx  
String sURL; //File URL e54wAypPOl  
long nStartPos; //File Snippet Start Position H@qA X  
long nEndPos; //File Snippet End Position /d&zE|!  
int nThreadID; //Thread's ID "b8<C>wY  
boolean bDownOver = false; //Downing is over * h!gjbi  
boolean bStop = false; //Stop identical /=*h\8c~  
FileAccessI fileAccessI = null; //File Access interface -[|R \'i  
!0CC&8C`  
SHOg,#mV  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 5(^&0c>P  
{ x?9rT 0D  
this.sURL = sURL; Waj6.PCFm  
this.nStartPos = nStart; >u ,Ac:  
this.nEndPos = nEnd; Fc M  
nThreadID = id; S4aN7.'Q  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 L%}k.)yev  
} o|*ao2a  
T ]hVO'z  
f',n '  
public void run() @#hd8_)A.  
{ y4PR&^l?g  
while(nStartPos < nEndPos && !bStop) V##=-KZ  
{ Q0K2md_%x  
@e8b'w3  
ig5 d-A  
try{ :hr% 6K7  
URL url = new URL(sURL); 9fj3q>Un,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b R> G%*a  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0+L:+S  
String sProperty = "bytes="+nStartPos+"-"; 1G$fU zS  
httpConnection.setRequestProperty("RANGE",sProperty); M{cF14cQ  
Utility.log(sProperty); <ZcJC+k  
/'k4NXnW3  
YRa{6*M  
InputStream input = httpConnection.getInputStream(); |ZZl3l=]  
//logResponseHead(httpConnection); 4r&DW'  
ntR@[)K  
2[!#Xf  
byte[] b = new byte[1024]; Wi7!J[ B  
int nRead; B_R J;.oH  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @`R#t3)8JP  
{ T'_#Dwmj*  
nStartPos += fileAccessI.write(b,0,nRead); yvR3|  
//if(nThreadID == 1) &O8vI ,M  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )45~YDS;t  
} Q^13KWvuV  
c=d` DJ  
v~E\u  
Utility.log("Thread " + nThreadID + " is over!"); 7Z%EXDm4/c  
bDownOver = true; @jh\yjrW  
//nPos = fileAccessI.write (b,0,nRead); 1i=lJmr  
} %!DdjC&5*  
catch(Exception e){e.printStackTrace ();} JTGA\K  
} zplAH!s5''  
} P:D@ 5  
?{=& Ro  
hc7"0mVd{  
//打印回应的头信息 @M( hyS&on  
public void logResponseHead(HttpURLConnection con) kXW5bR  
{ JG^fu*K  
for(int i=1;;i++) _*iy *:(o  
{ PmjN!/  
String header=con.getHeaderFieldKey(i); !O )je>A  
if(header!=null) vciO={M  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <Wr n/%tL  
Utility.log(header+" : "+con.getHeaderField(header)); 8O^<#lh  
else Rtywi}VV2  
break; RnV#[bM{  
} B`<a~V  
} o|7ztpr  
hl} iw_e  
*ggai?  
public void splitterStop() G/ sRi wL  
{ Pk ?M~{S  
bStop = true; aU\R!Y$/"  
} xaN[ru@  
aHR+4m~)  
=|+%^)E  
} 62.)fCQ^  
8*x/NaH /\  
U{C& R&z  
/* tD^$}u6  
**FileAccess.java yDapl(  
*//文件访问(定位,写) 'Lu d=u{  
package NetFox; F:~k4uTW\b  
import java.io.*; pQ,|l$^m  
=w;~1i% .k  
~'#yH#o  
public class FileAccessI implements Serializable{ aG&t gD{  
aN5"[&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 zI7iZ"2a  
RandomAccessFile oSavedFile; 4k_y;$4WN  
long nPos; W0+m A  
<SKzCp\  
Oh=E!  
public FileAccessI() throws IOException A.+Qa  
{ 1v~1?+a\2  
this("",0); dbG902dR  
} ~ugyUpY"  
{i"t h(J$  
[;Y*f,UG_-  
public FileAccessI(String sName,long nPos) throws IOException ,p' ;Xg6ez  
{ ,a34=,  
oSavedFile = new RandomAccessFile(sName,"rw"); HVz|*?&6  
this.nPos = nPos; 3f-J%!aH  
oSavedFile.seek(nPos); g1{2E<b 5  
} F\2<q$Zn+  
Dqg01_O9O  
=))VxuoN  
public synchronized int write(byte[] b,int nStart,int nLen) Yln[ZmK9g  
{ ,1 ^IFBJ  
int n = -1; B8`!A  
try{ '/F%  ff  
oSavedFile.write(b,nStart,nLen); !j%#7  
n = nLen; @(CJT-Ak  
} h4E[\<?  
catch(IOException e) PI&@/+  
{ B=)tq.Q7  
e.printStackTrace (); ==npFjB  
} +W+o~BE  
FT6~\9m(  
IFbN ]N0  
return n; G2yQHTbl  
} si1Szmx,  
m't8\fo^w  
-ZH6*7!  
} XP(fWRT1  
8,L)=3m-  
-5y=K40  
/* AP9>_0=  
**SiteInfoBean.java ldWrv7. P  
*/ ^WUG\@B  
package NetFox; )@_5}8  
c,Yd#nokC  
A>C8whx  
public class SiteInfoBean { 4tlLh`-8  
@DuSii#.S  
!h70<Q^  
private String sSiteURL; //Site's URL Ap!Y 3C  
private String sFilePath; //Saved File's Path FvVM}l'  
private String sFileName; //Saved File's Name r2=4Wx4(  
private int nSplitter; //Count of Splited Downloading File >k8FUf(c  
IN?rPdY  
&+")~2 +  
public SiteInfoBean() evlz R/  
{//nSplitter的缺省值为5 78kT}kgW  
//default value of nSplitter is 5 g]9A?#GyE  
this("","","",5); ;v m$F251  
} ^q\9HBHT  
QFU1l"(qGk  
eT@, QA(3  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;oWak`]f  
{ ok/{ w  
sSiteURL= sURL; P vW~EJ  
sFilePath = sPath; QygbfW6u  
sFileName = sName; Jj7he(!_1  
this.nSplitter = nSpiltter; %Wa. 2s  
:,Mg1Zf  
C/YjMYwKgv  
} c52S2f7  
O[^u<*fi{  
x%%OgO +>  
public String getSSiteURL() h`pXUnEZ  
{ kB=\a(  
return sSiteURL; .iZo/_  
} O_^;wey0}?  
-$o4WSd~  
Iz9b5  
public void setSSiteURL(String value) aUbmEHFTV  
{ ~ ":}Rs  
sSiteURL = value; 8}{W.np_  
} %Mr^~7nN  
N.?)s.D(  
M6H#Y2!ZbC  
public String getSFilePath() W5R /  
{ ~ }?*v}  
return sFilePath; b9TsuY  
} -HUlB|Q8r  
A3Oe=rB  
$kd9^lj#[  
public void setSFilePath(String value) 5'S~PQka*  
{ [)t1"  
sFilePath = value; 1Y{pf]5Wx  
} Q$8K-5U%  
OpFm:j3  
PEPf=sm  
public String getSFileName() Q=#N4[W'  
{ !Hx[ `3  
return sFileName; ,O`~ D~$  
} rvp#[RAaS}  
.?)gn]#  
6Ej.X)~'K  
public void setSFileName(String value) C(}N*e1  
{ h+j{;evN  
sFileName = value; !M;><b}=5  
} m.w.h^f$&  
tWaM+W  
FS7@6I2Ts  
public int getNSplitter() @3Gr2/a  
{ ^n9)rsb  
return nSplitter; ayr CLv  
} aM|;3j1p  
I8Q!`K J  
J4#rOS  
public void setNSplitter(int nCount)  &sg~owz  
{ ;3Z6K5z*f  
nSplitter = nCount; ^]X\boWlI  
} ?<STl-]&  
} DE!c+s_g4  
!z2KQ 4C  
q}cm"lO$  
/* GGez!?E%  
**Utility.java K(}g!iT)~  
*/ +{L=cWA"  
package NetFox; l$ufW|  
!yD$fY  
D+"+m%^>C  
public class Utility { GBYwS{4  
)Y:C'*.r  
og`K! d~  
public Utility() rmJ`^6V  
{ Z7dyPR  
HcCT=x7:  
y&6 pc   
} Cq[<CPAS  
fVz0H1\J&  
//线程睡眠 w@x||K=Z  
public static void sleep(int nSecond) ^NXxMC( e+  
{ '+v[z=.8]  
try{ #Q@~ TW  
Thread.sleep(nSecond); ).IK[5Q`  
} #oJ%i+V  
catch(Exception e) J~|:Q.Rt`  
{ 4(&sw<k  
e.printStackTrace (); ffR<G&"n~b  
} pvhN.z  
} ..Bf-)w  
zKfY0A R  
//日志 c7A]\1 ~  
public static void log(String sMsg) [Gc9 3PA7q  
{ ',]^Qu`a  
System.err.println(sMsg); x9\]C' *sO  
} } p `A>  
7V-uQ)*  
5M\bH'1  
public static void log(int sMsg) ,c|Ai(U  
{ 7)*q@  
System.err.println(sMsg); rmeGk&*R8  
} Y'yGhpT~  
} $0*D7P^8  
B^Hh rz!  
a xz-H`oq4  
/* %xdyG Al:  
**TestMethod.java 4o<' fY  
*/ #N'bhs  
package NetFox; O? 0`QMY  
w%$J<Z^-?  
gP`CQ0t  
public class TestMethod { Hb\['VhzM  
Cy6%f?j  
vF9fXY=  
public TestMethod() p8MN>pLP%  
{ ///xx/weblogic60b2_win.exe Bi7&yS5V  
try{ A().1h1_k  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Bh;N:{&^Eu  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); lsU`~3nr  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?@QcKQ@  
fileFetch.start(); iN1_ T  
} ?8YbTn1f)  
catch(Exception e){e.printStackTrace ();} s#FX2r3=Fg  
o @nsv&i  
d$y?py  
} g/gaPc*86  
a}[rk*QmZ  
'^(qlCI  
public static void main(String[] args) (3&P8ZGNR  
{ q-qz-cR  
new TestMethod(); aX? tnDv  
} W!JEl|]  
} 4xgfm.9I^  
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