http断点续传简单实现（java)

/* Ms * `w5n  
**SiteFileFetch.java m+3U[KKvG  
*/ J%|n^^ /un  
package NetFox; iS/faXe5  
import java.io.*; v;=|-y  
import java.net.*; N,oN3mFF  
"
}91wfG9  
:h(r2?=7  
public class SiteFileFetch extends Thread { 948lL&  
~a5-xWEZ  
ggP#2I\  
SiteInfoBean siteInfoBean = null; //文件信息Bean `fL81)!jI#  
long[] nStartPos; //开始位置 f>i" j  
long[] nEndPos; //结束位置 MPS{MGVjbJ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 pz uR H1[  
long nFileLength; //文件长度 j$%uip{  
boolean bFirst = true; //是否第一次取文件 q3SYlL'a  
boolean bStop = false; //停止标志 \H6[6*JuB  
File tmpFile; //文件下载的临时信息 h3udS{9'8  
DataOutputStream output; //输出到文件的输出流 _,G^#$pH  
\NgBF  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Pl9Ky(Q`V  
public SiteFileFetch(SiteInfoBean bean) throws IOException S|_}
0  
{ #0F6{&; M  
siteInfoBean = bean; a,EApUWw  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); EId_1F;V^  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~"IjT'W3  
if(tmpFile.exists ()) @/DHfs4O  
{ Q*GJREC  
bFirst = false; L)mb.U$`c|  
read_nPos(); 2)W~7GED  
} $@R[$/  
else VQMPs{tm  
{ ^o|Gx  
nStartPos = new long[bean.getNSplitter()]; uFXu9f+  
nEndPos = new long[bean.getNSplitter()]; 8
3|7#L  
} pT=YV k  
~"t33U6  
L'KgB=5K&i  
q|r/%[[!o  
} x9lG$0k:V  
r^jiK\*  
Z~WUILx,  
public void run() ~Wox"h}(  
{ *fIb|r  
//获得文件长度 Js'#=  
//分割文件 >E:V7Fa  
//实例FileSplitterFetch n$})}kj  
//启动FileSplitterFetch线程 [!Jd.zm  
//等待子线程返回 AD=qB5:  
try{ 4XCy>;4u  
if(bFirst) ":G\  
{ $vQ#ah/k  
nFileLength = getFileSize(); <)J83D0$E  
if(nFileLength == -1) c[n4{q1  
{ w:0=L`<Eu  
System.err.println("File Length is not known!"); GmJ4AYEP  
} ~dpU DF  
else if(nFileLength == -2) foi@z9  
{ W ^MF3  
System.err.println("File is not access!"); \]a@ NBv  
} <Y9 L3O`[  
else |hlc#t?  
{ OZ'=Xtbn  
for(int i=0;i<nStartPos.length;i++) 4)zHk
N+  
{ ~53uUT|B  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Z%t"~r0PS  
} aSy^(WN8  
for(int i=0;i<nEndPos.length-1;i++) h>A~..  
{ @S%ogZz*m  
nEndPos = nStartPos[i+1]; *nj={Ss&  
} ("+J*u*kq_  
nEndPos[nEndPos.length-1] = nFileLength; n*Q~<`T  
} ROv(O;.Ty  
} *G6Py,- !f  
I>(3\z4s  
+;ILj<!Z7  
//启动子线程 W'B=H1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; pel{
;r  
for(int i=0;i<nStartPos.length;i++) "Q>gQKgL  
{ f <,E  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rKtr&w7X  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Hw(_l,Xf  
nStartPos,nEndPos,i); gHB*u!w7Z  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); s\CZ os&  
fileSplitterFetch.start(); ++HHUM  
} 8c6dTT4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t,f)!D$
 
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4=Wtv/ 3  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", hI^Hqv  
nEndPos = " + nFileLength); ]+!{^h$  
// fileSplitterFetch[nPos.length-1].start(); ;VLv2J*
 
E/OJ}3Rf  
/CE]7m,7~K  
//等待子线程结束 %/K'VE6pb  
//int count = 0; nQ$4W  
//是否结束while循环 g?}$"=B   
boolean breakWhile = false; ek^=Z`  
@jKiE%OP  
ZSBa+3;z  
while(!bStop) w6-A-M6hD  
{ _4#8o\  
write_nPos(); B;3lF;3`  
Utility.sleep(500); {N \ri{|  
breakWhile = true; "5 /i  
[32]wgw+{1  
$RFy9(>  
for(int i=0;i<nStartPos.length;i++) *tWZ.I<<  
{ TpHvZ]c  
if(!fileSplitterFetch.bDownOver) =J2cX`  
{  ?^8CD.|  
breakWhile = false; x344}\  
break; ?)Psf/  
} (P+TOu-y\  
} H/rJ:3  
if(breakWhile) <wI
z8V  
break; >q}Ns^ .'  
0wh4
sKm[X  
JQo"<<[  
//count++; \$g,Hgp/<  
//if(count>4) ![>j`i  
// siteStop(); y7x&/2  
} $X>$)U'p&-  
~]d3 f  
_#jR6g TY  
System.err.println("文件下载结束！"); cE|Z=}4I7  
} +9tm9<
F8  
catch(Exception e){e.printStackTrace ();} <\9M+  
} =SY`Xkj[  
,?3)L   
/OX;3" +1  
//获得文件长度 dr54D  
public long getFileSize() 5>S<9A|Q  
{ 60iMfcT  
int nFileLength = -1; ::lD7@Wg  
try{ 77]6_  
URL url = new URL(siteInfoBean.getSSiteURL()); )6t=Bel  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w[/_o,R  
httpConnection.setRequestProperty("User-Agent","NetFox"); Uyuvmt>  
e2}5< 7  
03!!# 5iJ  
int responseCode=httpConnection.getResponseCode(); ; xz}]@]Ar  
if(responseCode>=400) >k)zd-  
{
H2cY},  
processErrorCode(responseCode); Wf}x"*  
return -2; //-2 represent access is error _ Cu,"  
} 88}=V
S  
[8Yoz1(smA  
; *@lH%u  
String sHeader; xc&&UKd  
,t!K? Y  
v=Y) A?  
for(int i=1;;i++) S+LS!b  
{ v
?)u1-V0  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); "fq8)  
//Utility.log(in.readLine()); Vi5&%/Y  
sHeader=httpConnection.getHeaderFieldKey(i); o=}vK[0u  
if(sHeader!=null) @5)THYAx4  
{ 03$lgD
Q  
if(sHeader.equals("Content-Length")) SR<*y

O  
{ ,RYahu  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )2YZ [~3  
break; JKMcdD?'  
} \U
\k$ (  
} }vof| (Yh  
else |E7)s;}D  
break; uA1DTr?z  
} {-'S#04  
} l4
LowV7  
catch(IOException e){e.printStackTrace ();} 1oVjx_I5y  
catch(Exception e){e.printStackTrace ();} #ozQF~
 
Cjn)`Q8  
1(ud(8?|  
Utility.log(nFileLength); !arTR.b\  
noLb  
1$^=M[v  
return nFileLength; gvi]#|  
} `tjH#
W`  
"p[FFg  
d J;y>_  
//保存下载信息（文件指针位置） "v9i;Ba>+  
private void write_nPos() K7 N)VG  
{ %w0Vf$  
try{ Ov5*&*P  
output = new DataOutputStream(new FileOutputStream(tmpFile)); cYafQyU  
output.writeInt(nStartPos.length); $sTvXf:g  
for(int i=0;i<nStartPos.length;i++) k"V@9q;*  
{ 3|FZ!8D  
// output.writeLong(nPos); }s7ibm'  
output.writeLong(fileSplitterFetch.nStartPos); IxxA8[^V  
output.writeLong(fileSplitterFetch.nEndPos); @N'0:0Nb_  
} {q}#  Sq  
output.close(); ji(Y?vhQt  
} 3IK+&hk  
catch(IOException e){e.printStackTrace ();} VSJ08Ngi   
catch(Exception e){e.printStackTrace ();} 5{@Hpj/B  
} xr<.r4  
K#LG7faj  
RlH~<|XK  
//读取保存的下载信息（文件指针位置） XJ.ERLR.  
private void read_nPos() NxyrP**j  
{ g^qbd$}  
try{ FlPPz  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); +l,6}tV9  
int nCount = input.readInt(); ?g5u#Q>!  
nStartPos = new long[nCount]; ONkHHyT  
nEndPos = new long[nCount]; M\f1]L|8d  
for(int i=0;i<nStartPos.length;i++) \1p_6U7  
{ @}^eyS$|!  
nStartPos = input.readLong(); TP5?%SlJ  
nEndPos = input.readLong(); S/XkxGZ2  
} npW1Z3n  
input.close(); OGjeE4  
} $7 08\!  
catch(IOException e){e.printStackTrace ();} \~Yy
Y'J  
catch(Exception e){e.printStackTrace ();} ).Ei:/*j  
} ezOZHY>|#  
)= ,Lfj8x  
)/:&i<Q:  
private void processErrorCode(int nErrorCode) #1v>3H(  
{ ^uy2qO4Yw  
System.err.println("Error Code : " + nErrorCode); :cmQ w  
} i~k9s  
LcA~a<_  
77Fpb?0`  
//停止文件下载 XgfaTX*  
public void siteStop() fnUR]5\tc  
{ 9J$8=UuxWG  
bStop = true; PKx ewd  
for(int i=0;i<nStartPos.length;i++) ~4Gs\U:!Q  
fileSplitterFetch.splitterStop(); :jFKTG  
LE|*Je3a  
wlh V!a0>  
} .o2]ndT/J  
} nVTCbV  
//负责部分文件的抓取 4RH'G
nLa  
**FileSplitterFetch.java &tULSp@J  
*/ 4<['%7U_[  
package NetFox; sh6F-g  
fDn|o"  
^Fl6-|^~  
import java.io.*; e%v<nGN.-  
import java.net.*; JYbE(&l%de  
fC
2  
;?y*@*2u  
public class FileSplitterFetch extends Thread { %r<c>sFJN  
yW$ja|^E  
.
Z!!x  
String sURL; //File URL Y=oj0(Q*
 
long nStartPos; //File Snippet Start Position K8`M~P.  
long nEndPos; //File Snippet End Position _)7dy2%{q  
int nThreadID; //Thread's ID H(^O{JC]y!  
boolean bDownOver = false; //Downing is over w>IYrSaa>  
boolean bStop = false; //Stop identical <bwsK,C  
FileAccessI fileAccessI = null; //File Access interface VK*2`Z1  
*nB fF{y  
EBY=ccGE{  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <"uT=]wZ=  
{ 'oZ/fUl|7  
this.sURL = sURL; ob  
this.nStartPos = nStart; >-Qg4%m  
this.nEndPos = nEnd; 8 oHyNo  
nThreadID = id; 1Ftl1uf  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9})!~r;|  
} BX|+"AeF  
.wrNRU7
s  
K_iy^|0)5]  
public void run() qAsZ,ik  
{ }2.^n{Y  
while(nStartPos < nEndPos && !bStop) [?<"SJ,`  
{ G .~Psw#  
u
f*sI  
[_jTy;E  
try{ TqNEU<S/t  
URL url = new URL(sURL); yA%(!v5UT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); EO'[AU%~  
httpConnection.setRequestProperty("User-Agent","NetFox"); vgzNT4o  
String sProperty = "bytes="+nStartPos+"-"; U9;C#9E  
httpConnection.setRequestProperty("RANGE",sProperty); p6(n\egR  
Utility.log(sProperty); %Ke:%##Y  
"HW~|M7>(  
pa&*n=&cL  
InputStream input = httpConnection.getInputStream(); Aa;R_Jz  
//logResponseHead(httpConnection); D-.XSIEMu  
Ox"4 y  
?aInn:FE  
byte[] b = new byte[1024]; +]Oq{v:e  
int nRead; oy!W$ ?6  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) m:<cLc :.  
{
Xc2Oa  
nStartPos += fileAccessI.write(b,0,nRead); p+ymtPF  
//if(nThreadID == 1) OHzI!,2]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %-+lud  
} fbSl$jn.  
US+PI`  
@3bQ2jn   
Utility.log("Thread " + nThreadID + " is over!"); ?lzg )88I  
bDownOver = true; J<:qzwh  
//nPos = fileAccessI.write (b,0,nRead); *-bR~  
} [3s,U4a  
catch(Exception e){e.printStackTrace ();} ZD1UMB0$4  
} g2 uc+p  
} x%ZjGDFm  
"sz)~Q'W5  
"k\W2,q[  
//打印回应的头信息 VrhG=CK  
public void logResponseHead(HttpURLConnection con) B`a5%asJn  
{ w .l2  
for(int i=1;;i++)
7ZHM;_ -  
{ SX|b0S,  
String header=con.getHeaderFieldKey(i); ~130"WQ;  
if(header!=null) oUEpzv,J  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); jRK<FK  
Utility.log(header+" : "+con.getHeaderField(header)); A'qJke=  
else -san%H'  
break; 7t\W{y  
} h\KQ{-Bl  
} tv)x(MX  
:{C#<g`  
GVZ/`^ndM  
public void splitterStop() %;9f$:U  
{ !z
X`M1J  
bStop = true; /ocd
AW`0  
} +Ij>\;vM"  
02&mM%#  
bF:vD&Sf  
} ;}3wT,=sN  
cS,(HLO91  
zT0rvz1),M  
/* +o)S.a+7  
**FileAccess.java m.-l&@I2/<  
*//文件访问(定位，写) l%lkDh!$"  
package NetFox; 08vA;6zt  
import java.io.*; GAbX.9[V  
Os9xZ  
h<i.@&  
public class FileAccessI implements Serializable{ TPp%II'*  
2}1(j  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ~.mnxn  
RandomAccessFile oSavedFile; 5)o-$1s A  
long nPos; :h?"0,  
/
iNCb&[  
uXW<8( %W  
public FileAccessI() throws IOException  Yul-.X  
{  =w0Rq~  
this("",0); gSK (BP|  
} +60zJ4  
&fq-U5zH  
Skl1%`  
public FileAccessI(String sName,long nPos) throws IOException Nqp%Z7G  
{ p0? XR  
oSavedFile = new RandomAccessFile(sName,"rw"); =&xamA)  
this.nPos = nPos; d
~uK/R-KD  
oSavedFile.seek(nPos); ZT95g  
} L{Epkay,{  
:51Q~5
k4  
P~iu|j  
public synchronized int write(byte[] b,int nStart,int nLen) PX52a[wNDH  
{ +w:[By"  
int n = -1; Z<K[  
try{ ^o,Hu
#  
oSavedFile.write(b,nStart,nLen); qS>P,>C  
n = nLen; &6FRw0GX  
} =:v\}/  
catch(IOException e) o\1"ux;b  
{ `Z>4}<~+  
e.printStackTrace (); :}FMauHh  
} $jo}?Y+  
N \[Cuh8Fe  
`;*%5WD%  
return n; yPn5l/pDDr  
} u2y?WcMv  
S%-L!V ,  
-4Zf0r1u  
} :,y V?E6]  
d%VGfSrKq  
W@AZ
<(RI:  
/* G+ Y`65  
**SiteInfoBean.java D$;mur'  
*/ j\f;zb?F  
package NetFox; jY$Bns&.w  
2!cP[Ck  
i;y<gm"  
public class SiteInfoBean { 724E(?>J  
}E[S%W[  
tx}{E<\>$  
private String sSiteURL; //Site's URL k4'rDJfB  
private String sFilePath; //Saved File's Path XUfj 0  
private String sFileName; //Saved File's Name "]JE]n}Ulg  
private int nSplitter; //Count of Splited Downloading File v$
p<6^kJ  
x&+/da-E/5  
X8<<;?L  
public SiteInfoBean() n
ORm7sa9  
{//nSplitter的缺省值为5 XB
UO  
//default value of nSplitter is 5 M/:kh,3  
this("","","",5); fBS;~;l  
} > YKvwbCf8  
fI`6]?W  
Ti#2D3  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) FGG Fi(  
{ PbJn8o  
sSiteURL= sURL; ]}i_NqW)  
sFilePath = sPath; V9I5/~0c  
sFileName = sName; @sav8]  
this.nSplitter = nSpiltter; r^n%PH<  
]Hc`<P  
acdaDY  
} Ra&HzK?  
`n Y!nh6!  
eEb(TG~,Y  
public String getSSiteURL() A&~G  
{ i*#Gq6qZq  
return sSiteURL; h35x'`g7+r  
} \,!FL))yC  
29z+<?K{  
epJVs0W  
public void setSSiteURL(String value) K;,n?Q w  
{ Z 3m5DK  
sSiteURL = value; gnlGL[r|  
} Pan^@B=Q  
P7&a~N$T6W  
`8\_ ]w0  
public String getSFilePath() /P<RYA~  
{ D!Owm&We  
return sFilePath; Ry,_%j3  
} aU<0<Dx  
ow:c$Zq  
xv]P-q0  
public void setSFilePath(String value) ':R)i.TS  
{ iSUn}%YFz!  
sFilePath = value; /PE3>"|wE  
} o_t2 Z  
\kF}E3~+#  
eA$9)K1GO  
public String getSFileName() 6P;IKOv^  
{ wWko9h=|mQ  
return sFileName; 3cBuqQ  
} AH;0=<n  
rOm)s

'  
q*{i/=~  
public void setSFileName(String value) T12?'JL^r  
{ n9<QSX&~<  
sFileName = value; e]!C Aj7uS  
} gs_"H  
Os?G_ziIB  
2/PaXI/Z  
public int getNSplitter() ~j^HDHY@  
{ T|GRkxd,E3  
return nSplitter; [(BA:x1  
} Nj1vB;4Nx  
WpP8J1KN[  
8b8ui  
public void setNSplitter(int nCount) 
K I  
{ Fx~=mYU
 
nSplitter = nCount; cR
4xy26s  
} Q%o ]&Hdn  
} I;qeDCM  
R44JK  
NS6#od ZeV  
/* )a.w4dH  
**Utility.java ;26a8g(  
*/ O(!J^J3_z  
package NetFox; 36,qh.LKn  
(~?P7RnU%  
@`G_6<.`  
public class Utility { 9`f]Rf"  
>:4}OylhM  
tQ< ou,  
public Utility() 
T)6p,l  
{ eh2w7@7Q  
\m1r(*Ar  
k|F<?:C  
} H[U$4 %t  
(=}U2GD*  
//线程睡眠 M\ vj&T{k  
public static void sleep(int nSecond) 3+u11'0=t  
{ %L.,:mtq)  
try{ ajq[ID  
Thread.sleep(nSecond); \CM/KrC
R  
}
Ytmt+9  
catch(Exception e) \|BtgT*$b  
{ B_i@D?bTD  
e.printStackTrace (); _Ft4F`pM  
} U 3aY =8B  
} #WwQ^6ESc  
1Y$ gt  
//日志 i64a]=  
public static void log(String sMsg) ?k<i e2  
{ tH,}_Bp  
System.err.println(sMsg); v T2YX5k&,  
} 9eo$Duws  
KFCrJ)  
dX-{75o5P  
public static void log(int sMsg) y-m<&{q  
{ &?f{.  
System.err.println(sMsg); &%+}bt5  
} S75wtz)e  
} fWhwI+  
}OZ%U
2PU  
U+CZv1  
/* C=2  
**TestMethod.java  Iz*'  
*/ f9W@!]LHJ  
package NetFox; }]$%aMxy T  
AWsO?|YT  

qX^#fk7]  
public class TestMethod { 2>Hl=bX  
=hxj B*")  
;XNe:g.CR  
public TestMethod() +[:"$?J  
{ ///xx/weblogic60b2_win.exe Qz2Yw `  
try{ !4\`g
?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); vQ>x5\r5O_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); S;sggeP7,  
SiteFileFetch fileFetch = new SiteFileFetch(bean); B!0o6)u'  
fileFetch.start(); h}k&#X)7  
} }J73{  
catch(Exception e){e.printStackTrace ();} .Qm"iOyM  
5+\[x`  
qqA(Swe)T  
} ~B;kFdcVXn  
3[B*l@}j  
j9)P3=s  
public static void main(String[] args) `[3Iz$K=  
{ _U(b  
new TestMethod(); VHwb 7f]gq  
} :akEl7/&  
} 3}e-qFlV8,  
点击下载更多相关资料