http断点续传简单实现（java)

/* UJ)pae  
**SiteFileFetch.java \=AA,Il  
*/ P5h|* ?=  
package NetFox; d9#Vq=H /  
import java.io.*; (Q^sK\  
import java.net.*; 0N.h:21(4  
!hBpon  
4hL%J=0:  
public class SiteFileFetch extends Thread { bf"'xn9  
i#]e&Bru5  
mm-s?+&M;  
SiteInfoBean siteInfoBean = null; //文件信息Bean 6lSz/V;  
long[] nStartPos; //开始位置 G^~[|a4`  
long[] nEndPos; //结束位置 Xv8-<Ks  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 L>1hiD&  
long nFileLength; //文件长度 xc:E>-  
boolean bFirst = true; //是否第一次取文件 PgWWa*Ew  
boolean bStop = false; //停止标志 9CY{}g  
File tmpFile; //文件下载的临时信息 =_7wd*,  
DataOutputStream output; //输出到文件的输出流 $*fJKR_N  

Ae+)RBpc  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） pk/#RUfT+  
public SiteFileFetch(SiteInfoBean bean) throws IOException H\67Pd(Z6  
{ Az`Aa0h]7  
siteInfoBean = bean; <(L@@.87R  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y%s:oHt  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1iy$n  
if(tmpFile.exists ()) F4
EAC|Y  
{ I,j4 BU4  
bFirst = false; mL{P4a 1xf  
read_nPos();
`Y#At3{  
} l_vGp  
else z8Q!~NN-K  
{ *qd:f!Q3  
nStartPos = new long[bean.getNSplitter()]; <'a~Y3B"o  
nEndPos = new long[bean.getNSplitter()]; Y'iX   
} ~t`^|cr|  
+I3jI <  
UN]gn>~j  
K,E/.Qe\C  
} t'eqk#rq  
,
ks2&e  
9%/hoA)  
public void run() +$dJA  
{ gg'1q3OjM  
//获得文件长度 ~VGnE:  
//分割文件 kQ`tY`3F  
//实例FileSplitterFetch yn4T!r "  
//启动FileSplitterFetch线程 xM*_1+<dT$  
//等待子线程返回 B$4*U"tk  
try{ >XD?zF)6  
if(bFirst) {3~VLdy  
{ ?\}Gi(VVE  
nFileLength = getFileSize(); uN|A}/hr]  
if(nFileLength == -1) `g)}jo`W  
{ Bt+^H6cb  
System.err.println("File Length is not known!"); $)i`!7`4=  
} 7L{1S v  
else if(nFileLength == -2) `ONjEl  
{ m>@hh#kBg  
System.err.println("File is not access!"); Xz+%Ym  
} *o6}>;  
else bx0.(Nv/X  
{ ;[v!#+yml  
for(int i=0;i<nStartPos.length;i++) R'Sd'pSDN  
{ LW %AZkAx  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); :QE5 7.  
} {%V(Dd[B6  
for(int i=0;i<nEndPos.length-1;i++) |VBt:dd<  
{ Yh":>~k?SY  
nEndPos = nStartPos[i+1]; {ZJO5*  
} m|a9T#B(  
nEndPos[nEndPos.length-1] = nFileLength; =kjKK
  
} g9_zkGc7  
} F^i3e31*t  
Wv;0PhF  
sZ.<:mu[  
//启动子线程 (m~>W"x/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; = tv70d'  
for(int i=0;i<nStartPos.length;i++) 4"d,=P.{  
{ 7=G2sOC  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S$6|KY u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ewZ?+G+m  
nStartPos,nEndPos,i); jh5QIZf=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); NVyBEAoh  
fileSplitterFetch.start(); w_9^YO!!  
} JzyCeM
=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,UNb#=
it  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ZoW1Cc&p  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", H?$dnwR  
nEndPos = " + nFileLength); xEb>6+-F@  
// fileSplitterFetch[nPos.length-1].start(); t*{L[c9.Uq  
,+=9Rp`md  
+&GV-z~o  
//等待子线程结束 #NS|9jW  
//int count = 0; 6x+ujUBkK  
//是否结束while循环 =~D? K9o  
boolean breakWhile = false; iSW2I~PD  
d t/AAk6  
o3J#hQrl  
while(!bStop) H;Wrcf2  
{ :6n#y-9^1  
write_nPos(); o+A7hBM^  
Utility.sleep(500); mw@Pl\=  
breakWhile = true; /]
0qI  
<Xf6?nyZ(  
rTPgHK]?l  
for(int i=0;i<nStartPos.length;i++) J2mHPVA3  
{ ^7gGtz2  
if(!fileSplitterFetch.bDownOver) zj 6I:Qr  
{ fPR_3qgQ  
breakWhile = false; _y@28t  
break; Y]z :^D  
} <r%K i`u(p  
} +;N]34>S7  
if(breakWhile) LGP"S5V  
break; r$7.  
&D,Iwq  
AIF?>wgq  
//count++; { 3G  
//if(count>4) bLqy7S9x  
// siteStop(); agIqca;  
} inh0p^  
p{f R$-d  
|z
-f8$  
System.err.println("文件下载结束！"); Y:^hd809  
} 'jev1u[  
catch(Exception e){e.printStackTrace ();} -Q WvB  
} !09)WtsEfx  
144Y.  
AdX))xgl  
//获得文件长度 OO:S2-]Y>e  
public long getFileSize() uLhGp@Dx  
{ 0PzSp ]  
int nFileLength = -1; |v&)O)Jg  
try{ Jo?LPR \6  
URL url = new URL(siteInfoBean.getSSiteURL()); VB |?S|<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %hB-$nE  
httpConnection.setRequestProperty("User-Agent","NetFox"); 
l.Q  
3CCs_AO  
ah>c)1DA*H  
int responseCode=httpConnection.getResponseCode(); B#K gU&Loo  
if(responseCode>=400) -y`Pm8  
{ Z8v\>@?5R  
processErrorCode(responseCode); c&['T+X  
return -2; //-2 represent access is error c_/BS n  
} \CB^9-V3  
!np_B0`  
l6M?[  
String sHeader; ,=/9Ld2w9  
,Py\Cp=Dw  
0.MB;gm:  
for(int i=1;;i++) <)qa{,GX\  
{ <=(K'eqC^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); tUu' gs|  
//Utility.log(in.readLine()); 5 jrR]X  
sHeader=httpConnection.getHeaderFieldKey(i); HqGI.  
if(sHeader!=null) -[mmT'sS  
{ )gpN 5TDd  
if(sHeader.equals("Content-Length")) ]_KWN$pd  
{ vYg
Ju-Sl  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /[R=-s ;  
break; * #yF`_p  
} K\xz|Gq  
} V@'Xj .ze  
else l@`k:?  
break; p=+Y7NE)  
} [(X~C*VdxM  
} 0h-NT\m  
catch(IOException e){e.printStackTrace ();} gtKih  
catch(Exception e){e.printStackTrace ();} D*l(p5[  
fB2ILRc  
ak7%  
Utility.log(nFileLength); " ityx?  
l\_!oa~  
R|?n  
return nFileLength; B`SX3,3  
} snbXAx1L  
:zW? O#aL-  
G|cjI*  
//保存下载信息（文件指针位置） 0\mf1{$"!7  
private void write_nPos() fTxd8an{  
{ u#6s^ )W  
try{ G^'We6<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *q}yfa35eR  
output.writeInt(nStartPos.length); ^-%'ItVO  
for(int i=0;i<nStartPos.length;i++) aB%.]b
i  
{ rCJ$Pl9R  
// output.writeLong(nPos); h;=~%2Y  
output.writeLong(fileSplitterFetch.nStartPos); FQek+[ox  
output.writeLong(fileSplitterFetch.nEndPos); <?41-p-;  
} }$)~HmZw  
output.close(); B9(w^l$kZ|  
} =Ti!9_~  
catch(IOException e){e.printStackTrace ();} gY+d[3N  
catch(Exception e){e.printStackTrace ();} NXD-  
} !\b-Ot(  
NG3?OAQTw  
#x 6/"Y2  
//读取保存的下载信息（文件指针位置） rL<N:@
HL  
private void read_nPos() _J*l,]}S  
{ \LUW?@gLa  
try{ 7,)E1dx -V  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); I(UK9H{0$  
int nCount = input.readInt(); Q``1^E'  
nStartPos = new long[nCount]; OcB&6!1u  
nEndPos = new long[nCount]; ;$tdn?|  
for(int i=0;i<nStartPos.length;i++) @de  ZZ  
{ pZ Uy (  
nStartPos = input.readLong(); ts=D

  
nEndPos = input.readLong(); }:?*n:g5  
} DXJw)%G w  
input.close(); y/@Bhzc  
} &q&z$Gc;m  
catch(IOException e){e.printStackTrace ();} f (C:J[;Z  
catch(Exception e){e.printStackTrace ();} @l3&vt2=J  
} :TVo2Zm[@  
e"1mdw"  
UhR^Y{W5  
private void processErrorCode(int nErrorCode) "IS; o o$g  
{ ,3rsjoKhd  
System.err.println("Error Code : " + nErrorCode); #
@nPB.  
} !"FEp  
H/t0#  
\[!{tbK`2  
//停止文件下载 >07i"a  
public void siteStop() !UT!PX)  
{ 2V8"jc  
bStop = true; Y"ta`+VJ  
for(int i=0;i<nStartPos.length;i++) 
`
pv  
fileSplitterFetch.splitterStop(); `D3q!e  
M*'8$|Z  
gHgqElr(  
} C{U*{0}  
} '`tFZfT  
//负责部分文件的抓取 5xT, O  
**FileSplitterFetch.java Ud"_[JtGM  
*/ <IU   
package NetFox; ,or;8aYc#  
[-`s`g-  
(4z_2a(Dl,  
import java.io.*; =f@
71D1  
import java.net.*; 2cu2S"r  
=H: N!!:  
Obu 6k[BE.  
public class FileSplitterFetch extends Thread { Lww&[|k.  
,aWI&ve6  
}2Ge??!  
String sURL; //File URL DI/d(oFv`  
long nStartPos; //File Snippet Start Position J<NpA(@^  
long nEndPos; //File Snippet End Position ZT"vVX-)G  
int nThreadID; //Thread's ID {%6 '|<`[  
boolean bDownOver = false; //Downing is over uih8ZmRt  
boolean bStop = false; //Stop identical lhQMR(
w^  
FileAccessI fileAccessI = null; //File Access interface Nnn~7  
,nog6\  
bs}SFTL  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Rhlm  
{ d~.hp  
this.sURL = sURL; HI1|~hOb'  
this.nStartPos = nStart; /g0' +DP  
this.nEndPos = nEnd; <bn|ni|c"  
nThreadID = id; 7aRy])x  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;Ym6ey0t  
}  )%9:k9  
H [M:iV  
E690'\)31  
public void run() .R)Ho4CE  
{ I+Y Z+  
while(nStartPos < nEndPos && !bStop) W
CaMPz  
{ 6wOj,}2Mn  
ui"`c%2n  
@Nm{H  
try{ gjiS+N[  
URL url = new URL(sURL); LvGo$f/9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "tbKbFn9  
httpConnection.setRequestProperty("User-Agent","NetFox"); K7$Q.  
String sProperty = "bytes="+nStartPos+"-"; p]e.E`'S  
httpConnection.setRequestProperty("RANGE",sProperty); * W"Pv,:  
Utility.log(sProperty); xhCNiYJ|  
qU&v50n  
3]\'Q}  
InputStream input = httpConnection.getInputStream(); dXWG`G_  
//logResponseHead(httpConnection); lh\`9F:  
Y3V2}  
dF|n)+C~R  
byte[] b = new byte[1024]; #BEXj<m+J  
int nRead; >0:=<RW  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )):D&wlq  
{ R{B5{~m>W@  
nStartPos += fileAccessI.write(b,0,nRead); ? _[q{i{  
//if(nThreadID == 1) AAi4} 8+\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); gsIp y  
} $?&distJ  
wLq#,X>%B  
nS!m1&DeD  
Utility.log("Thread " + nThreadID + " is over!"); C]zG@O!  
bDownOver = true; q)"yP\  
//nPos = fileAccessI.write (b,0,nRead); 5 yL"=3&+  
} <UW-fI)X  
catch(Exception e){e.printStackTrace ();} f1\mE~#}  
} >(gbUW  
} &61h*s  
/p|L.&`U  
9]S;%:64  
//打印回应的头信息 ^Y"|2 :  
public void logResponseHead(HttpURLConnection con) BE!WCDg,  
{ oJc v
 D  
for(int i=1;;i++) /7R0w  
{ OV^?cA  
String header=con.getHeaderFieldKey(i); (]"`>,ray  
if(header!=null) -+Ox/>k  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Jb!s#g   
Utility.log(header+" : "+con.getHeaderField(header)); o3:h!(#G  
else kc[<5^b5  
break; U uSCqI};  
} \uOR1z  
} aslb^  
`9DW}  
\k%j  
public void splitterStop() Q/
l388'  
{ xf3/J{n3  
bStop = true; 'Y5l3xQk  
} Pu2cU5n  
0w".o!2\U{  
fp$U%uj  
} 4='/]z  
NHD`c)Q  
TdrRg''@  
/* $mst\]&;  
**FileAccess.java ^%RIz!}  
*//文件访问(定位，写) CuYSvW  
package NetFox; zRA,Yi4;+  
import java.io.*; `6Yk-5  
)VkH':yCM  
l\
&Tw[O  
public class FileAccessI implements Serializable{ Vdb X4^V  
;TCT%j`^o  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 >^adxXw.o  
RandomAccessFile oSavedFile; cG4$)q;q  
long nPos; }N#hg>; B  
$&FeR*$|g  
j.g9O]pi  
public FileAccessI() throws IOException PLQLGb4f_;  
{ DZU} p  
this("",0); X[$FjKZh=F  
} L[}Ak1 A  
6cTd
SE  
)uH#+IU  
public FileAccessI(String sName,long nPos) throws IOException Q|nGY:98  
{ hv9k9i7@l  
oSavedFile = new RandomAccessFile(sName,"rw"); f26hB;n  
this.nPos = nPos; $w ,^q+  
oSavedFile.seek(nPos); j%Z%_{6Ds*  
} S!.H _=z%p  
<iznB8@  
KOVR=``"/  
public synchronized int write(byte[] b,int nStart,int nLen) R}0!F2  
{ mI3 \n  
int n = -1; oz/Nx{bg  
try{ q,2 +\i  
oSavedFile.write(b,nStart,nLen); eGlPi|  
n = nLen; :eW`El  
} 94GF8P  
catch(IOException e) yq\p%z$:  
{ g+/m:(7[s|  
e.printStackTrace (); pcO0xrI  
} L [=JHW  
<P1x3  
"'*w_H0  
return n; J=AF`[  
} <%:,{u6  
K}9c$C4  
}(Dt,F`  
} .u$o^; z!  
)~H&YINhn  
nx'Yevi0$  
/* qfl#ki`,  
**SiteInfoBean.java >m4Q*a4M  
*/ fFJu]  
package NetFox; kr>H,%3~  
2s<uT  
rJ)8KY>  
public class SiteInfoBean { 9a3mN(<  
)lDmYt7me  
%Ae
43  
private String sSiteURL; //Site's URL "6 \
_/l  
private String sFilePath; //Saved File's Path H&E3RU>`  
private String sFileName; //Saved File's Name YK6zN>M}E  
private int nSplitter; //Count of Splited Downloading File 7dtkylW  
?5jq)xd2  
R.$1aqA}  
public SiteInfoBean() Xjs`iK=w  
{//nSplitter的缺省值为5 ,)%$Zxng  
//default value of nSplitter is 5 qM8"* dL  
this("","","",5); SVJt= M  
} RSK5 }2  
1?,1EYT"  
-wrVhCd~g]  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) j$Wd[Ja+O  
{ lmpBf{~ S  
sSiteURL= sURL; vj hh4$k  
sFilePath = sPath; )0N^rw kW  
sFileName = sName; A#KfG1K>  
this.nSplitter = nSpiltter; %8$ldNhV  
q3}WO]TBj  
}\3
jcnn  
} cPbAR'  
?3Y~q;I]O  
EEdU\9DH(  
public String getSSiteURL() lXOT>$qR<  
{ qEajT"?  
return sSiteURL; tv'=xDCp  
} 83g$k 9lG.  
s5 ($b  
$ n"*scyI  
public void setSSiteURL(String value) J`xCd/G  
{ 35/K9l5  
sSiteURL = value; `|WEz
W~  
} p`/c&}
 
@M&qH[tK-A  
 /wT<p  
public String getSFilePath() 8"yZS)09  
{ 0AD8X+M{P  
return sFilePath; eI3ZV^_Ps  
} A5?q&VS}p  
X;7hy0Y  
B!1Bg9D  
public void setSFilePath(String value) V[2}  
{ /X;/}fk  
sFilePath = value; Jp"yb`w  
} TX).*%f[r  
kJK*wq]U6  
,#U[
)}i
m  
public String getSFileName() %00cC~}4  
{ SZ1yy["  
return sFileName; |Pi! UZB  
} -CLBf'a  
&a.A8v)  
7j8lhrM}^  
public void setSFileName(String value) DR7JEE  
{ i ?PgYk&}  
sFileName = value;
c8LMvL  
} ]-;M
Y@  
lokKjs  
WG*),P?  
public int getNSplitter() yw1-4*$c  
{ Ey=ymf.}  
return nSplitter; 7n,=`0{r  
} J`[gE`d  
055C1RV%  
HD'adj_,  
public void setNSplitter(int nCount) V1haAP[#  
{ +kN,OK~  
nSplitter = nCount; Zc'^iDAY  
} ,b4o
V  
} uS5G(}[
 
25 cJA4  
-Fq`#"  
/* [bw1!X3  
**Utility.java n?;h-KKO:  
*/ SlG^ H  
package NetFox; j WSgO(y  
}Ogb|8  
bh(}f.@ 9  
public class Utility { ?)T@qn+  
@]!9;?so  
6_:I~TTX  
public Utility() Fv*Et-8tN5  
{ e_"m\e#N  
ut#pg+#Q  
5mS/,fs@  
} y)"rh/;  
#0PZa$kM(o  
//线程睡眠 n =WH=:&  
public static void sleep(int nSecond) 2Z5_@Y  
{ )|_L?q#w!'  
try{ a?yU;IKJ  
Thread.sleep(nSecond); r.lHlHl  
} Wm}gnNwA  
catch(Exception e) \E[6wB>uN%  
{ pKno~jja  
e.printStackTrace (); r@/@b
{=  
} Q :.i[  
} _a f $0!  
cUr!U\X[  
//日志 na|sKE;{  
public static void log(String sMsg) \KzH5?  
{ @v#,SF{  
System.err.println(sMsg); 7377g'jL  
} BeN]D  
I\x9xJ4x  
684d&\(s  
public static void log(int sMsg) >JAWcT)d  
{ &_u.q/~  
System.err.println(sMsg); a#k7 aOT0  
} 
c&
I  
} e`:^7$  
,@/O\fit)  
\m%c"'[  
/* QM* T?PR  
**TestMethod.java ]-9w'K d  
*/ fERO(
o  
package NetFox; Xhq6l3M  
M9""(`U  
T9XUNR{&  
public class TestMethod { .xuzu#-  
jRd$Vt  
#lg R"%  
public TestMethod() !/!ga)Y  
{ ///xx/weblogic60b2_win.exe _6V1oe2  
try{ iEZ+Znon  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); CJER&"em7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); % P Ex  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .#-F@0a  
fileFetch.start(); Rk[a|T&  
} L
~^5Ez6U  
catch(Exception e){e.printStackTrace ();} q2s
0g*z  
cdh0b7tjn  
":vEWp+g  
} 7RWgc]@?>  
El@*Fo  
Gw
\..O  
public static void main(String[] args) A*wf: mW0c  
{ &^#u=w?^x  
new TestMethod(); RgA"`p7{  
} CGzu(@dd\  
} 9^ZtbmUf
 
点击下载更多相关资料