http断点续传简单实现（java)

/* q*B(ZG  
**SiteFileFetch.java BO3%p  
*/ j/Rm~!q  
package NetFox; ZQQ0}  
import java.io.*; f}U@e0Lsb  
import java.net.*; e-.s63hm  
"G,$Sqi@  
MEZc/Ru-[  
public class SiteFileFetch extends Thread { =9@t6   
7)y9%-}  
(hv>vfY@  
SiteInfoBean siteInfoBean = null; //文件信息Bean 5gnmRd  
long[] nStartPos; //开始位置 >84:1`  
long[] nEndPos; //结束位置 P-c<[DSM'I  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 3~&h9#7Ke  
long nFileLength; //文件长度 :4, OA  
boolean bFirst = true; //是否第一次取文件 (@y te  
boolean bStop = false; //停止标志 QY]G+3W  
File tmpFile; //文件下载的临时信息 3vK,vu q  
DataOutputStream output; //输出到文件的输出流 @p}"B9h*^  
(iw)C)t*u  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） n'-?CMH`  
public SiteFileFetch(SiteInfoBean bean) throws IOException =TzmhX5  
{ uh_2yw_  
siteInfoBean = bean; X_nxC6[m%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); d#*n@@V4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); = rLL5<  
if(tmpFile.exists ()) 6rD Oa~<B  
{ [O52Bn  
bFirst = false; 4`Z8EV  
read_nPos();
|-SImxV  
} -Bl!s^-'  
else L[s8`0  
{ KnjowK  
nStartPos = new long[bean.getNSplitter()]; [esR!})  
nEndPos = new long[bean.getNSplitter()]; }co*%F{1  
} _jr'A-M  
^Td_B03)  
a~nErB  
?U;KwS]%  
} ; OpN&q+  
K V-}:u(  
>TqMb8e_  
public void run() 2/]74d8  
{ cLpkgK&a  
//获得文件长度 %tRQK$]c  
//分割文件 ?\D=DIN-r  
//实例FileSplitterFetch Cm5:_K`;]  
//启动FileSplitterFetch线程 R^*h|7)E  
//等待子线程返回 n,E=eNc  
try{ |
VPJaiC~  
if(bFirst) Q-:IE T  
{ +g6t)Gl  
nFileLength = getFileSize(); n)'5h &#  
if(nFileLength == -1) rL=_z^.P  
{ l5R0^!t  
System.err.println("File Length is not known!"); Bh\>2]~@a  
} ;HPQhN_  
else if(nFileLength == -2) :jc ?T  
{ !PIpvx{aX  
System.err.println("File is not access!"); )GpH5N'EI  
} z:_o3W.E  
else U=a'(fX  
{ g;Lk 'Ky6  
for(int i=0;i<nStartPos.length;i++) j$z<
wR7j0  
{ '.mHx#?7  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); V>YZ^>oeH  
} Ym WVb  
for(int i=0;i<nEndPos.length-1;i++) Y,%d_yR
[  
{ %di]1vQ  
nEndPos = nStartPos[i+1]; U(jZf{`Mz  
} [4_JK  
nEndPos[nEndPos.length-1] = nFileLength; ;F;"Uw  
} JGB 9Z   
} 1Y-m=~J7  
wCwJ#-z.=  
3bGJ?hpp  
//启动子线程 mx'!I7b(L/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; W]t!I}yPR  
for(int i=0;i<nStartPos.length;i++) cxNb!G  
{ SX4"HadV>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), CfWtCA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0xe!tA  
nStartPos,nEndPos,i); {4@+ 2)l  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *nPB+
@f  
fileSplitterFetch.start(); w!=Fi  
} p? dXs^ c  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *+-L`b{SX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); TC=djC4$/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", FccT@,.F  
nEndPos = " + nFileLength); .[E"Kb}=  
// fileSplitterFetch[nPos.length-1].start(); &s|a\!>l  
z`^DQ8+\j  
z DP  
//等待子线程结束 .)zX<~,  
//int count = 0; W
xi|(}  
//是否结束while循环 )tRqt9Th*  
boolean breakWhile = false; sU/R$Nbr  
7HpfHqJ7  
H</Mh*Fl2G  
while(!bStop) 99\;jz7  
{ ?ep'R&NV  
write_nPos(); A@W/  
Utility.sleep(500); /ox9m7Fz7  
breakWhile = true; QBNnvg4v  
b~1]}9TJ  
g@va@*|~d  
for(int i=0;i<nStartPos.length;i++) 0!:1o61  
{ [`_ZlC  
if(!fileSplitterFetch.bDownOver) JMUk=p<\  
{ B4<W%lm  
breakWhile = false; Q bg,q  
break; $8{|25 *E  
} T.fmEl  
} FuiEy=+  
if(breakWhile) Nf#8V|  
break; RcASFBNpS  
!F|mCEU  
7^fpbrj  
//count++; lR^OS*v  
//if(count>4) gm-I)z!tz  
// siteStop(); vSt7&ec  
} DRBRs-D  
+0,{gDd+  
C;T:'Uws  
System.err.println("文件下载结束！"); =*AAXNs@3  
} y}fF<qih'>  
catch(Exception e){e.printStackTrace ();} `+4>NT6cu9  
} ,<^7~d{{3m  
UogkQ& B  
@wy&Z  
//获得文件长度 ,Tb~+z|-[  
public long getFileSize() wX0m8"g@  
{ 5&y;r  
int nFileLength = -1; Tr^Egw]  
try{ T[z]~MJL  
URL url = new URL(siteInfoBean.getSSiteURL()); ;>eD`Wh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3 e19l!B  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6hE. i x  
,+u.FQv~  
=1JS6~CTLN  
int responseCode=httpConnection.getResponseCode(); _?vh#6F  
if(responseCode>=400) "!9hcv-;  
{ Lv`*+;1K  
processErrorCode(responseCode); B]`!L/  
return -2; //-2 represent access is error n>)'!  
} /D]V3|@E  
X"hoDg  
sG/mmZHYzr  
String sHeader; d$3;o&VUNI  
wIrjWU2  
.HM1c  
for(int i=1;;i++) Y:~A-_  
{ %{fa .>6  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); G2bZl% ,D  
//Utility.log(in.readLine()); RGeM.  
sHeader=httpConnection.getHeaderFieldKey(i); :QndeUw  
if(sHeader!=null) -:hiLZJ7-  
{ <K~> :4c  
if(sHeader.equals("Content-Length"))
9>t
 
{ wknr^A  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ')d&:K*M  
break; I^M%+\  
} q(i^sE[y  
} SWAggW)  
else 73-*
|@6  
break; 5/v,|  
} y^rcUPLT  
} YL)epi^  
catch(IOException e){e.printStackTrace ();} <Rs#y:  
catch(Exception e){e.printStackTrace ();} h\oAW?^  
u,zA^%  
x>>#<hOz[  
Utility.log(nFileLength); qk;vn}auD]  
-8L22t  
ho1Mo  
return nFileLength; vhw"Nl  
} Z~g I)  
di@4'$5#  
\m3'4#  
//保存下载信息（文件指针位置） cTA8F"UGD  
private void write_nPos() n{>Ge,enP0  
{ |H:JwxH  
try{ .6,+q2tyk,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); LQ,RQ
~!  
output.writeInt(nStartPos.length); dLtSa\2Hn  
for(int i=0;i<nStartPos.length;i++) 0WasE1t|  
{ [-Zp[  
// output.writeLong(nPos); ]Qo.X~]  
output.writeLong(fileSplitterFetch.nStartPos); nkKiYr  
output.writeLong(fileSplitterFetch.nEndPos); 56;(mbW  
} ^i"C%8  
output.close(); HF9\SVR B  
} vybQ}dscn  
catch(IOException e){e.printStackTrace ();} yIab3/#`  
catch(Exception e){e.printStackTrace ();} 9uXuV$.  
} U>q&p}z0H  
q P<n<  
Sv*@3x  
//读取保存的下载信息（文件指针位置） 6^W6As0  
private void read_nPos() Kn9O=?Xh;  
{ uS9:cdH  
try{ ~R;9a"nr  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); AML8.wJ  
int nCount = input.readInt(); 16iymiLz&  
nStartPos = new long[nCount]; !Gv*iWg  
nEndPos = new long[nCount]; c0J=gZiP  
for(int i=0;i<nStartPos.length;i++) /jR]sC)xs  
{ xwjim7#_:  
nStartPos = input.readLong(); 1E(~x;*)  
nEndPos = input.readLong(); N30w^W&  
} ]r#YU0  
input.close(); g$&uD  
} :NB,Dz+i  
catch(IOException e){e.printStackTrace ();} }E01B_T9z  
catch(Exception e){e.printStackTrace ();} Qfhhceb6#J  
} U=?hT&w\S  
@WppiZ$  
R&z)  
private void processErrorCode(int nErrorCode) ;z6Gk&?  
{ JvA6kw,  
System.err.println("Error Code : " + nErrorCode); kmJ{(y)w  
} PGT*4r21  
Qg)=4(<Hr  
(nhv#&Fd+  
//停止文件下载 G1;.\i  
public void siteStop()
S(7_\8h  
{ +]n.uA-`[a  
bStop = true; I91pX<NBf  
for(int i=0;i<nStartPos.length;i++) < q6z$c)K  
fileSplitterFetch.splitterStop();  b>N)H  
8>:kv:MId  
QN%w\JXS  
} ?/mkFDN  
} *.
H1m{V  
//负责部分文件的抓取 xS~OAcxg  
**FileSplitterFetch.java LPjsR=xi  
*/ _1z|QC  
package NetFox; 4dDDi,)U  
=F!DwaZ  
u3!aKXnv<  
import java.io.*; ,/.U'{  
import java.net.*; jTNfGu0x  
F&{RP>  
S ("Zzq`  
public class FileSplitterFetch extends Thread { Vb|;@*=R&Q  
^wL n  
)4d)G5{  
String sURL; //File URL t6.hg3Y  
long nStartPos; //File Snippet Start Position m){.{Vn]  
long nEndPos; //File Snippet End Position \bt+46y@]  
int nThreadID; //Thread's ID jB8n\8Bs  
boolean bDownOver = false; //Downing is over `={s*^Ta  
boolean bStop = false; //Stop identical zNE"5  
FileAccessI fileAccessI = null; //File Access interface
;()
.  
f%LzWXA  
FHNK%Ko  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException z
w{cli&S  
{ H].G%,2'  
this.sURL = sURL; UcCkn7}  
this.nStartPos = nStart; s*R\!L  
this.nEndPos = nEnd; JPS7L}Kv  
nThreadID = id; \NYtxGV[Z  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 P#o/S4  
} !Jo3>!,j  
dzYB0vut@  
O*3x'I*a  
public void run() =*q|568  
{ lVywc:X  
while(nStartPos < nEndPos && !bStop) 4\HB rd#P  
{ h&7]Bp  
[3a-1,  
55
vpnRM  
try{ '1)BZ!  
URL url = new URL(sURL); @`:n+r5u  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C;DNL^  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ep%5wR  
String sProperty = "bytes="+nStartPos+"-"; 0dKI+zg
r  
httpConnection.setRequestProperty("RANGE",sProperty); !HA[:-JCz  
Utility.log(sProperty); |>(@n{  
I*e85wef  
G Q&9b_  
InputStream input = httpConnection.getInputStream(); m178S3  
//logResponseHead(httpConnection); S7-ka{S  
Vp $]  
fH.:#O:  
byte[] b = new byte[1024]; %K^l]tWa@  
int nRead; |irqv< r  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) dw)SF,  
{ %?^T^P  
nStartPos += fileAccessI.write(b,0,nRead); $|v_ pjUu]  
//if(nThreadID == 1) Lm<"W_  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ||y5XXs  
} 9X
8{"J  
9Vx2VjK2'  
IVYWda0m  
Utility.log("Thread " + nThreadID + " is over!"); Bcx-t)[  
bDownOver = true; n{F$,a  
//nPos = fileAccessI.write (b,0,nRead); D_GIj$%N[  
}
yD iL  
catch(Exception e){e.printStackTrace ();} q<>  
} W G2 E3y  
} JZp*"UzQr  
SWr?>dl  
DpIv <m]  
//打印回应的头信息 OL]^4m  
public void logResponseHead(HttpURLConnection con) \F%5TRoC  
{ ;dl>  
for(int i=1;;i++) r}
OK3J  
{ [h8j0Q@Q  
String header=con.getHeaderFieldKey(i); 8tWOV
LquJ  
if(header!=null) yp=Hxf  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); LTu cs}  
Utility.log(header+" : "+con.getHeaderField(header)); 03*` T  
else 
VOBzB]  
break; u7>b}+ak&  
} CIh@H6|  
} D%v4B`4ua'  
!dB {E  
:8}QKp  
public void splitterStop() *Dld?Q  
{ f[3DK
A  
bStop = true; ;aBK4<-vl  
} -SaH_Nuj  
=whZ?,u1   
0uzm@'^  
} Ec| Gom?  
q10gKVJum  
W=M`Bkw{  
/* <}b`2/wP  
**FileAccess.java %sb)U~gP  
*//文件访问(定位，写) ZdHfZ3)dB  
package NetFox; _[-+%RP  
import java.io.*; 9I8{2]  
>N>WOLbb7(  
U'S}7g
ya  
public class FileAccessI implements Serializable{ X3#/|>
 
FL!W oTB  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 '3Yci(t+  
RandomAccessFile oSavedFile; I|lz;i}$  
long nPos; Z~{0XG\Y  
2g1[E_?  
/5Wy)-  
public FileAccessI() throws IOException a'w~7y!}  
{ |R:gu\gG  
this("",0); R6~x!  
} I%^Ks$<"  
Pw/Z;N;:V  
+MPM^m  
public FileAccessI(String sName,long nPos) throws IOException m"\jEfjO  
{ 0Vv6B2<  
oSavedFile = new RandomAccessFile(sName,"rw"); kf+]bV  
this.nPos = nPos; 2?ac\c6"  
oSavedFile.seek(nPos); ]Mi ~vG q  
} ?P[uf  
Z^,C><Yt  
9ctvy?53H  
public synchronized int write(byte[] b,int nStart,int nLen) fk4s19;?  
{ IbC(/i#%`  
int n = -1; Y3r m')c  
try{ IlsXj`!e  
oSavedFile.write(b,nStart,nLen); O{a<f7 W  
n = nLen; $8o(_8Q)  
} \|nF55W [  
catch(IOException e) 1"3|6&=  
{ ^RytBwzKM  
e.printStackTrace (); . $uvQpyh  
} o^;$-O!/  
6H67$?jMyJ  
<jF]SN  
return n; cc7*O  
} yC !`6$  
wXp A1,i  
IW3ZHmrpA  
} ]&\HAmOQS  
xaSvjc\  
5bM/ v  
/* Zpg/T K  
**SiteInfoBean.java -_Pd d[M  
*/ Qk<W(  
package NetFox; gO%#'Eb2  
,ii*[{X?  
C%d\DuJ5'~  
public class SiteInfoBean { RvKP&  
S!<YVQq  
lxy_O0n  
private String sSiteURL; //Site's URL y0cHs|8  
private String sFilePath; //Saved File's Path ;NH5 L,  
private String sFileName; //Saved File's Name 9Y!N\-x`  
private int nSplitter; //Count of Splited Downloading File / pzdX%7  
S-{[3$  
c
jt<&b*  
public SiteInfoBean() x@I*(I  
{//nSplitter的缺省值为5 <l]P <N8^  
//default value of nSplitter is 5 u Jy1vI  
this("","","",5); YO7Y1(`  
} e*p7(b-  
zWpJ\/k~  
zbK=yOIOd  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) /^^t>L  
{ XL@i/5C[  
sSiteURL= sURL; ~K}iVX  
sFilePath = sPath; \Km!#:  
sFileName = sName; e5KsKzu a  
this.nSplitter = nSpiltter; $X8(OS5d'  
,#[0As29u  
tFt56/4  
} zY~  
5vs~8|aRo  
nf&PDv1  
public String getSSiteURL() Bz<
T{f  
{ bh|M]*Pq  
return sSiteURL; s.I%[kada  
} >(mp$#+w  
3~Od2nk(x  
"*W:  
public void setSSiteURL(String value) 2^w3xL"   
{ WV&T   
sSiteURL = value; ^Gt&c_gH  
} u~n*P``{  
P'.MwS  
.zQ:u{FT  
public String getSFilePath() )9F-h8 &"  
{ 52?zBl`|  
return sFilePath; stuj,8  
} >QO^h<.>  
)3#gpM  
Fw5|_@&k  
public void setSFilePath(String value) _+PiaJ&'  
{ c} )U:?6  
sFilePath = value; 3/c3e
{,!  
} 85CH% I#  
li'h&!|]  
c'cK+32  
public String getSFileName() WLl_;BgN  
{ EdFCaW}""  
return sFileName; r09gB#K4  
} 873$EiyXR  
]j> W9n?  
hkV;(Fr&z  
public void setSFileName(String value) 0WT]fY?IS  
{ a(AKVk\  
sFileName = value; ]D?//  
} ta"uxL\gge  
G165grGFd  
~hK7(K  
public int getNSplitter() Aq'yr,  
{ zh`!x{Z?^  
return nSplitter;  8:=&=9%  
} pF kA,  
+UbSqp1BS  
&*2\1;1tB  
public void setNSplitter(int nCount) biAI*t  
{ AsFn%8_I  
nSplitter = nCount; _CqVH5U?  
} _8t5rF  
} @>`+eg][?P  
<vMna< /d  
K$v SdpC  
/* rEz-\jLD~  
**Utility.java +8qtFog$\g  
*/ o6`4y^Q{/  
package NetFox; 'a.n
  
%Aaf86pkp  
;fomc<  
public class Utility { .EeX
q}a[  
j"(o>bv7  
"Tw4'AY'P  
public Utility() EmrUzaGD  
{ od~^''/b  
(Z:(f~;  
0XouHU  
} UNLmnj;-Q  
X3[gi`  
//线程睡眠 W\]bh'(  
public static void sleep(int nSecond) ;R[  xo!  
{ &Tz@lvOv%  
try{ vByt_X  
Thread.sleep(nSecond); =&+]>g{T  
} 5)h#NkA\J  
catch(Exception e) &L7u//  
{ C]S~DK1  
e.printStackTrace (); B ~u9"SR.  
} 6oTWW@  
} {g8uMt\4  
kk|7{83O  
//日志 GJZGHUB=>  
public static void log(String sMsg) PJd7t%m;  
{ h>ZNPP8N  
System.err.println(sMsg); Oi#4|*b{W  
} ]vj.s/F~  
758`lfz=_  
nW)-bAV<  
public static void log(int sMsg) wQ1_Q8:Z  
{ 'Br:f_}  
System.err.println(sMsg); y98v  
} s|er+-'  
} tW<i;2 l  
R7)\wP*l5  
5zk<s`h  
/* E :gS*tsY  
**TestMethod.java w+A:]SU  
*/ S
kb,cKU  
package NetFox; 0e./yPTT  
'XW[uK]w)  
>?Y)evW  
public class TestMethod { 05
sWN0  
Z_b^K^4  
1XfH,6\8i  
public TestMethod() :~uvxiF  
{ ///xx/weblogic60b2_win.exe Yz<,`w5/6~  
try{ V+\L@mz;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); nP]tc  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); X;2I' Kg  
SiteFileFetch fileFetch = new SiteFileFetch(bean); IZ
){xI  
fileFetch.start(); 99QMMup  
} !LGnh  
catch(Exception e){e.printStackTrace ();} ku2gFO  
yf|,/{S  
!Cqm=q{K  
} Wp2W:JX:  
@|I:A  
R$>]7-N}  
public static void main(String[] args) @ P:b\WCI  
{ 4Vv~  
new TestMethod(); 'K|Jg.2  
} k8>(-W"A  
} }s*H|z  
点击下载更多相关资料