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http断点续传简单实现(java)

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/* "9!CsloWhz  
**SiteFileFetch.java C9E@$4*  
*/ Ozs&YZ  
package NetFox; >A1;!kGE#  
import java.io.*; @8V~&yqq  
import java.net.*; H?j!f$sw  
K_LwYO3  
=s1Pf__<k  
public class SiteFileFetch extends Thread { #[NNb?`F  
zNJ-JIo%  
rqYx\i?  
SiteInfoBean siteInfoBean = null; //文件信息Bean y`-5/4  
long[] nStartPos; //开始位置 CFiO+p&  
long[] nEndPos; //结束位置 I07_o"3>qr  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 RTvzS]  
long nFileLength; //文件长度 oHkjMqju  
boolean bFirst = true; //是否第一次取文件 1<3!   
boolean bStop = false; //停止标志 = j S  
File tmpFile; //文件下载的临时信息 !gFUC<4bu  
DataOutputStream output; //输出到文件的输出流 kIYV%O   
2^=.jML[  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) nAW`G'V#  
public SiteFileFetch(SiteInfoBean bean) throws IOException pN7 v7rs  
{ 1U~yu&  
siteInfoBean = bean; F9 C3i  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;n=A245W\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ob"yz}  
if(tmpFile.exists ()) SDICN0X*  
{ *p7_rY  
bFirst = false; O,?aVgY  
read_nPos(); - WK  
} JM Ikr9/$  
else S*?x|&a  
{ + +G %~)S:  
nStartPos = new long[bean.getNSplitter()]; /a:L"7z  
nEndPos = new long[bean.getNSplitter()]; XpibI3:<  
} xzTF| Z\  
qn|~z@"  
.?p\=C@C+  
rty&\u@}  
} IRl(H_.  
-[.A6W  
\t@4)+s/)  
public void run() ]*JH~.p  
{ 7.tEi}O&_g  
//获得文件长度 HVK./y qy  
//分割文件 :_"%o=  
//实例FileSplitterFetch yaKw/vV  
//启动FileSplitterFetch线程 }?XNA.Wz  
//等待子线程返回 n 0CS =  
try{ ?tFsSU  
if(bFirst) .q9wyVi7GI  
{ UIi`bbJ  
nFileLength = getFileSize(); >PMLjXK  
if(nFileLength == -1) 5WG:m'$$  
{ k>q}: J9V  
System.err.println("File Length is not known!");  F5FzT^  
} qI#ow_lL#  
else if(nFileLength == -2) uV+.(sjH  
{ ;gNoiAxW  
System.err.println("File is not access!"); ;#Pc^Yzc1  
} DB;Nr3x  
else 61{IXx_  
{ F_C_K"[s  
for(int i=0;i<nStartPos.length;i++) \cRe,(?O  
{ gTjhD(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /yS/*ET8  
} 2rJeON  
for(int i=0;i<nEndPos.length-1;i++) bjYaJtn  
{ Vm <9/UG<  
nEndPos = nStartPos[i+1]; Jdp@3mP  
} k=):>}  
nEndPos[nEndPos.length-1] = nFileLength; yCG<qQz  
} @%sr#YqY  
} 1I -LGe[Q  
+F3`?6UXz  
VPqMbr"L[  
//启动子线程 zS+_6s  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; R x.]m0  
for(int i=0;i<nStartPos.length;i++) W:z!fh-  
{ #8[iqvE  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7f\@3r  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), A T'P=)F@  
nStartPos,nEndPos,i); #cD20t  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *.ZU" 5e  
fileSplitterFetch.start(); aR~Od Ys  
} I~.d/!>Z  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <OC|z3na_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .&Ok53]b  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", xRU ~h Q  
nEndPos = " + nFileLength); du k:: |{F  
// fileSplitterFetch[nPos.length-1].start(); KGoHn6jM  
l`A4)8Y@  
,t=12R]>  
//等待子线程结束 ,dO$R.h  
//int count = 0; 81<0B @E  
//是否结束while循环 Z 2x%  
boolean breakWhile = false; :u$+lq  
Qo;#}%}^^  
)Mj $/  
while(!bStop) eX@7f!uz  
{ J \V.J/  
write_nPos(); GxR, 3  
Utility.sleep(500); {BlKVsQ  
breakWhile = true; U\\nSU  
,@'M'S  
+\O[)\  
for(int i=0;i<nStartPos.length;i++) Udh!%QP%[w  
{ 6Y[|xu:N8Y  
if(!fileSplitterFetch.bDownOver) WDdp(<  
{ k;9"L90  
breakWhile = false; ']]&<B}mz  
break; GXE6=BO  
} @\UoZv(  
} qm&Z_6Pw  
if(breakWhile) 4/B n9F  
break; Ft)Z'&L   
_%$(D"^j  
ef;Ta|#  
//count++; ttK`*Ng  
//if(count>4) BLvI[b|3gn  
// siteStop(); KZxA\,Y'5  
} _,i+gI[  
5@{+V!o,  
Mn=5yU  
System.err.println("文件下载结束!"); 8{GRrwQ>  
} 23;e/Qr  
catch(Exception e){e.printStackTrace ();} .V\ M/q\Tv  
} !dW77kLTg  
qJ|n73yn  
r4D 6I,  
//获得文件长度 *!gj$GK@%  
public long getFileSize() QF fKEMN  
{ X}5aE4K/  
int nFileLength = -1; ;I+"MY7D  
try{ #!FLX*,  
URL url = new URL(siteInfoBean.getSSiteURL()); Q#i^<WUpg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,OQ!lI_`R  
httpConnection.setRequestProperty("User-Agent","NetFox"); XT|!XC!|  
weOzs]uc  
&z\]A,=T c  
int responseCode=httpConnection.getResponseCode(); WSY&\8   
if(responseCode>=400) -|DSfI#j  
{ @M V%&y*z.  
processErrorCode(responseCode); PZdYkbj  
return -2; //-2 represent access is error epH48)2  
} .2b) rKo~  
^!*?vHx:  
Z-{!Z;T)z  
String sHeader; (&6C,O~n^.  
/I' n]  
?]=fC{Rh  
for(int i=1;;i++) 9 o7d3ir)  
{ #f'(8JjY  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Y"uFlHN&i  
//Utility.log(in.readLine()); Jb~-)n2  
sHeader=httpConnection.getHeaderFieldKey(i); E00zf3Jgv'  
if(sHeader!=null) xmDX1sL**  
{ Ohm>^N;  
if(sHeader.equals("Content-Length")) G@) I  
{ !_`T8pJ`  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); toipEp<ci  
break; !j(KbAhWZ  
} MGO.dRy_  
} LC/w".oq?  
else fxDY:l  
break; hG,gY;&[6  
} 2.2Z'$W  
} 6[9E^{(z  
catch(IOException e){e.printStackTrace ();} 4M8AYh2)  
catch(Exception e){e.printStackTrace ();} vII8>x%*  
RZfC ?  
1>*]jj}  
Utility.log(nFileLength); >5Zp x8W  
~^.&nph  
6,xoxNoPP3  
return nFileLength; NEO~|B*oDU  
} `~(C\+gUp  
x~GV#c  
s9A'{F  
//保存下载信息(文件指针位置) tji,by#E/%  
private void write_nPos() !dLz ?0  
{ LIH>IpamN  
try{ J1<fE(X  
output = new DataOutputStream(new FileOutputStream(tmpFile)); JXeqVKF  
output.writeInt(nStartPos.length); 1V`]sfRK  
for(int i=0;i<nStartPos.length;i++) -aNTFt~|[  
{ skcMGEB  
// output.writeLong(nPos); x 0  
output.writeLong(fileSplitterFetch.nStartPos);  &1Fcwj  
output.writeLong(fileSplitterFetch.nEndPos); EGwY|+3  
} Snt=Hil`  
output.close(); H/V%D O  
} |?Q(4(D`*  
catch(IOException e){e.printStackTrace ();} &Jj> jCg  
catch(Exception e){e.printStackTrace ();} E|9LUPcb  
} YeJ95\jf  
g]xZ^M+  
~,e!t.339  
//读取保存的下载信息(文件指针位置) t%z7#}9$  
private void read_nPos() >*}qGk  
{ 3i(k6)H$4  
try{ SEchF"KJQF  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); BHmA*3?  
int nCount = input.readInt(); ~rCnST  
nStartPos = new long[nCount]; n@L!{zY  
nEndPos = new long[nCount]; <J-OwO a-1  
for(int i=0;i<nStartPos.length;i++) 8"LaP3U  
{ )O- x1U  
nStartPos = input.readLong(); l``1^&K  
nEndPos = input.readLong(); @\l> <R9V  
} F.8{ H9`  
input.close(); w=e,gNO  
} 6sy%KO*A  
catch(IOException e){e.printStackTrace ();} F'CUkVC0~P  
catch(Exception e){e.printStackTrace ();} +lha^){  
} GIVs)~/Eq  
qd|*vE  
CES FkAj~  
private void processErrorCode(int nErrorCode) Ux icqkX  
{ 24N,Bo 3  
System.err.println("Error Code : " + nErrorCode); #>'1oC{  
} H[N&Wiq/|  
pjj 5  
G^mk<pH  
//停止文件下载 'v|2} T*  
public void siteStop() ^RWt  
{ P'9aZd  
bStop = true; g&0GO:F`  
for(int i=0;i<nStartPos.length;i++) 4_.k Q"'DH  
fileSplitterFetch.splitterStop(); K[sM)_I  
?XOeMI  
9jPb-I-   
} 2Bjp{)*  
} {t/!a0\HS  
//负责部分文件的抓取 <M'IR f/D  
**FileSplitterFetch.java 9_>4~!x`  
*/ iKabo,~  
package NetFox; Y(SI`Xo[  
b"FsT  
yL Q&<\  
import java.io.*; r3j8[&B"  
import java.net.*; Zc4hjg  
Ic=V:  
$g$`fR)  
public class FileSplitterFetch extends Thread { )q l?}  
#6H<JB  
pn $50c  
String sURL; //File URL J#x91Jh  
long nStartPos; //File Snippet Start Position ONjc},_  
long nEndPos; //File Snippet End Position d}o1 j  
int nThreadID; //Thread's ID >Au<y,Tw  
boolean bDownOver = false; //Downing is over 78QFaN$  
boolean bStop = false; //Stop identical ?3Jh{F_+  
FileAccessI fileAccessI = null; //File Access interface 2mlE;.}8  
|%V.Lae  
I(<G;ft<}  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException u3. PHZ  
{ >rFvT>@NU  
this.sURL = sURL; % 9D@W*Z  
this.nStartPos = nStart; /3TorB~Y  
this.nEndPos = nEnd; BkZ%0rw%  
nThreadID = id; KncoIw  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 'j)eqoj  
} `2fuV]FW  
tJu<#h X  
sMS`-,37u  
public void run() "G,*Z0V5  
{ |wb7`6g  
while(nStartPos < nEndPos && !bStop) | fI%L9  
{ 7.Mh$?;i9  
?0(B;[xEJ  
O^xt  
try{ *tO<wp&  
URL url = new URL(sURL); B)Q'a3d#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (;j7 {(  
httpConnection.setRequestProperty("User-Agent","NetFox"); @iP6 N  
String sProperty = "bytes="+nStartPos+"-"; hrL<jcv|  
httpConnection.setRequestProperty("RANGE",sProperty); ww,c)$  
Utility.log(sProperty); 4B y-+C*  
5->PDp  
OX`n`+^D  
InputStream input = httpConnection.getInputStream(); 6+u'Tcb  
//logResponseHead(httpConnection); d$TW](Bby  
$F-XXBp  
PW`Tuj  
byte[] b = new byte[1024]; H\k5B_3OU  
int nRead; >eTlew<5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) CbHNb~  
{ :9YQX(l8  
nStartPos += fileAccessI.write(b,0,nRead); -0X> y  
//if(nThreadID == 1) @iRVY|t/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1}uDgz^  
} c'B"Onu@m*  
"n6Y^  
J7_H.RPa  
Utility.log("Thread " + nThreadID + " is over!"); !:t9{z{Ixg  
bDownOver = true; |i`@!NrFL  
//nPos = fileAccessI.write (b,0,nRead); ;gMh]$|"  
} "P{&UwMmh  
catch(Exception e){e.printStackTrace ();} Xdq, =;  
} *YtNt5u  
}  B~NC  
~/U0S.C  
CN=&Je%I  
//打印回应的头信息 ~tLR  
public void logResponseHead(HttpURLConnection con) _'7/99]4g}  
{ *02( J  
for(int i=1;;i++) W*<]`U_.  
{ <C$<(Dw5  
String header=con.getHeaderFieldKey(i); jyGVbno`  
if(header!=null) 2 QmUg  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ]p!J]YV ]0  
Utility.log(header+" : "+con.getHeaderField(header)); i4I0oRp  
else v/czW\z  
break; fI1;&{f   
} Du>HF;Fv  
} 3I5WDuq  
OVyy}1Hx  
88>Uu!M=f  
public void splitterStop() Z~(XyaN  
{ JLu0;XVK  
bStop = true; Ln_l>X6j51  
} j1 F+,   
%-l:_A  
PBL^xlg  
} OD]J@m  
"AouiZkh  
XX-T",  
/* qYiAwK$  
**FileAccess.java r(i)9RI+(  
*//文件访问(定位,写) 4c=kT@=jX  
package NetFox; (@ E#O$'  
import java.io.*; {{3H\ rR  
S7a6ntei  
 W6O.E  
public class FileAccessI implements Serializable{ 1[l>D1F?  
n6 G&^Oj  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 : xZC7"  
RandomAccessFile oSavedFile; F?} *ovy  
long nPos; udGGDH  
%h"< IA S.  
A{2$hKqHi  
public FileAccessI() throws IOException txo?k/w  
{  s7 o*|Xv  
this("",0); #`4^zU)  
} t4@g;U?o  
6\Vu#r  
MNqyEc""  
public FileAccessI(String sName,long nPos) throws IOException g u =fq\`  
{ \hW73a!  
oSavedFile = new RandomAccessFile(sName,"rw"); ]zU<=b@  
this.nPos = nPos; Sqf.#}u<=  
oSavedFile.seek(nPos); KN:dm!A  
} :EwA$`/  
%_MR.J+m2  
yl<$yd0Zdu  
public synchronized int write(byte[] b,int nStart,int nLen) }AW)R&m  
{ }pnFJ  
int n = -1; xqWrW)  
try{ ,?<h] !aQ  
oSavedFile.write(b,nStart,nLen); 1vs>2` DLa  
n = nLen; W lQ=CRY  
} Kw0V4UF  
catch(IOException e) 0~b6wuFl  
{ !7`=rT&  
e.printStackTrace (); pE/3-0;}N  
} d4>-a^)V  
8ex:OTzn|  
rg^\BUa-W,  
return n; 4VJzs$  
} 2Lekckgv  
"!Oh#Vf  
DUKmwKM"k  
} yr9A0F0  
qj"syO  
[l%fL9  
/* /B@% pq  
**SiteInfoBean.java  +wW  
*/ _@pf1d$  
package NetFox; kqigFcz!Y  
&@utAuI  
11<@++,i  
public class SiteInfoBean { L +rySP  
P9i9<pR  
vDeG20.?Z  
private String sSiteURL; //Site's URL sQ:VrXwP  
private String sFilePath; //Saved File's Path 9=~H6(m>  
private String sFileName; //Saved File's Name N"1x]1'   
private int nSplitter; //Count of Splited Downloading File RrU~"P1C  
k\&IFSp  
<<On*#80w  
public SiteInfoBean() 0S:!Gv +  
{//nSplitter的缺省值为5 qVD!/;l  
//default value of nSplitter is 5 @VC9gd O/  
this("","","",5); Qv0>Pf  
} @52=3  
7R<u=U  
RQS:h]?:l  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) m)|.:sj  
{ '"]>`=R  
sSiteURL= sURL; f+TBs_  
sFilePath = sPath; yCkW2p]s,K  
sFileName = sName; *o e0=  
this.nSplitter = nSpiltter; &Wv`AoV  
fFZ` rPb  
F `pyhc>1;  
} XJlDiBs9=Q  
7{+Io  
\LoSUl i  
public String getSSiteURL() o(X90X  
{ Hu9-<upc&  
return sSiteURL; Z!RRe]"y  
} +ersP@G  
IJ_ 'w[k  
*4hOCQ[  
public void setSSiteURL(String value) 1f@U :<:  
{ xH`j7qK.  
sSiteURL = value; ]IHD:!Z-=  
} WrHgF*[  
K+ 7yUF8XP  
'x45E.wYw  
public String getSFilePath() {b-0_  
{ Z\*5:a]  
return sFilePath; LN~N Fjs  
} +6#%P  
Mdltzy=)L  
w*6!?=jP  
public void setSFilePath(String value) ,p*ntj{  
{ rtYb"-&  
sFilePath = value; ~E3SC@KL  
} C:s^s  
x<{;1F,k3  
&w;^m/zP3  
public String getSFileName() > G4HZE  
{ 5}X<(q(  
return sFileName; anz9lGG#  
} VM<oUKh_3  
V 4\^TO`q=  
1%/ NL?8#  
public void setSFileName(String value) i^yH?bH @~  
{ 2{sD*8&`  
sFileName = value; m|nL!Wc  
} J/]o WC`u  
`u p-m=zA  
9 N*S-Po=  
public int getNSplitter() >p]WCb'PH  
{ 5Aa31"43n  
return nSplitter; `uNvFlP  
} L.IoGUxD  
I!F}`d  
,Ou1!`6?t  
public void setNSplitter(int nCount) %2Xus9;k#  
{ f74%YY  
nSplitter = nCount; ~ C/Yv&58  
} qL%.5OCn(  
} c#\ah}]Vo  
oRT  
QLF,/"  
/* 8u:v:>D.'  
**Utility.java n!kk~65|  
*/ PuCwdTan_  
package NetFox; Y-Ziyy  
)tN?: l  
LY\ddI*s  
public class Utility { KlVi4.]  
>YJ8u{Z{o  
]/ZA/:Oa+  
public Utility() e9z$+h  
{ G!!-+n<  
#RR:3ZP ZC  
HsjELbH  
} e?^ \r)1  
3r~>~ueZ  
//线程睡眠 PmPyb>HK=P  
public static void sleep(int nSecond) HO%E-5b9  
{ 2d5}`>  
try{ #sz]PZ\  
Thread.sleep(nSecond); ?$30NK3G  
} bk\dy7  
catch(Exception e) ;xW8Z<\-  
{ #Dj"W8'zh  
e.printStackTrace (); aW`:)y&f  
} zmy4tsmX  
} AkYupP2]v  
G8 ^0 ^@o  
//日志 ":UWowJO  
public static void log(String sMsg) 2X qTyf<  
{ pY{; Yn&t  
System.err.println(sMsg); 'L>&ZgLy  
} rQu  
+Fc ET  
~ V@xu{  
public static void log(int sMsg) N `,7FI}  
{ HZQDe&  
System.err.println(sMsg); Hk<X  
} d'N(w7-Y  
} hw&ke$Fg#  
XPHQAo[(s  
Cp .1/  
/* S+.21,  
**TestMethod.java ri/t(m^{W  
*/ w8AJ#9W  
package NetFox; #d }0}7ue  
^?$D.^g  
& cM u/}  
public class TestMethod { c8^+^.=pX  
:3111}>c  
-kG3k> by_  
public TestMethod() (w5u*hx  
{ ///xx/weblogic60b2_win.exe |Hx%f  
try{ =8$|_  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); m.1LxM$8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5xh!f%6  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @Ufa -h5"(  
fileFetch.start();  =3h+=l[  
} !7A"vTs  
catch(Exception e){e.printStackTrace ();} :.C+?$iuX  
,|e}Y [  
??%)|nj.  
} U>/<6 Wd  
IY];Ss&i  
bin6i2b  
public static void main(String[] args) ]*bAF^8i  
{ X HWh'G9  
new TestMethod(); k-{yu8*';  
} r/UYC"K3  
} R'S c  
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