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http断点续传简单实现(java)

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/* l_p2Riv  
**SiteFileFetch.java Nf\LN$ &8  
*/ o+'6`g'8  
package NetFox; f:} x7_Q  
import java.io.*; sgFEK[w.y  
import java.net.*; k,*XG$2h  
mzgfFNm^G)  
!Vk^TFt`  
public class SiteFileFetch extends Thread { KWHY4  
7[)E>XRE  
4WB0Pt{  
SiteInfoBean siteInfoBean = null; //文件信息Bean ktIFI`@ w)  
long[] nStartPos; //开始位置 UK!(G  
long[] nEndPos; //结束位置 !Uo4,g6r+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 $UwCMPs X  
long nFileLength; //文件长度 ]f_p 8?j"  
boolean bFirst = true; //是否第一次取文件 9.#<b |g  
boolean bStop = false; //停止标志 mfr|:i  
File tmpFile; //文件下载的临时信息 z{QqY.Gu{G  
DataOutputStream output; //输出到文件的输出流 W=?<<dVYD  
? J0y|  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Z`i(qCAd(  
public SiteFileFetch(SiteInfoBean bean) throws IOException %N._w!N<5n  
{ 6gDN`e,@  
siteInfoBean = bean; {Sh ;(.u^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); z$sT !QL~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 9 68Ez  
if(tmpFile.exists ()) Pq$n5fZC !  
{ 1% `Rs  
bFirst = false; Di{de`  
read_nPos(); wCBplaojJ  
} :ws<-Qy  
else (bS&D/N.  
{ }SZd  
nStartPos = new long[bean.getNSplitter()]; ~} ~4  
nEndPos = new long[bean.getNSplitter()]; Vurq t_nb  
} %cn<ych G  
Kg]J/|0\  
tH4B:Bgj!  
#'`{Qv0,  
} c:('W16  
n$R)>n Y  
2=}FBA,2  
public void run() [-w%/D%@  
{ Hl=xW/%6y  
//获得文件长度 2\$oV  
//分割文件 yHaGkm  
//实例FileSplitterFetch c71y'hnT  
//启动FileSplitterFetch线程 H5an%kU|j  
//等待子线程返回 sLk-x\P]|  
try{ \;Weizq5  
if(bFirst) x+]"  
{ 6A ah9   
nFileLength = getFileSize(); (9)Q ' 'S  
if(nFileLength == -1) ]:n,RO6  
{ uY*L,j^)  
System.err.println("File Length is not known!"); *Pr )%  
} l]SX@zTb  
else if(nFileLength == -2) *4 n)  
{ zbiLP83  
System.err.println("File is not access!"); 0g;|y4SN=  
} Z_NCD`i;  
else =_^X3z0  
{ ,esmV-  
for(int i=0;i<nStartPos.length;i++) ar,7S&s H  
{ \U_@S.  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); eO1lnO|  
}  !VpoZ  
for(int i=0;i<nEndPos.length-1;i++) J}t%p(mb  
{ -?a 26o%e  
nEndPos = nStartPos[i+1]; lTsjxw o  
} "@n%Z  
nEndPos[nEndPos.length-1] = nFileLength; dh\P4  
} =(^3}x  
} l^ }c!  
j<$2hiI/?&  
l,).p  
//启动子线程 G~m<;  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2<3K3uz  
for(int i=0;i<nStartPos.length;i++) !R$`+wZ62  
{ \)e'`29;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6LhTBV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), v:#tWEbo-  
nStartPos,nEndPos,i); ~LC-[&$  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); KPki}'GO  
fileSplitterFetch.start(); -\MG}5?!  
} 7EJ+c${e.-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q b%J8juRf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); I^]nqK  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Vvo 7C!$z  
nEndPos = " + nFileLength); 6\t@)=C,Q  
// fileSplitterFetch[nPos.length-1].start(); dN6?c'iN?2  
~J]qP#C  
rl.}%Ny  
//等待子线程结束 7 8,n%=nG  
//int count = 0; .\mj4*?/  
//是否结束while循环 P<-@h1p,  
boolean breakWhile = false; k:%%/  
$~kA B8z  
W*G<X.Hf  
while(!bStop) {`_i`  
{ g)B]FH1  
write_nPos(); |y*c9  
Utility.sleep(500); Rb;'O89Hj@  
breakWhile = true; F"kAkX>3}  
rM SZ"  
SX#&5Ka/  
for(int i=0;i<nStartPos.length;i++) ^rz_f{c]-  
{ C# pjmT_  
if(!fileSplitterFetch.bDownOver) :'ptuY  
{ CN ?gq^  
breakWhile = false; jWgX_//!  
break; s#MPX3itK  
} +|f@^-  
} YYS0`  
if(breakWhile) O0:q;<>z  
break; |BYRe1l6l  
ykJ>*z  
$Kd>:f=A  
//count++; 7$#u  
//if(count>4) UZ";a453r  
// siteStop(); xx $cnG  
} BLFdHB.$T  
8,|kao:  
3$/IC@+  
System.err.println("文件下载结束!"); ';"VDLb3  
} MOC/KNb  
catch(Exception e){e.printStackTrace ();} YZ7.1`8  
} A(XKyEx  
j1Ezf=N6`  
4z)]@:`}z  
//获得文件长度 {[F A#  
public long getFileSize() )gi9f1n`  
{ d5-qZ{W  
int nFileLength = -1; r<\u6jF  
try{ }2oc#0  
URL url = new URL(siteInfoBean.getSSiteURL()); X{VOAcugr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M\=2uKG#  
httpConnection.setRequestProperty("User-Agent","NetFox"); |?9HU~B  
Ca-j?bb!  
! P4*+')M  
int responseCode=httpConnection.getResponseCode(); 2zpr~cB=  
if(responseCode>=400) DwF hK*  
{ @|!z9Y*  
processErrorCode(responseCode); :KO2| v\  
return -2; //-2 represent access is error Va8&Z  
} b Zt3|  
n@w%Zl  
9 $X-  
String sHeader; -qoH,4w  
8Y?;x}  
q(}bfIf  
for(int i=1;;i++) V8(-  
{ pot~<d`:K"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9u:Q,0\  
//Utility.log(in.readLine()); 2rMpgV5  
sHeader=httpConnection.getHeaderFieldKey(i); ^Dx&|UwiZa  
if(sHeader!=null) w =KPT''!  
{ %)n=x ne  
if(sHeader.equals("Content-Length")) jdBLsy@  
{ Pz^544\~ou  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 4P0}+  
break; @ P|y{e6  
} ?Ob3tUz2  
} Ss`LLq0LO  
else W!<U85-#S  
break; Xr{v~bf  
} s`U J1eJ  
} 28nFRr  
catch(IOException e){e.printStackTrace ();} SAz   
catch(Exception e){e.printStackTrace ();} ~ K=b\xc^  
Mp]rUPK  
pJ{Y lS{  
Utility.log(nFileLength); <vP=zk  
?# fQ~ s  
f!"w5qC^  
return nFileLength; gFh*eCo   
} @XVTU  
;G!q Y  
Ep}s}Stlr}  
//保存下载信息(文件指针位置) uw7zWJ n  
private void write_nPos() tVjsRnb{  
{ ElXFeJ%[G  
try{ s@C}P  
output = new DataOutputStream(new FileOutputStream(tmpFile)); IK]d3owA  
output.writeInt(nStartPos.length); y}H!c;  
for(int i=0;i<nStartPos.length;i++) \Cj B1] I  
{ wS*E(IAl  
// output.writeLong(nPos); Q.[0ct  
output.writeLong(fileSplitterFetch.nStartPos); P*o9a  
output.writeLong(fileSplitterFetch.nEndPos); ;=N# `l  
} ;\]@K6m/Ap  
output.close(); *`U~?q}  
} dRDnJc3  
catch(IOException e){e.printStackTrace ();} He)%S]RLk  
catch(Exception e){e.printStackTrace ();} v2?ZQeHr_(  
} h$*!8=M  
S[N5 ikg  
T;uX4,|(  
//读取保存的下载信息(文件指针位置) F5Va+z,jg  
private void read_nPos() +qoRP2  
{ b]y2+A.n  
try{ h\e.e3/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Y0>y8U V  
int nCount = input.readInt(); *2?@ |<(r  
nStartPos = new long[nCount]; &FD>&WRV  
nEndPos = new long[nCount]; iB{V^ksU  
for(int i=0;i<nStartPos.length;i++) ]?*wbxU0  
{ 7 3m1  
nStartPos = input.readLong(); f<H2-(m  
nEndPos = input.readLong(); Q;u pau  
} HV.t6@\};  
input.close(); O84i;S+-p  
} #F#%`Rv1  
catch(IOException e){e.printStackTrace ();} g 'gdgfvn  
catch(Exception e){e.printStackTrace ();} #S(Hd?34,  
} v1[29t<I!  
=fbWz  
:r[`.`  
private void processErrorCode(int nErrorCode) OY d !v`<  
{  `]X>V,  
System.err.println("Error Code : " + nErrorCode); +0~YP*I`/  
} vbNBLCwug  
2|L&DF:G  
PdCEUh\>y  
//停止文件下载 9my^ Y9B  
public void siteStop() q7!{?\T%  
{ OH88n69  
bStop = true; Z7#+pPt!  
for(int i=0;i<nStartPos.length;i++) N0lC0 N?_J  
fileSplitterFetch.splitterStop(); eJSxn1GW  
g ?k=^C  
. ^u,.  
} #jk_5W  
} >bxS3FCX  
//负责部分文件的抓取 `g,..Ns-r  
**FileSplitterFetch.java k\IbIv7?i  
*/ [~ fraK,)  
package NetFox; R@0R`Zs  
p[-O( 3Y  
Jv i#)  
import java.io.*; 1,~D4lD|  
import java.net.*; y^k$Us  
/,dz@   
8QK&_n*  
public class FileSplitterFetch extends Thread { Gq6*SaTk  
<UI [%yXj  
Si7*& dw=  
String sURL; //File URL aYeR{Y]  
long nStartPos; //File Snippet Start Position <[v[ci  
long nEndPos; //File Snippet End Position %RVZD#zr  
int nThreadID; //Thread's ID IcEdG(  
boolean bDownOver = false; //Downing is over JVJMgim)0  
boolean bStop = false; //Stop identical \lY_~*J  
FileAccessI fileAccessI = null; //File Access interface 4JEpl'5^Q  
pJ=#zsE0  
;*N5Y}?j'  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException :Al!1BJQ  
{ ;j7#7MN2_E  
this.sURL = sURL; p'k0#R$  
this.nStartPos = nStart; (mOtU8e  
this.nEndPos = nEnd; =vPj%oLp'a  
nThreadID = id; 5\v3;;A[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 CAe!7HiR  
} &L:!VL{I  
GVz6-T~\>  
Zc yc*{DS  
public void run() *_e3 @g  
{ N;R^h? '  
while(nStartPos < nEndPos && !bStop) LLI.8kn7  
{ 43w}qY1  
>sF)Bo Lc  
BWNi [^]  
try{ lFk R=!?=  
URL url = new URL(sURL); so; ]&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G5!^*jf  
httpConnection.setRequestProperty("User-Agent","NetFox"); \^LFkp  
String sProperty = "bytes="+nStartPos+"-"; <$YlH@;)`a  
httpConnection.setRequestProperty("RANGE",sProperty); Lr+$_ t}r  
Utility.log(sProperty); D=$)n_F  
=%7-ZH9  
Q/?$x*\>  
InputStream input = httpConnection.getInputStream(); "&] -2(  
//logResponseHead(httpConnection); -4K5-|>O  
TrNF=x>  
0"R|..l/  
byte[] b = new byte[1024]; #G3<7PK  
int nRead; u NyVf7u  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ni<(K 0~  
{ [WJ+h~~ o  
nStartPos += fileAccessI.write(b,0,nRead); Ni>[D"|  
//if(nThreadID == 1) Smh,zCc>s  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vI?, 47Hj+  
} [7-?7mp!B  
h;Qk @F  
sT.ss$HY9,  
Utility.log("Thread " + nThreadID + " is over!"); TvM~y\s  
bDownOver = true; 2eogY#  
//nPos = fileAccessI.write (b,0,nRead); q)GdD==  
} maZ)cW?  
catch(Exception e){e.printStackTrace ();} K}y f>'O  
} xo)P?-  
} [UR-I0 s!/  
6Zo}(^Ovz  
/1 dT+>  
//打印回应的头信息 ^ 9sjj  
public void logResponseHead(HttpURLConnection con) W)/#0*7  
{ 5G#n"}T  
for(int i=1;;i++) ("@!>|H  
{ F@t3!bj9  
String header=con.getHeaderFieldKey(i); <b.D&  
if(header!=null) #Z#-Ht  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); x^ni1=kU  
Utility.log(header+" : "+con.getHeaderField(header)); b>W %t  
else R_KH"`q  
break; $qiya[&G4  
} ~u{uZ(~  
} SM '|+ d  
kM 6 Qp  
NbobliC=  
public void splitterStop() |)&%A%m  
{ GyIV Hby  
bStop = true; Xvv6~  
} =l6mL+C  
#E?4E1bnB  
%>yL1BeA4  
} \+etCo   
M:8R -c#![  
`uFdwO'DD  
/* {ax:RUQxy  
**FileAccess.java wJ]d&::@h  
*//文件访问(定位,写) oDR%\VY6T  
package NetFox; ^~dWU>  
import java.io.*; H|*m$| $,  
[ 3Gf2_  
RN1_S  
public class FileAccessI implements Serializable{ ig!+2g  
_#niyW+?~  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 do%&m]#;  
RandomAccessFile oSavedFile; eRYK3W  
long nPos; \RiP  
_-D{-Bu#  
uZ5p#M_  
public FileAccessI() throws IOException +0&/g&a\R  
{ eDMO]5}Ht  
this("",0); ]lbuy7xj63  
} }6#  
|=w@H]r  
y `UaB3q  
public FileAccessI(String sName,long nPos) throws IOException = &]L00u.  
{ ^c<Ve'-  
oSavedFile = new RandomAccessFile(sName,"rw"); Wri<h:1  
this.nPos = nPos; /(cPfZZ  
oSavedFile.seek(nPos); !Ee:o"jG{  
} A<{{iBEI`  
d~H`CrQE*  
:]KAkhFkbb  
public synchronized int write(byte[] b,int nStart,int nLen) L#J1b!D&<6  
{ fl(wV.Je|  
int n = -1; \Z/@C lCm  
try{ s#11FfF`  
oSavedFile.write(b,nStart,nLen); *T/']t  
n = nLen; Wc#24:OKe3  
} 6'/ #+,d'  
catch(IOException e) NOva'qk  
{ UVP vOtZj  
e.printStackTrace (); UfGkTwoo=  
} 29Ki uP  
XwmL.Gg:]7  
[~HN<>L@C  
return n; W4S,6(  
} <YY14p  
>Ry01G]_/h  
*pq\MiD/  
} ! mHO$bQ"  
CrLrw T  
X8|,   
/* C_Dn{  
**SiteInfoBean.java s_Sk0}e  
*/ #mF"1QW  
package NetFox; K-4PI+qQ\  
z_HdISy0  
/x hKd]Q  
public class SiteInfoBean { Vk suu@cch  
5+vaE 2v  
_/|\aqF.  
private String sSiteURL; //Site's URL aUp g u"  
private String sFilePath; //Saved File's Path 80I#TA6C  
private String sFileName; //Saved File's Name ^W ^OfY  
private int nSplitter; //Count of Splited Downloading File @dK Tx#gZ  
7I}uZ/N  
Y]>t[Lo%  
public SiteInfoBean() eFgA 8kY)  
{//nSplitter的缺省值为5 7dWS  
//default value of nSplitter is 5 ,bi^P>X  
this("","","",5); P0@,fd<  
} TbU#96"~.  
4 KiY6)  
(=0.inZ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~$'awY  
{ ;l+Leex  
sSiteURL= sURL; # d  
sFilePath = sPath; Vr}'.\$  
sFileName = sName; l#o ~W`  
this.nSplitter = nSpiltter; .A|udZ,  
)5, v!X)  
=bOW~0Z1  
} {c'lhUB  
]Ze1s02(  
\e*]Ls#jS  
public String getSSiteURL() 0kh6@y3  
{ %J(:ADu]  
return sSiteURL; I9Xuok!0>=  
} ye&;(30Oq  
nlP;nlW  
~ljXzD93Z  
public void setSSiteURL(String value) 0J9x9j`&j  
{ lA]8&+,ZM  
sSiteURL = value; ?,mmYW6TjB  
} 1}x%%RD_  
HJ"GnZp<  
uRvP hkqm  
public String getSFilePath() ,+k\p5P  
{ [y(MCf19  
return sFilePath; @gblW*Zhk  
} 4(+PD&_J  
%b$>qW\*&  
)A6<c%d =x  
public void setSFilePath(String value) q V =!ORuj  
{ )9g2D`a4  
sFilePath = value; |Cv!,]9:r  
} ( .:e,l{U%  
ah"o~Cbj  
/uc>@!F  
public String getSFileName() >MZ/|`[M  
{ yWK)vju"  
return sFileName; A.SvA Yn  
} ?,z}%p  
$Sq:q0  
)lkjqFQ(  
public void setSFileName(String value) `Di{}/2  
{ Oketwa  
sFileName = value; J.a]K[ci  
} x2xRBkRg=  
V3Bz Mw\9r  
[agMfn  
public int getNSplitter() _BufO7 `.  
{ YK_ 7ip.a[  
return nSplitter; )~>YH*g  
} U^PgG|0N  
dtDFoETz  
)0`C@um  
public void setNSplitter(int nCount) hN_]6,<\  
{ X|dlt{Gf   
nSplitter = nCount; yi[x}ffdE  
} Rq-ZL{LR7  
} -"x$ZnHU  
]Wup/o  
W/N7vAx X  
/* 5xiEPh  
**Utility.java ).O)p9  
*/ KNl$3nX  
package NetFox; inL(X;@yo  
"]*tLL:`  
0-gAyiKx?  
public class Utility { @7 }W=HB  
>P(.:_ ^p  
Uo49*Mr  
public Utility() ?,/ }`3Vw  
{ h[ ZN+M  
kJU2C=m@e2  
 " bG2:  
} PT ~D",k  
JF]JOI6.e  
//线程睡眠 sO Y:e/_F  
public static void sleep(int nSecond) +@UV?"d  
{ 42{~Lhxt  
try{ (FV >m  
Thread.sleep(nSecond); (7Qo  
} hH.G#-JO  
catch(Exception e) BtZyn7a  
{ GgU/ !@  
e.printStackTrace (); g(g& TO  
} [g,}gyeS(  
} \V:^h [ad  
z?zL97H  
//日志 >_} I.\ X  
public static void log(String sMsg) }H2 R3icE  
{ qs6aB0ln  
System.err.println(sMsg); 3|7QU ld  
} %<5'=t'|-U  
|Tw~@kT@  
AA_%<zK  
public static void log(int sMsg) 7)m9"InDI  
{ 1C.VnzRnJ  
System.err.println(sMsg); WIOV2+  
} ICCc./l|  
} M5B# TAybC  
MD]>g>  
[QTV9  
/* ~[: 2I  
**TestMethod.java *Ex|9FCt$  
*/ 1YA% -~  
package NetFox; ;S{(]K7i  
'-6~tWC~7  
%y@AA>x!  
public class TestMethod { g0H[*"hj  
'qi}|I  
P>L +t`'  
public TestMethod() <3iMRe  
{ ///xx/weblogic60b2_win.exe 0(I j%Wi,  
try{ )jj0^f1!j  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); J,G lIv.A  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); QJNFA}*>  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \v{=gK  
fileFetch.start(); V~bD)?M  
} X]=t>   
catch(Exception e){e.printStackTrace ();} ;<5q]/IHK  
R]dg_Da  
[lAp62i5  
} wr4:Go`  
NI5``BwpO  
fM}#ON>Z  
public static void main(String[] args) E]6 6]+;0_  
{ Bx!-"e  
new TestMethod(); _@g;8CA  
} tkhCw/  
} YqG7h,F  
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