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http断点续传简单实现(java)

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/* {e>}.R  
**SiteFileFetch.java X0P<ifIv  
*/ ~#(bX]+A  
package NetFox; mufF_e)  
import java.io.*; Z\LW<**b  
import java.net.*; #gi&pR'$  
W;Fcp  
=]etw  
public class SiteFileFetch extends Thread { 'nW:2(J  
R},mq&f5  
?vM{9!M  
SiteInfoBean siteInfoBean = null; //文件信息Bean Hyc19|  
long[] nStartPos; //开始位置 +O\6p  
long[] nEndPos; //结束位置 1gCp/m2r7  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ' 71D:%p  
long nFileLength; //文件长度 |bB..b  
boolean bFirst = true; //是否第一次取文件 b\6w[52m  
boolean bStop = false; //停止标志 #J1a `}x  
File tmpFile; //文件下载的临时信息 s}/YcUK  
DataOutputStream output; //输出到文件的输出流 IvH0sS`F  
MPNBA1s  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) "4Anh1,js  
public SiteFileFetch(SiteInfoBean bean) throws IOException 8 I,(\<Xv  
{ "64pVaT4  
siteInfoBean = bean; %o*afd  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >W 8!YOc  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .X YSO  
if(tmpFile.exists ()) QeU>%qKT  
{ )mp0k%  
bFirst = false; VYlg+MlT0  
read_nPos(); =C5 [75z#+  
} h:j-Xd$H+  
else uw;s](~E  
{ H^'EY:|  
nStartPos = new long[bean.getNSplitter()]; "f5u2=7 }  
nEndPos = new long[bean.getNSplitter()]; VZw("a*TB  
} 3$WK%"%T  
N=:yl/M  
,!u^E|24  
#YhKAG@|  
} .KK"KO5k  
:t9(T?2  
H6e ^" E  
public void run() <>2QDI6_  
{ )3z.{.F  
//获得文件长度 ?Yz.tg  
//分割文件 Fda<cS]  
//实例FileSplitterFetch )lH?XpfTjm  
//启动FileSplitterFetch线程 1!BV]&,[  
//等待子线程返回 w;{k\=W3Ff  
try{ scN}eg:5  
if(bFirst) 2lXsD;[  
{ 4}#*M2wb  
nFileLength = getFileSize(); J& yDX>  
if(nFileLength == -1) ];j8vts&  
{ A\k-OP]  
System.err.println("File Length is not known!"); lzl4pnj  
} n |.- :Zy  
else if(nFileLength == -2) AE^&hH0^  
{ M> 1V3 sM  
System.err.println("File is not access!"); b%T-nY2  
} dk;Ed  
else AGOK%[[Ws  
{ }2DeqY  
for(int i=0;i<nStartPos.length;i++) b]CJf8'u  
{ M`iJ6L  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); aLhTaB-va  
} zKgW9j<(  
for(int i=0;i<nEndPos.length-1;i++) LF{qI?LG  
{ *1%=?:$(r6  
nEndPos = nStartPos[i+1]; P),%S9jP;  
} vJXd{iQE@C  
nEndPos[nEndPos.length-1] = nFileLength; H+_oK ]/  
} r}03&h~Hc&  
} -hhE`Y  
[xM07%:  
-7;RPHJs  
//启动子线程 ~+^,o_hT  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; rA{h/T"  
for(int i=0;i<nStartPos.length;i++) 28Q`O$=v  
{ 4#4kfGoT  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uA\A4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), O(WFjmHx  
nStartPos,nEndPos,i); r|0C G^:C  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Re,0RM\  
fileSplitterFetch.start(); WDgp(Av!  
} nE::9Yh8z  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  '6 w|z^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); QR79^A@5  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", &t p5y}=n  
nEndPos = " + nFileLength); $#"}g#u  
// fileSplitterFetch[nPos.length-1].start(); hFQC%N. '  
Zad+)~@!tq  
-cIc&5CS  
//等待子线程结束 6^|bKoN/ f  
//int count = 0; "B)DX*-\?  
//是否结束while循环 C|z`hNp  
boolean breakWhile = false; VwtGHF'  
^JY R^X>_  
@RT yCr  
while(!bStop) MS,H12h  
{ bYG}CO  
write_nPos(); yHT}rRS8  
Utility.sleep(500); c WK@O>  
breakWhile = true; o{>hOs &  
VO++(G)  
vP&*(WfO)  
for(int i=0;i<nStartPos.length;i++) ?86h:9  
{ X(E f=:  
if(!fileSplitterFetch.bDownOver) )Q7;)iPY#  
{ u'?t'I  
breakWhile = false; &QCqaJ-  
break; V 9=y@`;  
} 15nc  
} +wT,dUin_<  
if(breakWhile) B}r@xz  
break; oJXZ}>>iT  
iAup',AZg  
[iL2c=_  
//count++; hhYo9jTHW  
//if(count>4) +R#*eo;o7  
// siteStop(); hRc\&+#/  
} 6jF~zI^  
kv`x  
1F[; )@  
System.err.println("文件下载结束!"); j-yD;N  
} MZL~IX  
catch(Exception e){e.printStackTrace ();} /<|J\G21  
} rr9HC]63  
j:{<    
& qd:o}  
//获得文件长度 5zEl`h  
public long getFileSize() 7g(rJGjtg  
{ 5O)Z}  
int nFileLength = -1; >@]E1Qfe  
try{ 5<d Y,FvX  
URL url = new URL(siteInfoBean.getSSiteURL()); P=u)Q _  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); mHw1n=B  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;Oe6SNquT  
_);1dcnR  
Qy4AuMU2  
int responseCode=httpConnection.getResponseCode(); Z/Mp=273  
if(responseCode>=400) ;&:UxmTf  
{ y fP&Q<|  
processErrorCode(responseCode); r Ld,Izi  
return -2; //-2 represent access is error U76:F?MH  
} 2hU4g e?6  
frGUT#9?n  
: PQA9U|  
String sHeader; O7rm(  
O#u)~C?)8  
'OF)`5sj  
for(int i=1;;i++) I<[(hPQUf  
{ qn4Dm ^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \a|gzC1G  
//Utility.log(in.readLine()); YK"({Z>U  
sHeader=httpConnection.getHeaderFieldKey(i); v SWqOv$  
if(sHeader!=null) {/B) YR  
{ M~ *E!  
if(sHeader.equals("Content-Length")) m=%W<8[V  
{ )[qY|yu  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Z.YsxbH3  
break; NK,)"WE  
} G.<9K9K  
} Zvr(c|Q  
else `=CF | I  
break; A.z~wu%(  
} a?+) K  
} RsrZ1dhPvV  
catch(IOException e){e.printStackTrace ();} >1joCG~  
catch(Exception e){e.printStackTrace ();} &dOV0y_  
Q[~O`Lz  
^Jc~G~x4*  
Utility.log(nFileLength); w8@MUz}/#  
xES+m/?KlZ  
6EPC$*Xp!  
return nFileLength; /md`tqI>i<  
} ]=]'*Z%  
$dwv1@M2  
%iJ6;V 4  
//保存下载信息(文件指针位置) L6Ynid.k  
private void write_nPos() J!yc9Q  
{ <u^41  
try{ ! '2'db  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -B`;Sx  
output.writeInt(nStartPos.length); bF B;N+>  
for(int i=0;i<nStartPos.length;i++) xn6E f"  
{ hXM C!~Th  
// output.writeLong(nPos); q)@.f.  
output.writeLong(fileSplitterFetch.nStartPos); O`@$YXuD  
output.writeLong(fileSplitterFetch.nEndPos); EDnmYaa)dZ  
} av`b8cGg  
output.close(); tgrQ$Yjk  
} lXB_HDY  
catch(IOException e){e.printStackTrace ();} 1J<-P9 vk+  
catch(Exception e){e.printStackTrace ();} :ye)%UU"|:  
} C*c=@VAa  
8<_WtDg  
`5q`ibyPI  
//读取保存的下载信息(文件指针位置) {]Lc]4J  
private void read_nPos() (:[><-h.  
{ zIdQ^vm8Q  
try{ =U,;/f  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ylo@  
int nCount = input.readInt(); kMI\GQW  
nStartPos = new long[nCount]; czHO)uQ?d`  
nEndPos = new long[nCount]; 9Ft)VX  
for(int i=0;i<nStartPos.length;i++) 59EAqz[:  
{ *[vf47)r!  
nStartPos = input.readLong(); oh:t ex<  
nEndPos = input.readLong(); ` 0\hm`  
} Z?v9ub~%  
input.close(); ? 4.W _  
} y()#FRp7  
catch(IOException e){e.printStackTrace ();} O+'Pq,hn  
catch(Exception e){e.printStackTrace ();} HP?e?3.T  
} 5_`.9@eh.  
BwL: B\  
071w o7  
private void processErrorCode(int nErrorCode) ]k,fEn(  
{ $@K+yOq+u  
System.err.println("Error Code : " + nErrorCode); M5%xp.B  
} 7Y!^88,f.  
IE,g  
Qh{=Z^r  
//停止文件下载  gu"Agct4  
public void siteStop() 'fg`td  
{ ~xHr/:  
bStop = true; xQmk2S` y  
for(int i=0;i<nStartPos.length;i++) Kvk;D ]$  
fileSplitterFetch.splitterStop(); [&Qrk8EN  
(Ojg~P4;&  
8fDnDA.e  
} Dnd  
} `NGCUGQ_7  
//负责部分文件的抓取 #z5'5|3  
**FileSplitterFetch.java *, {b]6v  
*/ <p<gx*%  
package NetFox; _$, .NK,6  
$'&`k,a3|P  
/}M@MbGMM  
import java.io.*; Rf8|-G-}#  
import java.net.*; B!8]\D  
[[bMYD1eO  
(jQL?  
public class FileSplitterFetch extends Thread { @A yC0}  
1"!<e$&$X  
F<^,j7@  
String sURL; //File URL ^Yn6kF  
long nStartPos; //File Snippet Start Position x^C,xP[#Y;  
long nEndPos; //File Snippet End Position @c{Z?>dUc#  
int nThreadID; //Thread's ID 31bKgU{  
boolean bDownOver = false; //Downing is over ]cA){^.Jz  
boolean bStop = false; //Stop identical Q)Ppx7)  
FileAccessI fileAccessI = null; //File Access interface NIYAcLa@n8  
rW1 > t+  
}>p)|Y T"/  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3g5i5 G\  
{ \l]jX: 9(  
this.sURL = sURL; ;Y)?6^"  
this.nStartPos = nStart; Z 4t9q`}h  
this.nEndPos = nEnd; ^ S%4R'  
nThreadID = id; UQTt;RS*zS  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 s2d;601*b  
} 9@:&E  
k:d'aP3  
i5)trSM|  
public void run() qkR.{?x  
{ GLk7# Y  
while(nStartPos < nEndPos && !bStop) 3S.rIai+  
{ }~A-ELe:  
y`\/eX  
xXHz)w  
try{ op"Cc  
URL url = new URL(sURL); }uZh oA  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SmtH2%yI  
httpConnection.setRequestProperty("User-Agent","NetFox"); O81})r*Y  
String sProperty = "bytes="+nStartPos+"-"; w|RG  
httpConnection.setRequestProperty("RANGE",sProperty); [#)$BXG~y  
Utility.log(sProperty); #xts*{u-#  
_ b#9^2o  
FiIN \  
InputStream input = httpConnection.getInputStream(); (zTr/  
//logResponseHead(httpConnection); hz )L+  
u2!8'-Ai  
qOk4qbl[  
byte[] b = new byte[1024]; 2{&|%1Jg  
int nRead; ,@[Q:fY  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) E=7" };  
{ pX!S*(Q{  
nStartPos += fileAccessI.write(b,0,nRead); <'s1+^LC  
//if(nThreadID == 1) N;ssO,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X|8Y z3:o  
} Kj'm<]u  
\DfvNeF  
* y`^Fc  
Utility.log("Thread " + nThreadID + " is over!"); u/k#b2BqL  
bDownOver = true; -;Hd_ ~O>j  
//nPos = fileAccessI.write (b,0,nRead); we{*%8I;  
} +z9;BPw %  
catch(Exception e){e.printStackTrace ();} ;2bG-v'4vO  
} eo,m ^&  
} 44S<(Re  
C#vh2'  
(:@qn+ a  
//打印回应的头信息 2{{M{#}S.  
public void logResponseHead(HttpURLConnection con) C~6aX/:  
{ f2yc]I<lr~  
for(int i=1;;i++) b7"pm)6  
{ SHh g&~B  
String header=con.getHeaderFieldKey(i); A #ZaXu/:X  
if(header!=null) "\> <UJ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); a{]1H4+bQ  
Utility.log(header+" : "+con.getHeaderField(header)); hBN!!a|l  
else Iy e  
break; `~*qjA  
} LsBDfp5/  
} drN^-e  
8zZR %fZ  
<G6wpf8M  
public void splitterStop() <Z#u_:5@  
{ ~;U!?  
bStop = true; &_!BMzp4  
} *Z{W,8h*s  
o F @{&  
>Z>*Iz,LP  
} ( 6r9y3'  
^=W%G^jJy  
rWa7"<`p  
/* m*["  
**FileAccess.java M0_K%Z(zaR  
*//文件访问(定位,写) spFsrB  
package NetFox; Tk+\Biq   
import java.io.*; ,g^Bu {?  
nA+[[(6  
lt(,/  
public class FileAccessI implements Serializable{ (|bht0  
} #%sI"9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 rLP4l~V   
RandomAccessFile oSavedFile;  rro,AS}  
long nPos; 7tfFRUw  
pk"JcUzR  
@*_#zU#g  
public FileAccessI() throws IOException h=)Im )  
{ )(?s=<H  
this("",0); xG<S2R2VQh  
} S;*,V |#QD  
>"ZTyrK  
- FE)  
public FileAccessI(String sName,long nPos) throws IOException x6F\|nb  
{ !.p!  
oSavedFile = new RandomAccessFile(sName,"rw"); @Z.Ne:*J  
this.nPos = nPos; iiRK3m  
oSavedFile.seek(nPos); ZZlR:D  
} [i&z_e)  
9E (>mN  
cL=P((<K?  
public synchronized int write(byte[] b,int nStart,int nLen) RV&2y=eb  
{ Gt-  -7S  
int n = -1; 9:@os0^O  
try{ |5g*pXu{  
oSavedFile.write(b,nStart,nLen); }H^#}  
n = nLen; d(fgv  
} TcRnjsY$  
catch(IOException e) L{(r@Vu  
{ 7N'F]x  
e.printStackTrace (); a^sR?.+3  
} F3wRHq  
M2V.FYV{j>  
%zX'u.}8#  
return n; )rj.WK.  
} f1\x>W4z~\  
n1$##=wK]  
R HF;AX n  
} R[#5E|` `9  
\ iP[iE=  
zBc7bbK  
/* s"a*S\a;b  
**SiteInfoBean.java P,wFib^1  
*/ XY%8yII6  
package NetFox; 8 5s{;3  
0A}'.LI  
oWJ}]ip  
public class SiteInfoBean { ifBJ$x(B.  
6aK%s{%3s  
|y=CmNG,  
private String sSiteURL; //Site's URL A.<X78!^  
private String sFilePath; //Saved File's Path q F}5mUcZ4  
private String sFileName; //Saved File's Name rj{'X  /  
private int nSplitter; //Count of Splited Downloading File hO(HwG?8t  
[ BN2c  
<{cPa\  
public SiteInfoBean() u1<xt1K  
{//nSplitter的缺省值为5 $_)f|\s  
//default value of nSplitter is 5 <[pU rJfTr  
this("","","",5); d$Mj5wN:q  
} zpa'G1v  
X\$M _b>O  
Jg%sl& 65  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =`/X Wem  
{ eyo)Su  
sSiteURL= sURL; iPkG=*Ip(%  
sFilePath = sPath; ] c'owj  
sFileName = sName; _$Fi]l!f  
this.nSplitter = nSpiltter; [;X YT  
~I'Z=Wo  
*X<De  
} jCa{WV:K}  
qi/%&)GZ  
c%B=TAs5c  
public String getSSiteURL() WMI/Y 9N  
{ xr6Q5/p1  
return sSiteURL; v}cm-_*v  
} `zep`j&8^  
NS&~n^*k<  
DO %YOv  
public void setSSiteURL(String value) i[YYR,X|  
{ V<d'psb 6  
sSiteURL = value; cBm3|@7  
} }!.7QpA$  
-(1e!5_-@  
tv;3~Y0i  
public String getSFilePath() -7+Fb^"L  
{ X^@d@xU4v  
return sFilePath; [hFyu|I !  
} Z:n33xh=<  
.{8lG^0U<  
n_c0=YH  
public void setSFilePath(String value) w=f8UtY9@A  
{ -R\}Q"  
sFilePath = value; )s^XVs.-  
} L\"=H4r  
s5z@`M5'm  
:;|x'[JoE?  
public String getSFileName() {O"dj;RU  
{ C6, Bqlio  
return sFileName; c=Z#7?k=Uz  
} n09|Jzv9  
! q1Ql18n  
{+`ep\.$&  
public void setSFileName(String value) XRNL;X%}7  
{ N;D+]_;0|  
sFileName = value; X0=R @_KY  
} 'kUrSM'*$N  
$MsM$]~  
[jLx}\]  
public int getNSplitter() nl?|X2?C  
{ 8[y7(Xw  
return nSplitter; zd;xbH//)b  
} w'qV~rN~tc  
RP(FV<ot  
C3memimN  
public void setNSplitter(int nCount) o<!#1#n+:  
{ pcEB-boI9  
nSplitter = nCount; JHMj4Zkp  
} LBM:>d5  
} V5A7w V3~  
yBr{nFOgdY  
4H " *.l  
/* Nd6N:1 -  
**Utility.java h2tzv~  
*/ \zoJr)  
package NetFox; iu:e>r  
}- +;{u  
8)H"w$jq  
public class Utility { %R_8`4IQ  
=|G PSRQ  
5N[Y2  
public Utility() }k ,Si9O  
{ *'`-plS7  
3Y r   
e~}+.B0  
} ^7_<rs   
>MhkNy  
//线程睡眠 &MKv _  
public static void sleep(int nSecond) ,Y&kW'2  
{ p<J/J.E  
try{ %Ajf|Go0/G  
Thread.sleep(nSecond); lc/2!:g  
} p~e6ah?1  
catch(Exception e) Z2LG/R  
{ {!EbGIh  
e.printStackTrace (); "%Rx;xw|  
} P|6m%y  
} i\ PN  
j5RM S V  
//日志 g|T' oK  
public static void log(String sMsg) *k=}g][?  
{ 2xjS;lpw  
System.err.println(sMsg); k,&W5zBKe  
} G N{.R7  
*.K}`89T  
~E`l4'g?  
public static void log(int sMsg) N .SszZh  
{ Nd( $s[  
System.err.println(sMsg); BE m%x 0y  
} $B(B  
} MW&;{m?2(  
~o8$/%Oeb/  
7aU*7!U  
/* JY_' d,O  
**TestMethod.java U}{r.MryFG  
*/ M`5^v0,C  
package NetFox; 6DExsB~@  
eH6#'M4+\  
TRQva8d?  
public class TestMethod { KpK'?WhX7^  
T[7- 3[w<)  
b. t]p  
public TestMethod() 3W27R  
{ ///xx/weblogic60b2_win.exe sDwSEg>#B  
try{ t;? q#!uc  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3XA^{&}  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); TQ>1u  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =izB :  
fileFetch.start(); &KD m5p  
} _-h3>.;h9  
catch(Exception e){e.printStackTrace ();} ;=E3f^'s  
KQ2]VN"?_  
E.BMm/WH  
} 3)`}#`T  
 %RJW@~!  
6x.#K9@q4  
public static void main(String[] args) B,A/ -B\  
{ L1J"_.=P  
new TestMethod(); LUCpZ3F1  
} / AW]12_  
} 19lx;^b  
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