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http断点续传简单实现(java)

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/* TA5M4r6  
**SiteFileFetch.java #UIg<:  
*/ Atw^C+"vW&  
package NetFox; "zc!QHpSd  
import java.io.*; "m5ZZG#R`  
import java.net.*; Joj8'  
*z~Y*Q0  
S/aPYrk>6  
public class SiteFileFetch extends Thread { l.! ~t1i  
9X~^w_cdk  
2(|V1]6D?  
SiteInfoBean siteInfoBean = null; //文件信息Bean I+SL0  
long[] nStartPos; //开始位置 ^&%?Q_]  
long[] nEndPos; //结束位置 iV=#'yY  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 L3\{{QOA  
long nFileLength; //文件长度 n\4+xZr  
boolean bFirst = true; //是否第一次取文件 AS;{{^mM(  
boolean bStop = false; //停止标志 ~XRr }z_Lq  
File tmpFile; //文件下载的临时信息 suwj1qYJ4  
DataOutputStream output; //输出到文件的输出流 7[\B{N9&W  
z=sqO'~  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) To+{9"$,  
public SiteFileFetch(SiteInfoBean bean) throws IOException 8*ysuL#  
{ xPv&(XZR  
siteInfoBean = bean; h&{pMmS3,  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); W` V  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); w,7 GC5j\  
if(tmpFile.exists ()) 3z<t#  
{ tuSgh!  
bFirst = false; `,O^=HBM  
read_nPos(); zb(u?U  
} +TX]~k79Oq  
else =&'j;j  
{ OZ&aTm :  
nStartPos = new long[bean.getNSplitter()]; KN=Orx7Gy  
nEndPos = new long[bean.getNSplitter()]; }e$);A|  
} F=H=[pSe  
'*:YC  
.O(UK4Mb  
d8>D=Ve  
} rv%Xvs B  
&!=3Fbn  
g;pymz  
public void run() wpvaTHo  
{ |bh:x{h  
//获得文件长度 -eya$C  
//分割文件 4^5s\ f B  
//实例FileSplitterFetch UJI1n?~  
//启动FileSplitterFetch线程 RK0IkRXQd  
//等待子线程返回 6lPGop]js]  
try{ Q=[&~^ Y)  
if(bFirst) C-7.Sa  
{ `i-&Z`  
nFileLength = getFileSize(); ]iPdAwc.1  
if(nFileLength == -1) j:#[voo7  
{ uIu0"pv`x  
System.err.println("File Length is not known!"); | v+b?@  
} >jcNo3S  
else if(nFileLength == -2) =uH`EkY:  
{ bCsQWsj^NW  
System.err.println("File is not access!"); s`{O-  
} |@ + x9|'W  
else :;EzvRy  
{ Hd:ZE::Q'#  
for(int i=0;i<nStartPos.length;i++) "6ZatRUd  
{ .d2s4q\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); cg4,PI% hz  
} & 3gni4@@  
for(int i=0;i<nEndPos.length-1;i++) rRMC< .=  
{ )}R0'QGd  
nEndPos = nStartPos[i+1]; v1: 5 r  
} G100L}d"N  
nEndPos[nEndPos.length-1] = nFileLength; ;Wr$hDt^  
} SWu=n1J.?H  
} 84k;d;  
z')'8155  
~7*HZ:.  
//启动子线程 nV<YwqK  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Gr_I/+<  
for(int i=0;i<nStartPos.length;i++) QeK~A@|F&  
{ jooh`| `P  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X,p&S^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), w/R^Vwq  
nStartPos,nEndPos,i); Uc&0>_Z  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #M:W?&.  
fileSplitterFetch.start(); ^E9@L ??  
} :Q%&:[2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nQ mkDPjU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); *I~F7Z]|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", e= '3gzz  
nEndPos = " + nFileLength); PW}Yts7p  
// fileSplitterFetch[nPos.length-1].start(); d;>:<{z@CD  
#2pgh?  
V!oyC$eV  
//等待子线程结束 `jJb) z3D  
//int count = 0; :Qf^@TS}O  
//是否结束while循环 P<bA~%<7"[  
boolean breakWhile = false; l|DOsI'r  
cu Nwv(P  
GovGh? X#x  
while(!bStop) *e^ ZH  
{ j*P@]&e7d  
write_nPos(); sh0O~%]g  
Utility.sleep(500); 1vobfZ-w9  
breakWhile = true; Y }0-&  
/%.K`BMN  
{MIs%w.G  
for(int i=0;i<nStartPos.length;i++) N @k:kI  
{ L-fAT'!'  
if(!fileSplitterFetch.bDownOver) '+`CwB2  
{ ( \]_/ W  
breakWhile = false; RE Hfk6YE  
break; <-$4?}  
} > vgqf>)kk  
} /OViqZ;9  
if(breakWhile) f1JvP\I0Q  
break; /({5x[  
VRD2e ,K  
Blu^\:?#z-  
//count++; Rq;R{a  
//if(count>4)  p.zU9rID  
// siteStop(); 0ya_[\  
} 2-8<uUy  
#ujcT%1G  
`P'{HT  
System.err.println("文件下载结束!");  ?9AByg  
} #x'C  
catch(Exception e){e.printStackTrace ();} *rA!`e*  
} sO6+L #!  
pnf3YuB  
}=wSfr9g  
//获得文件长度 #u#s'W  
public long getFileSize() Nz2}Ma 2  
{ ZV&=B%J bs  
int nFileLength = -1; %!WQ;(  
try{ wLW!_D,/R  
URL url = new URL(siteInfoBean.getSSiteURL()); }UX>O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); JBuorc  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1,4kw~tA  
gbo{Zgf<  
!j\  yt  
int responseCode=httpConnection.getResponseCode(); ?vvjwys@  
if(responseCode>=400) z. 7 UfLV9  
{ _c`Gxt%  
processErrorCode(responseCode); P4s:wuJ^  
return -2; //-2 represent access is error K2NnA  
} IUwY/R9Q  
lO<Ujb#"R  
~aBALD0D;  
String sHeader; S0\:1B  
R D)dw  
GK:*|jV  
for(int i=1;;i++) &bTadd%0  
{ yBeSvsm  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 7qu hp\  
//Utility.log(in.readLine()); wN;o++6V  
sHeader=httpConnection.getHeaderFieldKey(i); <TDgv%eg0  
if(sHeader!=null) ?eeE[F  
{ ,)%nLc  
if(sHeader.equals("Content-Length")) 9-9`;Z  
{ c_%vD~6W-  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); F7a\Luae  
break; `$Q $l  
} 24]O0K  
} o:m:9dn  
else }(ot IqE  
break; M7UVL&_z%  
} P oC*>R8  
} =TU"B-*  
catch(IOException e){e.printStackTrace ();} GN(PH/fO9  
catch(Exception e){e.printStackTrace ();} )R,*>-OPJL  
I8e{%PK  
Gu9Ap<>!  
Utility.log(nFileLength);  gryC#  
mR?OSeeB  
~G ,n>  
return nFileLength; 3]/w3|y  
} pl'n 0L<l  
izOtt^#DZt  
t4 $cMf  
//保存下载信息(文件指针位置) gy,B+~p  
private void write_nPos() qJUu9[3'm  
{ (7&[!PS  
try{ 'lg6<M%#[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9tqX77UK  
output.writeInt(nStartPos.length); fk;39$[  
for(int i=0;i<nStartPos.length;i++) @>&UoH}2  
{ a'W-&j  
// output.writeLong(nPos); -g_PJ.Hk  
output.writeLong(fileSplitterFetch.nStartPos); C {gYrz)  
output.writeLong(fileSplitterFetch.nEndPos); #*XuU8q?  
} 8+Oyhd*|  
output.close(); 3/P2&m  
} 0vf2wBK'T  
catch(IOException e){e.printStackTrace ();} NkA|T1w7  
catch(Exception e){e.printStackTrace ();} n*hHqZl  
} ?tg(X[h{S  
7l%O:M(\  
(?;Fnq  
//读取保存的下载信息(文件指针位置) x~Y]c"'D  
private void read_nPos() ,accw}G  
{ ?HAWw'QW  
try{ |'Z6M];8t  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); n:x6bPal]  
int nCount = input.readInt(); Nq Ve{+1x  
nStartPos = new long[nCount]; _.yBX\tf[  
nEndPos = new long[nCount]; =X]$J@j  
for(int i=0;i<nStartPos.length;i++) >@` D@_v  
{ ]t(;bD hT  
nStartPos = input.readLong(); \k;*Ej~.  
nEndPos = input.readLong(); rt^<=|Z  
} !ku5P+y$  
input.close(); [r<lAS{ .  
} VYMs`d[  
catch(IOException e){e.printStackTrace ();} c"H*9u:  
catch(Exception e){e.printStackTrace ();} s^)wh v`C  
} 5$`ihO?  
,FlF.pt  
#iJ+}EW _  
private void processErrorCode(int nErrorCode) ;gP@d`s  
{ XN'x`%!*3#  
System.err.println("Error Code : " + nErrorCode); 9YwK1[G6/  
} s: ~3|D][  
#0zMPh /U}  
IhhB^E|  
//停止文件下载 uwU;glT  
public void siteStop() L?23Av0W  
{ cL?FloPc*  
bStop = true; M\ B A+  
for(int i=0;i<nStartPos.length;i++) j:0(=H!#  
fileSplitterFetch.splitterStop(); gR )xw)!  
~kj1L@gy   
i*_T\_=  
} t n>$5}^;  
} ^`!5!|  
//负责部分文件的抓取 ]*'V#;s  
**FileSplitterFetch.java NffZttN  
*/ {|9x*I  
package NetFox; q$Gf9&ZO  
]hJ#%1  
NnRR"'  
import java.io.*; nB[Aw7^|A  
import java.net.*; 0hp*(, L  
M[g9D  
cNZuwS~,  
public class FileSplitterFetch extends Thread { }uz*6Z(S  
FFQ=<(Ki  
7Y"CeU-S  
String sURL; //File URL / q*n*j  
long nStartPos; //File Snippet Start Position U ]Ek 5p  
long nEndPos; //File Snippet End Position 8!(4;fN$j.  
int nThreadID; //Thread's ID ?ey!wcv~  
boolean bDownOver = false; //Downing is over mR\rK&'6  
boolean bStop = false; //Stop identical ^rO3B?_  
FileAccessI fileAccessI = null; //File Access interface Vv8e"S  
p~vq1D6  
5xtIez]x?  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Ztu _UlGC  
{ 8+5 z-vd  
this.sURL = sURL; uQIa"u7  
this.nStartPos = nStart; WqlX'tA  
this.nEndPos = nEnd;  ky0Fm W  
nThreadID = id; J5b>mTvb  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;'CWAJK  
} 16Ym*kWIps  
V<A_c^unO  
EdbL AagI6  
public void run() C]59@z;+bN  
{ E2+x?Sc+  
while(nStartPos < nEndPos && !bStop) ^@5#jS2  
{ I CCmE#n  
E`]lr[  
;<i`6e  
try{ c'ExZ)RJ  
URL url = new URL(sURL); J\VG/)E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^LO=&Cq  
httpConnection.setRequestProperty("User-Agent","NetFox"); nK=-SQ  
String sProperty = "bytes="+nStartPos+"-"; f_y+B]?'M  
httpConnection.setRequestProperty("RANGE",sProperty); k`[ L  
Utility.log(sProperty); u2%/</]h  
MY1s  
XaOq&7  
InputStream input = httpConnection.getInputStream(); l?F-w;wHN  
//logResponseHead(httpConnection); Ss ;C1:  
cK6M8:KW  
.hd<,\nW  
byte[] b = new byte[1024]; = zJY5@^'7  
int nRead; UlF=,0P  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9U$n;uA  
{ j{PuZ^v1  
nStartPos += fileAccessI.write(b,0,nRead); [+dOgyK  
//if(nThreadID == 1) v,qK= ]ty  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); DY<Br;  
} K.'II9-{  
OT/*|Pn9  
U,q ]  
Utility.log("Thread " + nThreadID + " is over!"); 0kEz i  
bDownOver = true; gwHNz5 a*V  
//nPos = fileAccessI.write (b,0,nRead); TNs ;#Q  
} }$EcNm$%  
catch(Exception e){e.printStackTrace ();} >5G2!Ns'  
} $#E?`At{I  
} CDOqdBQ  
N4y$$.uv2  
M8j%bmd(,  
//打印回应的头信息 $$QbcnOf$  
public void logResponseHead(HttpURLConnection con) 2\ 3}y(  
{ (NPDgR/  
for(int i=1;;i++) qC<!!473?  
{ $7 1(g$6#  
String header=con.getHeaderFieldKey(i); ETQ.A< v  
if(header!=null) H3< `  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); DY]\@<ez  
Utility.log(header+" : "+con.getHeaderField(header)); Gc6`]7 s  
else eF)vx{s  
break; DSiI%_[Ud  
} <tp\+v! u  
} =fy~-FN_  
,#;%ILF4%  
2Hltgt,  
public void splitterStop() "7Qc:<ww  
{ 0{u31#0j  
bStop = true; ^ ]Mlkd:  
} } ti+tM*  
Z[+H$=$%  
eyPh^c]?`8  
} gHCk;dmq81  
oB$7m4xO\  
-?)` OHc^  
/* NY]`1yy  
**FileAccess.java Zr!he$8(2  
*//文件访问(定位,写) (W.euQy  
package NetFox; erG@8CG  
import java.io.*; @H'pvFLK?  
pMJK?- )  
hN% h.;s  
public class FileAccessI implements Serializable{ sR%,l  
8'c_&\kdv  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -4:L[.2  
RandomAccessFile oSavedFile; 8GC(?#Kb  
long nPos; 5|zISK%zHS  
u[25U;xo  
{-X8MisI  
public FileAccessI() throws IOException P=ARttT`(  
{ %DJxUuh  
this("",0); K&{*sa r  
} 3'(w6V  
@r.u8e)l  
,]ALyWGuX  
public FileAccessI(String sName,long nPos) throws IOException fG;(&Dx  
{ 'MEO?]Tf.^  
oSavedFile = new RandomAccessFile(sName,"rw"); ?V|t7^+:  
this.nPos = nPos; P<@Yux#  
oSavedFile.seek(nPos); +/idq  
} mRI W9V  
JvFU7`4@  
i,G )kt'H  
public synchronized int write(byte[] b,int nStart,int nLen) &W1{o&  
{ 9p,<<5{  
int n = -1; v&CKtk!3{  
try{ T?=[6  
oSavedFile.write(b,nStart,nLen); F[ca4_lK  
n = nLen; RU`m|<  
} ~ ;aSE  
catch(IOException e) neC]\B[Xm  
{ e<|'   
e.printStackTrace (); enu",wC3  
} ,$ICv+7]  
<{\UE~  
J?Kgev%  
return n; !?Tu pi  
} n1Ag o3NM  
ii%n:0+zm  
v5i?4?-Z  
} E|f&SEnzK  
a8fLj  
1zE_ SNx  
/* VN=S&iBa/  
**SiteInfoBean.java WZ"g:Khw  
*/ #N-NI+qX  
package NetFox; qx! NU}6  
GnbXS>  
= Mc]FCV  
public class SiteInfoBean { V%~u8b  
maANxSzi  
!" E&Tk}  
private String sSiteURL; //Site's URL =Ewa}$-  
private String sFilePath; //Saved File's Path l\8 l.xP  
private String sFileName; //Saved File's Name ldJ eja~Xl  
private int nSplitter; //Count of Splited Downloading File ],%}}UN  
C3`2{1  
-Kt36:|  
public SiteInfoBean() _tE$a3`  
{//nSplitter的缺省值为5 mea]m)P  
//default value of nSplitter is 5 Gq5)>'D?  
this("","","",5); >M7e'}0 ;  
} u(KeS`  
&Vi"m!Bf  
MS Ui_|7  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) r\+AeCyb"p  
{ "HR &Rf k  
sSiteURL= sURL; {rr ED  
sFilePath = sPath; ~Ra1Zc$o:  
sFileName = sName; IXp P.d  
this.nSplitter = nSpiltter; L4SvE^2+  
:SSlUl4sU$  
[!>2[bbl  
} ;(3fr0cr:  
>gDsjHQ6;  
_nRY5YnL4P  
public String getSSiteURL() /Ny/%[cu  
{ >u5}5OP7  
return sSiteURL; dL"$YU9 z  
} {]-nYHGL  
jr" ~  
{m}B=u  
public void setSSiteURL(String value) ih1s`CjG  
{ 7I4G:-V:^  
sSiteURL = value; hIa@JEIt  
} ,2?"W8,  
gDnG!i+  
Ai iOs?  
public String getSFilePath() /= P!9d {  
{ Ov%9S/d  
return sFilePath; /B!"\0G/,  
} \@4QG.3&  
zqYfgV  
d; @Kz^  
public void setSFilePath(String value) 9a)D8  
{ Db yy H_  
sFilePath = value; _p{ag 1gP  
} />\.zuAr&  
J.":oD  
 6" 3!9JC  
public String getSFileName() ^~MHxF5d  
{ (FMGW (  
return sFileName; /S9Mu )1Y  
} R4}G@&Q  
13A11XTp  
7w )#[^  
public void setSFileName(String value) zE.4e&m%Z?  
{ {NE;z<,*:  
sFileName = value; T4Z("  
} 7K9+7I&C  
4E3HYZ  
A'|W0|R9  
public int getNSplitter() :KX/GN!n  
{ I?-9%4 8iM  
return nSplitter; Ltcr]T(Ic  
} ..;LU:F  
(B]Vw+/  
l%B1JGu*F  
public void setNSplitter(int nCount) %8 cFzyE*  
{ F>A-+]X3o  
nSplitter = nCount; IG +nrTY0  
} }Sp MHR`  
} ?Pmj}f  
iCk34C7  
biGaP#"0  
/* GLc+`,.  
**Utility.java K r]!BI?z  
*/ N!RyncJ  
package NetFox; Jc9SHCJ  
? dSrY  
2%vwC]A  
public class Utility { ,O a)  
@uY%;%Pa8  
[W{`L_"  
public Utility() aDza"Ln  
{ 94nvh:n  
Xg!Mc<wA[  
>YoK?e6  
} u# =N8  
"cJ5Fd:*  
//线程睡眠 Vzbl* Zmx  
public static void sleep(int nSecond) @292;qi  
{ Y/Y746I  
try{ lt0(Kf g  
Thread.sleep(nSecond); b'9G`Y s^  
} ~,':PUkiV  
catch(Exception e) %I Y-0\  
{ &B3\;|\  
e.printStackTrace (); [+GQ3Z\  
} T_AZCl4d  
} k~=-o>}C  
|BYD]vK  
//日志 E?Q=#+}U  
public static void log(String sMsg) <;9 vwSH>  
{ b@,=;Y)O  
System.err.println(sMsg); ,b{G(sF  
} RSmxwx^  
MiOSSl};  
zi*D8!_C  
public static void log(int sMsg) B0Z*YsbXL  
{ L4kYF~G:4  
System.err.println(sMsg); W97Ka}Y  
} >+oQxml6nI  
} Vp5qul%  
I8^z\ef&  
YVW!u6W'[6  
/* T/ S-}|fhQ  
**TestMethod.java ,u]kZ]  
*/ J_P2%b=C  
package NetFox; m@HU;J\I  
XTW/3pB  
}3[ [ONA  
public class TestMethod { bJ. ((1$  
>Ckb9A  
$ HUCp9  
public TestMethod() 3v0)oK  
{ ///xx/weblogic60b2_win.exe Nt/*VYUn  
try{ HM[BFF[;/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); kFk+TXLDIt  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); O~aS&g/sf  
SiteFileFetch fileFetch = new SiteFileFetch(bean); RNvtgZ}k{X  
fileFetch.start(); de ](l687I  
}  pd X9G  
catch(Exception e){e.printStackTrace ();} OZt'ovY  
t]vX9vv+D  
;#xhlR* ~  
} ?'_iqg3  
>656if O  
o_G.J4 V  
public static void main(String[] args) T,?^J-h^  
{ ',1rW  
new TestMethod(); xOu cZ+  
} ,hOJe=u46  
} 7?hC t  
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