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http断点续传简单实现(java)

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/* 4GL-3e  
**SiteFileFetch.java 5C G ,l  
*/ >l$qE  
package NetFox; cD6T4  
import java.io.*; dw"Tv ~  
import java.net.*; TTfU(w%&P  
Yu`KHvur  
ZQVr]/W^r  
public class SiteFileFetch extends Thread { o)M=; !  
>$g+Gx\v4  
|)4aIa  
SiteInfoBean siteInfoBean = null; //文件信息Bean TA~FP#.  
long[] nStartPos; //开始位置 FUD M]:XQ  
long[] nEndPos; //结束位置 vhEXtjL  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 &|LP>'H;  
long nFileLength; //文件长度 Mq#sSBE<K  
boolean bFirst = true; //是否第一次取文件 b}C6/ zW  
boolean bStop = false; //停止标志 KiaQ^[/q  
File tmpFile; //文件下载的临时信息 [8Yoz1(smA  
DataOutputStream output; //输出到文件的输出流 V+Tu{fFF7E  
g?mfpwZj  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 6]mFw{6qn1  
public SiteFileFetch(SiteInfoBean bean) throws IOException `yvH0B -  
{ x,+2k6Wn!  
siteInfoBean = bean; ` &E-  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 1c2zFBl.&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); n{@^ne4 m  
if(tmpFile.exists ()) _P:}]5-|  
{ .O1Kwu  
bFirst = false; 9[9 ZI1*s  
read_nPos(); M In6p  
} HXg#iP^tv  
else VOa7qnh4:[  
{ #K4lnC2qz  
nStartPos = new long[bean.getNSplitter()]; >}p'E9J?r  
nEndPos = new long[bean.getNSplitter()]; 4Gsbcl{  
} 5RUhrE   
5TB==Fj ?  
;LhNz()b  
,iy;L_N  
}  Bm\OH#  
sT;:V  
!ot$Q  
public void run() >~vZ+YO  
{ tw*n+{]hi  
//获得文件长度 g3h:oQCS  
//分割文件 ]CnqPLqL  
//实例FileSplitterFetch ).8i*Ys,:  
//启动FileSplitterFetch线程 Li{R?Osx  
//等待子线程返回 EXz{Pqz  
try{ Y;B#_}yF  
if(bFirst) Cr;d !=  
{ (e~vrSk+)~  
nFileLength = getFileSize(); l`' lqnhv  
if(nFileLength == -1) /iwL$xQQ  
{ MB#KLTwnT  
System.err.println("File Length is not known!"); A:JW Ux  
} % njcWVP;  
else if(nFileLength == -2) "{X_[  
{ d=$1Z. ]  
System.err.println("File is not access!"); 'y<<ce*   
} 3v:c".O2O  
else J_tI]?jrU  
{ l4LowV7  
for(int i=0;i<nStartPos.length;i++) U*R  
{ }w%W A&"W  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); sP` k{xG  
} $mF(6<w  
for(int i=0;i<nEndPos.length-1;i++) F# a)"$j;  
{ E~| XY9U36  
nEndPos = nStartPos[i+1]; /`x)B(b  
} sO;]l"{<  
nEndPos[nEndPos.length-1] = nFileLength; }8\"oA6  
} =JK# "'  
} 8ba*:sb  
(+=TKI<=  
;xl_9Ht/  
//启动子线程 noLb  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !P"=57d}"l  
for(int i=0;i<nStartPos.length;i++) zm9_[0  
{ ` g5S  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mm@)uV<\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), zr1,A#BV  
nStartPos,nEndPos,i); uV'w0`$y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <Ky6|&!  
fileSplitterFetch.start(); ==W`qC4n?n  
} tG"lI/  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 50Kv4a"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); lDd8dT-Q.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 1r-#QuV#  
nEndPos = " + nFileLength); #]_S)_Z-  
// fileSplitterFetch[nPos.length-1].start(); 1qgzb  
(8?5REz  
w]Fi:kV  
//等待子线程结束 _;x7vRWmN  
//int count = 0; FhyA_U%/nF  
//是否结束while循环 5( }Qg9%  
boolean breakWhile = false; A!\-e*+W=  
GSh~j-C'  
4-dV%DgC  
while(!bStop) G._E9  
{ oP0ZJK&;  
write_nPos(); -?K?P=B;X  
Utility.sleep(500); ?{bAyh/  
breakWhile = true; *wY { ~zh  
nOE 1bf^l  
kpU-//lk+  
for(int i=0;i<nStartPos.length;i++) ti}g?\VT  
{ 5 Y|(i1  
if(!fileSplitterFetch.bDownOver) Ksu_4dE  
{ /t<C_lLM  
breakWhile = false; 9}TQ u0  
break; a!?&8$^<  
} }s7ibm'  
} -Jj"JN.  
if(breakWhile) ji~P?5(:  
break; C*f3PB=H_  
'r2VWavT  
6IQkP9P(  
//count++; JL7"}^  
//if(count>4) dAZh# i[  
// siteStop(); = IkG;gg  
} e=<%{M&  
>dTJ  
w'-J24>=  
System.err.println("文件下载结束!"); [Tq\K ^!^  
} VIi/=mO]  
catch(Exception e){e.printStackTrace ();} *P mk1h2  
} Q:+cLl&;hB  
OlV'#D   
V`7^v:  
//获得文件长度 !_|rVg.  
public long getFileSize() k\J 6WT  
{ 9j6  
int nFileLength = -1; >10pk  
try{ .vbUv3NI  
URL url = new URL(siteInfoBean.getSSiteURL()); p 7YfOUo k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5 1\N+  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]("5O V5  
wv~?<DF  
yye( ^  
int responseCode=httpConnection.getResponseCode(); W,[b:[~v  
if(responseCode>=400) B9-Nb 4  
{ )^ky @V  
processErrorCode(responseCode); Js7D>GWP!  
return -2; //-2 represent access is error ).Ei:/*j  
} .L X8ko  
yM8<)6=  
J3$Ce%<   
String sHeader; KP[H&4eoC  
#Ang8O@y  
#O |Z\|n  
for(int i=1;;i++) mO UIGlv  
{ GG}(*pOr  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); J7C2:zj  
//Utility.log(in.readLine()); SuHv{u45  
sHeader=httpConnection.getHeaderFieldKey(i); mN9Uyz5G  
if(sHeader!=null) 7JedS  
{ ;{Sgv^A  
if(sHeader.equals("Content-Length")) e0#/3$\aSV  
{ 2[*r9%W  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); R&Oqm hT!  
break; (;11xu  
} =>0+BD  
} #] @<YKoV{  
else <Rl:=(]i~  
break; V`n;W6Q17  
} -UPlQL  
} 3]X9 z  
catch(IOException e){e.printStackTrace ();} Jhyb{i8RR  
catch(Exception e){e.printStackTrace ();} G|p3NhLgO=  
~4Gs\U:!Q  
MWHGB")J  
Utility.log(nFileLength); nA\9UD<G.  
4l2xhx  
es` A<  
return nFileLength; n tfwR#j  
} Vo\RtM/6{  
XQ{G)  
UI*^$7z1 +  
//保存下载信息(文件指针位置) 1Ugyjjlz  
private void write_nPos() ?`nF"u>  
{ YGA( "<  
try{ qX GAlCq@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ::xH C4tw  
output.writeInt(nStartPos.length); D{](5?$`|  
for(int i=0;i<nStartPos.length;i++) >tq,F"2amC  
{ @R|Gz/  
// output.writeLong(nPos); CTbz?Kn  
output.writeLong(fileSplitterFetch.nStartPos); %("Bq"Q8  
output.writeLong(fileSplitterFetch.nEndPos); NjCdkT&g  
} cdDMV%V  
output.close(); #>|l"1   
} ;9{x""  
catch(IOException e){e.printStackTrace ();} Kzs]+Cl  
catch(Exception e){e.printStackTrace ();} x=>+.'K  
} ">n38:?R  
[U]ouh)  
nC3U%*l  
//读取保存的下载信息(文件指针位置) uh~/ybR  
private void read_nPos() P~)ndaQ  
{ <&?gpRK   
try{ Y}bJN%M  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); `>1"v9eF  
int nCount = input.readInt(); idC4yH42  
nStartPos = new long[nCount]; 2 NgEzY 5  
nEndPos = new long[nCount]; LWB"}#vt  
for(int i=0;i<nStartPos.length;i++) G36}4  
{ U#O 6l-xe]  
nStartPos = input.readLong(); <(]e/}  
nEndPos = input.readLong(); *ay>MlcV2=  
} ?,J N?  
input.close(); b[^=GF>e  
} 8QeM6;^/5  
catch(IOException e){e.printStackTrace ();} S^GB\uJ  
catch(Exception e){e.printStackTrace ();} >A$J5B >d  
} Fr}e-a  
Y2 &N#~l*  
T4 dYC'z  
private void processErrorCode(int nErrorCode) qIwI]ub~  
{ 3 <V{.T  
System.err.println("Error Code : " + nErrorCode); # $:ddO Y  
} |\ 1?CYx  
9E (VU.  
8 oHyNo  
//停止文件下载 \(a9rZ9  
public void siteStop() fq){?hk~O  
{ OXC7 m  
bStop = true; G\\zk  
for(int i=0;i<nStartPos.length;i++) }mjJglK!N  
fileSplitterFetch.splitterStop(); OE!:`Bo3T  
GfAt-huL(  
T,72I  
} ~-,P1 u!  
} +e0]Y8J{  
//负责部分文件的抓取 !*:Zcg?7n  
**FileSplitterFetch.java u"K-mr#$[o  
*/ ~RVx~hh  
package NetFox; J?XEF@?'G  
Ve,_;<F]S  
1NO<K`  
import java.io.*; ExDH@Lb  
import java.net.*; Jy'ge4]3  
H!Y`?Rc  
*'+OA6  
public class FileSplitterFetch extends Thread { %d+:0.+`n  
IB x?MU#.  
+igFIoHTM  
String sURL; //File URL td@F%*  
long nStartPos; //File Snippet Start Position R>"E Xq  
long nEndPos; //File Snippet End Position " }@QL`  
int nThreadID; //Thread's ID z.g'8#@  
boolean bDownOver = false; //Downing is over :\Z;FA@g(g  
boolean bStop = false; //Stop identical .`!|^h%0  
FileAccessI fileAccessI = null; //File Access interface C#X0Cn0ln  
A2z%zMlZc  
B.&ly/d  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException NIDK:q dR  
{ +[9~ta|j  
this.sURL = sURL; 9n!<M)E  
this.nStartPos = nStart; 4 uv'l3  
this.nEndPos = nEnd; ZpPm>|w  
nThreadID = id; LSQ2pB2V  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 <lM]c  
} %-+lud  
/vFw5KUu  
_9E7;ew  
public void run() o/9(+AA>  
{ da3]#%i0  
while(nStartPos < nEndPos && !bStop) $4`RJ{ZJw]  
{ _pQ9q&i4  
guv)[:cd;  
,MwwA@,9-  
try{ rMqWXGl`(  
URL url = new URL(sURL); " *xQN "F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); / sENoQR  
httpConnection.setRequestProperty("User-Agent","NetFox"); I<*U^e  
String sProperty = "bytes="+nStartPos+"-"; dL>0"UN}-  
httpConnection.setRequestProperty("RANGE",sProperty); b0]y$*{j  
Utility.log(sProperty); H~+D2A  
!`vm7FN"u  
__""!Yz  
InputStream input = httpConnection.getInputStream(); 3ug{1 M3  
//logResponseHead(httpConnection); TuphCu+Oh  
4YkH;!M>ji  
{4&G\2<^^  
byte[] b = new byte[1024]; @B$ Y`eK\  
int nRead; E7+ y W  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 8 vB~1tl;  
{ Wx"bW ICc  
nStartPos += fileAccessI.write(b,0,nRead); b/oJ[Vf  
//if(nThreadID == 1) p"/1Kwqx  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &C3J6uCm+  
} /reSU 2  
i\G@kJNnF  
6q?C"\_  
Utility.log("Thread " + nThreadID + " is over!"); 7Xv.C&jzd  
bDownOver = true; %;9f$:U  
//nPos = fileAccessI.write (b,0,nRead); !z X`M1J  
} /ocdAW`0  
catch(Exception e){e.printStackTrace ();} +Ij>\;vM"  
} NA[yT  
} bF:vD&Sf  
;}3wT,=sN  
cS,(HLO91  
//打印回应的头信息  m2%uGqz  
public void logResponseHead(HttpURLConnection con) $lci{D32,  
{ 7ZS 5u+o  
for(int i=1;;i++) M)6_Ta l  
{ ,T_HE3K  
String header=con.getHeaderFieldKey(i); =35^k-VS  
if(header!=null) VB*$lx X  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |UM':Ec  
Utility.log(header+" : "+con.getHeaderField(header)); 3*64)Ol7t]  
else 0R<@*  
break; G@h6>O  
} ]i\D*,FfU  
} t/HMJ  
Uf{cUY,j_  
QvK/31*QG  
public void splitterStop() V{;Mh u`+  
{ |~k=:sSz{  
bStop = true; [zIX&fPk$  
} V;ZyAp  
~m y\{q  
!Pt|Hk dr  
} #ldNWwvRGj  
^-PlTmT  
(w?@qs!  
/*  =w0Rq~  
**FileAccess.java _;$VH4(BI  
*//文件访问(定位,写) 'Wl) )lB  
package NetFox; &fq-U5zH  
import java.io.*; S1wt>}w0$  
Nqp%Z7G  
l%.3hId-  
public class FileAccessI implements Serializable{ +ww paR`  
J`;G9'n2  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ,ju1:`  
RandomAccessFile oSavedFile; 8$-Wz:X&  
long nPos; MOP %vS   
e2UbeP  
Ps7(4%  
public FileAccessI() throws IOException +w:[By"  
{ Z<K[  
this("",0); &G5+bUF,  
} YMad]_XOP  
)!hDF9O  
d4/snvq  
public FileAccessI(String sName,long nPos) throws IOException yC4JYF]JN  
{ 3>yb$ZU"-  
oSavedFile = new RandomAccessFile(sName,"rw"); fyT:I6*  
this.nPos = nPos; *-T3'beg  
oSavedFile.seek(nPos); uu1-` !%  
} ~UB@IV6O  
Sm;&2"  
0FsGqFt  
public synchronized int write(byte[] b,int nStart,int nLen) AF ZHS\  
{ [Nr6 qxWg  
int n = -1; V' "p a  
try{ o;M"C[  
oSavedFile.write(b,nStart,nLen); / _-?NZ  
n = nLen; m*  |3  
} {l.) *#O  
catch(IOException e) 'y}l9alF  
{ xKEHN gen  
e.printStackTrace (); yp wVzCUG  
} Duj9PV`2  
8fTuae$^  
Yq4_ss'nB  
return n; kM*f9x  
} ,'m<um  
oOBN  
lLxKC7b  
} cgc| G  
KR%p*Nh+C  
HviL4iO  
/* >&RpfE[  
**SiteInfoBean.java ko@I]gi2  
*/ P )_g t  
package NetFox; 3X89mIDr  
&Ph@uZ\  
B-|:l 7  
public class SiteInfoBean { 0Q_AF`"  
;:vbOG#aSN  
%L}9nc%~eP  
private String sSiteURL; //Site's URL [?)}0cd0  
private String sFilePath; //Saved File's Path 6Y)'p .+g  
private String sFileName; //Saved File's Name [ahD%UxO5  
private int nSplitter; //Count of Splited Downloading File K SDo)7`  
bk}.^m!  
iE':ur<`  
public SiteInfoBean() )}9Ef"v|  
{//nSplitter的缺省值为5 [mJc c  
//default value of nSplitter is 5 ~A}"s-Kq5  
this("","","",5); -wvrc3F  
} NwIl~FNK  
`]_#_  
VT?J TW  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) tmDI2Z%7  
{ {1'XS,2  
sSiteURL= sURL; iyc}a6g  
sFilePath = sPath; qm4 Ejc<  
sFileName = sName; ;yqJEj_m(  
this.nSplitter = nSpiltter; ce.'STm=  
(\e,,C%;  
W=&\d`><k  
} HtgVD~[]  
8TD:~ee  
L:IaJ?+?  
public String getSSiteURL() fJn;|'H!  
{ ;3h[=hyS  
return sSiteURL; OvX z+C,  
} Z+' 7c|a  
BR8z%R  
.<gA a"  
public void setSSiteURL(String value) xv]P-q0  
{ ':R)i.TS  
sSiteURL = value; iSUn}%YFz!  
} /PE3>"|wE  
o_t2 Z  
\kF}E3~+#  
public String getSFilePath() eA$9)K1GO  
{ J~V`"uo  
return sFilePath; e57}.pF^  
} IfF<8~~E  
3:&!Q*i;  
-8HIsRh  
public void setSFilePath(String value) l"*qj#FD  
{ ;VSHXU'H  
sFilePath = value; z|=l^u6uS  
} >7!4o9)c  
B%6>2S=E  
1 ?]Gl+}  
public String getSFileName() w{?nX6a@p  
{ Jt43+]  
return sFileName; HB\<nK  
} ELk$ lm&@  
{oy(08 `6  
yyPkjUy[  
public void setSFileName(String value) MlkTrKdGi  
{ AA;\7;k{  
sFileName = value; eG72=l)Mz  
} yeFt0\=H  
$u|p(E:*  
4Smno%jq  
public int getNSplitter() <:-|>R".  
{ lj/ ?P9  
return nSplitter; i*:lZeU61  
} v}Gq.(b  
j/TsHJ=  
-Mb nYs)  
public void setNSplitter(int nCount) hzg&OW=:  
{ "G)-:!H  
nSplitter = nCount; nmn$$=~)  
} w}zl=w{G  
} KV k 36;$  
12gcma}  
PPU,o8E+  
/* kG[u$[B  
**Utility.java yBXdj`bV  
*/ ^:5 ;H=.  
package NetFox; %a<N[H3NV@  
SouPk/-B80  
@aN<nd`q)  
public class Utility { n7i;^=9 mM  
IFlDw}M!9  
3o9`Ko0  
public Utility() / *Z( ;-  
{ T3u%V_  
)TnxsFC  
 0$b)@  
} {-2I^Ym 5i  
~=aD*v<3d  
//线程睡眠 'IY?7+[  
public static void sleep(int nSecond) PEW^Vl-6q  
{ W&q]bi@C  
try{ ` :eXXE  
Thread.sleep(nSecond); %k_R;/fjW  
} GM%%7^uE  
catch(Exception e) DDq*#;dP  
{ N&K:Jp  
e.printStackTrace (); Q9tBHz  
} ~>3$Id:  
} B4bC6$Lg  
8fKt6T  
//日志 ogbLs)&+a  
public static void log(String sMsg) /@g D 8  
{ |G&<@8O  
System.err.println(sMsg); \\AufAkJ  
} ;f#%0W{":  
L,*2t JcC<  
tPIT+1.]z  
public static void log(int sMsg) xgn@1.}G  
{ ~ J^Gzl  
System.err.println(sMsg); !FX0Nx=oi  
} 1q]V/V}  
} 5, R\tJCK  
r" d/ 9  
[wWip1OR  
/* coT|t T  
**TestMethod.java w&jyijk(  
*/ !(~eeE}|lM  
package NetFox; W(Z_ac^e[  
j$'L-kK+  
zPEx;lO$  
public class TestMethod { jku_0Q0*?  
vQ>x5\r5O_  
S;sggeP7,  
public TestMethod() B!0o6)u'  
{ ///xx/weblogic60b2_win.exe >&6pBtC_  
try{ [tGAo/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); D^yZ!}Kl  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); HhDiGzOSi  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Tjma'3H*T0  
fileFetch.start(); eu@hmR8T  
} |s`j=<rNQI  
catch(Exception e){e.printStackTrace ();} }u:@:}8K  
(Gr8JpV  
O]>9\!0{  
} 4|YCBXWh  
r1b{G%;mJ  
h[b5"Uqj  
public static void main(String[] args) @]P#]%^D2  
{ 3}e-qFlV8,  
new TestMethod(); CG*eo!Nw  
} F$QN>wPpM  
} B{$4s8XU  
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