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http断点续传简单实现(java)

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/* J{^RkGF  
**SiteFileFetch.java <! )**  
*/ M%jPH  
package NetFox; Y"A/^]  
import java.io.*; UfS%71l.$  
import java.net.*; p+)YTzzc  
3U_2!zF3_  
a7N!B'y  
public class SiteFileFetch extends Thread { C8z{XSo  
da)NK!  
-B86U6^s  
SiteInfoBean siteInfoBean = null; //文件信息Bean ^%O]P`$  
long[] nStartPos; //开始位置 V5*OA??k<  
long[] nEndPos; //结束位置 \=_{na_  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Y ')x/H  
long nFileLength; //文件长度 0}_[DAd6  
boolean bFirst = true; //是否第一次取文件 !%$`Eq)M^7  
boolean bStop = false; //停止标志 qucq,Yw  
File tmpFile; //文件下载的临时信息 x c{hC4^V  
DataOutputStream output; //输出到文件的输出流 x?&$ci  
Q7W>qe%4  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) GnvL'ESa@M  
public SiteFileFetch(SiteInfoBean bean) throws IOException bw\@W{a%q  
{ O)vp~@ |  
siteInfoBean = bean; OpHsob~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); C*P7-oE2rh  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); B(M6@1m_  
if(tmpFile.exists ()) ..rOsg{  
{ 0jEL<TgC  
bFirst = false; n=[/Z!  
read_nPos(); Yk=PS[f  
} KEWTBBg  
else T#>7ub  
{ |P%Jw,}]9  
nStartPos = new long[bean.getNSplitter()]; }sxYxn~  
nEndPos = new long[bean.getNSplitter()]; thhwN A  
} Dc,I7F|%  
'q`^3&E  
cFJY^A  
E~6c-Lw  
} vh$%9ed  
Hro-d 1J7  
Dd\jHF>u  
public void run() R rda# h^  
{ >3Eo@J,?d  
//获得文件长度 R6(oZph  
//分割文件 9g<7i  
//实例FileSplitterFetch =zz ~kon9  
//启动FileSplitterFetch线程 AB4(+S*LA  
//等待子线程返回 :8OZ#D_Hl  
try{ D|{jR~J)xK  
if(bFirst) HPZ}*m'  
{ pej|!oX  
nFileLength = getFileSize(); 4T ~}  
if(nFileLength == -1) 62zYRs\Y)X  
{ 9g mW&{6q  
System.err.println("File Length is not known!"); !_Wi!Vr_  
} &wV]"&-  
else if(nFileLength == -2) o7$'cn  
{ \ZkA>oO".  
System.err.println("File is not access!"); ;XBI{CW  
} ]iUx p+  
else p9x(D/YP0  
{ 5rU[ T ir  
for(int i=0;i<nStartPos.length;i++) OOo3G~2r  
{ k=jk`c{<[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); r8xv#r1  
} h-[VH%  
for(int i=0;i<nEndPos.length-1;i++) $ 69oV:  
{ =o$sxb E(  
nEndPos = nStartPos[i+1]; 4GX-ma,  
} .?loO3 m  
nEndPos[nEndPos.length-1] = nFileLength; :s7m4!EF  
} \hx1o\  
} &__es{;P  
^y<<>Y'I  
xjKR R?  
//启动子线程 G U( _  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; `)_dS&_\  
for(int i=0;i<nStartPos.length;i++) 6;ixa hZV  
{ G6$kv2(k`@  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;5659!;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), zo4qG+>o  
nStartPos,nEndPos,i); Y!nJg1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3`t%g[D1  
fileSplitterFetch.start(); F9,DrB,B{  
} ,Y/ g2 4R  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !:q/Ye3.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,X`)ct  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", sTn<#l6  
nEndPos = " + nFileLength); hHV";bk  
// fileSplitterFetch[nPos.length-1].start(); e,W%uH>X  
NTYg[VTr  
[PNT\ElT  
//等待子线程结束 ?#}N1k\S  
//int count = 0; =A83W/4  
//是否结束while循环 e&&53?  
boolean breakWhile = false; BRgXr  
JvVWG'Z"  
iKX-myCz  
while(!bStop) ]&lY%"U$i  
{ _./Sk|C  
write_nPos(); )b)-ZS7  
Utility.sleep(500); xc=b |:A  
breakWhile = true; ^")Q YE  
MkfBu W;)  
U:^PC x`  
for(int i=0;i<nStartPos.length;i++) --$ 4Q(#  
{ Cv6'`",Yzm  
if(!fileSplitterFetch.bDownOver) _V7s#_p  
{ x!5'`A!W%  
breakWhile = false; )48QBz?  
break; TJK[ev};S  
} *Q ?tl\E  
} M l Jo`d  
if(breakWhile) _`&m\Qe>  
break; 1v.c 6~  
1Q<^8N)pf  
)u[emv$  
//count++; D1zBsi94D  
//if(count>4) \Q0[?k  
// siteStop(); 2mVD_ s[`  
} |H;F7Y_  
Qz5sxi  
ZX9TYN  
System.err.println("文件下载结束!"); pwL ;A3$|  
} < $J>9k  
catch(Exception e){e.printStackTrace ();} 49GkPy#]L=  
} .F   
JTSlWq4  
RP[{4 Q8  
//获得文件长度 le/,R@]B9  
public long getFileSize() hI]Hp3S  
{ B-ngn{Yc   
int nFileLength = -1; .HS"}A T  
try{ Ve}(s?hU5  
URL url = new URL(siteInfoBean.getSSiteURL()); _(%d(E2?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <D<4BnZ(  
httpConnection.setRequestProperty("User-Agent","NetFox"); "p_J8  
$rv8K j+  
Wh+{mvu#  
int responseCode=httpConnection.getResponseCode(); I&}L*Z?`  
if(responseCode>=400) 8 OY3A  
{ ]zE;Tw.S  
processErrorCode(responseCode); >,gg5<F-E  
return -2; //-2 represent access is error x@P y>f2  
} $PTP/^  
:61Tun  
EMwS1~3dD  
String sHeader; 3er nTD*`  
$HHs^tW  
+b0eE)  
for(int i=1;;i++) ~.{/0T  
{ G&D7a/G\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +)!YrKuu  
//Utility.log(in.readLine()); Q sZx) bO  
sHeader=httpConnection.getHeaderFieldKey(i); dP# |$1  
if(sHeader!=null) .7e2YI,S  
{ #hfXZVD  
if(sHeader.equals("Content-Length")) \KMToN&2  
{ tItX y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [I '0,y  
break; nw-xSS{  
} gw#5jW\  
} dgR g>)V  
else {MtpkUN  
break; 1C}NQ!.  
} mHV%I@`Y6  
} CtyoHvw+M  
catch(IOException e){e.printStackTrace ();} @e(o129  
catch(Exception e){e.printStackTrace ();} +giyX7BPJ  
{@6= Q 6L  
Wk~W Ozr}^  
Utility.log(nFileLength); 0h#l JS*  
_ky,;9G]  
_ "?.!  
return nFileLength; %<k2#6K  
} Gw>^[dmt!  
.AR#&mL9  
d4u})  
//保存下载信息(文件指针位置) e@Fo^#ImDx  
private void write_nPos() lD)%s!  
{ Rp.Sj{<2  
try{ zL$@`Eh-KP  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *w^C"^*  
output.writeInt(nStartPos.length); f[<m<I  
for(int i=0;i<nStartPos.length;i++) B:5Rr}eY+  
{ )WRLBFi3  
// output.writeLong(nPos); *W.C7=  
output.writeLong(fileSplitterFetch.nStartPos); <;vbsksZeH  
output.writeLong(fileSplitterFetch.nEndPos); f,h J~  
} h].<t&  
output.close(); $Z.7zH  
} @Z*W  
catch(IOException e){e.printStackTrace ();} Dd'm U  
catch(Exception e){e.printStackTrace ();} >.Chl$)<  
} YLqGRE`W  
$bW3_rl%X  
 f\]sz?KY  
//读取保存的下载信息(文件指针位置) _,p/l&<  
private void read_nPos() $+P>~X)  
{ ?oVx2LdD|  
try{ S=5<^o^h3  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); OVm\  
int nCount = input.readInt(); X &uTSgN  
nStartPos = new long[nCount]; /xsF90c\h  
nEndPos = new long[nCount]; }+)fMZz  
for(int i=0;i<nStartPos.length;i++) wT;0w3.Z  
{ Z>QF#."m  
nStartPos = input.readLong(); kE:nsXI )  
nEndPos = input.readLong(); XG}C+;4Aw  
} pOGeru u?  
input.close(); v=0(~<7B  
}  a][f  
catch(IOException e){e.printStackTrace ();} \]</w5 Pi,  
catch(Exception e){e.printStackTrace ();} GGNvu )"  
} BzkooJ  
 3L< wQ(  
7op`s5i  
private void processErrorCode(int nErrorCode) dYT%  
{ SQ44  
System.err.println("Error Code : " + nErrorCode); ^Y=\#-Dd  
} k3u "A_"c  
F20E_2;@@  
[<2<Y  
//停止文件下载 P^ A!.}d  
public void siteStop() {9?JjA  
{ ?ATOXy  
bStop = true; W}m)cn3@  
for(int i=0;i<nStartPos.length;i++) iL7DRQ1  
fileSplitterFetch.splitterStop(); R9'b-5q  
:yRo3c  
/35R u}c  
} + fC=UAZ  
} @LS@cCC,a  
//负责部分文件的抓取 rX4j*u2u  
**FileSplitterFetch.java kW *f.!  
*/ tQ8.f  
package NetFox; dYG,_ji  
v'U{/ ,x  
y`\@N"Cf  
import java.io.*; fa++MNf}3  
import java.net.*; :Pvzl1  
gYNjzew'  
1$D_6U:H0  
public class FileSplitterFetch extends Thread { +b.g$CRr  
$CY~5A`l9  
@aAW*D~-J  
String sURL; //File URL |%J{RA  
long nStartPos; //File Snippet Start Position -7*ET3NSI/  
long nEndPos; //File Snippet End Position v/](yT  
int nThreadID; //Thread's ID [Yo,*,y31  
boolean bDownOver = false; //Downing is over brW :C? }  
boolean bStop = false; //Stop identical 3?c3<`TW  
FileAccessI fileAccessI = null; //File Access interface 5k`l $mW{  
%6t2ohO"  
\ Pj  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException !zkZQ2{Wn  
{ u -;_y='m  
this.sURL = sURL; eIz<)-7:  
this.nStartPos = nStart; : ]sUpO  
this.nEndPos = nEnd; $K]m{  
nThreadID = id; [#l*_0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 MXw hxk#E  
} b6Wqr/  
byLft 1  
b:Wm8pp?  
public void run() /LvRP yj@  
{  Of"  
while(nStartPos < nEndPos && !bStop) T?x[C4wf+  
{ +?:7O=Y  
#pb92kA'  
e4!:c^?  
try{ X'd9[).  
URL url = new URL(sURL); $ {O#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Km(n7Ah"  
httpConnection.setRequestProperty("User-Agent","NetFox"); $"FQj4%d  
String sProperty = "bytes="+nStartPos+"-"; jBgP$g  
httpConnection.setRequestProperty("RANGE",sProperty); @ o3T  
Utility.log(sProperty); =<{np  
)+[ gd/<C.  
P0W*C6&71|  
InputStream input = httpConnection.getInputStream(); *pSQU=dmS  
//logResponseHead(httpConnection); [3(7  4  
+ Af"f' )  
[U5\bX@$  
byte[] b = new byte[1024]; kS_(wp A  
int nRead; `Gn50-@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) s$cK(S#  
{ b6U2GDm\s  
nStartPos += fileAccessI.write(b,0,nRead); Y&S24aql  
//if(nThreadID == 1) #:[t^}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qv]}$WU  
} vgsJeV`}I  
lr`&mZ( j  
9f hsIe  
Utility.log("Thread " + nThreadID + " is over!"); ;\]b T;#  
bDownOver = true;  f4Xk,1Is  
//nPos = fileAccessI.write (b,0,nRead); ?AJKBW^  
} PcA2/!a  
catch(Exception e){e.printStackTrace ();} )TVFtI=,NN  
} mS~o?q-n  
} *v9 2  
d/BM&r  
LcUh;=r}&  
//打印回应的头信息 ~\Hc,5G  
public void logResponseHead(HttpURLConnection con) EdlTdn@A  
{ <kGU,@6PF  
for(int i=1;;i++) F P* lQRA  
{ hWD;jR  
String header=con.getHeaderFieldKey(i); M%ICdIc'  
if(header!=null) ujlY! -GM  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); \/: {)T~  
Utility.log(header+" : "+con.getHeaderField(header)); [R=yF ~-  
else 3~uW I%I`  
break; $, ,op(  
} Jtr"NS?a]  
} ~/98Id}v  
L3@82yPo!  
/J=v]<87a  
public void splitterStop() ~:Ll&29i  
{ SKkUU^\#R`  
bStop = true; nEJY5Bz$  
} n 2)@S0{  
GBRa.;Kk  
/atW8 `&  
} R)QC)U  
/ro=?QYb  
m9.{[K"  
/* ] lrWgm  
**FileAccess.java n[G&ksQI  
*//文件访问(定位,写) 2/"u5  
package NetFox; IIn"=g=9  
import java.io.*; G/7cK\^u  
ioYGZ%RG#  
5@+,Xh,H|t  
public class FileAccessI implements Serializable{ ,N!o  
2E}*v5b,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ? }kG`q  
RandomAccessFile oSavedFile; (O.d>  
long nPos; *7ZN]/VRT  
C -\S/yd  
;<j0f~G`  
public FileAccessI() throws IOException y CVI\y\B  
{ @~YYD#'vNY  
this("",0); \$*7 >`k  
} LUM@#3&  
0{,Z{&E  
de p=&  
public FileAccessI(String sName,long nPos) throws IOException (Iaf?J5{  
{ `$W_R[  
oSavedFile = new RandomAccessFile(sName,"rw"); '}B+r@YCN  
this.nPos = nPos; Q9Kve3u-i  
oSavedFile.seek(nPos); mi,E-  
} P<M?Qd 1.  
$W!!wN=B  
gG*X^Uo  
public synchronized int write(byte[] b,int nStart,int nLen) ZWc]$H?  
{ ykV 5  
int n = -1; 05b_)&4R  
try{ A v2 08}Y  
oSavedFile.write(b,nStart,nLen); - jb0o/:  
n = nLen; + HK8jCa  
} 7 "20hAd  
catch(IOException e) x{n`^;Y1  
{ JM x>][xD  
e.printStackTrace (); pe]A5\4c  
} 60J;sGW  
H!5\v"]WB  
nxWY7hU  
return n; ]:Ns f|C0  
} Yu)NO\3&  
f !I[>&n  
GO` Ru 8  
} $\]&rZVi  
El.hu%#n*G  
C8Qa$._  
/* S|7!{}  
**SiteInfoBean.java Y }$/e  
*/ ow_W%I=6  
package NetFox; {2=jAz'?  
pTPi@SBaP{  
lI*o@wQg  
public class SiteInfoBean { = \'}g?  
n `&/ D  
==3dEJS  
private String sSiteURL; //Site's URL Tn*9lj4  
private String sFilePath; //Saved File's Path QdL`|  
private String sFileName; //Saved File's Name o0ifp=V y  
private int nSplitter; //Count of Splited Downloading File ADDSCY=,  
++6`sMJ  
="Ho%*@6  
public SiteInfoBean() *AO,^R&e.  
{//nSplitter的缺省值为5 'EbWFMjy  
//default value of nSplitter is 5 QPx_-  
this("","","",5); Pv_Jm  
} 9N@W\DT  
,z;cbsV-{  
3Z5D)zuc  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) j27?w<  
{ `j,Yb]~s79  
sSiteURL= sURL; i BF|&h(\  
sFilePath = sPath; %?}33yV  
sFileName = sName; i~I%D%;  
this.nSplitter = nSpiltter; 2NC.Z;  
bCo7*<I4  
L ^q""[  
} w80oXXs[#  
,l !Ta "  
_FH`pv  
public String getSSiteURL() B8f8w)m  
{ `|{-+m  
return sSiteURL; oW ::hB  
} "P 7nNa  
; <&*rnH  
ar__ Pf6r  
public void setSSiteURL(String value) &;^YBW:I  
{ uJzG|$;  
sSiteURL = value; @;*Ksy@1O  
} ^hc!FD  
OGK}EI  
,]9P{k]O  
public String getSFilePath() 9oYgl1}d  
{ * @ 3Ag(  
return sFilePath; hIy~B['  
} B"h#C!E  
@ [:ZS+1  
jrr EAp  
public void setSFilePath(String value) W>) M5t4i  
{ d,+Hd2o^X  
sFilePath = value; B2>H_dmQ  
} ;Lc Z`1  
3EJj9}#x"'  
G<}()+L  
public String getSFileName() ?zh9d%R  
{ B3We|oe!  
return sFileName; rDm~h~u5  
} 1oR7iD^  
Zq+v6fk_Mn  
>3p \m  
public void setSFileName(String value) [k.tWA,&  
{ cpL7!>^=  
sFileName = value; FHj" nB  
} ur)9x^y  
l4F%VR4KT  
%|auAq&w  
public int getNSplitter() _Gn2o2T  
{  7''??X  
return nSplitter; W0dSsjNio  
} ZGexdc%  
3@kf@ Vf  
Bmr>n6|  
public void setNSplitter(int nCount) uGwm r  
{ 6a[}'/  
nSplitter = nCount; |:nn>E}ZA/  
} ;&9)I8Us  
} J"!vu.[  
Ubh{!Y  
Pt@%4 :&-h  
/* #VB')^d<U  
**Utility.java j. *VJazb;  
*/ KhCzD[tf  
package NetFox; TMs,j!w?I  
Mva3+T  
O(tX8P Q5N  
public class Utility { }tH[[4tw,  
nSF``pp+  
uch>AuF:  
public Utility() PqyA1  
{ R)M_|ca  
f6_];]yP  
Xcrk;!IB?  
} pM{nh00[  
Z.W66\8~}^  
//线程睡眠 s[K^9wz  
public static void sleep(int nSecond) RlqQ  
{ &ISb~5  
try{ UOGuqV-  
Thread.sleep(nSecond); :l2g#* c  
} M t*6}Cl  
catch(Exception e) _* IPk  
{ "S&@F/  
e.printStackTrace (); iT;@bp  
} DHw&+MY  
} P y>{t4;S  
!@x+q)2  
//日志 FuUD 61JHY  
public static void log(String sMsg) /0W9g  
{ @*0cMO;SpG  
System.err.println(sMsg); :9R=]#uD  
} HJ2*y|u  
21ppSN >  
}w/;){gu  
public static void log(int sMsg) Iq#ZhAk  
{ b{d4xU8'  
System.err.println(sMsg); Ti2Ls5H}  
} `} m Q  
} JXixYwm  
~`GhS<D  
kdxz!  
/* WYIQE$SEv  
**TestMethod.java sK"9fU  
*/ yf?h#G%24  
package NetFox; T;diNfgg  
N7b1.]<  
OdQT2PA_  
public class TestMethod { Qd_Y\PzS  
.MVYB\6Q0  
4EXB;[ ]  
public TestMethod() rUlS'L;$"  
{ ///xx/weblogic60b2_win.exe Cv>o.Bp|  
try{ iweD @b  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 'S<%Xm  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); a8dXH5_  
SiteFileFetch fileFetch = new SiteFileFetch(bean); rrnNn'  
fileFetch.start(); u>Rb ?`  
} 'lo  
catch(Exception e){e.printStackTrace ();} o7TN,([W  
RQkyCAGx  
iJv48#'ii  
} xrqv@/kJ  
jSOS}!=  
IcrL   
public static void main(String[] args) D?~8za`5  
{ lJzl6&  
new TestMethod(); tM,%^){p$  
} ' JdkUhq1V  
} WKr X,GF  
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