http断点续传简单实现（java)

/* 6F&]Mk]V8  
**SiteFileFetch.java KeHE\Fq^V  
*/ Tocdh.H|  
package NetFox; m'"VuH?^  
import java.io.*; r~fl=2>yQ  
import java.net.*; O*/-I pM  
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[,$mpJCI  
public class SiteFileFetch extends Thread { j=QR*8*  
'*;eFnmvs:  
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SiteInfoBean siteInfoBean = null; //文件信息Bean kCjI`=7$[  
long[] nStartPos; //开始位置 f#Cdx"  
long[] nEndPos; //结束位置 ~(L+4
]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 y$9t!cx  
long nFileLength; //文件长度 G/3lX^Z>  
boolean bFirst = true; //是否第一次取文件 d4h(F,K7V  
boolean bStop = false; //停止标志 Y9y*":&%  
File tmpFile; //文件下载的临时信息 I%C:d#p  
DataOutputStream output; //输出到文件的输出流 NWwtq&pz2  
u,SZ-2K!7~  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） M &EJFpc*  
public SiteFileFetch(SiteInfoBean bean) throws IOException !;C(p
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{ cE>/iZc  
siteInfoBean = bean; Eq;frnw>q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); (Ha}xwA~(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); U9sub6w6  
if(tmpFile.exists ()) ~EkGG .  
{ 3CuoBb8  
bFirst = false; afq +;Sh  
read_nPos(); QjN3j*@  
} K2`WcEe  
else G/44gKl  
{ A?KKZ{P
l  
nStartPos = new long[bean.getNSplitter()]; @_ZW
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nEndPos = new long[bean.getNSplitter()]; l^?A8jG  
} @7 HBXP
 
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} S%#Mu|  
,8?*U]}  
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public void run() Bin&:%|9?  
{ ]=<@G.[=  
//获得文件长度 Yx c >+mx  
//分割文件 @|A&\a-"J  
//实例FileSplitterFetch sswAI|6ou  
//启动FileSplitterFetch线程 ZaindX{.1  
//等待子线程返回 g]JI}O*5  
try{ LgKEg90w(  
if(bFirst) qqred>K  
{ 1K',Vw_  
nFileLength = getFileSize(); 0Hf-~6  
if(nFileLength == -1) vAxtNRS  
{ >m{-&1Tx  
System.err.println("File Length is not known!"); !&%bl  
} Y%8QFM  
else if(nFileLength == -2) ~3]8f0^%m  
{ ?IO/zkeXg  
System.err.println("File is not access!"); <WkLwP3^  
}
:b)@h|4  
else cu|q&  
{ sOenR6J<$  
for(int i=0;i<nStartPos.length;i++) c3-bn #  
{ [/]3:|  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); L6qA=b~iz  
} 'o9V0#$!  
for(int i=0;i<nEndPos.length-1;i++)
/tP  
{ G&Sg.<hn  
nEndPos = nStartPos[i+1]; \?}.+v  
} w=2X[V}  
nEndPos[nEndPos.length-1] = nFileLength; M!@[lJ  
} $yJfAR  
} JDlIf  
\/zS@fz  
Pw1H)<X  
//启动子线程 Cvy;O~)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; cH ?]uu(  
for(int i=0;i<nStartPos.length;i++) F@3,>~[%I  
{ qpCi61lTDJ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 'KG`{K$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {'[1I_3  
nStartPos,nEndPos,i); %VZ\4+8S  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I`1=VC]^8  
fileSplitterFetch.start(); S?$T=[yY)  
} bN)?szh&Y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y0^FTSQ|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,B><la87  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", " OtLJ  
nEndPos = " + nFileLength); G<DUy^$i  
// fileSplitterFetch[nPos.length-1].start(); L}+!<Ug  
@"0qS:s]X  
X)S4rW%  
//等待子线程结束 ~ME=!;<_  
//int count = 0; ^&%?Q_]  
//是否结束while循环 J4; ".Y=  
boolean breakWhile = false; 3ji#
"cX  
*']RYu?X  
|@nXlZE  
while(!bStop) `)fGw7J {  
{ wVTo7o%U  
write_nPos(); nq;)!Wry  
Utility.sleep(500); ;.Y`T/eWS  
breakWhile = true; .^,vK7  
B#}RMFIj  
9S^-qQH3}  
for(int i=0;i<nStartPos.length;i++) "%Ak[04'  
{ -rfO"D>  
if(!fileSplitterFetch.bDownOver) O<*iDd`(e  
{ \<%a`IA!*  
breakWhile = false; vL7}0n>tz  
break; ^B/{  
} y[vjqfdmU  
} 8VnZ@*  
if(breakWhile) ZO~N|s6B^  
break; h)rHf
3:  
jZGmTtx  
q0<g#jK  
//count++; &'R]oeag  
//if(count>4) S@_GjCpn
 
// siteStop(); 03xQ%"TU<  
} f &H`h
 
UkUdpZ.[il  
Yr!3mU-Uvt  
System.err.println("文件下载结束！"); ^t*BWJxPC  
} g8C+j6uR0  
catch(Exception e){e.printStackTrace ();} lUrchLoDt  
} "^\4xI  
S=o/n4@}  
4 ClW*l  
//获得文件长度 n\QG-?%Pi  
public long getFileSize() @"6BvGU2s  
{ 22GtTENd1h  
int nFileLength = -1; p|Ln;aYc  
try{ 607#d):Y  
URL url = new URL(siteInfoBean.getSSiteURL()); Z7(hW,60  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); FKaY w  
httpConnection.setRequestProperty("User-Agent","NetFox"); (C!fIRY  
<J- aq;p  
#2}S83 k  
int responseCode=httpConnection.getResponseCode(); #2pgh?  
if(responseCode>=400) `jJb) z3D  
{ #xO`k1W.  
processErrorCode(responseCode); C'{Z?M>  
return -2; //-2 represent access is error } nQHP4'  
} _PuMZjGL  
i'a M#4V  
+q3W t|  
String sHeader; fx*Swv%r  
fUa`YryQ  
Dj[D|%9a  
for(int i=1;;i++) nkpQM$FW  
{ HGPbx$!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); qoEOM%dAqV  
//Utility.log(in.readLine()); <Wl! Qog'  
sHeader=httpConnection.getHeaderFieldKey(i); k(s3~S2h  
if(sHeader!=null) xa K:@/  
{ sR5dC_  
if(sHeader.equals("Content-Length")) /6>2,S8Ar  
{ 2-8<uUy  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #ujcT%1G  
break; R(csJ4F  
} B-o"Y'iXs  
} wTOB'  
else \"n&|_SZ\  
break; ^E5Xpza  
} k%hif8y  
} /H\ZCIu/7  
catch(IOException e){e.printStackTrace ();} o'W &gkb9  
catch(Exception e){e.printStackTrace ();} ] $5rh8  
@%RDw*L(  
8R)*8bb  
Utility.log(nFileLength); :kgwKuhL  
|gT$M_}  
D|OX]3~  
return nFileLength; SMnbI
.0  
} O9!<L.X,%  
]Dx5t&  
z.7 UfLV9  
//保存下载信息（文件指针位置） _c`Gxt%  
private void write_nPos() P4s:wuJ^  
{ 64[j:t=N  
try{ !DLIIKO78  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -OoXb( I4  
output.writeInt(nStartPos.length); $+$+;1[  
for(int i=0;i<nStartPos.length;i++) sjztT<{Q^-  
{ t@b';Cuv  
// output.writeLong(nPos); bE0cW'6r  
output.writeLong(fileSplitterFetch.nStartPos); a}MOhM6T  
output.writeLong(fileSplitterFetch.nEndPos); >/Slk{  
} 7quhp\  
output.close(); &7}-Xvc  
} HAP9XC(F]  
catch(IOException e){e.printStackTrace ();} O75i
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catch(Exception e){e.printStackTrace ();} D*heYh  
} BoFJ8Ukq|  
7HFw*;  
oU67<jq  
//读取保存的下载信息（文件指针位置） AM\`v'I*6  
private void read_nPos() I/fERnHM/+  
{ h}.0Ne  
try{ g(|p/%H  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); cLX~NPD/  
int nCount = input.readInt(); C#;}U51:t  
nStartPos = new long[nCount]; :;rd!)5  
nEndPos = new long[nCount]; UtY<R  
for(int i=0;i<nStartPos.length;i++) Ktg6*L/  
{ 3xbA]u;gp  
nStartPos = input.readLong(); E}yl@8g:#  
nEndPos = input.readLong(); r*y4Vx7  
} "c=\?   
input.close(); !i0:1{.  
} g5_]^[upw  
catch(IOException e){e.printStackTrace ();} I9TOBn|6  
catch(Exception e){e.printStackTrace ();} J/WPffqD  
} vA"yy"B+ V  
dfO84Z} 5  
iw<+rh*C  
private void processErrorCode(int nErrorCode) J$@3,=L6V  
{ -&%#R_RV  
System.err.println("Error Code : " + nErrorCode); {'EQ%H$q  
} 0t'WM=W<!8  
&U!@l)<  
HSq&'V  
//停止文件下载 #*XuU8q?  
public void siteStop() 8+Oyhd*|  
{ r>A,7{  
bStop = true; 0vf2wBK'T  
for(int i=0;i<nStartPos.length;i++) pv;}Sv$ ]-  
fileSplitterFetch.splitterStop(); l. !5/\  
}D{y u+)  
|-=^5q5  
} dKi+~m'w  
} K%Jy?7 U  
//负责部分文件的抓取 L-",.U*;  
**FileSplitterFetch.java D'c,z[  
*/ szGp<x
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package NetFox; Tgc)'8A;BN  
cT-XF  
c2-NXSjsW  
import java.io.*; gVEW*8  
import java.net.*; Gd%KBb  
j)]mN$Sa:  
r^q@rL>   
public class FileSplitterFetch extends Thread { ]F
L=E3U  
3I@j=:(%Y  
h1q?kA  
String sURL; //File URL l0l2fwz(  
long nStartPos; //File Snippet Start Position X70G@-w  
long nEndPos; //File Snippet End Position rK9X68)  
int nThreadID; //Thread's ID IEmtt^C  
boolean bDownOver = false; //Downing is over ":tQYo]d  
boolean bStop = false; //Stop identical BMgiXdv.B  
FileAccessI fileAccessI = null; //File Access interface ~f;d3dJ]/  
58ev (f  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException H3nx8R$j](  
{ VMe~aUd  
this.sURL = sURL; ;n?H/(6X8>  
this.nStartPos = nStart; |Rf4^vN  
this.nEndPos = nEnd; $&OoxC  
nThreadID = id; ag+$
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 oEGe y8?  
} (ylpH`  
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public void run() tn>$5}^;  
{ 4U(W~O  
while(nStartPos < nEndPos && !bStop)
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{ YQ:FBj  
tH`!?  
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try{ QI0d:7!W1  
URL url = new URL(sURL); -NGY+
1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i?.MD+f8  
httpConnection.setRequestProperty("User-Agent","NetFox"); h%|Jkx!v-t  
String sProperty = "bytes="+nStartPos+"-"; -U`]/  
httpConnection.setRequestProperty("RANGE",sProperty); >j%HVRW  
Utility.log(sProperty); gf$5pp-  
KU|dw^Yk  
sL[&y'+  
InputStream input = httpConnection.getInputStream(); 1\X1G>60m  
//logResponseHead(httpConnection); *F42GiBZR  
URz$hcI8  
Y&6vTU  
byte[] b = new byte[1024]; N<}{oIsZ+  
int nRead; Y_ b;1RN  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Bb_R~1 l  
{ !vH7vq  
nStartPos += fileAccessI.write(b,0,nRead); [7]Kvb2t  
//if(nThreadID == 1) @zSI@Oq_  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +l+8Z:i<  
} Vv8e"S  
YII1Z'q  
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Utility.log("Thread " + nThreadID + " is over!"); N|WZk2 "  
bDownOver = true; z%Pbs[*C  
//nPos = fileAccessI.write (b,0,nRead); =BzyI  
} )u)]#z  
catch(Exception e){e.printStackTrace ();} jq#uBU%  
} U bUl]  
} ?BtWM4Id8  
!Bcd\]q  
w 4-E@>%  
//打印回应的头信息 G$kspN*"A  
public void logResponseHead(HttpURLConnection con) A2LqBirkl  
{ wDJbax?  
for(int i=1;;i++) TY6 D.ikA  
{ MBXja#(k  
String header=con.getHeaderFieldKey(i); g?'pb*PR  
if(header!=null) lv\C(^mGq  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); nK=-SQ  
Utility.log(header+" : "+con.getHeaderField(header)); f_y+B]?'M  
else G9"2h \  
break; x;w&JS1V  
} *8ykE  
} X2^`Znq9  
nKPvAe(  
mMo<C_~w&  
public void splitterStop() ~Y]*TP  
{ BiI?eT+  
bStop = true; RKB--$ibj  
} K89 AZxH  
i]oSVXx4WC  
QbA+\  
} )xwWig.  
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o0t/  
/* C QO gR GW  
**FileAccess.java unn2MP'  
*//文件访问(定位，写) \@6PA  
package NetFox; _o'_ z
]  
import java.io.*; QhV!%}7  
zfAHE{c  
$w!;~s  
public class FileAccessI implements Serializable{ AT.WXP0$A  
$!F_K  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 '!Gnr[aR  
RandomAccessFile oSavedFile; qo{2 CYG\+  
long nPos; 2
9#&q`J  
PgZeDUPP  
wa/ :JE  
public FileAccessI() throws IOException 3%c{eZxG=  
{ 9nIBs{`/Ac  
this("",0); Q(Uj5aX  
} -OY[x|0  
~&)  
Rf7*Ut wVr  
public FileAccessI(String sName,long nPos) throws IOException 2pa: 3O  
{ %{'hpT~h  
oSavedFile = new RandomAccessFile(sName,"rw"); GjF'03Z4  
this.nPos = nPos; N#<h/  
oSavedFile.seek(nPos); 1QkAFSl3  
} s
+m,ASj  
^3`CP4DT  
m#y?k1GY  
public synchronized int write(byte[] b,int nStart,int nLen) 7/^`y')  
{ 5@_c<   
int n = -1; 5<1,`Bq@  
try{ =+@IpXj  
oSavedFile.write(b,nStart,nLen); 5\1C@d  
n = nLen; B1\@ n$  
} @#sBom+K`  
catch(IOException e) ai/VbV'|  
{ ZLK@x.=  
e.printStackTrace (); )'\pa2  
} %*4
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f?xc-lX5R  
9AJMm1_  
return n; L\p@1N?K  
} qSj$0Hq5XI  
p_z_d6?  
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} ^'"sFEV7RN  
$'M:H
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.^]=h#[e
 
/* >C|/%$kk:f  
**SiteInfoBean.java WHh=hts\  
*/ N[G<&f9  
package NetFox; 8p3pw=p  
8!e1T,:b  
3)SO-Bz\  
public class SiteInfoBean { JStT"*4j  
X8U._/'N  
+{* @36A5A  
private String sSiteURL; //Site's URL JpuF6mQ  
private String sFilePath; //Saved File's Path t-#Y6U}b+  
private String sFileName; //Saved File's Name \W73W_P&g  
private int nSplitter; //Count of Splited Downloading File oe1Dm  
UMe@[E=  
e%#8]$  
public SiteInfoBean() Q<]~>cd^  
{//nSplitter的缺省值为5 DkO>?n:-C  
//default value of nSplitter is 5 <&&xt ?I.  
this("","","",5); nr/^HjMV  
} m*VM1kV  
1EW-%GQO  
S&BJR!FQ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]@@3]  
{ 7.O1 ~-  
sSiteURL= sURL; qGS]2KY  
sFilePath = sPath; | ?Js)i  
sFileName = sName; pq;)l(Hi  
this.nSplitter = nSpiltter; @C),-TM  
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4v#3UG  
} r{m"E^K,  
8e_ITqV%  
=A,32&;@N  
public String getSSiteURL() V0p@wG3  
{ Q^qG=  
return sSiteURL; x)@G+I\u  
} @21G[!%J  
]#
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h[c HCVM:  
public void setSSiteURL(String value) =Mc]FCV  
{ V%~u8b  
sSiteURL = value; f#xqu+)Z  
} F*WWv&\X  
qcxq-HS2'  
|q$br-0+  
public String getSFilePath() 7. y L>  
{ MmOGt!}9A  
return sFilePath; HaeF`gI^Ee  
} >c~~
i-=  
=U3,P%  
J[<3Je=>$  
public void setSFilePath(String value) ^=)? a;V  
{ ,wmPK;j  
sFilePath = value; `m5cU*@D  
} htg+V-,  
LyA=(h6  
l'N>9~f  
public String getSFileName() UQz8":#V  
{ ~Ra1Zc$o:  
return sFileName; _\ n'uW$  
} x9PEYhL?  
!F{5"$  
* wN+Ak q  
public void setSFileName(String value) UP:+1Sp9  
{ &libC>a[  
sFileName = value; 3"'|Ql.H  
} ]3#_BL)M8p  
U[~BW[[@f  
~..h=  
public int getNSplitter() tZ1iaYbvV  
{ wxPg*R+t  
return nSplitter; <_""4  
} 7I4G:-V:^  
hIa@JEIt  
,2?"W8,  
public void setNSplitter(int nCount) DSix(bs9  
{ 7<{Zq8)  
nSplitter = nCount; 6<A\U/  
} )|/t}|DIx  
} Qwx}e\=  
hB<.u  
Y VTY{>
Q  
/* C<A82u;t%@  
**Utility.java \@4QG.3&  
*/ zqYfgV  
package NetFox; d; @Kz^  
ihH!"HH+  
b]6;:Q!d  
public class Utility { />\.zuAr&  
J.
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public Utility() ?AY596  
{ 4BuS? #_  
_*Vq1D]C  
-GP+e`d  
} L~V 63K  
C%#C|X193  
//线程睡眠 u ` 9Eh;  
public static void sleep(int nSecond) /eR@&!D '  
{ LnZz=  
try{ ~;m~)D  
Thread.sleep(nSecond); W5:S+  
} _?Jm.nT  
catch(Exception e) !0`ZK-nA6  
{ NLb/Bja  
e.printStackTrace (); D'O[0?N"g  
} z[qM2  
} hFa\x5I5  
@]*z!>1  
//日志 /]]\jj#^  
public static void log(String sMsg) 1;L!g*!E  
{ #=t:xEz  
System.err.println(sMsg); iG!MIt*  
} 7+T\  
r~nrP=-%  
x)#k$QU  
public static void log(int sMsg) }9P)<
[>  
{ 9L:v$4{LU  
System.err.println(sMsg); e~rBV+f  
} uK(+WA  
} & PHHacp  
E_?3<)l)RI  
Q;r 0#"  
/* 7F?^gMi  
**TestMethod.java ; @Gm@d  
*/ &$hfAG]"  
package NetFox; :CHCVoh@95  
XNu2G19jb  
KU33P>a"[k  
public class TestMethod { .:RoD?px  
[Z Ea3/  
Bb:jy!jq_  
public TestMethod() *N'B(j/  
{ ///xx/weblogic60b2_win.exe ?\\ ]u  
try{ h"%
6tpV-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ['-ln)96.
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `34[w=Zm  
SiteFileFetch fileFetch = new SiteFileFetch(bean); oL}FD !}  
fileFetch.start(); ~,':PUkiV  
} %I Y-0\  
catch(Exception e){e.printStackTrace ();} ,{z$M  
>wcsJ{I  
FIU(2  
} |BYD]vK  
E?Q=#+}U  
9zO;sg;3  
public static void main(String[] args) kV6>O C&^  
{ {AIZ,  
new TestMethod(); ~sSB.g  
} -ZihEyG?V  
} :sT<<LtI-  
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