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http断点续传简单实现(java)

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/* ob E:kNE9  
**SiteFileFetch.java 4QE=f(u;h  
*/ -0$:|p?@^  
package NetFox; 7rcA[)<'  
import java.io.*; ^ Hg/P8q  
import java.net.*; eIg+PuQD]  
1 tPVP  
87i"   
public class SiteFileFetch extends Thread { f ba&`  
0x@A~!MoP  
p* RC  
SiteInfoBean siteInfoBean = null; //文件信息Bean 1Dq<{;rWb  
long[] nStartPos; //开始位置 bhD ~ 4Rz  
long[] nEndPos; //结束位置 (YwalfG {C  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 R2rsJ  
long nFileLength; //文件长度 1"?]= j:  
boolean bFirst = true; //是否第一次取文件 :Hk_8J  
boolean bStop = false; //停止标志 $2KK:{VX  
File tmpFile; //文件下载的临时信息 _1  p DA  
DataOutputStream output; //输出到文件的输出流 /Pvk),ca  
:&qhJtGo  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) yl$F~e1W  
public SiteFileFetch(SiteInfoBean bean) throws IOException GAw(mH*  
{ 2ev*CX6.  
siteInfoBean = bean; @4drjT  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 1a$IrQE  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); := <0=JE#  
if(tmpFile.exists ()) }_}KVI  
{ w2{g,A|  
bFirst = false; qZ*f%L(  
read_nPos(); +~Tu0?{Z 0  
} ZIpD{>/  
else -#.< 12M  
{ d yh<pX/$  
nStartPos = new long[bean.getNSplitter()]; nA_%2F'W}  
nEndPos = new long[bean.getNSplitter()]; {,?ss$L  
} iA'As%S1  
/[ K_ &  
bO3GVc+S  
dU]/$7  
} JJ ?I>S N!  
?^u^im  
rkDi+D6`q  
public void run() u7s"0f`  
{ GqLq  gns  
//获得文件长度 {6*#3m Kk  
//分割文件 7 Wl-n  
//实例FileSplitterFetch ~$<UE}qp  
//启动FileSplitterFetch线程 CqFeF?xd8h  
//等待子线程返回 =dzWmL<~8  
try{ $DebXxJw0l  
if(bFirst) kz B\'m,l  
{ khx.yRx  
nFileLength = getFileSize(); raE Mm  
if(nFileLength == -1) 19c@`?  
{ "(`2eXRn  
System.err.println("File Length is not known!"); w^q7n  
} (ChD]PWQ  
else if(nFileLength == -2) *geN [ [  
{ >&U @f  
System.err.println("File is not access!"); q .J sf+  
} ])w[   
else h2~4G)J  
{ T95t"g?p  
for(int i=0;i<nStartPos.length;i++) W .I\J<=V  
{ %S@L|t  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); M`7y>Ud  
} hmC*^"C>U=  
for(int i=0;i<nEndPos.length-1;i++) lnh+a7a)  
{ dJ ~Zr)>  
nEndPos = nStartPos[i+1]; lCIDBBjy^  
} kn"q:aD  
nEndPos[nEndPos.length-1] = nFileLength; !'G~k+  
} C <B<o[:H  
} $,fy$ Qk,S  
,LhCFw{8?~  
$t}<85YCQ  
//启动子线程 V'G Ju  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; CMW,slC_3  
for(int i=0;i<nStartPos.length;i++) DyO$P#~?  
{ G2:%g(  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mi,&0xDe a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9\JQ7$B  
nStartPos,nEndPos,i); SA;#aj}rV  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R>/ NE!q  
fileSplitterFetch.start(); xY<{qHcX  
} 2`?!+")  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0w=R_C)s  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); //f  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", t2>fmQIQ  
nEndPos = " + nFileLength); 7Nzbz3  
// fileSplitterFetch[nPos.length-1].start(); VT%:zf  
k; ZxY"^  
"=1;0uy]  
//等待子线程结束 ;*2>ES  
//int count = 0; @7oL#-  
//是否结束while循环 lDxc`S  
boolean breakWhile = false;  :A1:  
 _; Y`  
@-&MA)SN  
while(!bStop) T{+Z(L  
{ B<?w h0  
write_nPos(); pkgjTXR2b  
Utility.sleep(500); lIRlMLuG  
breakWhile = true; "IQ/LbOqm_  
=elpH^N  
#V,R >0"  
for(int i=0;i<nStartPos.length;i++) K/=|8+IDL  
{ k8AW6oO/i  
if(!fileSplitterFetch.bDownOver) n'1'!J; Q  
{ yQNV@T<o  
breakWhile = false; P"/G  
break; n>>Qn&ym  
} 9$ qm>,o  
} ?9{~> 4@  
if(breakWhile) _)T5lEFl=  
break; ml`8HXK0  
FRu]kZv2  
'o_:^'c  
//count++; P!G858V(  
//if(count>4) #S]ER907  
// siteStop(); vw,rF`LjZ  
} p Z: F:  
TS2ZF{m  
Uu 8,@W+  
System.err.println("文件下载结束!"); #Lv2Zoi>G  
} 6 Orum/|h  
catch(Exception e){e.printStackTrace ();} ~Wo)?q8UY,  
} Y_woKc*  
G3G#ep~)vC  
!8NC# s  
//获得文件长度 G 0%6ch^%  
public long getFileSize() ,'xYlH3s  
{ *37uy_EpV  
int nFileLength = -1; L>y J  
try{ W\&8au ds  
URL url = new URL(siteInfoBean.getSSiteURL()); uN([*'0Cg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ZOCDA2e(j  
httpConnection.setRequestProperty("User-Agent","NetFox"); t3(]YgF  
J &pO%Q=b  
FCi U  
int responseCode=httpConnection.getResponseCode(); .sC?7O =  
if(responseCode>=400) (8.Z..PH  
{ }J">}j]/  
processErrorCode(responseCode); TJ q~)Bm  
return -2; //-2 represent access is error +t5U.No  
} >Cw<BIF  
&0 >Loja`^  
R}^~^#  
String sHeader; 6f')6X'x  
"#[!/\=?:  
)M6w5g  
for(int i=1;;i++) Q8!) !r%  
{ S4=~`$eP  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); )OiT{-m  
//Utility.log(in.readLine()); 'Vyt4^$%  
sHeader=httpConnection.getHeaderFieldKey(i); o(DOQGl  
if(sHeader!=null) I!e})Y  
{ =jB08A  
if(sHeader.equals("Content-Length")) [<DZ*|+  
{ KD`IX-r{s  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &l3iV88  
break; Oo"^%F~%  
} KMI_zhyB  
} z!l.:F  
else .pvi!NnL-  
break; &?mD$Eo  
} Ty vtmx M  
} ,lZB96r0  
catch(IOException e){e.printStackTrace ();} ,AxdCT  
catch(Exception e){e.printStackTrace ();} _%5R o6  
]]Cb$$Td  
O8B\{T1  
Utility.log(nFileLength); &f ^,la  
$5Xh,DOg  
6d_'4B  
return nFileLength; yzqVz_Fi*W  
} s2Mb[#:a"  
{ ^cV lC_  
q Y#n'&  
//保存下载信息(文件指针位置) ?>I;34tL(  
private void write_nPos() ^h69Kr#d4  
{ ZosP(Tdq  
try{ j#cYS*^H  
output = new DataOutputStream(new FileOutputStream(tmpFile)); N[s}qmPha  
output.writeInt(nStartPos.length); -$\+' \  
for(int i=0;i<nStartPos.length;i++) $0 vb^  
{ -r-k_6QP  
// output.writeLong(nPos); ^J$2?!~  
output.writeLong(fileSplitterFetch.nStartPos); 0aG ni|  
output.writeLong(fileSplitterFetch.nEndPos); rg^'S1x|  
} bD/~eIcWL  
output.close(); 3AU;>D^5  
} Kx>qz.wwI?  
catch(IOException e){e.printStackTrace ();} Pi]19boM.  
catch(Exception e){e.printStackTrace ();} xai*CY@cQ  
} _f$^%?^  
YB-h.1T-  
;M)QwF1  
//读取保存的下载信息(文件指针位置) z6*X%6,8  
private void read_nPos() N@t|7~  
{ wK?vPS  
try{ Tj:B!>>  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); |S_eDjF  
int nCount = input.readInt(); -[cTx[Z,  
nStartPos = new long[nCount]; HMSO=)@+  
nEndPos = new long[nCount]; Qk:Y2mL  
for(int i=0;i<nStartPos.length;i++) 8fl`r~bqZ  
{ uScMn/%  
nStartPos = input.readLong(); R%?9z 8-  
nEndPos = input.readLong(); Yt;MV)  
} ML|FQ  
input.close(); RZXjgddL  
} \G*0"%!U  
catch(IOException e){e.printStackTrace ();} Y$"O VC  
catch(Exception e){e.printStackTrace ();} bbE!qk;hEP  
} jYk&/@`Ly  
Dfmjw  
hb}+A=A=+  
private void processErrorCode(int nErrorCode) ynthDE o  
{ ? m DI#~)  
System.err.println("Error Code : " + nErrorCode); E|iQc8gr&  
} F(>Np2oi6  
1*\o.  
h2G$@8t}I  
//停止文件下载 Sc;BCl{=|  
public void siteStop() 4K\G16'$v  
{ [_k1jHr48N  
bStop = true; pH9VTM.*  
for(int i=0;i<nStartPos.length;i++) \NPmym_ 6J  
fileSplitterFetch.splitterStop(); .P8&5i)'P,  
fp`;U_-&0  
;ub;l h3  
} V<GHpFi0  
} X $jWo@  
//负责部分文件的抓取 ZOh`(})hy  
**FileSplitterFetch.java b,7k)ND1F  
*/ EJMM9(DQ7  
package NetFox; ,o86}6Ag  
B3 8]~'8  
l9{hq/V  
import java.io.*; GeH#I5y  
import java.net.*; g6j?,c|y  
9jM}~XvV  
H\ F :95  
public class FileSplitterFetch extends Thread { Lt64JH^lz  
(A9Fhun  
0X6YdW_2X  
String sURL; //File URL J')o|5S1N  
long nStartPos; //File Snippet Start Position geru=7  
long nEndPos; //File Snippet End Position Z^3rLCa  
int nThreadID; //Thread's ID m*&]!mM"0G  
boolean bDownOver = false; //Downing is over ?9 <:QE;I>  
boolean bStop = false; //Stop identical I|qo+u)  
FileAccessI fileAccessI = null; //File Access interface )_HA>o_?C:  
y0L_"e/  
c"f-3kFv  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException wr$("A(  
{ oH97=>  
this.sURL = sURL; ,wQ5.U,  
this.nStartPos = nStart; DhKS pA  
this.nEndPos = nEnd; 'j#*6xD  
nThreadID = id; C0T;![/4A  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 p|U?86 t  
} &6/[B_.  
9+Np4i@  
Cio 1E-4  
public void run() 'OITI TM  
{  -*1d!  
while(nStartPos < nEndPos && !bStop) f,U.7E  
{ ;17E(tl  
)|ju~qbf  
P) Jgs  
try{ L +b6!2O,  
URL url = new URL(sURL); u-QB.iQ+s  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ha]VWt%}  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]E5o1eeg  
String sProperty = "bytes="+nStartPos+"-"; xQ f*  
httpConnection.setRequestProperty("RANGE",sProperty); BtkOnbz8X  
Utility.log(sProperty); 3#3n!(  
`V}q-Zdy  
t% d Z-Ym  
InputStream input = httpConnection.getInputStream(); 0yk]o5a++  
//logResponseHead(httpConnection); h0g8*HY+}  
^9v4OUG  
l!D}3jD  
byte[] b = new byte[1024]; ~[t[y~Hup  
int nRead; zfJT,h-{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) b6,iZ+]  
{ Z@4Ar fl  
nStartPos += fileAccessI.write(b,0,nRead); ` 'DmDg  
//if(nThreadID == 1) 5AFJC?   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); is?{MJZ_  
} .Y tKS  
w'>pY  
R$R *'l  
Utility.log("Thread " + nThreadID + " is over!"); !z\h| wU+  
bDownOver = true; j*|VctM  
//nPos = fileAccessI.write (b,0,nRead); =/@D8{pU  
} <$D`Z-6  
catch(Exception e){e.printStackTrace ();} sA+ }TNhq  
} /:cd\A}  
} ju8> :y8  
1KU! tL  
Cwv9 a^  
//打印回应的头信息 hZ|z|!g0  
public void logResponseHead(HttpURLConnection con) yl'u'-Zb6  
{ Ki;*u_4{  
for(int i=1;;i++) g_;\iqxL  
{ /J]5H  
String header=con.getHeaderFieldKey(i); jk;j2YNPw  
if(header!=null) 1.}d.t  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); A @i  
Utility.log(header+" : "+con.getHeaderField(header)); tm|ZBM  
else z<MsKD0Q  
break; tR# OjkvX  
} '+@=ILj>  
} akmkyrz'&  
$zUP?Gq!  
KqHyG  
public void splitterStop() em y[k  
{ bTI|F]^!  
bStop = true; ?e%ZOI  
} lt/1f{v[:  
1y:-N6  
W8G,=d}6  
} FUiRTRIYe  
Pd8![Z3  
8=!D$t\3  
/* 0- B5`=yU  
**FileAccess.java XgZD%7  
*//文件访问(定位,写)  4j*  
package NetFox; u2tfF  
import java.io.*; lqy Qf$t  
y#`tgJ:  
G?yLo 'Ulo  
public class FileAccessI implements Serializable{ irZ])a  
49eD1h3'X[  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |44Ploz2b  
RandomAccessFile oSavedFile; M$ wC=b  
long nPos; R7%#U`Q^A  
+V2F#fI/  
\UA[  
public FileAccessI() throws IOException (|2t#'m  
{ ."g`3tVK  
this("",0); B.=FSow  
} .7J#_* N V  
RTYvS5 G  
<3n Mx^  
public FileAccessI(String sName,long nPos) throws IOException )Om*@;r(  
{ ~-k9%v`  
oSavedFile = new RandomAccessFile(sName,"rw"); jV i) Efy  
this.nPos = nPos; td$E/h=3  
oSavedFile.seek(nPos); IYv`IS"  
} x5pdS:  
_T60;ZI+^  
'B |JAi?  
public synchronized int write(byte[] b,int nStart,int nLen) ?d*z8w  
{ @@f"%2ZR[  
int n = -1; GC-5X`Sq  
try{ .e#w)K  
oSavedFile.write(b,nStart,nLen); x[p|G5  
n = nLen; KR} ?H#%  
} 9+|$$)  
catch(IOException e) Q3'llOx  
{ +w`2kv  
e.printStackTrace (); w?L6!)oiz  
} b1I]>\  
PrqlTT}Px  
aj='b.2)  
return n; &$+AXzn  
} ,~U>'&M;  
x>K Or,f  
4Z3su^XR  
} 6jaEv#  
KYm0@O>;  
&C_j\7Dq  
/* cVv=*81\  
**SiteInfoBean.java `bq<$e  
*/ }RF(CwZr(  
package NetFox; phXGn m  
rI{; IDV  
Z-%\ <zT  
public class SiteInfoBean { ic:zsuEm  
G[PtkPSJ  
ScOK)nL"  
private String sSiteURL; //Site's URL 38B2|x  
private String sFilePath; //Saved File's Path 4> K42m  
private String sFileName; //Saved File's Name VD*6g%p  
private int nSplitter; //Count of Splited Downloading File zpn9,,~u  
"Fr.fhh'~  
iQ67l\{R  
public SiteInfoBean() |d2SIyUc  
{//nSplitter的缺省值为5 _;S-x  
//default value of nSplitter is 5 0D.Mke )  
this("","","",5); fUWG*o9  
} ,L2ZinU:  
n` _{9R  
>b}o~F^J  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [\e eDa  
{ ktXM|#  
sSiteURL= sURL; N{!i=A  
sFilePath = sPath; Vr)S{k-Q  
sFileName = sName; KfEx"94  
this.nSplitter = nSpiltter; dES"@?!^  
5DU6rks%  
y-b%T|p9  
} 9.M4o[  
,2oWWsC7  
eb{nWP  
public String getSSiteURL() Tk[ $5u*,  
{ oH?b}T=9jz  
return sSiteURL; 9rX&uP)j^#  
} O/(`S<iip  
]jQutlg|  
x8B}ZIbT9  
public void setSSiteURL(String value)  Mx?d  
{ net@j#}j-  
sSiteURL = value; &m7]v,&  
} ~vhE|f  
p`dU2gV  
x_}:D *aI  
public String getSFilePath() |^I0dR/w:  
{ 2,oKVm+  
return sFilePath; NiEUW.0  
} W(Fv l  
tY<4%~%X  
U}[d_f  
public void setSFilePath(String value) H2\;%K 2  
{ |A~jsz6pI  
sFilePath = value; uAq~=)F>,  
} ZU4nc3__  
\)904W5R  
[b%D3-}'  
public String getSFileName() SM#]H-3  
{ U$.@]F4&  
return sFileName; 65P0,b6"OT  
} /t57!&  
2;`1h[,-^  
/9*B)m"  
public void setSFileName(String value) (N6i4 g6  
{ xh,qNnGGi  
sFileName = value; kx{{_w  
} @})|Z}~  
IqHV)A  
wk D^r(hiH  
public int getNSplitter() bHYy}weZ  
{ rQs)O<jl  
return nSplitter; #4% ]o%.  
} %P/Jq#FE .  
Oc#syfO  
]i)c{y  
public void setNSplitter(int nCount) BwGfTua  
{ K`WywH3-  
nSplitter = nCount; . B9iLI  
} drP=A~?&:  
} *b}HNX|  
3?9IJ5p  
py!|\00}  
/* `Bp.RXsd*  
**Utility.java ,/%=sux  
*/ ^7U G$A  
package NetFox; &*,#5.  
HxV=F66"  
XGWSdPJLr  
public class Utility { *boR`[Ond  
Qf+\;@  
.CABH,Po:  
public Utility() xb~yM%*c  
{ 5h-SCB>P  
F=e8IUr  
HGs $*  
} D6Ui!  
 :D6 ON"6  
//线程睡眠 u(>^3PJ+  
public static void sleep(int nSecond) !qh]6%l  
{ Smn;(K  
try{ Uw. `7b>B  
Thread.sleep(nSecond); 8,4"uuI  
} { ]{/t-=  
catch(Exception e) VU(v3^1"  
{ EF[@$j   
e.printStackTrace (); {_[N<U:QT&  
} W0@n/U  
} %COX7gV  
eK?MKe  
//日志 t7Iv?5]N  
public static void log(String sMsg) HZC"nb}r4  
{ x.!V^HQSN  
System.err.println(sMsg); ZF9z~9  
} ]?kZni8j_  
2\MT;;ZTZ  
4K#>f4(U`g  
public static void log(int sMsg) xQ-<WF1i  
{ *xxx:*6rk;  
System.err.println(sMsg); KE5kOU;  
} q]ku5A\y  
} kW Ml  
p Z|V 3  
x_N'TjS^{  
/* (l~AV9!m:  
**TestMethod.java RUnSCOdX  
*/ _?m(V=z>  
package NetFox; Eex~xiiV  
x:NY\._  
S]e|"n~@  
public class TestMethod { _~l5u8{^6  
WdH$JTk1  
;>EM[u  
public TestMethod() >=I|xY,  
{ ///xx/weblogic60b2_win.exe #4Rx]zW^%  
try{ TCwFPlF|  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); o4F2%0gJ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); s^G.]%iU  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 6 6EV$*dRL  
fileFetch.start(); n?!">G  
} &WuN&As!Z  
catch(Exception e){e.printStackTrace ();} C\Wmq [  
}_M~2L?i  
~?Qe?hB  
} 9iIhte.  
Z*]9E^  
8yR.uMI$/  
public static void main(String[] args) <sGVR5NR  
{ K( c\wr\6  
new TestMethod(); ,i?nWlh+  
} b7?uq9  
} r"3=44St  
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