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http断点续传简单实现(java)

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/* < }K9 50  
**SiteFileFetch.java ~ 6=6YP  
*/ we}5'bS>  
package NetFox; pi;fu  
import java.io.*; &H,UWtU+  
import java.net.*; $Y$s*h_-/<  
&a >UVs?=  
{R7RBX  
public class SiteFileFetch extends Thread { SRHD"r^@  
1)xj 'n  
<|3F('Q"  
SiteInfoBean siteInfoBean = null; //文件信息Bean HA$7Q~{N-t  
long[] nStartPos; //开始位置 DDT]A<WUV  
long[] nEndPos; //结束位置 4;jAdWj3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  u+]8Sq  
long nFileLength; //文件长度 L q;=UE  
boolean bFirst = true; //是否第一次取文件 #Ic-?2Gn4<  
boolean bStop = false; //停止标志 hzy#%FaB  
File tmpFile; //文件下载的临时信息 ,-Yl%R.W=  
DataOutputStream output; //输出到文件的输出流 , *Z!Bd8  
6.QzT(  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) =&?BPhJE  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~$ "P\iJ  
{ #6Fc-ysk:  
siteInfoBean = bean; NB)22 %  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); b,RQ" {  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); DqBiBH[%h  
if(tmpFile.exists ()) $+[ v17lF  
{ fUS1`  
bFirst = false; |VML.u:N  
read_nPos(); Wc{/K6]f  
} kt hy9<!$  
else XXPpj< c  
{ Z[zRZ2'i5  
nStartPos = new long[bean.getNSplitter()]; |Skhx9};  
nEndPos = new long[bean.getNSplitter()]; ,9~2#[|lq  
} %pImCpMR  
[#C(^J*@c  
xEqr3(  
p6W|4_a?  
} *TP>)o  
qv$m5CJvK  
3etW4  
public void run() QNgfvy  
{ (<xl _L:*.  
//获得文件长度 '@,M 'H{  
//分割文件 6Y&`mgMF'  
//实例FileSplitterFetch Bh<6J&<n  
//启动FileSplitterFetch线程 AqucP@  
//等待子线程返回 |#`qP^E  
try{ , LVZ  
if(bFirst) jkfc=O6^  
{ k^*S3#"  
nFileLength = getFileSize(); QL`Hb p  
if(nFileLength == -1) aLt2fB1)  
{ N)^` 15w  
System.err.println("File Length is not known!"); $irF  
} cCbZ*  
else if(nFileLength == -2) F!&$Z .  
{ yw+LT,AQ.  
System.err.println("File is not access!"); ?I332,,q  
} J>p6')Y6~  
else 7 HM%Cd  
{ `(o:;<&3  
for(int i=0;i<nStartPos.length;i++) GX ;~K  
{ B6xM#)  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); }*s`R;B|,  
} =WM^i86  
for(int i=0;i<nEndPos.length-1;i++) Dg o -Os@  
{ 2nkymEPu  
nEndPos = nStartPos[i+1]; b .|k j  
} 0Tq=nYZA  
nEndPos[nEndPos.length-1] = nFileLength; :B  9>  
} 25{-GaB  
} 6tF_u D  
qPF`=#  
jiqE^j3;  
//启动子线程 Dbl+izF3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _T\cJcWf  
for(int i=0;i<nStartPos.length;i++) &hu>yH>j  
{ ~EtwX YkRZ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;7E c'nC4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), y XT8:2M  
nStartPos,nEndPos,i); R,dbq4xkl  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f@Yo]FU  
fileSplitterFetch.start(); 1s/548wu  
} 1Y'NG<d _  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "."ow|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); B-UsMO  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Fj4>)!^kM  
nEndPos = " + nFileLength); {2F@OfuCF  
// fileSplitterFetch[nPos.length-1].start(); @8*lqV2  
^:~!@$*;6  
Hg5 :>?Lw@  
//等待子线程结束 @L$!hTaP  
//int count = 0; d$hBgJe>N  
//是否结束while循环 -}(2}~{e(  
boolean breakWhile = false; Kv9Z.DY  
H)+QkQb}  
e2^TQv2(=e  
while(!bStop) 1]69S(  
{ s@IgaF {  
write_nPos(); 4-m6e$p;  
Utility.sleep(500); vb6kr?-i*  
breakWhile = true; Qk72ra)  
lhC hk7l  
QQJf;p7  
for(int i=0;i<nStartPos.length;i++) s  }Ql9  
{ R,ZG?/#uM9  
if(!fileSplitterFetch.bDownOver) 6n^@Ps  
{ LXqPNVp#  
breakWhile = false; s'|t2`K("  
break; ?4^ 0xGyE  
}  />6ECT  
} 0SDnMij&bf  
if(breakWhile) #a9O3C/MP  
break; u'nQC*iJb  
t)1`^W}  
6?'7`p  
//count++; ,u>[cRqw  
//if(count>4) Ol~M BQs  
// siteStop();  TJ1h[  
} =*1NVi $n  
h+ud[atk.  
stUUez>  
System.err.println("文件下载结束!"); Re&"Q8I.8  
} SL-;h#-y 4  
catch(Exception e){e.printStackTrace ();} C]p@7"l  
} .G#li(NWH  
A,BYi$  
f ,4erTBH  
//获得文件长度 MqJ5|C.q  
public long getFileSize() C!|LGzs0  
{ "Kdn`zN{  
int nFileLength = -1; }B a_epM  
try{ vd)zvI  
URL url = new URL(siteInfoBean.getSSiteURL()); 8CZ%-}-%$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kRc+OsY9  
httpConnection.setRequestProperty("User-Agent","NetFox"); Qz3Z_V4k9  
le]~Cy0  
> K?OsvX  
int responseCode=httpConnection.getResponseCode(); Fn7OmxfD  
if(responseCode>=400) MXa^ g"  
{ uZZRFioX|  
processErrorCode(responseCode); pQKSPr  
return -2; //-2 represent access is error a eeor  
} -5 8q 6yA  
O`Gq7=X  
1"L"LU'  
String sHeader; r5Tdp)S  
<l $ d>,  
Z Cjw)To(  
for(int i=1;;i++) a5GLbanF  
{ yji[Yde;|  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {eV8h}KIl  
//Utility.log(in.readLine()); [IQ|c?DxpL  
sHeader=httpConnection.getHeaderFieldKey(i); ? ep#s$i  
if(sHeader!=null) ".tL+A[  
{ }&t>j[  
if(sHeader.equals("Content-Length")) p*&0d@'r  
{ ,_fz)@)  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 4] uj+J  
break; BUJ\[/  
} P0jr>j@^-  
} 9MYk5q.X:  
else Cq"KKuf  
break; ~?AEtl#&"  
} <ZF|2  
} Ch_rV+  
catch(IOException e){e.printStackTrace ();} U8w_C\Q  
catch(Exception e){e.printStackTrace ();} `daqzn  
67YC;J]n=z  
akxNT_   
Utility.log(nFileLength); hd(FOKOP  
AO$AT_s  
lGl'A}]#$  
return nFileLength; UtQey ;w  
} <4"-tYa  
M  9t7y  
FM >ae-L-  
//保存下载信息(文件指针位置) jdP )y]c  
private void write_nPos() hTr5Q33y>  
{ /Hyz]46  
try{ CwA_jOp  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ~ELMLwn.  
output.writeInt(nStartPos.length); '7-Yo Q  
for(int i=0;i<nStartPos.length;i++) ,vJt!}}  
{ aa`(2%(:  
// output.writeLong(nPos); jO-?t9^  
output.writeLong(fileSplitterFetch.nStartPos); f'^uuO#x  
output.writeLong(fileSplitterFetch.nEndPos); '4[=*!hs!  
} G^~[|a 4`  
output.close(); ;Y$>WKsV  
} 6Dlm. ~G  
catch(IOException e){e.printStackTrace ();} 0 =j }`  
catch(Exception e){e.printStackTrace ();} -n|bi cP  
} xH-d<Ht,7  
~&i4FuK  
h[ DNhR  
//读取保存的下载信息(文件指针位置) Y%s:oHt  
private void read_nPos() \k.`xG?  
{ E-bswUVaEE  
try{ p,Ff, FfH  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9-KhJq%  
int nCount = input.readInt(); Oj5UG*  
nStartPos = new long[nCount]; ~RhUg~o  
nEndPos = new long[nCount]; 2bp@m;g$  
for(int i=0;i<nStartPos.length;i++) <v_=k],W  
{ 'o >)E>  
nStartPos = input.readLong(); 4Gc M  
nEndPos = input.readLong(); ,ks2&e  
} MtLWpi u@[  
input.close(); "|SMRc  
} CLR1 CGnn7  
catch(IOException e){e.printStackTrace ();} zM9#1^X  
catch(Exception e){e.printStackTrace ();} " O&93#8  
} N:1aDr;  
-8TJ:#|N  
`g)}jo`W  
private void processErrorCode(int nErrorCode) Mt[yY|Ec|  
{ ToXWFX  
System.err.println("Error Code : " + nErrorCode); 6>>; fy2  
} ZZw`8 E  
[{znwK@  
"TV'}HH  
//停止文件下载 )pB#7aEw  
public void siteStop() o.+;]i}D  
{ {f/qI`  
bStop = true; PobX;Z  
for(int i=0;i<nStartPos.length;i++) @T'^V0!-q:  
fileSplitterFetch.splitterStop(); 1 ^~&"s U  
g9_zkGc7  
{keZ_2  
} sZ.<:mu[  
} D JP6Z  
//负责部分文件的抓取 $*Ucfw1T  
**FileSplitterFetch.java zTz}H*U  
*/ ?bTfQH vX  
package NetFox; [BWq9uE  
rPV Q#iB  
(`x_MTLL  
import java.io.*; !NXjax\r  
import java.net.*; aO6\ e>  
;Rrh$Ag  
Y-VDi.]W  
public class FileSplitterFetch extends Thread { =C"[o\]VV  
iSW2I~PD  
>p_W(u@ z$  
String sURL; //File URL -t`kb*O3`  
long nStartPos; //File Snippet Start Position o+A7hBM^  
long nEndPos; //File Snippet End Position 8fC4j`!  
int nThreadID; //Thread's ID H4$qM_N  
boolean bDownOver = false; //Downing is over nL@'??I1  
boolean bStop = false; //Stop identical xL}i9ozZ  
FileAccessI fileAccessI = null; //File Access interface cc@W 6W  
(lk9](;L  
wi(Y=?=  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #mxOwvJ  
{ vygzL U^  
this.sURL = sURL; d?,'$$aB  
this.nStartPos = nStart; > p`,  
this.nEndPos = nEnd; "<,lqIqA;  
nThreadID = id; ~q$]iwwqT  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Y(Q 0m|3P  
} q<3nAE$?=  
 Nx}nOm  
F O!Td  
public void run() <Ap_#  
{ `Os=cMR  
while(nStartPos < nEndPos && !bStop) g4K+AK  
{ r\NqY.U&  
l:HQ@FX  
1w,_D.1'  
try{ p`tz*ewC  
URL url = new URL(sURL); I _nQTWcm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |9* Rnm_  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,d"T2Hy  
String sProperty = "bytes="+nStartPos+"-"; b<h((]Q>^  
httpConnection.setRequestProperty("RANGE",sProperty); c_/BS n  
Utility.log(sProperty); hkK>h  
m=l>8  
u 3WU0Z`  
InputStream input = httpConnection.getInputStream(); |G j.E  
//logResponseHead(httpConnection); .N(R~_  
G%F#I  
ysaRH3M  
byte[] b = new byte[1024]; OC! {8MR  
int nRead; ]_KWN$pd  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) _i =*0Q  
{ * #yF`_p  
nStartPos += fileAccessI.write(b,0,nRead); >6es 5}  
//if(nThreadID == 1) *G"hjc$L  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "4b{YWv  
} `?VK(<w0q  
hY)zKX_r  
ZCCCuB  
Utility.log("Thread " + nThreadID + " is over!"); CD1Ma8I8  
bDownOver = true; -rDfDdT  
//nPos = fileAccessI.write (b,0,nRead); CL<-3y*  
} u`ir(JIj]  
catch(Exception e){e.printStackTrace ();} 3.Fko<D4jD  
} Z$z-Hx@%  
} 7F`\Gz_2  
k>i88^kPV  
3M#x)cW  
//打印回应的头信息 wgz]R  
public void logResponseHead(HttpURLConnection con) 'o='Q)Dk  
{ Df"PNUwA"  
for(int i=1;;i++) PKlR_#EB?  
{ {$S"S j  
String header=con.getHeaderFieldKey(i); lDS y$  
if(header!=null) PqspoH 0OI  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9O g  
Utility.log(header+" : "+con.getHeaderField(header));  Wvb ~j  
else &XNt/bK -?  
break; m2SJ\1 J=  
} 8UB2 du@?  
} m%9Yo%l~  
~n -N  
r'noB<| e  
public void splitterStop()  II'.vp  
{ Mg >%EH/'  
bStop = true; GwO`@-}E  
} :1d;jx>  
]ty$/{hx'  
k;qS1[a  
} =2q#- ,t  
ybpOk  
"]3o93 3 D  
/* Aa-5k3:x]=  
**FileAccess.java 5$i(f8*  
*//文件访问(定位,写) Q 1i5"'][  
package NetFox; 46M=R-7=  
import java.io.*; 0aq{Y7sYU  
foPM5+.G  
NXLb'mH~  
public class FileAccessI implements Serializable{ <IU   
Sj)?!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Qraq{'3  
RandomAccessFile oSavedFile; ((?"2 }1r  
long nPos; ZK ?V{X{";  
nVlZ_72d  
%-YWn`yEm  
public FileAccessI() throws IOException rhYARr'  
{ D=LsoASVI  
this("",0); S^q^=q0F  
} `4ga~Ch  
-^np"Jk  
V6>{k_0{V  
public FileAccessI(String sName,long nPos) throws IOException 9k4z__Ke  
{ 'oGMr=gp<&  
oSavedFile = new RandomAccessFile(sName,"rw"); EAh|$~X  
this.nPos = nPos; -5os0G80  
oSavedFile.seek(nPos); (gdzgLHy  
}  w@mCQ$  
N f?\O@  
C(sz/x?11  
public synchronized int write(byte[] b,int nStart,int nLen) gjiS+N[  
{ )#Ecm<.^  
int n = -1; sw$JY}Q8x  
try{ 7h. [eMLPB  
oSavedFile.write(b,nStart,nLen); ?y%Mm09  
n = nLen; 79Aa~+i'_  
} 'mv|6Y  
catch(IOException e) PTpfa*t  
{ -R$Q`Xw  
e.printStackTrace (); t& yuo E  
} ?iaO+G&|  
g5nL7;`N  
p:| 7d\r  
return n; V+u0J"/8  
} W$}2 $}r0U  
AAi4} 8+\  
(6)|v S  
} $?&distJ  
r"7 !J[u  
|>JRJ"CFE  
/* KrTlzbw&p\  
**SiteInfoBean.java pfMmDl5|  
*/ gE23C*!'&:  
package NetFox; EBmkKiI;  
V' sq'XB  
o3'Za'N.  
public class SiteInfoBean { 9WL$3z'*  
{o %OG/!1  
;A?86o'?  
private String sSiteURL; //Site's URL 9*a"^  
private String sFilePath; //Saved File's Path I_`$$-|  
private String sFileName; //Saved File's Name Q-e(>=Gv_  
private int nSplitter; //Count of Splited Downloading File $B )jSxSy  
RHI?_gf&  
. N5$s2t  
public SiteInfoBean() 7$kTeKiP  
{//nSplitter的缺省值为5 \NL*$SnxP  
//default value of nSplitter is 5 &7w*=f8I  
this("","","",5); wA";N=i=  
} ATD4 %|a9h  
?J5E.7o  
W> $mU&ew[  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) fc^d3wH0L  
{ D' h%.  
sSiteURL= sURL; |zp}u(N  
sFilePath = sPath; 8J0#lu  
sFileName = sName; )4FW~o<i  
this.nSplitter = nSpiltter; \2 [  
{%v{iE>  
U5;Y o+z  
} Oz5Ze/HBN  
E>1%7" i<  
t|59/R  
public String getSSiteURL() m>^#:JK  
{ UmP\;  
return sSiteURL; 6P`!yBAu  
} HA;G{[X  
`_.(qg   
<)$JA  
public void setSSiteURL(String value) O<+x=>_  
{ aB~=WWLR\  
sSiteURL = value; !@f!4n.e|I  
} *qw//W   
l7S&s&W @  
jGKI|v4U(  
public String getSFilePath() 6hf6Z 3  
{ '+\.&'A  
return sFilePath; X8   
} NfXEW-  
l\t<_p/I)^  
x|A{|oFC  
public void setSFilePath(String value) x4/f5  
{ X[$FjKZh=F  
sFilePath = value; lm(k[]@  
} 1y6{3AZm<  
*l8:%t\  
1|H(q  
public String getSFileName()  kSU]~x  
{ 9>[ *y8[:0  
return sFileName; KOVR=``"/  
} M>|R&v  
7\Wq:<JL  
PG'+vl  
public void setSFileName(String value) Hge0$6l  
{ bjB4  
sFileName = value; F@kd[>/[  
} gwv s  
J4q_}^/2w  
bv4G!21]*;  
public int getNSplitter() vuNq7V*}  
{ &265 B_'D  
return nSplitter; VgcLG ]tE[  
} 4{Af 3N  
:B5M#D!dO  
J=AF`[  
public void setNSplitter(int nCount) 3YJa3fflK  
{ =.8fES  
nSplitter = nCount; W60C$*h  
} @0U={qX  
} s(s hgI 3g  
@_C?M5v  
PNhxF C.  
/* qfl#ki`,  
**Utility.java b]xE^zM-I`  
*/ zpBkP-%}E  
package NetFox; [}Pi $at  
S_dM{.!Z(,  
><3!J+<?  
public class Utility { }q D0-  
9a3mN(<  
oeIza<:=R  
public Utility() GR>kxYM%q  
{ IH$ZPux  
;FO( mL(  
u#~q86k  
} xmBGZ4f%  
ERz{, >G?  
//线程睡眠 xfADks2w  
public static void sleep(int nSecond) R.$1aqA}  
{ {bD:OF  
try{ k5/W'*P  
Thread.sleep(nSecond); RA$q{$arb  
} :DoE_  
catch(Exception e) .}ePm(  
{ n>\2_$uDI  
e.printStackTrace (); lmpBf{~ S  
} ;X)b=  
} }`^D O Ar  
~zph,bk  
//日志 q3}WO] TBj  
public static void log(String sMsg) } za "rU  
{ ((cRe6  
System.err.println(sMsg); O#72h]  
} x_$`#m{hL5  
}(/\vTn*1  
jSd[  
public static void log(int sMsg) wjc&S'[  
{ ViYfK7Z  
System.err.println(sMsg); uN+]q qCf  
} 28x:]5=jb  
} GiS:Nq`$(  
i.Z iLDs\7  
8Ai\T_l  
/* 6'45c1e   
**TestMethod.java 0AD8X+M{P  
*/ (Qf. S{;  
package NetFox;  KGJ *h  
EaKbG>  
CWa~~h<r-  
public class TestMethod { DVz_;m6)  
14z ?X%  
4~ i?xo=;v  
public TestMethod() hI 1or4V  
{ ///xx/weblogic60b2_win.exe {@ Z=b 5/P  
try{ }*?,&9/_)  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); UU*v5&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); l!mx,O`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); <rxtdI"3  
fileFetch.start(); G.3yuok9  
} NOFuX9/'w  
catch(Exception e){e.printStackTrace ();} 5 BLAa1  
<S3s==Cg  
2{<o1x,Ym  
} mI'&!@WG  
lc\{47LwZ  
3 #"!Hg  
public static void main(String[] args) i2+_~$f  
{ "p]!="\  
new TestMethod(); @Yn+ir0>O  
} U^8S@#1Q  
} L%jIU<?Z7  
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