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http断点续传简单实现(java)

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/* rU |%  
**SiteFileFetch.java @s|G18@  
*/ Y'+mC  
package NetFox; GboZ T68  
import java.io.*; [y&uc  
import java.net.*; <dKHZ4  
-y'tz,En.  
w+Y_TJ%  
public class SiteFileFetch extends Thread { dAr=X4LE  
{ V$}qa{P  
.Q!pQ"5  
SiteInfoBean siteInfoBean = null; //文件信息Bean s>I~%+V.?:  
long[] nStartPos; //开始位置 J(Fk@{!F.*  
long[] nEndPos; //结束位置 FvXpqlp  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 n #S?fsQN  
long nFileLength; //文件长度 :I2spBx  
boolean bFirst = true; //是否第一次取文件 )E*-  
boolean bStop = false; //停止标志 B.4Or]  
File tmpFile; //文件下载的临时信息 98Y1-Z^ .  
DataOutputStream output; //输出到文件的输出流 RDOV+2K  
oi7Y?hTj  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) LYke\/ md  
public SiteFileFetch(SiteInfoBean bean) throws IOException +62}//_?  
{  (,R\6  
siteInfoBean = bean; c{3P|O&.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); U.Fs9F4M#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); F*J bTEOn  
if(tmpFile.exists ()) jGUegeq  
{ b=kY9!GN,v  
bFirst = false; L>n^Q:M  
read_nPos(); "#8I &xZK  
} zXW;W$7V4  
else Dn48?A[v  
{ ~IFafAO&  
nStartPos = new long[bean.getNSplitter()]; |)OC1=As  
nEndPos = new long[bean.getNSplitter()]; #!C|~=  
} 5^N y6t  
OyQ[}w3o|  
~cf)wrP  
K?u:-QX^  
} Ie}7#>S  
sitgz)Ki^  
rrSFmhQUk  
public void run() 7|k2~\@q  
{ K_fJ{Vc>O  
//获得文件长度 Flaqgi/j  
//分割文件 \rY\wa  
//实例FileSplitterFetch 2S//5@~_m  
//启动FileSplitterFetch线程 sWKv> bx  
//等待子线程返回 kbSl.V%)  
try{ n] 8*yoge  
if(bFirst) {S`Rr/E|%  
{ N}Or+:"O:q  
nFileLength = getFileSize(); NNBT.k3)  
if(nFileLength == -1) nK`H;k  
{ zp\_5[qJ;  
System.err.println("File Length is not known!"); Pf~0JNnc  
} *G[` T%g  
else if(nFileLength == -2) Mehp]5*  
{ *i"Mu00b  
System.err.println("File is not access!"); p\}!uS4 (  
} l-2lb&n  
else #!>`$  
{ & j*Ylj}  
for(int i=0;i<nStartPos.length;i++) {KSy I#  
{ 1ZXRH;J40  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); PHMp, z8  
} i "aQm  
for(int i=0;i<nEndPos.length-1;i++) @h\i<sh!^  
{ !Pu7%nV.  
nEndPos = nStartPos[i+1]; jX,A.  
} KVHK~Y-G  
nEndPos[nEndPos.length-1] = nFileLength; ]UrlFiR  
} a YY1*^  
} bd3>IWihp  
&zPM# Q  
.UU)   
//启动子线程 z'zC  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !q8A!P4|'  
for(int i=0;i<nStartPos.length;i++) \5b<!Nl  
{ _+gpdQq\p  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )+.AgqxI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Cyud)BZvm  
nStartPos,nEndPos,i); akQb%Wq  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5;[0Q  
fileSplitterFetch.start(); ?h8/\~Dw  
} z.W1Za  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vIFx'S~D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); WX+@<y}%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", M+4S>Sjw  
nEndPos = " + nFileLength); U}{\qs-zt  
// fileSplitterFetch[nPos.length-1].start(); XlGB`P>?KD  
]xhH:kW4  
)' 2vUt`_7  
//等待子线程结束 |h:3BV_  
//int count = 0; 'v@1_HHW\  
//是否结束while循环 [{J1b  
boolean breakWhile = false; &jDRRT3  
tdC kvVE  
XB%`5wwd  
while(!bStop) * =O@D2g0  
{ gKb5W094@  
write_nPos(); s3M#ua#mX  
Utility.sleep(500); CzT_$v_  
breakWhile = true; Vb2")+*:  
*c@]c~hY,  
&J=x[{R  
for(int i=0;i<nStartPos.length;i++) S*rcXG6Q^  
{ YGLR%PYv"  
if(!fileSplitterFetch.bDownOver) F,XJGD*  
{ UOI Z8Po  
breakWhile = false; <7X+-%yb;  
break; *tT5Zt/&Sr  
} St1>J.k_  
} c{f1_qXN  
if(breakWhile) &l~=c2  
break; =`%%*  
3*b!]^d:D  
&S# bLE  
//count++; ~ K|o@LK  
//if(count>4) %P]-wBJw  
// siteStop(); QLTE`t5w3'  
} g? \pH:|79  
{c$%3iQq  
B Zw#ACU  
System.err.println("文件下载结束!"); _d<\@Tkw  
} #60<$HO:Z  
catch(Exception e){e.printStackTrace ();} 4>@-1nt}  
} KL*UU,qU  
k?=V?JWY  
&nZ.$UK<  
//获得文件长度 j8p'B-yS  
public long getFileSize() ?r~](l   
{ ]9pcDZB  
int nFileLength = -1; k4nA+k<WI`  
try{ #kGxX@0  
URL url = new URL(siteInfoBean.getSSiteURL()); 8%9OB5?F6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |zL.PS  
httpConnection.setRequestProperty("User-Agent","NetFox"); Xq%!(YD|  
KBGJB`D*  
uO-R:MC  
int responseCode=httpConnection.getResponseCode(); /h%MWCZWm^  
if(responseCode>=400) :hxZ2O?5_  
{ @)8C  
processErrorCode(responseCode); h-h}NCP  
return -2; //-2 represent access is error Jh:-<xy)  
} 3'2}F%!Mv  
1')/BM2  
  s/'gl  
String sHeader; & ~[%N O  
Wkv **X}  
Afa{f}st  
for(int i=1;;i++) g@"6QAP  
{ O^gq\X4}  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); PZl(S}VY  
//Utility.log(in.readLine()); =U".L  
sHeader=httpConnection.getHeaderFieldKey(i); ]QU52R@M  
if(sHeader!=null) Onoi6^G  
{  g^E n6n)  
if(sHeader.equals("Content-Length")) i&FC-{|Z  
{ QX~*aqS3s8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Ic&t_B*i}]  
break; XT_BiZ%l5O  
} ?8 C+wW  
} M !OI :v  
else vR~*r6hX8  
break; 49Ue2=PP#  
} @kwD$%*0  
} #(*WxVE  
catch(IOException e){e.printStackTrace ();} 6YU2  !x  
catch(Exception e){e.printStackTrace ();} C5RDP~au  
uf)W? `e~  
Lou4M  
Utility.log(nFileLength); .^.UJo;4G  
AQ 7e  
^! ZjK-$A<  
return nFileLength; cCV"(Oo[H|  
} {Q(6 .0R  
P[nWmY  
.Na>BR\F  
//保存下载信息(文件指针位置) NV-9C$<n2!  
private void write_nPos() /9w}[y*E  
{ |H_)u  
try{ Pe wPl0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); X7c*T /  
output.writeInt(nStartPos.length); p go\(K0  
for(int i=0;i<nStartPos.length;i++) Z#MODf0H@  
{ q=1SP@;\6  
// output.writeLong(nPos); '/ &"  
output.writeLong(fileSplitterFetch.nStartPos); :M[E-j;  
output.writeLong(fileSplitterFetch.nEndPos); 4l`gAE$  
} \]ODpi 2  
output.close(); 2aje$w-  
} Z|?XQ-R5  
catch(IOException e){e.printStackTrace ();} V_W=MWs&+  
catch(Exception e){e.printStackTrace ();} ^:)&KV8D|  
} wbS++cF<  
610k#$  
^&rb I,D  
//读取保存的下载信息(文件指针位置) z:G9Uu3H(  
private void read_nPos() E0DEFB  
{ _gGy(`  
try{ ? sewU9*  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); L2h+[f  
int nCount = input.readInt(); 6~/H#8Kdn  
nStartPos = new long[nCount]; P*T)/A%4  
nEndPos = new long[nCount]; )eV40l$ M  
for(int i=0;i<nStartPos.length;i++) w9PY^U.Y3e  
{ ::`j@ ]  
nStartPos = input.readLong(); GQZUC\cB  
nEndPos = input.readLong(); J;kbY9e  
} j5)qF1W,  
input.close(); 7=AKQ7BB>b  
} vZDQ@\HrC  
catch(IOException e){e.printStackTrace ();} ,`7GI*Vq  
catch(Exception e){e.printStackTrace ();} 5UM[Iz  
} 5,((JxX$  
H= y-Y_R  
Le'\x`B  
private void processErrorCode(int nErrorCode) j&mL]'Zy  
{ PYf`a`dH  
System.err.println("Error Code : " + nErrorCode); A{o{o++  
} v: 0i5h&M  
]1[;A$7  
XN0Y#l  
//停止文件下载 V V4_  
public void siteStop() k1H0hDE  
{ C/Z"W@7#;  
bStop = true; TatyD**(  
for(int i=0;i<nStartPos.length;i++) yEny2q}  
fileSplitterFetch.splitterStop(); -&A[{m<,>  
Mww]l[1'EL  
D{l((t3=T  
} h5gXYmk  
} 9 $S,P|  
//负责部分文件的抓取 u~kwNN9t3  
**FileSplitterFetch.java p{J_d,JH  
*/ K]oPh:E  
package NetFox; ] 6gu  
rh_({rvQ  
v8IL[g6"  
import java.io.*; Z9D4;1  
import java.net.*; vSA%A47G  
8#Z5-",iw  
/ fq6-;co+  
public class FileSplitterFetch extends Thread { PS22$_}   
("oA{:@d  
M5V1j(URE  
String sURL; //File URL ~e+w@ lK  
long nStartPos; //File Snippet Start Position gsp 7N  
long nEndPos; //File Snippet End Position KIFx &A  
int nThreadID; //Thread's ID "/fs%F  
boolean bDownOver = false; //Downing is over h;KK6*Z*$E  
boolean bStop = false; //Stop identical S\ZAcz4  
FileAccessI fileAccessI = null; //File Access interface C5MqwNX  
OT@yPG  
DN<M?u]  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?<6@^X"  
{ #Z0-8<\  
this.sURL = sURL; (kY@7)d'e  
this.nStartPos = nStart; 9DPb|+O-  
this.nEndPos = nEnd; %N1"* </q  
nThreadID = id; djGs~H>;U_  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 cWM:  
} 5NFRPGYX  
a%*_2#  
-K^41W71  
public void run() tgB=vIw?3  
{ +99Bi2H}o  
while(nStartPos < nEndPos && !bStop) P7UJ-2%Y+  
{ cJ/4G l  
JnHNkCaU  
~of,,&  
try{ wASX\D }  
URL url = new URL(sURL); ="2/\*.SL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _r5wF(Y?7  
httpConnection.setRequestProperty("User-Agent","NetFox"); - wWRm  
String sProperty = "bytes="+nStartPos+"-"; U(Z!J6{c  
httpConnection.setRequestProperty("RANGE",sProperty); I=odMw7Hj  
Utility.log(sProperty); TzY *;  
S(tEw Xy  
URQ@=W7  
InputStream input = httpConnection.getInputStream(); dN0mYlu1|  
//logResponseHead(httpConnection); & g$rrpTzv  
xW0Z'==  
)# PtV~64  
byte[] b = new byte[1024]; AIv<f9*.:  
int nRead; *m&%vj.Kc  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }Aw47;5q;  
{ ^Et ,TF\  
nStartPos += fileAccessI.write(b,0,nRead); u GAh7Sop  
//if(nThreadID == 1) A _i zSzC1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .R\p[rv&  
} FJF3B)Va|  
q0g1E Jar  
;AJ< LC  
Utility.log("Thread " + nThreadID + " is over!"); :~er h}~ps  
bDownOver = true; ` yYvYc  
//nPos = fileAccessI.write (b,0,nRead); zb?kpd}r  
} Z)5klg$c  
catch(Exception e){e.printStackTrace ();} >3!DOv   
} q}s K  
} qw2)v*Fn  
d EI a=e|  
#'8)u)!  
//打印回应的头信息 6i-*N[!U  
public void logResponseHead(HttpURLConnection con) )WmZP3$^TX  
{ 1\IZcJ {  
for(int i=1;;i++) t2U$m'(A&  
{ vbedk+dd?A  
String header=con.getHeaderFieldKey(i); m#;.yR  
if(header!=null) kU1 %f o  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 7JS#a=D#  
Utility.log(header+" : "+con.getHeaderField(header)); &urb!tQ>&  
else gW}}5Xq  
break; eVrNYa1>H  
} (rIXbekgB  
} JSRg?p\  
v4D!7 t&v"  
s.KOBNCFa  
public void splitterStop() \6i 9q=  
{ jceHK l  
bStop = true; L\YZT| K(  
} 8:<1|]]  
wa2~C [  
a}w&dE$!-  
} c[Yq5Bu{y  
GajI\_o  
 t9]r  
/* cmae&Atotw  
**FileAccess.java v >NTh  
*//文件访问(定位,写) sY_fq.Z  
package NetFox; Xz" JY  
import java.io.*; bu;vpNa  
=O;eY?  
P^ by'b+zI  
public class FileAccessI implements Serializable{ *x5o=)Y  
oUCVd}wH  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 %bN"bxv^  
RandomAccessFile oSavedFile; JLt{f=`%F  
long nPos; L-SdQTx_  
]2g5Ka[>w  
X9SJ~n  
public FileAccessI() throws IOException aL{EkiR  
{ 5t TLMZ`o  
this("",0); j_hjCQ  
} 2 e )  
gZ=) qT]Pj  
k#BU7Exij  
public FileAccessI(String sName,long nPos) throws IOException (]o FB$  
{ YK7gd|LR]  
oSavedFile = new RandomAccessFile(sName,"rw"); Ed4_<:  
this.nPos = nPos; 5QNBB|X@  
oSavedFile.seek(nPos); =xl7vHn7  
} ?NQD#  
6CCZda@  
+HYN$>  
public synchronized int write(byte[] b,int nStart,int nLen) N <ja6Ac  
{ Id; mn}+~  
int n = -1; Q^\{Zg)p  
try{ ;H`=):U  
oSavedFile.write(b,nStart,nLen); Ti /;|lP@  
n = nLen; ,80jMs  
} Z(#XFXd  
catch(IOException e) 34HFrMi  
{ X}kVBT1w+x  
e.printStackTrace (); ^a: Saq-}  
} ikeJDKSG  
@?(nwj~ s`  
+ ?[ ACZF  
return n; QJb7U5:B+  
} `1}HWLBX.  
\3,$YlG  
%jYQ  
} 8.6no  
9N`+ O  
yN%3w0v  
/* Q3'(f9 x  
**SiteInfoBean.java ] `b<"  
*/ [J(@$Qix  
package NetFox; o%y+Y;|?J  
bL6L-S  
R V_MWv  
public class SiteInfoBean { d{vc wZQ  
ot&j HS'  
;))[P_$zB  
private String sSiteURL; //Site's URL :T8u?@ .  
private String sFilePath; //Saved File's Path qen44;\L  
private String sFileName; //Saved File's Name  WMt&8W5  
private int nSplitter; //Count of Splited Downloading File ~7FEY0/  
P*?d6v,r  
T9&,v<f  
public SiteInfoBean() zzDNWPzsA  
{//nSplitter的缺省值为5 e)fJd*P  
//default value of nSplitter is 5 HPv&vdr3  
this("","","",5); %`t]FV^#  
} *rujdQf  
$_%2D3-;D  
'US8"83  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) )of5229  
{ &z{dr ~  
sSiteURL= sURL; *RUd!]bh  
sFilePath = sPath; VuYWb)@  
sFileName = sName; ^H@!)+ =  
this.nSplitter = nSpiltter; oi%5t)VsS  
a,F8+ Pb>  
81%qM7v9H  
} WHdqO8  
j};pv2  
,4h! "c  
public String getSSiteURL() 8VBkIYgb  
{ v)v{QNQp^  
return sSiteURL; a!SR"3 k  
} KBUAdpU8  
QBN=l\m+  
0e7O#-  
public void setSSiteURL(String value)  h;:Se  
{ g(z#h$@S  
sSiteURL = value; Q}k_#w  
} 7k[`]:*o  
=]2RC1#}e  
MfZ}xu  
public String getSFilePath() ~0Q\Lp);  
{ @5dB b+0J  
return sFilePath; &D&5UdN x  
} PG-cu$\??  
VygXhh^7\  
c DEe?WS  
public void setSFilePath(String value) ~I8"l@H>  
{ q^T&A[hMPx  
sFilePath = value; ID{Pzmt-  
} 8O;rp(N.n  
}SJLBy0  
sbq44L)  
public String getSFileName() H8=vQy  
{ /(WX!EEsB  
return sFileName; }AeE|RNc  
} Npg5Z%+y  
0N} wD-  
ho SU`X  
public void setSFileName(String value) }y -AoG  
{ Xy KKD&j  
sFileName = value; s1*WK&@  
} D; 35@gtj  
\e5,`  
JVIcNK)  
public int getNSplitter() (0+GLI8  
{ OA8b_k~  
return nSplitter; L;(3u'  
} u0 'pR# m|  
.-1{,o/&Q  
!MG>z\:  
public void setNSplitter(int nCount) (fLbg,  
{ =>9.@`.  
nSplitter = nCount; NiJ?no  
} gC,0+Y~  
} _,-M8=dL%*  
-$!Pf$l@  
Kw5+4R(5  
/* _`Yvfz3  
**Utility.java _QtQPK\+  
*/ (w7cdqe  
package NetFox; WTy8N  
uvK%d\d  
O.40^u~  
public class Utility { vng8{Mx90*  
h}VYA\+<B  
5F_:[H =   
public Utility() gCBZA;/  
{ m#}{"d&J  
v.8S V]  
;hJ/t/7  
} 4>ce,*B1  
~4 xBa:*z  
//线程睡眠 ~Sem_U`G  
public static void sleep(int nSecond) %cjGeS6}  
{ BKlc{=  
try{ gt~2Br4  
Thread.sleep(nSecond); <?va) ou  
} =rtA{g$)+  
catch(Exception e) Q9'p3"yoE  
{ 3b/vyZF  
e.printStackTrace (); #di_V"  
} RlPByG5K  
} lL+^n~g  
W2LblZE!  
//日志 25@j2K(  
public static void log(String sMsg) _w,0wn9N$  
{ )aA9z(x  
System.err.println(sMsg); JGNxJ S<]  
} 59J$SE  
:H8L(BsI  
CH+&  
public static void log(int sMsg) . t%Vx  
{ R3!vS+5rR  
System.err.println(sMsg); HnY"6gTNK  
} "}aM*(l+\  
} z7pXpy \  
KcF+!;:  
Y_YIJ@  
/* YqCK#zT/  
**TestMethod.java 6zZR:ej  
*/ ]@}BdMlHp  
package NetFox; q;~>h  
]c=1-Rl  
i1 Sc/  
public class TestMethod { AFUl   
_%%"Y}  
myX0<j3G5  
public TestMethod() >^HTghgRD  
{ ///xx/weblogic60b2_win.exe w:+#,,rwzV  
try{ X[Gk!d r#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); QNwAuH T  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); zFQkUgb  
SiteFileFetch fileFetch = new SiteFileFetch(bean); fzG1<Gem  
fileFetch.start(); ]H7Mx\  
} /\I%)B47^9  
catch(Exception e){e.printStackTrace ();} <5vB{)Tq  
;!sGfrs 0$  
r@UY$z  
} 0! %}  
80>!qG  
{S(T1ua  
public static void main(String[] args) $s!meg@s  
{ uL AXN  
new TestMethod(); " CoR?[,x  
} jn Y3G  
} ]}y'3aW  
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