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http断点续传简单实现(java)

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/* 1Imb"E  
**SiteFileFetch.java JDMsco+j5  
*/ l)0yv2[h  
package NetFox; Xb*>7U/'T  
import java.io.*; lU3Xd_v O  
import java.net.*; %x$mAOUv  
0I.!  
'V Y\ut  
public class SiteFileFetch extends Thread { )4/UzR$  
,!^w  
|1 LKdP  
SiteInfoBean siteInfoBean = null; //文件信息Bean ZW8;?# _  
long[] nStartPos; //开始位置 gkv,Om  
long[] nEndPos; //结束位置 e}"k8 ./  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 1]jUiX=T  
long nFileLength; //文件长度 ,PyPRPk  
boolean bFirst = true; //是否第一次取文件 rg+3pX\{  
boolean bStop = false; //停止标志  M Xl!  
File tmpFile; //文件下载的临时信息 z:W1(/W~  
DataOutputStream output; //输出到文件的输出流 ~leLQsZ  
:&D$Q 4  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Z@:R'u2Lk  
public SiteFileFetch(SiteInfoBean bean) throws IOException }pPt- k  
{ }Qvoms<k  
siteInfoBean = bean; wsCT9&p  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ok9G9|HA  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %6<2~  
if(tmpFile.exists ())  *FoPs  
{ QnDLSMx)  
bFirst = false; fm,:8%  
read_nPos(); V=H}Ecd  
} `_+m3vHG  
else QmB,~x{j>  
{ Zk=*7?!!  
nStartPos = new long[bean.getNSplitter()]; %kh#{*q$  
nEndPos = new long[bean.getNSplitter()]; WR/o @$/  
} FxCZRo&  
+Qh[sGDdY  
dGW {l]N  
!K3})& w  
} HDmx@E.@  
F{k$Atb?g/  
+T0op4  
public void run() MA\m[h]  
{ 7tSJniB  
//获得文件长度 {p`mfEE (  
//分割文件 mC i[Ps  
//实例FileSplitterFetch $Y6I_U  
//启动FileSplitterFetch线程 J I<3\=:+  
//等待子线程返回 Ia629gi5s  
try{ Rj[ hhSx 2  
if(bFirst) 0"EoC  
{ d0(Cn}m"c  
nFileLength = getFileSize(); &E bI Op  
if(nFileLength == -1)  ep+  
{ ?Jt$a;  
System.err.println("File Length is not known!"); 8|O=/m^]  
} bGv* -;*  
else if(nFileLength == -2) M`GP^Ta  
{ <i{K7}':  
System.err.println("File is not access!"); q-3]jHChh  
} xXX/]x>  
else 5h0>!0  
{ pb#mg^8  
for(int i=0;i<nStartPos.length;i++) XCDSmZ  
{ AoBoFZLl3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); CSL#s^4T  
} >1 @Ltvm  
for(int i=0;i<nEndPos.length-1;i++) Y\xUT>(J7  
{ _\.{6""  
nEndPos = nStartPos[i+1]; s5l3V2k  
} =SAV|  
nEndPos[nEndPos.length-1] = nFileLength; o(*F])d;  
} "PMQyzl  
} *8bK')W  
f~ =r*&U  
f1mHN7hxW  
//启动子线程 A\z`c e!  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8eluO ?p  
for(int i=0;i<nStartPos.length;i++) -v+&pG?m  
{ `>6T&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M;+IZr Wkl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), +4et7  
nStartPos,nEndPos,i); 2j&v;dmh<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F8<"AI  
fileSplitterFetch.start(); g5+7p@'fV  
} a(;!O}3_)(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *5k+t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); a?F!,=F  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }7ehF6  
nEndPos = " + nFileLength); m:uPEpcU  
// fileSplitterFetch[nPos.length-1].start(); rn8cdM N  
+r]zs^'  
hmpr%(c`  
//等待子线程结束 n[,XU|2  
//int count = 0; C&+6>L@  
//是否结束while循环 Ipe n  
boolean breakWhile = false; -)v@jlg02  
w##^}nHOR  
${I*nh>=  
while(!bStop) ?>$l  
{ #Exp51  
write_nPos(); * **a2Z/(  
Utility.sleep(500); aI3CNeav  
breakWhile = true; eF~dQ4RZ  
NBYH;h P  
Ag9?C*  
for(int i=0;i<nStartPos.length;i++) d%_OT0Ei  
{ DY\J[l<<  
if(!fileSplitterFetch.bDownOver) NI aFI(  
{ M5g\s;y;  
breakWhile = false; T 2F6)e  
break; =>iA gp'#  
} Qkcjr]#^$  
} j$Ab>}g]  
if(breakWhile) j8Cho5C  
break; !cSq+eD  
HCWNo  
oD9^ID+  
//count++; =LkR!R=  
//if(count>4) l +*&:Q/  
// siteStop(); U75Jp%bL  
} I%j_"r9-I  
v&a4^s  
gw36Ec<M  
System.err.println("文件下载结束!"); ;G\8jP'   
} X] %itA  
catch(Exception e){e.printStackTrace ();} 8NBT|N~N  
} (wRgus  
c(#;_Ve2P  
 -I.d}[  
//获得文件长度 UCW V2Mu  
public long getFileSize() _>+8og/%@  
{ zcrY>t#l  
int nFileLength = -1; Dre2J<QL  
try{ ",6M)3{|c  
URL url = new URL(siteInfoBean.getSSiteURL()); -m *Sq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t>=fTkB  
httpConnection.setRequestProperty("User-Agent","NetFox"); N IdZ  
%D$]VSP;  
%yBB?cp+_  
int responseCode=httpConnection.getResponseCode(); s\!>"J bAQ  
if(responseCode>=400) 2c6g>?  
{ 86]p#n_>Fv  
processErrorCode(responseCode); KlRr8 G!Z  
return -2; //-2 represent access is error *(C(tPhC  
} ~t9tnLc$  
C|pdv  
fU=B4V4@  
String sHeader; .7K7h^*F  
'AN>`\mR$  
1-lu\"H`  
for(int i=1;;i++) cufH?Xg<  
{ , ]bB9tid  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F~ h7{@\  
//Utility.log(in.readLine()); '%q$` KDb  
sHeader=httpConnection.getHeaderFieldKey(i); AGLscf.  
if(sHeader!=null) 9$2/MT't  
{ 'yMF~r3J  
if(sHeader.equals("Content-Length")) /p8dZ+X  
{ 0 $,SF3K  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0u\GO;  
break; uEX!xx?Q#  
} .l.a(_R  
} ]]zPq<b2  
else FCnm1x#  
break; "'D=,*  
} /`mks1:pK  
} :Nz9xD$S5  
catch(IOException e){e.printStackTrace ();} 6I%5Q4Ll  
catch(Exception e){e.printStackTrace ();} l<A|d{"]  
uD^cxD  
[eC2"&}  
Utility.log(nFileLength); )ubiB^g'm  
MdvcnaCG  
%44leINx  
return nFileLength; 8uWa=C)  
} 3.*8)NW  
p>4-s, W  
NuQdSj_>  
//保存下载信息(文件指针位置) "g1)f"pL  
private void write_nPos() ~^1{B\I  
{ d~i+ I5  
try{ JU)dr4S?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); S[J}UpV  
output.writeInt(nStartPos.length); <$IM8Y5p+w  
for(int i=0;i<nStartPos.length;i++) NA~Vg8  
{ c}2jmwq  
// output.writeLong(nPos); AJF#Aw `o  
output.writeLong(fileSplitterFetch.nStartPos); ui/a|Q  
output.writeLong(fileSplitterFetch.nEndPos); =`H@%  
} gcl5jB5)>  
output.close(); 1pgU}sRk  
} Xg;}R:g '  
catch(IOException e){e.printStackTrace ();} .nx2";oi  
catch(Exception e){e.printStackTrace ();} woK&q7Vn  
} DK: o]~n  
[q8 P~l  
+[\FD; >  
//读取保存的下载信息(文件指针位置) mc? Vq  
private void read_nPos() J;8IY=  
{ @~"h62=] -  
try{ $#9;)8J  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 5>D>% iaHv  
int nCount = input.readInt(); :&V h?  
nStartPos = new long[nCount]; l)1r+@) \  
nEndPos = new long[nCount]; U@uGNMKR  
for(int i=0;i<nStartPos.length;i++) jtW!"TOY  
{ CVL3VT1j0  
nStartPos = input.readLong(); 3u*4o=4e  
nEndPos = input.readLong(); L.*M&Ry  
}  3KlbP  
input.close(); K8GP@yD]M  
} 1mOh{:1u  
catch(IOException e){e.printStackTrace ();} Vt:~q{9*k  
catch(Exception e){e.printStackTrace ();} YIQ 4t  
} aBNc(?ri  
\ `~Ly-  
3Q.#c,`jV  
private void processErrorCode(int nErrorCode) '7hu 2i5  
{ P}n_IV*@  
System.err.println("Error Code : " + nErrorCode); DgId_\Ze  
} Z>:NPZODf  
qr"3y  
5q3JI  
//停止文件下载 =.Pw`.  
public void siteStop() . qO@Q=  
{ Z'`<5A%;  
bStop = true; GfoLae  
for(int i=0;i<nStartPos.length;i++) !Xf5e*1IS  
fileSplitterFetch.splitterStop(); 4&<oFW\r  
.o(fe\KHf  
Dp,L/1GQ8  
} ?+@n3]`0  
} |W,& Hl7  
//负责部分文件的抓取 4;e5H_}Oo  
**FileSplitterFetch.java sJL&:!}V>  
*/ 4tRYw0f47  
package NetFox; `i3NG1 v0  
+~m46eI  
I8hz(2jI  
import java.io.*; S 6@u@C  
import java.net.*; }7|1  
T*Y~\~Jhu  
cLpYW7vZ[  
public class FileSplitterFetch extends Thread { W <9T0sZ  
9UdM`v)(  
Y2N>HK0  
String sURL; //File URL k9sh @ENy  
long nStartPos; //File Snippet Start Position w1EXh  
long nEndPos; //File Snippet End Position T"{>t  
int nThreadID; //Thread's ID ugdQAg  
boolean bDownOver = false; //Downing is over M8kPj8}{  
boolean bStop = false; //Stop identical 2e+UM$  
FileAccessI fileAccessI = null; //File Access interface pnl{&<$C%C  
9vuyv*-}e  
*'Sd/%8{  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException l: HTk4$0  
{ s 1 A.+  
this.sURL = sURL; ~Z\8UsVN  
this.nStartPos = nStart; DrKP%BnS  
this.nEndPos = nEnd; bkOv2tZ  
nThreadID = id; :%l TU  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 I&D5;8  
} ~8'sBT  
}*M6x;t  
,Xu-@br{  
public void run() "Gsc;X'id  
{ Z;h t  
while(nStartPos < nEndPos && !bStop) $SlIr<'*"  
{ H4WP~(__  
9P1OP Xv*p  
tqz3zIQ  
try{ k :(SCHf  
URL url = new URL(sURL); b.2aHu( 3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G?L HmTHg  
httpConnection.setRequestProperty("User-Agent","NetFox"); lp.ldajN  
String sProperty = "bytes="+nStartPos+"-"; @x*c1%wg  
httpConnection.setRequestProperty("RANGE",sProperty); kYzIp  
Utility.log(sProperty); vLv@&lMW  
!y\'EW3|G  
\T4v|Pw\  
InputStream input = httpConnection.getInputStream(); W>${zVu  
//logResponseHead(httpConnection); 52@C9Q,  
8H%;WU9-  
wg9t)1k{e  
byte[] b = new byte[1024]; 1h^:[[!c  
int nRead; iowTLq!?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) xs{3pkTYD  
{ ;;!yC  
nStartPos += fileAccessI.write(b,0,nRead); 3U<cWl@  
//if(nThreadID == 1) QVv#fy1"6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j_qbAP  
} bZ dNibN  
GoJ.&aH $  
sfpZc7  
Utility.log("Thread " + nThreadID + " is over!"); mUNn%E:7@{  
bDownOver = true; +jAGGv^)  
//nPos = fileAccessI.write (b,0,nRead); MU($|hwiL  
} :">!r.Q  
catch(Exception e){e.printStackTrace ();} 6Pz4\uE=  
} piJu+tUy  
} RFi S@.7  
?qmRbDI  
<ykU6=  
//打印回应的头信息 qSM|hHDo)  
public void logResponseHead(HttpURLConnection con) R   
{ 5GI,o|[s6  
for(int i=1;;i++) iJ ($YvF4  
{ 9)h"-H;5:  
String header=con.getHeaderFieldKey(i); WltQ63u  
if(header!=null) uFX#`^r`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &pP;Neh;  
Utility.log(header+" : "+con.getHeaderField(header)); "SNn^p59k  
else 8Q.T g.  
break; /74QMx?  
} rF3wx.  
} u0}vWkn\4  
]MqMQLG0t  
]V[q(-Jk  
public void splitterStop() M=8.Bp|Ye  
{ 5us:adm[pD  
bStop = true; 2+RUTOv/d  
} Y@NNrGDkT*  
2% MC Yn  
[xK3F+  
} MOQ6 :  
U2ohHJ``  
UBv,=v  
/* Yc`o5Q\>  
**FileAccess.java a Fl;BhM  
*//文件访问(定位,写) T tfo^ksw  
package NetFox; HNb/-e ,"  
import java.io.*; UZWioxsKr+  
5A,K6f@:g  
{IjF+@I  
public class FileAccessI implements Serializable{ hE &xE;  
=R^%(Py  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 R &n Pj~  
RandomAccessFile oSavedFile; 3Lfqdqj  
long nPos; rExnxQ<e  
l.(v^3:X  
\9.bt:k@OT  
public FileAccessI() throws IOException a`wc\T^  
{ C/_ZUF(V  
this("",0); 2d>z1%'  
} zp6C3RG(  
ay4 %  
.L+6 $8m  
public FileAccessI(String sName,long nPos) throws IOException {WJm  
{ 0}<|7?  
oSavedFile = new RandomAccessFile(sName,"rw"); y3vdUauOn  
this.nPos = nPos; #`~C)=-  
oSavedFile.seek(nPos); x!hh"x  
} Dxtp2wu%t  
oph}5Krd)  
Lk|hQ  
public synchronized int write(byte[] b,int nStart,int nLen) at@G/?  
{ X enE^e+9  
int n = -1; *=) cQeJ  
try{ t1]K<>g  
oSavedFile.write(b,nStart,nLen); i)\ L:qF5  
n = nLen; "RedK '7g  
} YP 6` L  
catch(IOException e) 6=kEyJT'  
{ 6d:zb;Iz  
e.printStackTrace (); S2E8G q9  
} rDl*d`He!  
"<6G6?sz  
S&e0u%8mc  
return n; .nTwPrG  
} lVd^ ^T*fh  
T=<@]$?  
@efh{  
} =pr` '  
# q~e^A b  
Y$o< 6[7  
/* #akpXdXs  
**SiteInfoBean.java zofa-7'Bn  
*/ w2Us!<x  
package NetFox; 90Pl$#cb2  
16w|O |^<  
m&xW6!x  
public class SiteInfoBean { GC<l#3+  
&\#sI9  
,NOsFO-`<  
private String sSiteURL; //Site's URL I?]ohG K  
private String sFilePath; //Saved File's Path B3:ez jj  
private String sFileName; //Saved File's Name q6@Lp^f  
private int nSplitter; //Count of Splited Downloading File e%@'5k\SK  
*RDn0d[  
tG:25T0  
public SiteInfoBean() kh!FR u h  
{//nSplitter的缺省值为5 {mm)ay|M  
//default value of nSplitter is 5 kd>hhiz|  
this("","","",5); !6n_}I-W  
} >l]Xz*HE  
5rwu!Y;7*  
Ua<5U5  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 6q*9[<8  
{ t;\kR4P  
sSiteURL= sURL; ) dn(G@5  
sFilePath = sPath; cT<1V!L4  
sFileName = sName; +:8fC$vVfC  
this.nSplitter = nSpiltter; H0:E(}@   
O&vVv _zh  
bT\1>  
} * ;-*x6  
J{'>uD.@  
^.1)};i  
public String getSSiteURL() 4^:\0U F  
{ #G .ulX  
return sSiteURL; .Fs7z7?Y  
} mi ik%7>W  
? Fi=P#  
e 63uLWDT  
public void setSSiteURL(String value) O|\J}rm'  
{ ! _f9NK  
sSiteURL = value; E4xj?m^(y=  
} M2d$4-<  
=V-A@_^!c  
%Da8{%{`Pc  
public String getSFilePath() 34z"Pm  
{ R,gR;Aarw  
return sFilePath; |h-QP#]/  
} 4P'*umJi  
H+1-]'g`  
ZU85P0  
public void setSFilePath(String value) jB`,u|FG  
{ D'7SAFOM  
sFilePath = value; ?sab*$wG  
} X59: C3c  
'L 8n-TyL  
pczug-nB  
public String getSFileName() V`X2> -Ex  
{ 1|RANy  
return sFileName; <PapskO>  
} /~}}"zx&  
[ad@*KFxy3  
* vflscgt  
public void setSFileName(String value) cJN7bA {  
{ W=vG$  
sFileName = value; 1>*#%R?W  
} : e]a$  
F5?m6`g?  
 5V6G=H  
public int getNSplitter() aEM%R<e  
{ !+1<E*NQ S  
return nSplitter; W{%TlN  
} KB%"bqB|  
H18Tn!RDS  
d`P7}*; `  
public void setNSplitter(int nCount) }lh I\q  
{ 0*rQ3Z  
nSplitter = nCount; |o{:ZmzM  
} [K9'<Qnu  
} 2Or'c`|  
'ixwD^x  
vI2^tX 9  
/* x$IX5:E#e  
**Utility.java %1H[Wh(U  
*/ q<\,  
package NetFox; 2@9Tfm(=  
#bMuvaP~  
/4c\K-Z;  
public class Utility { L!rw[x  
p89wNSMl[  
{U!8|(  
public Utility() 8S%52W|  
{ [21 =5S  
kB/D!1 "  
Qk\A c  
} eln&]d;  
0(mkeIzJt/  
//线程睡眠 ZkAU17f  
public static void sleep(int nSecond) jgbLN/_{  
{ odPL {XFj  
try{ o>/YAX:.!T  
Thread.sleep(nSecond); aemc2b*  
} c%&: 6QniZ  
catch(Exception e) : y5<go8e  
{ zY,r9<I8_x  
e.printStackTrace (); T(e!_VY|m  
} rypTKT|U;  
} >)spqu]  
|_`E1Y}}  
//日志 Eve.QAl|  
public static void log(String sMsg) O>^C4c!  
{ r9 ui|>U"  
System.err.println(sMsg); 3jlh}t>$l  
} Fb7#<h  
t: #6sF  
HuwU0:*  
public static void log(int sMsg) 6 G3\=)  
{ 0TGLM#{  
System.err.println(sMsg); |P -8HlOr  
} %,D<O,N  
}  A-4h  
/ C>wd   
q~3,yyu  
/* EmODBTu+  
**TestMethod.java +m8!U=Zi  
*/ vgUb{D  
package NetFox; =,Dqqf  
,`gl&iB  
<^zHE=h"  
public class TestMethod { P?t" jKp'  
f. FYR|%tq  
hir4ZO%Zt  
public TestMethod() &|!7Z4N  
{ ///xx/weblogic60b2_win.exe SQqD:{#g"  
try{ 3'^k$;^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6(G?MW.  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _cc#Qlw 7  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Q5FM8Q  
fileFetch.start(); R,|d`)T  
} xf b]b2  
catch(Exception e){e.printStackTrace ();} x\J#]d.  
#Sa27$&.>  
,:??P1  
} 2n `S5(V  
VY)9|JJCO  
h=(DX5:A  
public static void main(String[] args) IdXZoY  
{ nzmDA6d  
new TestMethod(); xia|+  
} t`+'r}=d  
} * 1Od-3  
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