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http断点续传简单实现(java)

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/*  _!E)a  
**SiteFileFetch.java s> JWNP  
*/ O^KIB%}fu  
package NetFox; ?k+>~k{}a  
import java.io.*; s}bv o  
import java.net.*; ,O`~ D~$  
nP#|JRn=  
rA[wC%%  
public class SiteFileFetch extends Thread { LW*v/`@  
Mh8s@g  
W \XLf,_+  
SiteInfoBean siteInfoBean = null; //文件信息Bean < m/@_"  
long[] nStartPos; //开始位置 10{zF_9yx  
long[] nEndPos; //结束位置 )=%TIkeF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ##BfI`FJ  
long nFileLength; //文件长度 Ih^ziDcW  
boolean bFirst = true; //是否第一次取文件 Q<T+t0G\O-  
boolean bStop = false; //停止标志 ?V' zG&n@  
File tmpFile; //文件下载的临时信息 cA{7*=G?  
DataOutputStream output; //输出到文件的输出流 J1"16Uu  
wAF<_NG#  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) J3c8WS{:  
public SiteFileFetch(SiteInfoBean bean) throws IOException Zce/&  
{ l'twy$V4|~  
siteInfoBean = bean; ayr CLv  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;%!]C0 ?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $HP<C>^Z8  
if(tmpFile.exists ()) yhh\?qqy  
{ z~Is E8  
bFirst = false; @ ('/NjTZ  
read_nPos(); CJe~>4BT  
} 4^_'LiX3[  
else ;3Z6K5z*f  
{ %JPBD]&M  
nStartPos = new long[bean.getNSplitter()]; x@? YS  
nEndPos = new long[bean.getNSplitter()]; =H;F{J "  
} !pxOhO.V  
{3eg4j.Z  
fzZ`O{$8  
!z2KQ 4C  
} X{ f#kB]w  
&9F(C R  
_m*FHi  
public void run() 36UUt!}p  
{ U5yBU9\G  
//获得文件长度 EGxCNB  
//分割文件 =:_DXGW2H  
//实例FileSplitterFetch 9y?)Ga  
//启动FileSplitterFetch线程 odh cU5  
//等待子线程返回 lw=!v%L  
try{ q#\4/Dt  
if(bFirst) D+"+m%^>C  
{ v4vIcHDs  
nFileLength = getFileSize(); 'nN'bVl/  
if(nFileLength == -1) ;S+]Z!5LT  
{ x&*2R#Ai  
System.err.println("File Length is not known!"); u{5+hZ  
} xl ,(=L]  
else if(nFileLength == -2) L~{3W  
{ W]I+Rlv)U  
System.err.println("File is not access!"); Wgb L9'}B  
} I6Ga'5bV  
else W9:(P  
{ GD0Q`gWNe  
for(int i=0;i<nStartPos.length;i++) p mUG`8SY  
{ vbEO pYCS  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1.I58(0~+  
} f"R'Q|7D  
for(int i=0;i<nEndPos.length-1;i++) 5+[ 3@  
{ +*Zjo&pc  
nEndPos = nStartPos[i+1]; 4WP@ F0@n3  
} ne 8rF.D  
nEndPos[nEndPos.length-1] = nFileLength; 6)yi^v  
} "=,IbC  
} )`K!XX$%  
dO4J f9)  
p(. z#o#  
//启动子线程 FK~*X3'  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 65U&P5W  
for(int i=0;i<nStartPos.length;i++) Ru@ { b`  
{ -8Hv3J'=  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ffR<G&"n~b  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), z!aU85y  
nStartPos,nEndPos,i); YK>?;U+|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }///k]_Sh  
fileSplitterFetch.start(); ){4!  
} zKfY0A R  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %+@<T<>J<k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); EIF"{,m  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6cX Z3;a  
nEndPos = " + nFileLength); s9,Z}]Th  
// fileSplitterFetch[nPos.length-1].start(); Ou{VDE  
zg$NrI&  
m1Xc3=Y  
//等待子线程结束 -{E S 36  
//int count = 0; FD/=uIXH2  
//是否结束while循环 @  \*Zq  
boolean breakWhile = false; IlZ$Jd  
!md1~g$rN  
6 #k mV  
while(!bStop) y wmC>`0p  
{ [:8+ +#KD  
write_nPos(); E|y  
Utility.sleep(500); @#"6_{!j_X  
breakWhile = true; B-h@\y  
4 {+47=n  
ZG( Pz9{K  
for(int i=0;i<nStartPos.length;i++) ^ /)%s3  
{ b\p2yJ\  
if(!fileSplitterFetch.bDownOver) mD7kOOMY  
{ 3&zcdwPj  
breakWhile = false; ^00C"58A  
break; =>L2~>[  
} !+ (H(,gI  
} =-]NAj\  
if(breakWhile) aSIoq}c(  
break; h/]));p  
dg#w!etB  
R%"'k<`#  
//count++; |LirjC4  
//if(count>4) <=%=,Yk  
// siteStop();  ?%*p!m  
} :kvQ3E0  
V^< Zs//7  
pYh\l.@qf  
System.err.println("文件下载结束!"); yM*_"z!L  
} Rbcu5.6  
catch(Exception e){e.printStackTrace ();} Jk57| )/  
} T@d4NF#  
O@a7MzJ  
)!Zm*(  
//获得文件长度 lsU`~3nr  
public long getFileSize() { a_&L  
{ 2E0oLl[  
int nFileLength = -1; D~)bAPAD  
try{ 3x)jab  
URL url = new URL(siteInfoBean.getSSiteURL()); D!mx&O9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f1q0*)fk  
httpConnection.setRequestProperty("User-Agent","NetFox"); \7G.anY  
[y"Yi PK  
yC[Q-P*rG  
int responseCode=httpConnection.getResponseCode(); d 9]zB-A  
if(responseCode>=400) 9yp'-RKjw  
{ B#4'3Y-3  
processErrorCode(responseCode);  Y+Cv9U0  
return -2; //-2 represent access is error nnCz!:9p  
} '^(qlCI  
D{6<,#P{w  
PV-B<Y  
String sHeader; =g?k`v p  
3*N0oc^m  
aX? tnDv  
for(int i=1;;i++) W8M(@* T  
{ Z<#h$XUA  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Lc0=5]D   
//Utility.log(in.readLine()); ucFfxar"  
sHeader=httpConnection.getHeaderFieldKey(i); |}Z2YDwO/  
if(sHeader!=null) 4jW <*jM  
{ KgXu x-q  
if(sHeader.equals("Content-Length")) .f`KP!p.  
{ "Iacs s0;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); jXIVR'n(  
break; \pXo~;E\  
} *mn"G K6  
} 7=a e^GKo  
else _% i!LyG  
break; 0~e6\7={  
} (?ZS 9&y}  
} 4ULdf|oP"  
catch(IOException e){e.printStackTrace ();} c| X }[  
catch(Exception e){e.printStackTrace ();} Q}#xfrprF  
y<PQ$D)  
zA| )9Dq  
Utility.log(nFileLength); ~-'-<-  
!J[!i"e  
wI?AZd;`'  
return nFileLength; :VE0eJ]J6  
} );{76  
;#=y5Q4  
'`j MNKn\  
//保存下载信息(文件指针位置) OV`li#H  
private void write_nPos() J:G{  
{ W&7(  
try{ goc; .~?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); eQ<G Nvm  
output.writeInt(nStartPos.length); yh{U!hG  
for(int i=0;i<nStartPos.length;i++) AsR}qqG  
{ Wz;@Rl|F  
// output.writeLong(nPos); l0eh}d  
output.writeLong(fileSplitterFetch.nStartPos); %`lLX/4~  
output.writeLong(fileSplitterFetch.nEndPos); >]kZ2gVt  
} MJU*Sq  
output.close(); 68~5Dx  
} Zi<(>@z2  
catch(IOException e){e.printStackTrace ();} DuIgFp  
catch(Exception e){e.printStackTrace ();} ~|{_Go{ Q  
} _O&P!hI  
37 *2/N2  
zb.sh  
//读取保存的下载信息(文件指针位置) S 9;FD3  
private void read_nPos() Bnw^W _  
{ <DhuY/o  
try{ 2\CZ"a#[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]PB95%  
int nCount = input.readInt(); S$/SFB$)~W  
nStartPos = new long[nCount]; 60l!3o"p!  
nEndPos = new long[nCount]; MHS|gR.c  
for(int i=0;i<nStartPos.length;i++) 0O(Vyy  
{ (O/W`qo  
nStartPos = input.readLong(); oSl}A,aQ(  
nEndPos = input.readLong(); gi+FL_8CzU  
} !ZY1AhGZ  
input.close(); @]L$eOV_  
} 3?TUt{3g  
catch(IOException e){e.printStackTrace ();} Eo@rrM:  
catch(Exception e){e.printStackTrace ();} t-Ble  
} t-SZBNb  
B/B`=%~5_^  
H %ScrJ#V  
private void processErrorCode(int nErrorCode) Nx!7sE*b$1  
{ n>,? V3ly  
System.err.println("Error Code : " + nErrorCode); f/{ClP.  
} CKX3t:HP0  
d"S\j@  
_p<wATv?7t  
//停止文件下载 SVPksr  
public void siteStop() j{@li1W@  
{ % @!hf!  
bStop = true; h<7@3Ur  
for(int i=0;i<nStartPos.length;i++) zr wzI+4  
fileSplitterFetch.splitterStop(); zuF]E+  
Mtn{63cK  
uJa.]J~L=  
} Fe2t[y:8h  
} ;8cTy8  
//负责部分文件的抓取 ek d[|g  
**FileSplitterFetch.java f||S?ns_  
*/ ~|ha9 1  
package NetFox; wdIJ?\/763  
rj/nn)vv;  
31N5dIi,  
import java.io.*; fn8|@)J  
import java.net.*; w8F`RRHEE  
'fZ\uMdTx  
hJ?PV@xy  
public class FileSplitterFetch extends Thread { ^~s!*T)\  
H-eHX3c7  
NleMZ  
String sURL; //File URL 9 $^b^It  
long nStartPos; //File Snippet Start Position H%{k.#O  
long nEndPos; //File Snippet End Position :bkmm,%O  
int nThreadID; //Thread's ID -X-sykDm  
boolean bDownOver = false; //Downing is over J^zB 5W,)  
boolean bStop = false; //Stop identical gI/(hp3ob  
FileAccessI fileAccessI = null; //File Access interface {uxTgX  
0JW =RW  
u.}H)wt  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <(1[n pS&+  
{ hb1eEn  
this.sURL = sURL; !1l~'/r  
this.nStartPos = nStart; I(b]V!mj:  
this.nEndPos = nEnd; :g{ybTSEe  
nThreadID = id; >b8-v~o{  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 m14'u GC  
} <VhD>4f{]  
wWM[Hus  
/$9We8  
public void run() (^58$IW71  
{ zX6Q7Bc  
while(nStartPos < nEndPos && !bStop) 4r#4h4`y|  
{ [J55%N;#1  
TV/EC#48  
BC#O.93`  
try{ whFJ]  
URL url = new URL(sURL); 4ZkaH(a1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z7k ku:9  
httpConnection.setRequestProperty("User-Agent","NetFox"); }taG/kE62  
String sProperty = "bytes="+nStartPos+"-"; lkJe7 +s  
httpConnection.setRequestProperty("RANGE",sProperty); 5=1Ml50  
Utility.log(sProperty); 4h T!DS  
cGlpJ)'-{  
|gU)6}V@  
InputStream input = httpConnection.getInputStream(); EtQ:x$S_  
//logResponseHead(httpConnection); 24\^{3nOK  
cI-@nV  
Cv;#8Wj}  
byte[] b = new byte[1024]; JD9=gBN\?  
int nRead; tD,I7%|@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) TY?O$d2b3  
{ D5Z)"~'  
nStartPos += fileAccessI.write(b,0,nRead); -op)X>  
//if(nThreadID == 1) ? U =Mdw  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >?.jN|  
} Lz!H@)-mr  
h+Y>\Cxg  
2SlI5+u  
Utility.log("Thread " + nThreadID + " is over!"); N$u: !  
bDownOver = true; V5gr-^E  
//nPos = fileAccessI.write (b,0,nRead); _>_ "cKS  
} 6NQ`IC  
catch(Exception e){e.printStackTrace ();} 3E}j*lo  
} 3mL(xpT.8z  
} lHE \Z`  
R0K{wY58  
AEUR` .  
//打印回应的头信息 O^_CqT%  
public void logResponseHead(HttpURLConnection con)  j}w  
{ ^FZ9q  
for(int i=1;;i++) +^%)QH>9   
{ KL"_h`UW  
String header=con.getHeaderFieldKey(i); 6q,CEm  
if(header!=null) (px3o'lsh  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); S|?P#.=GX  
Utility.log(header+" : "+con.getHeaderField(header)); g'2}Y5m$`  
else @.,'A[D!K  
break; +wZ|g6vMct  
} =&~ K;=:  
} n*caP9B  
V(Cxd.u   
|hX\ep   
public void splitterStop() R7c42L\QA  
{ D`U,T& @  
bStop = true; qC q?`0&#  
} 2iC BF-,  
T "#DhEM  
?QtM|e  
} ]C{N4Ni^Z  
.N7&Jy  
E+ /XKF  
/* tH:?aP*2  
**FileAccess.java -![{Zb@  
*//文件访问(定位,写) V0n8fez b  
package NetFox; $QwzL/a  
import java.io.*; O2xqNQ`d  
n^nQrRIp  
UJjtDV3@_g  
public class FileAccessI implements Serializable{ UG]x CkDS  
uWi pjxS  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 99n;%W>  
RandomAccessFile oSavedFile; M0hR]4T  
long nPos; g!i45]6[Nw  
Z% ]LZ/O8  
w^:@g~  
public FileAccessI() throws IOException 5i'KGL  
{ "2 D{X  
this("",0); h;mOfF  
} '-#gQxIpD  
*z]P|_:&G  
@6-3D/=  
public FileAccessI(String sName,long nPos) throws IOException =@nW;PUZ  
{ G0Z$p6z  
oSavedFile = new RandomAccessFile(sName,"rw"); s !I I}'Je  
this.nPos = nPos; s"~,Zzy@j  
oSavedFile.seek(nPos); 4C3i  
} u,~+ho@  
^ '_Fd  
a(uQGyr[k1  
public synchronized int write(byte[] b,int nStart,int nLen) ?OGs+G  
{ IvI;Q0E-3  
int n = -1; Z/:W.*u  
try{ ?.ofs}  
oSavedFile.write(b,nStart,nLen); \aN5:Yy  
n = nLen; p*JP='p  
} @P[%6 d  
catch(IOException e) F5{GMn;j  
{ rLbFaLeQ  
e.printStackTrace (); AP9\]qZ(7  
} m"o=R\C  
rMJ4w['J=  
24f N3  
return n; 9e&*+ +vf  
} mXu";?2  
J3'0^JP*  
PGb}Y {  
} 0:x+;R<P*w  
-:wV3D  
Vkqfs4t  
/* \2Kl]G(w%y  
**SiteInfoBean.java aw7pr464  
*/ {@s6ly].  
package NetFox; $>Gf;k  
"AIS6%,  
#t VGqf  
public class SiteInfoBean { R^.c  
/q!_f!<q4x  
EPM(hxCIQ  
private String sSiteURL; //Site's URL S-brV\v7  
private String sFilePath; //Saved File's Path buHUBn[3)  
private String sFileName; //Saved File's Name \_+Af`  
private int nSplitter; //Count of Splited Downloading File 7j"B-k#  
F^!mgU X  
f Qw|SW  
public SiteInfoBean() Eb8z`@p  
{//nSplitter的缺省值为5 5KssfI a  
//default value of nSplitter is 5 luz,z( v  
this("","","",5); !m9g\8tE  
} ul"Z% 1]  
QdIoK7J 9  
zeH=py[n  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) fJi?~[5<  
{ t2qWB[r  
sSiteURL= sURL; :k~ p=ko  
sFilePath = sPath; w!Z,3Yc)  
sFileName = sName; /|<0,ozoJ  
this.nSplitter = nSpiltter; @2\UjEo~  
jQ(%LYX$  
U* T :p>&  
} Kn\$\?u  
, - _ReL  
J^Wqa$<;"  
public String getSSiteURL() OW8TiM mK  
{ ; d}  
return sSiteURL; <q|eG\01S  
} XsMETl"Av4  
=I+5sCF{g  
RP wP4Z  
public void setSSiteURL(String value) X<H+Z2d  
{ ~>}7+p ?;  
sSiteURL = value; Ll^9,G"Tt  
} <a2Kc '  
1$"wN z  
O[ ^zQA  
public String getSFilePath() MO79FNH2\  
{ v2mqM5Z  
return sFilePath; jF5oc   
} L/O:V^1  
1:"ZS ]i  
opCQ=G1  
public void setSFilePath(String value) AOCiIPw  
{ dr4m}v.  
sFilePath = value; o4&#,m+ :  
} [_p&,$z8[  
DzY`O@D[  
s06R~P4  
public String getSFileName() yMf["AvG  
{ _\FA}d@N  
return sFileName; y;HJ"5.Mw  
} 4$v08z Z  
6r)qM)97  
1;+(HB  
public void setSFileName(String value) R=HcSRTkA  
{ vu)V:y  
sFileName = value; jyjK~ !0  
} h,'m*@Eg  
}sGH}n<9*  
i(<do "Am<  
public int getNSplitter() _NM=9cWd  
{ " gi 1{  
return nSplitter; 5LxzET"P  
} cUr'mb  
]F,v#6qi  
Ea3 4x  
public void setNSplitter(int nCount) U^$l$"~"  
{ LpSd/_^b  
nSplitter = nCount; %:.00F([r  
} a7l-kG=R;  
} $RV'DQO  
-ID!kZx  
n15lX,FI  
/* C`C$i>X7^  
**Utility.java ]i:O+t/U  
*/ &k {1N.  
package NetFox; Yy8%vDdJO  
jQ Of+ZE  
w1|YR  
public class Utility { `LCxxpHi|  
_6Fj&mw(u  
}U7 ><I  
public Utility() 8I=migaxP  
{ |;P9S  
?QCHkhU  
oNr~8CA`  
} \~ h7  
_}wy|T&7k&  
//线程睡眠 o@G <[X|ke  
public static void sleep(int nSecond) _&6&sp<n  
{ d[I}+%{[  
try{ BM]sW:-v  
Thread.sleep(nSecond); FA;uu\  
} lO0 PZnW9  
catch(Exception e) kculHIa\.  
{ |JH1?n  
e.printStackTrace (); p)=Fi}#D\  
} Yv jRJ  
} bi[gyl#  
c>RS~/Y  
//日志 ~*h` ?A0  
public static void log(String sMsg) h+h`0(z  
{ p,+$7f1S  
System.err.println(sMsg); bPtbU :G  
} QA&BNG  
8z, |N#  
ByPzA\;e  
public static void log(int sMsg) @[4Tdf  
{ )fz<n$3|$#  
System.err.println(sMsg); CzZm C]5  
} 38T2IN  
} c B9`U4<  
=-dk@s  
htGk:  
/* y2eeE CS]  
**TestMethod.java Awad!_VdHS  
*/ n.$wW =  
package NetFox; C.$`HGv  
C0F#PXU y  
<<P& MObqj  
public class TestMethod { "b"Q0"w  
0SBiMTm  
g^DPb pWxu  
public TestMethod() T6ajWUw  
{ ///xx/weblogic60b2_win.exe "!6 Ax-'  
try{ X} v]iX  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); RWi~34r  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~h{v^ }  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3N,!y  
fileFetch.start(); IU`&h2KZ.  
} ApYri|^r  
catch(Exception e){e.printStackTrace ();} q E`  
3g]Sp/  
fhAK^@h  
} L 59q\_|  
rSVU|O3m;  
9+\3E4K  
public static void main(String[] args) gs_nUgcA  
{ r9@Q="J_)  
new TestMethod(); GJY7vS^#  
} ?B2 T'}~  
} ^\uj&K6l  
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