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http断点续传简单实现(java)

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/* 9BB<. p  
**SiteFileFetch.java xI'<4lo7Z  
*/ \/4ipU.  
package NetFox; &|P@$O>  
import java.io.*; N]: "3?%  
import java.net.*; v,r}q1.E}  
XhFa9RC  
ke|v|@  
public class SiteFileFetch extends Thread { (5{|']G  
IjN3 jU  
';??0M  
SiteInfoBean siteInfoBean = null; //文件信息Bean 1Nx.aji  
long[] nStartPos; //开始位置 vTjgW?9  
long[] nEndPos; //结束位置 R|H9AM ~E  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "!XeK|Wi  
long nFileLength; //文件长度 m}0US;c#f  
boolean bFirst = true; //是否第一次取文件 OlhfBu)~  
boolean bStop = false; //停止标志 NAhV8  
File tmpFile; //文件下载的临时信息 ed*Cx~rT  
DataOutputStream output; //输出到文件的输出流 'nI2RX  
!*u5HVn  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) @lAOi1m,,  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?HVsIAU  
{ ]CH@ T9d5V  
siteInfoBean = bean; v vlfL*f  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); {6)fZpd)@  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); S5d:?^PGg  
if(tmpFile.exists ()) RH ow%2D  
{ 3tI=? E#  
bFirst = false; sj2v*tFb  
read_nPos(); l.1)%q&@^  
} @``kt*+K+  
else +Uq9C-Iu  
{ g~.,-V}  
nStartPos = new long[bean.getNSplitter()]; uOc>~ITPS  
nEndPos = new long[bean.getNSplitter()]; MQE=8\  
} ,T"pUeVJ  
+] B  
F1R91V|  
_3tHzDSG#  
}  m3 ;  
HKq 2X4J$  
@8Drhx  
public void run() (p`'Okw  
{ YS,kjL/  
//获得文件长度 v83uGEq(  
//分割文件 shxr^   
//实例FileSplitterFetch KSVIX!EsX  
//启动FileSplitterFetch线程 (}O)pqZ>  
//等待子线程返回 a*CP1@O  
try{ 3/:O8H  
if(bFirst) 0~A<AF*t  
{ UA{sUj+?  
nFileLength = getFileSize(); # j*$ `W;  
if(nFileLength == -1) >OE.6)'Rm  
{ [Z,A quCU(  
System.err.println("File Length is not known!"); r\vB-nJ  
} yk#yrxM  
else if(nFileLength == -2) qyUcjc%[  
{ p*!@z|F>U  
System.err.println("File is not access!"); Vv' e,m  
} MTb}um.($  
else PTA;a 0A  
{ n)} J<  
for(int i=0;i<nStartPos.length;i++) y 4,2Xs9,  
{ >NB}Bc  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); CSc*UX+  
} l}335;(  
for(int i=0;i<nEndPos.length-1;i++) W)^:*z  
{ 0ang~_  
nEndPos = nStartPos[i+1]; /OgXNIl]  
} r4JXbh6Tt  
nEndPos[nEndPos.length-1] = nFileLength; 3k;U#H  
}  vi4 1`  
} )&+_T+\  
vPmP<c)cb  
h@Ea$1'e,  
//启动子线程 7E Y~5U/4  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \bQ|O7s  
for(int i=0;i<nStartPos.length;i++) 7;;W{W%  
{ z A&0H  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,M7sOp6}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), f Otrn  
nStartPos,nEndPos,i); fj0+a0h  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i0-!!  
fileSplitterFetch.start(); j6Jz  
} =t@m:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~0ZEnejy  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); D\(,:_ge  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 78+H|bH8  
nEndPos = " + nFileLength); MP[v 9m@  
// fileSplitterFetch[nPos.length-1].start(); \*LMc69  
E}k#-+u<S4  
eN/s W!:P|  
//等待子线程结束 sl6p/\_w  
//int count = 0; v7Knu]  
//是否结束while循环 <ofXNv;`  
boolean breakWhile = false; E=~H,~  
dr~MyQ  
GOJi/R.{  
while(!bStop) +n,8o:fU:  
{  ~Zl`Ap  
write_nPos(); r4 +w?=`  
Utility.sleep(500); )@eBe^  
breakWhile = true; |r}%AN6+  
T~"tex]  
ZhxMA*fL  
for(int i=0;i<nStartPos.length;i++) +D?d)lK  
{ YtW#MG$f  
if(!fileSplitterFetch.bDownOver) @kvp2P+O  
{ ez(4TtT  
breakWhile = false; bIp;$ZHy`K  
break; `6~*kCj5  
} t)cG_+rJ  
} G]P4[#5  
if(breakWhile) :U)e 8  
break; Lom%eoH)  
32~Tf,  
e"r}I!.  
//count++; eoEb\zJ  
//if(count>4) ujz %0Mq;  
// siteStop(); + W@r p#  
} $nn~K  
<g*rTqT'  
R%#c~NOO  
System.err.println("文件下载结束!"); ?b#?Vz  
} 7IK<9i4O  
catch(Exception e){e.printStackTrace ();} ++&F5'?g  
} $)n{}8^  
]2h[.qa  
bx6@FKns}  
//获得文件长度 @;rVB  
public long getFileSize() ykM#EyN  
{ N"r ;d+LTL  
int nFileLength = -1; _'I9rGlx3  
try{ m9L+|r  
URL url = new URL(siteInfoBean.getSSiteURL()); H ~ks"D1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M<ad>M  
httpConnection.setRequestProperty("User-Agent","NetFox"); l$zNsf.  
YvYavd  
>F+:ej  
int responseCode=httpConnection.getResponseCode(); bzJKoxU  
if(responseCode>=400) 6:B5PJq  
{ A:D\!5=  
processErrorCode(responseCode); *s%s|/  
return -2; //-2 represent access is error 6,@M0CX  
} N.64aL|1  
'h81\SKFK9  
RLKO0 #  
String sHeader; J&3;6I &  
3M@>kIT8  
Ce:R p?  
for(int i=1;;i++) aLsGden|  
{ Ev^Xs6 }"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^k_!+8"q{  
//Utility.log(in.readLine()); k&~vVx  
sHeader=httpConnection.getHeaderFieldKey(i); R +\y" .  
if(sHeader!=null) 4k#B5^iJ  
{ " Y%\qw/wq  
if(sHeader.equals("Content-Length")) 2X*epU_1h  
{ xDQ$Ui.  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8vT:icl  
break; 2sU"p5 j  
} }s)Z:6;(,q  
} #e|eWi>  
else {xH \!!"T  
break; /ZzlC#`  
} %kcg#p+tE  
} 3R{-\ZMd  
catch(IOException e){e.printStackTrace ();} ;zCHEz  
catch(Exception e){e.printStackTrace ();} qnA:[H;F  
#-@{rgH  
JfVay I=  
Utility.log(nFileLength); .1pEq~>  
yr=r? h}  
VKs\b-1  
return nFileLength; "|Pl(HX  
} /C(L(X  
YLCwo]\+>  
a6]!4  
//保存下载信息(文件指针位置) sW]n~kTt'  
private void write_nPos() nuCK7X  
{ \O0fo^+U,,  
try{ r[,KE.^6~#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); uZYeru"w  
output.writeInt(nStartPos.length); <]9MgfAe  
for(int i=0;i<nStartPos.length;i++) lyi}q"Kn*;  
{ G{"1  I  
// output.writeLong(nPos); %b*%'#iK  
output.writeLong(fileSplitterFetch.nStartPos); JJ+<?CeHD  
output.writeLong(fileSplitterFetch.nEndPos); c8'8DM  
} I#Bz UF  
output.close(); Ym6ec|9;  
} (8*lLZ  
catch(IOException e){e.printStackTrace ();} `j(+Y  
catch(Exception e){e.printStackTrace ();} T2->  
} asF- mf;D  
<G&v  
_ 4W#6!  
//读取保存的下载信息(文件指针位置) c !;wp,c  
private void read_nPos() x:bYd\ EJ[  
{ 3Yf$WE8#l  
try{ gON6jnDO  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {c1qC zM4  
int nCount = input.readInt(); O-B3@qQ. h  
nStartPos = new long[nCount]; Q?tV:jogY  
nEndPos = new long[nCount]; G8&'*7Bb  
for(int i=0;i<nStartPos.length;i++) Yn#8uaU  
{ PWmz7*/  
nStartPos = input.readLong(); ,qfa,O  
nEndPos = input.readLong(); y{"E) YY  
} 7*5ctc!dG  
input.close(); I,S'zHR  
} dL\8^L  
catch(IOException e){e.printStackTrace ();} KF'M4P  
catch(Exception e){e.printStackTrace ();} &Ch)SD  
} J)G3Kq5>:b  
y8 Nb 8m  
HUghl2L.<  
private void processErrorCode(int nErrorCode) l<HRD  
{ U<t-LF3  
System.err.println("Error Code : " + nErrorCode); em]K7B=  
} K$ &wO.  
gP<_DEd^`  
,YY#ed&l  
//停止文件下载 -hzza1DP  
public void siteStop() 4 * OU  
{ S3_4i;K\  
bStop = true; HDEG/k/~m  
for(int i=0;i<nStartPos.length;i++) +doT^&2u*  
fileSplitterFetch.splitterStop(); br;G5^j3?  
]M2<I#hF.  
./ :86@O  
} ]/bE${W*]  
} i#lo? \PO>  
//负责部分文件的抓取 HZm i ?  
**FileSplitterFetch.java 4yA`);r62  
*/ 6+5Catsn  
package NetFox; V!P3CNK  
]Rye AJ3  
AAW7@\q.  
import java.io.*; |z'?3?,~  
import java.net.*; j+9 S  
R]Oy4U,f  
(*ng$z Z$  
public class FileSplitterFetch extends Thread { V\"5<>+O  
[!le 9aNg  
jE#8&P~  
String sURL; //File URL sV<4^n7  
long nStartPos; //File Snippet Start Position w b[(_@eZ  
long nEndPos; //File Snippet End Position k)s 7Ev*  
int nThreadID; //Thread's ID =5`@:!t7  
boolean bDownOver = false; //Downing is over /)1-^ju  
boolean bStop = false; //Stop identical TJpv"V  
FileAccessI fileAccessI = null; //File Access interface gp)ds^  
`VsGa  
Lm|X5RVq  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException S:YL<_oI|  
{ j 7 URg>i0  
this.sURL = sURL; nrIL_  
this.nStartPos = nStart; !cb#fl  
this.nEndPos = nEnd;  ?~.&Y  
nThreadID = id; {wP|b@(1t  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 BcLt95;.\  
} Y+GeT#VHe  
'EV  *-_k  
G C'%s  
public void run() _zh5KP[{  
{ ku?_/-ko]  
while(nStartPos < nEndPos && !bStop) ]e.+u  
{ E<uOk  
QZr<=}   
u`@f ~QP0  
try{ h*UUtLi%WU  
URL url = new URL(sURL); P;%QA+%7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); MPbPq3an  
httpConnection.setRequestProperty("User-Agent","NetFox"); (OB8vTRXP  
String sProperty = "bytes="+nStartPos+"-"; r6JkoP Mh  
httpConnection.setRequestProperty("RANGE",sProperty); 8>q% 1]X  
Utility.log(sProperty); P@YL.'KU)  
GiXde}bm  
fZ}Y(TG/  
InputStream input = httpConnection.getInputStream(); Y}uQ`f  
//logResponseHead(httpConnection); 4P!DrOB  
s RQh~5kM  
ok[=1gA#h  
byte[] b = new byte[1024]; M7R&J'SAY  
int nRead; t3$gwO$  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) JF%=Bc$C  
{ io7U[#  
nStartPos += fileAccessI.write(b,0,nRead); C-u/{CP  
//if(nThreadID == 1) kA!(}wRL  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K<6x4ha  
} ':D&c  
2nkj;x{H$  
EAw#$Aq=  
Utility.log("Thread " + nThreadID + " is over!"); \!Zh="hN  
bDownOver = true; a~F@3Pd  
//nPos = fileAccessI.write (b,0,nRead); ;J-Ogt@d7  
} V2{#<d-T!  
catch(Exception e){e.printStackTrace ();} xsDa!  
} <C%-IZv$  
} (V.,~t@  
$sF#Na4^  
e[mhbFf-  
//打印回应的头信息 j9ta0~x1*6  
public void logResponseHead(HttpURLConnection con) 4V|z)=)A  
{ yM:~{;HLF  
for(int i=1;;i++) h#>L:Wf5E  
{ Hu8atlpo  
String header=con.getHeaderFieldKey(i); F.pHL)37  
if(header!=null) *}ee"eHs  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); AH'4H."o/9  
Utility.log(header+" : "+con.getHeaderField(header)); A}bHfn|  
else eD{ @0&   
break; 8='21@wrN  
} <nTmZ-;  
} ef}E.Bl  
3 9{"T0  
h Yc{ 9$  
public void splitterStop() lzs(i 2pA  
{ *rcuhw"^b#  
bStop = true; S"TMsi  
}  OI_/7@L  
ESxC{ "  
/~l/_Jct@G  
} }&T<wm!  
Of7) A  
I49l2>  
/* >'-w %H/  
**FileAccess.java ix7 e] )m(  
*//文件访问(定位,写) ]9&q'7*L  
package NetFox; `3y!XET  
import java.io.*; (_qBsng:  
{IPn\Bka  
O%K?l}e  
public class FileAccessI implements Serializable{ @=NVOJy}c  
e*2&s5 #RT  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 (Ef2 w[ '  
RandomAccessFile oSavedFile; f:[d]J|  
long nPos; w}W@M,.^  
&O6;nJEI  
m/hi~. D9  
public FileAccessI() throws IOException YNC0Z'c9  
{ ?FV7|)f  
this("",0); dD^_^'i  
} j&[.2PW\  
u1) TG "+0  
W]D`f8r9  
public FileAccessI(String sName,long nPos) throws IOException / }XsuH  
{ r($_>TS&"  
oSavedFile = new RandomAccessFile(sName,"rw"); `@$"L/AJ  
this.nPos = nPos; B}q  
oSavedFile.seek(nPos); X}j'L&{F@  
} 0?F@iB~1F  
AZy~Q9Kc  
-':"6\W  
public synchronized int write(byte[] b,int nStart,int nLen) noaN@K[GO  
{ RZd4(7H=q  
int n = -1; 7"n1it[RJ8  
try{ sh !~T<yy  
oSavedFile.write(b,nStart,nLen); W?^8/1U  
n = nLen; qXB03}] G  
} VX!Y`y^a  
catch(IOException e) ~*mOt 7G  
{ %<wQ  
e.printStackTrace (); u3M` 'YCb  
} y4/>Ol]  
N8 kb-2  
i_0 ,BV C  
return n; WAwfL?  
} 9xK4!~5V  
qX p,d  
1akD]Z  
} F9k I'<Q  
Q"OV>klk  
tB,.  
/* T6R7,Vt'v  
**SiteInfoBean.java EtR@sJ<  
*/ })zB".  
package NetFox; /OhaERv  
]Z.<c$  
R(2HY Z  
public class SiteInfoBean { iM?I /\  
us\%BxxI9  
}_a +X  
private String sSiteURL; //Site's URL 9{O2B5u1  
private String sFilePath; //Saved File's Path KH2F#[ !Lw  
private String sFileName; //Saved File's Name ol?z<53X]  
private int nSplitter; //Count of Splited Downloading File {+ C%D'  
Sv7>IVC?@  
t,=@hs hN  
public SiteInfoBean() r,u<y_YW  
{//nSplitter的缺省值为5 (o x4K{  
//default value of nSplitter is 5 2vqmsl ?  
this("","","",5); *Z]5!$UpC  
} mJ8{lXq3!  
:]B% >*;}  
P"R97#C  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) VY+(,\ )U  
{ e;A^.\SP  
sSiteURL= sURL; sR"zRn  
sFilePath = sPath; "pSH!0Ap\  
sFileName = sName; |D;_:x9  
this.nSplitter = nSpiltter; 9N~8s6Ob  
$6:XsrV\a  
wJ80};!  
} vQ-i xh  
e9~cBG|  
~K5Cr  
public String getSSiteURL() =bs.2aN&^  
{ {BFT  
return sSiteURL; F5N>Uqr*oN  
} n!0${QVnS  
2Vz'n@g=  
Sni&?tcY  
public void setSSiteURL(String value) jIAW-hc]  
{ -`zG_]=-  
sSiteURL = value; 0Jm]f/iZ  
} do:QH.q8)  
CS~=Z>6EjA  
uY&=eQ_Cb  
public String getSFilePath() Cz'xGW{  
{ !lR0w|  
return sFilePath; KWFyw>*)  
} ftYR,!&  
b@=z rhQ  
cT/3yf  
public void setSFilePath(String value) gB(9vhj $  
{ Eyr5jXt%;  
sFilePath = value; {E!$ xY8  
} _:wZmZU}  
p>k]C:h  
lZ}izl  
public String getSFileName() !"g=&Uy&  
{ VDB$"T9#  
return sFileName; a`7%A H)  
} OOCQsoN  
E^b pckP  
Dz[566UD  
public void setSFileName(String value) q<-%L1kc 1  
{ d32@M~vD  
sFileName = value; >$2E1HW.  
} |'ZN!2u  
X3P&"}a  
Px'R`1^  
public int getNSplitter() &g*klt'B  
{ j.k@6[ R>?  
return nSplitter; jmkRP"ZnA  
} C= >B_EO  
q&u$0XmV  
 qovQ9O  
public void setNSplitter(int nCount) (l Lu?NpIi  
{ ^fkCyE;=  
nSplitter = nCount; M6# \na  
} )yHJ[  
} @(Z( /P;:  
M[A-1]'  
m])Lw@#9W  
/* jyNb(Z  
**Utility.java ?#?e(mpo  
*/ g<f P:/  
package NetFox; $np=eT)  
T}UT 7W|  
T'hml   
public class Utility { P?uf?{  
8|w-XR  
$9G3LgcS  
public Utility() O'fk&&l  
{ |-|jf  
.\$Wy$ d  
d&hD[v  
} ; vMn/  
. =&Jo9  
//线程睡眠 ,aI,2U91  
public static void sleep(int nSecond) d;{y`4p)s  
{ (/'h4KS@  
try{ KZ]r8  
Thread.sleep(nSecond); .%_)*NUZ  
} $)Wb#B  
catch(Exception e) @\ }sb]  
{ TfL4_IAG.  
e.printStackTrace (); X&s7% ]n+  
} -)X{n?i  
} w5,6$#  
RYt6=R+f  
//日志 J=):+F=  
public static void log(String sMsg) }f0u5:;Zth  
{ JfkTw~'R  
System.err.println(sMsg); q'.;W@m  
} ( ]OFS;%  
f7Zf}1|  
?!H)zz6y  
public static void log(int sMsg) YX_vv!-]  
{ A]j}'  
System.err.println(sMsg); u)7*Rj^  
} Hr6wgYPi  
} H"O$&  
B3Mx,uXT\  
f4 Q( 1(C  
/* [g+y_@9s  
**TestMethod.java mk\i}U>`  
*/ _e_4Q)z-a  
package NetFox; x:qr\Rz  
H-Pq!9[DB  
AQe!Sqg'  
public class TestMethod { 2 % %|fU9  
l]$40 j  
} %+qP +O\  
public TestMethod() Y[ ?`\c|  
{ ///xx/weblogic60b2_win.exe WV2~(/hX&  
try{ v{.\iIg N  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 66 N)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); YwXXXh  
SiteFileFetch fileFetch = new SiteFileFetch(bean); N#UXP5C(  
fileFetch.start(); %[XY67A3I  
} ?I\v0H*  
catch(Exception e){e.printStackTrace ();} t=i/xG:5  
qC..\{z  
V}SyD(8~  
} ?ql2wWsQO  
O ^0"  
Mb/L~gd"  
public static void main(String[] args) 9Eg&CZ,9$D  
{ JR)/c6j  
new TestMethod(); 7G"7wYc>R  
} ,%Z&*n  
} SW#BZ3L  
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