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http断点续传简单实现(java)

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/* 2_vE  
**SiteFileFetch.java K~<pD:s  
*/ )wP0U{7?v  
package NetFox; }r]WB)_w  
import java.io.*; {k1s@KXtd  
import java.net.*; @I\Z2-J  
jz't!wj  
$ ;>,  
public class SiteFileFetch extends Thread { J9)wt ?%j  
=vT3SY  
M$1+,[^f  
SiteInfoBean siteInfoBean = null; //文件信息Bean }U7>_b2  
long[] nStartPos; //开始位置 2n?\tOm(V  
long[] nEndPos; //结束位置 &~pj)\_  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 IE$x2==)  
long nFileLength; //文件长度 6T< ~mn  
boolean bFirst = true; //是否第一次取文件 @pQv}%  
boolean bStop = false; //停止标志 EhEn|%S  
File tmpFile; //文件下载的临时信息 |~8\{IcZ  
DataOutputStream output; //输出到文件的输出流 '97)c7E  
LnZ*,>1 Z  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) `=uCp^ +v  
public SiteFileFetch(SiteInfoBean bean) throws IOException mvVVPf9  
{ w!:u|  
siteInfoBean = bean; .!KlN%As  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [4 g5 {eX  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \cPGyeq  
if(tmpFile.exists ()) `PSr64h:D  
{ nuw90=qj!]  
bFirst = false; q\O'r[&V  
read_nPos(); SjKIn-  
} 3 C=nC  
else ^4Tr @g#]"  
{ 0MMY{@n  
nStartPos = new long[bean.getNSplitter()]; ?XsL4HI x  
nEndPos = new long[bean.getNSplitter()]; Z{chAg\  
} si=/=h  
\>cZ=  
wz.Il-sm  
4I"QT(;  
} EYGJDv(S  
174H@   
+hY/4Tx<  
public void run() gwThhwR  
{ U'";  
//获得文件长度 dmP*2  
//分割文件 zN].W\("\  
//实例FileSplitterFetch pTGq4v@6x  
//启动FileSplitterFetch线程 o1MbHBb  
//等待子线程返回 r NU,(htS  
try{ 20^F -,z  
if(bFirst)  8czo#&  
{ `C=!8q  
nFileLength = getFileSize(); 5Ag]1k{  
if(nFileLength == -1) $msT,$NJ  
{ '0H +2  
System.err.println("File Length is not known!"); 8PXleAn  
} Y4@~NCU/  
else if(nFileLength == -2) ?-#w [J'6  
{ j0 =`Jf  
System.err.println("File is not access!"); (d^pYPr{  
} IAnY+= ^  
else ,U>g LTS  
{ 7*'_&0   
for(int i=0;i<nStartPos.length;i++) UbC)X iO  
{ X-Xf6&Uz  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Bf1GHn Xv  
} ;TmwIZ  
for(int i=0;i<nEndPos.length-1;i++) s]L`&fY]O  
{ Cd7 j G  
nEndPos = nStartPos[i+1]; Se"\PxBR  
} K_]LK  
nEndPos[nEndPos.length-1] = nFileLength; t@}<&{zk  
} A6lf-8ncx  
} feNr!/  
sN-5vYfC*  
TQ=\l*R(A  
//启动子线程 T]Tz<w W(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; l3-Ksw U  
for(int i=0;i<nStartPos.length;i++) Fj1/B0acS  
{ %|SbZ)gcQ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,>{4*PM(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), "^_p>C)T  
nStartPos,nEndPos,i); *sAoYx  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <6dD{{J]>p  
fileSplitterFetch.start(); jJ55Az?t:  
} Mk@_uPm  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bRNE:))r_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ><\mt  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 'G-VhvM v  
nEndPos = " + nFileLength); T:; e73  
// fileSplitterFetch[nPos.length-1].start(); J'@ I!Jc  
<+_OgF1G  
9!2KpuWji  
//等待子线程结束 r}f -.Fo  
//int count = 0; 7dPA>5"XD  
//是否结束while循环 ,:>>04O  
boolean breakWhile = false; g'pE z  
S_?}H  
>:OOuf#  
while(!bStop) qf)]!w U9  
{ 9!bD|-6y  
write_nPos(); xBB:b\  
Utility.sleep(500); akd~Z  
breakWhile = true; 2$\1v*:  
~JC``&6E=}  
yaR|d3ef?4  
for(int i=0;i<nStartPos.length;i++) ^o,@9GT s  
{ 1O(fI|gcO  
if(!fileSplitterFetch.bDownOver) Aba6/  
{ YXV![gw0  
breakWhile = false; E8%O+x}  
break; NNe'5q9  
} z W+wtYV4  
} k9}im  
if(breakWhile) }E?s*iP  
break; 2jx""{  
/^4)V8D_S  
xFg=Tyq:  
//count++; W!IK>IW"  
//if(count>4) AqN(htGvx  
// siteStop(); P Cw.NJd$  
} w?Q@"^IL  
'7Te{^<FQ$  
_9L2JN$R6  
System.err.println("文件下载结束!"); :&_@U$  
} oWXvkDN   
catch(Exception e){e.printStackTrace ();} &2QN^)q  
} rycscE4,  
2a? d:21 B  
ge[\%  
//获得文件长度 D;Az>]>q  
public long getFileSize() @Ki`g(],P  
{ >St  
int nFileLength = -1; h!d#=.R  
try{ !*CL>}-,  
URL url = new URL(siteInfoBean.getSSiteURL()); 0CTI=<;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +?mZ_sf8w  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^~(bm$4r  
X^aujK^@  
yGS._;#R  
int responseCode=httpConnection.getResponseCode(); T( ;BEyc?  
if(responseCode>=400) bZ3CJ f&mE  
{ 1 #EmZ{*  
processErrorCode(responseCode); <Xl G:nmY  
return -2; //-2 represent access is error 4=q\CK2^A  
} (/qY*?  
\;P Bx &  
-Ep-v4}  
String sHeader; YdeSJ(:  
dX+DE(y  
WBC'~h<@  
for(int i=1;;i++) {{2ZWK 6|  
{ U6M4}q(N]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); eQ C`e#%  
//Utility.log(in.readLine()); _k ~bH\(  
sHeader=httpConnection.getHeaderFieldKey(i); Q%t8cJ L  
if(sHeader!=null) ;| \Ojuf  
{ F}sfk}rp  
if(sHeader.equals("Content-Length")) [0J0<JnK  
{ R \`,Q'3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {BKI8vy  
break; J+z0,N[  
} qPzgGbmD9  
} > ]6Eb`v  
else V2.MZ9  
break; u_:" u  
} 7&T1RB'>  
} D, 3x:nK  
catch(IOException e){e.printStackTrace ();}  Y9PG  
catch(Exception e){e.printStackTrace ();} (_-z m)F7  
@Vb-BC,  
:T'"%_d5  
Utility.log(nFileLength);  Rl 6E  
lW>bX C  
V$:v~*Y9  
return nFileLength; (a)d7y.oo  
} kyY tL_SD  
;PLby]=O  
'9^x"U9c  
//保存下载信息(文件指针位置) e%UFY-2  
private void write_nPos() kA#>Xu/  
{ vk[Km[(U'  
try{ @$~%C) %u  
output = new DataOutputStream(new FileOutputStream(tmpFile)); #]:nQ (  
output.writeInt(nStartPos.length); }dB01Jl '  
for(int i=0;i<nStartPos.length;i++) S{ *RF)  
{ q$H'u[KQ06  
// output.writeLong(nPos); wt)tLMEv  
output.writeLong(fileSplitterFetch.nStartPos); tWc!!Hf2j  
output.writeLong(fileSplitterFetch.nEndPos); nq_sbli  
} K3\U'bRO  
output.close(); nwV\ [E  
} O<o_MZN  
catch(IOException e){e.printStackTrace ();} ^Z}INUv]7  
catch(Exception e){e.printStackTrace ();} V1"+4&R^T_  
} seq S*^7  
nk6xavQji  
Kb4u)~S:  
//读取保存的下载信息(文件指针位置) NCl={O9<j  
private void read_nPos() wAy;ZNu  
{ QF\NHV  
try{ gv<9XYByt  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =\_MJ?A$  
int nCount = input.readInt(); h^[K= J  
nStartPos = new long[nCount]; [g<6i.<I  
nEndPos = new long[nCount]; \Dr@n^hk@[  
for(int i=0;i<nStartPos.length;i++) oYqlN6n,=6  
{ #x "pG  
nStartPos = input.readLong(); E#_}y}7JY  
nEndPos = input.readLong(); tJg   
} qY0GeE>N  
input.close(); t;E-9`N  
} BIX%Bu0'f  
catch(IOException e){e.printStackTrace ();} qW7S<ouh  
catch(Exception e){e.printStackTrace ();} -bKli<C  
} WXXLD:gxI  
(MbI8B>  
{]|};E[}m  
private void processErrorCode(int nErrorCode) tQUp1i{j\  
{ G~YV6??  
System.err.println("Error Code : " + nErrorCode); HH[?LKd<  
} yjN|PqtSV  
>mh:OJH45  
PsLuyGR.<  
//停止文件下载 =;c? 6{<1  
public void siteStop() J}<k`af  
{ .cle^P  
bStop = true; 5H?`a7q N  
for(int i=0;i<nStartPos.length;i++) Q0nSOTQ  
fileSplitterFetch.splitterStop(); gxL5%:@  
HiVF<tN  
K3 "co1]u  
} n_?<q{GW  
} Po=)jkW  
//负责部分文件的抓取 #CVD:p  
**FileSplitterFetch.java uKtrG,/ p  
*/ iVnrv`k,  
package NetFox; 6P+8{ ?V&  
,uuQj]Dac+  
PZH]9[H  
import java.io.*; [)9bR1wh  
import java.net.*; 1kTJMtZG~  
e 0!a &w  
tQ] R@i  
public class FileSplitterFetch extends Thread { N6yqA)z?;  
(~/D*<A  
{P-KU RQ  
String sURL; //File URL blxH`O!  
long nStartPos; //File Snippet Start Position -Z]?v3 9  
long nEndPos; //File Snippet End Position sa*]q~ a  
int nThreadID; //Thread's ID /koNcpJ  
boolean bDownOver = false; //Downing is over !L-.bve!  
boolean bStop = false; //Stop identical (q3(bH~T)  
FileAccessI fileAccessI = null; //File Access interface O,:ent|  
o_os;  
&|Z:8]'P  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException T4qbyui{  
{ _0^<)OSY  
this.sURL = sURL; 6}{2W<  
this.nStartPos = nStart; Jp_{PR:&  
this.nEndPos = nEnd; F]SexP4:A  
nThreadID = id; E}\^GNT  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 MT;<\T  
} Q_LPLmM  
IN`05Q  
fm:/}7s  
public void run() ':F{st>&H  
{ *1}9`$  
while(nStartPos < nEndPos && !bStop) "D8x HHb  
{ uXu'I  
q^Oq:l$s  
N$?mula  
try{ /gXli)  
URL url = new URL(sURL); . |KxQn}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -twIF49  
httpConnection.setRequestProperty("User-Agent","NetFox"); GVn7#0x  
String sProperty = "bytes="+nStartPos+"-"; ,GZ(>|  
httpConnection.setRequestProperty("RANGE",sProperty); yq\)8Fe  
Utility.log(sProperty); %=\h=\wt  
L{'qZ#N[  
p;BdzV>  
InputStream input = httpConnection.getInputStream(); 4$d|}ajH  
//logResponseHead(httpConnection); d/Fjs0pt  
`;5UlkVZ5  
az0( 54M  
byte[] b = new byte[1024]; Og"50-  
int nRead; ObMsncn  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )v8;\1`s:  
{ k/!Vv#8  
nStartPos += fileAccessI.write(b,0,nRead); w0tlF:Eg  
//if(nThreadID == 1) c3i|q@ k  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); e +4p__TmZ  
} ^/mQo`[G  
LQNu]2  
m7^a4  
Utility.log("Thread " + nThreadID + " is over!"); ?i)-K?4Sb  
bDownOver = true; mmr>"`5.  
//nPos = fileAccessI.write (b,0,nRead); ,LWM}L  
} 3 +BPqhzf  
catch(Exception e){e.printStackTrace ();} W&BwBp]K  
} %w6> 3#e  
} X#1So.}c  
_(J- MCY\  
oQWS$\Rr.  
//打印回应的头信息 G-bG}9vc]  
public void logResponseHead(HttpURLConnection con) iN+p>3w^l  
{ tNmH*"wR<  
for(int i=1;;i++) B;hc|v{(  
{ 0%`\ 8  
String header=con.getHeaderFieldKey(i); f9&D0x?  
if(header!=null) 76$19  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +J_A *B  
Utility.log(header+" : "+con.getHeaderField(header)); (. 1<.PZp)  
else .l !:|Fd  
break; u%VO'}Gz  
} f![x7D$  
} .Eh~$wm  
zUIh8cAoE  
Z UAWSJ,s  
public void splitterStop() sB-c'`,w`  
{ 0ydAdgD  
bStop = true; eey <:n/Z  
} yTkYPx  
bN<c5  
d7$H})[^  
} T* -*U /  
@\u)k  
%jKR\f G  
/* 3,3{wGvHHW  
**FileAccess.java g%1!YvS3v  
*//文件访问(定位,写) roj/GZAy"  
package NetFox; <MA!?7Z|  
import java.io.*; (RWZ [-;)  
Y@M=6G  
REQ2pfk0  
public class FileAccessI implements Serializable{ Ml+.\'r  
h7[VXE  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 :v1'(A1t  
RandomAccessFile oSavedFile; +=$]fjE?  
long nPos; V:QfI  
kh^AH6{2  
qSkt }F%'  
public FileAccessI() throws IOException OA4NXl'  
{ RvYew!n  
this("",0); 0wAZ9AxA{  
} ruB&&C6)v  
sZ]O&Za~  
=qCVy:RL4  
public FileAccessI(String sName,long nPos) throws IOException (U/6~r'.L  
{ ;9=9D{-4+  
oSavedFile = new RandomAccessFile(sName,"rw"); Crm](Z?  
this.nPos = nPos; QRgWzaI  
oSavedFile.seek(nPos); uC 5mxZ  
} s-k~_C>Fw  
6jPaS!E  
(gl CTF9v  
public synchronized int write(byte[] b,int nStart,int nLen) C.%iQx`   
{ q+WOnTS  
int n = -1; tojJQ6;J  
try{ Z9~~vf#  
oSavedFile.write(b,nStart,nLen); E I)Pfx"0  
n = nLen; 3`SLMPI  
} *~prI1e(  
catch(IOException e) hk}M'  
{ K ,f1c}  
e.printStackTrace (); #s(B,`?N  
} <W|{zAyv  
(.<Gde#  
b0riiF  
return n; Xb)XV$0  
} $M$oNOT}Y  
T 7Lk4cU  
9n |H%AC  
} xqmJPbA  
%}+j4n  
Y\dK- M{$  
/* \>23_d0  
**SiteInfoBean.java ^p|@{4f]  
*/ P ,xayy  
package NetFox; h"#^0$f  
0Q]x[;!k  
- Kj$A@~x  
public class SiteInfoBean { ,UH`l./3DX  
o=w& &B  
PKwHq<vAsB  
private String sSiteURL; //Site's URL PX\}lTJ  
private String sFilePath; //Saved File's Path e9k}n\t3  
private String sFileName; //Saved File's Name 2ZNTg@o  
private int nSplitter; //Count of Splited Downloading File 0 (@8   
MfCu\[qOz  
/<zBcpVNV  
public SiteInfoBean() n KDX=73  
{//nSplitter的缺省值为5 +3]@0VM26;  
//default value of nSplitter is 5 m-*du(  
this("","","",5); Ocx=)WKdW  
} 9);a0}*5  
_S2QY7/  
p?0 a"5Q  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Lo7R^>  
{ /LPSI^l!m  
sSiteURL= sURL; sBZKf8@/  
sFilePath = sPath; g9GE0DbT`  
sFileName = sName; ~Jmn?9 3  
this.nSplitter = nSpiltter;  UZmz k  
UKMrR9[x*  
&R\ .^3  
} ]Ol@^$8}  
c}g^wLa  
q,0o:nI  
public String getSSiteURL() ^[\F uSL  
{ -;Cl0O%  
return sSiteURL; e|"`W`"-  
} Y]B2-wt-  
l: 1Zq_?v;  
WASs'Gx  
public void setSSiteURL(String value) M6pGf_qt  
{  {hZ_f3o  
sSiteURL = value; M2my>  
} FyZw='D  
s-o0N{b?#'  
}"Hf/{E$_"  
public String getSFilePath() pY ceMZ$  
{ bYgrKz@uK  
return sFilePath; 'JKFEUzM  
} \qNj?;B  
5a5 I+* c  
2+sNt6B2  
public void setSFilePath(String value) &0Wv+2l @  
{ &" K74  
sFilePath = value; Z3~$"V*ZB{  
} -'5:Cq   
f{^C+t{r  
42ttmN1F  
public String getSFileName() Mf/zSQk+  
{ 0&2TeqsLh)  
return sFileName; MFiX8zwhx+  
} |v[{k>7f  
% 89f<F\V  
;}=v|Dr&I.  
public void setSFileName(String value) A4Q8^^byY  
{ **fJAANc  
sFileName = value; $-jj%x\}  
} <M7@JgC &  
EAj2uV  
^qS[2Dy  
public int getNSplitter() T$0//7$')  
{ ,]y)Dy  
return nSplitter; 0rsdDME[  
} FL/@e$AK  
"9&6bBa  
zRL[.O9  
public void setNSplitter(int nCount) ! Hdg $,  
{ H2E!A2\m  
nSplitter = nCount; K$R1x1lc2  
} &]16Hb~  
} }yK_2zak5i  
A^bg*t,  
daGGgSbh  
/* C8-4 m68"  
**Utility.java 8QXxRD;0:  
*/ UfOF's_'<  
package NetFox; B9>3xxp(by  
z )a8 ^]`  
]y2(ZTNTs  
public class Utility { R1 hb-  
7t0\}e  
R1{ "  
public Utility() sn}U4=u  
{ -KCm#!  
bo0m/hVU  
j42U|CuK  
} ) e;)9~  
z,X ^;  
//线程睡眠 PfF7*}P  
public static void sleep(int nSecond) UyEyk$6SU  
{ N6Vn/7I5%  
try{ 6AUXYbK,  
Thread.sleep(nSecond); XB50>??NE  
} iVFHr<zk  
catch(Exception e) o'D{ql  
{ ,*bI0mFZ  
e.printStackTrace (); ^7.864  
} Tm.(gK  
} .B6$U>>NS^  
_^0yE_ili  
//日志 k$i76r  
public static void log(String sMsg) |9?67-  
{ M$FQoRwH  
System.err.println(sMsg); OzA"i y  
} U~s&}M\n  
V`l.F"<L  
v,KH2 (N  
public static void log(int sMsg) M9 fAv  
{ rPv+eM" >  
System.err.println(sMsg); #hH"g  
} D""d-oI[  
} U*(m'Ea  
u f.Zg;Vc  
%$~?DDNM  
/* 1YTnOiYS1  
**TestMethod.java ]O,!B''8k  
*/ y4/>3tz;  
package NetFox; 5Q?7 xTQ  
)^|zuYzN  
]mn(lK  
public class TestMethod { 0"ZB|^c=  
kgEGL]G>  
G!ty@ Fx  
public TestMethod() ",B92[}Ar  
{ ///xx/weblogic60b2_win.exe xzyV| (  
try{ 5dXC  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); i jg'X#E  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $83TA> <a  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ']Nw{}eS`  
fileFetch.start(); v< xe(dC  
} j;=+5PY  
catch(Exception e){e.printStackTrace ();} MV-fDqA(  
3G~ T_J&  
B;SYO>.W  
} PxM]3Aoa  
Gm}ecW  
LrX7WI  
public static void main(String[] args) %i]q} M  
{ JcvWE $  
new TestMethod(); %t([  
} 0vqXLFf   
} pfe9 n[  
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