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http断点续传简单实现(java)

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/* +EtL+Y (U  
**SiteFileFetch.java ^WZcM#~TL  
*/ |)7dh B  
package NetFox; ? ^E B"{  
import java.io.*; Y ~|C]O  
import java.net.*; w;RG*rv  
w _*|u  
-t<8)9q(  
public class SiteFileFetch extends Thread { O[tOpf@s.  
]Tb ?k+a  
Vh.9/$xQ  
SiteInfoBean siteInfoBean = null; //文件信息Bean ^X&n-ui   
long[] nStartPos; //开始位置 rM sd)  
long[] nEndPos; //结束位置 [%8t~zg  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 V8aLPJ0_  
long nFileLength; //文件长度 ((2 g  
boolean bFirst = true; //是否第一次取文件 NaR/IsN8%  
boolean bStop = false; //停止标志 8op,;Z7Y  
File tmpFile; //文件下载的临时信息 ugZ-*e7  
DataOutputStream output; //输出到文件的输出流 FXHcy:)}G  
{Q&@vbw'  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) zjzW;bo( d  
public SiteFileFetch(SiteInfoBean bean) throws IOException Y55Yo5<j/+  
{ X"S-f; b#  
siteInfoBean = bean; jK[~d Y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .3{PgrZ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #~ :j< =o  
if(tmpFile.exists ()) 9WJS.\G^  
{ DPU%4te  
bFirst = false; DP(JsZ}  
read_nPos(); %[x oA)0!  
} d:U2b"k=/u  
else YPjjSi:#  
{ C&&*6E5  
nStartPos = new long[bean.getNSplitter()]; "kE$2Kg  
nEndPos = new long[bean.getNSplitter()]; 3Ishe"  
} +}XFkH~  
Ddf7wszW  
[a\U8 w  
.=j]PckJO  
} y%y F34  
JAjXhk<=  
!N`$`qAK  
public void run() G lz0`z  
{ {HJzhIgCf  
//获得文件长度 (1 L9K;  
//分割文件 4`x.d  
//实例FileSplitterFetch 'Xl_,; W]  
//启动FileSplitterFetch线程 _1s\ztDpw  
//等待子线程返回 %Fh*$gzh*5  
try{ Y7|R vLWoP  
if(bFirst)  h :[8$]  
{ [7K-L6X  
nFileLength = getFileSize(); -P+@n)?T6  
if(nFileLength == -1) CaSoR |  
{ Ya#,\;dTT  
System.err.println("File Length is not known!"); 6' 9ITA  
} o3_dHbdI  
else if(nFileLength == -2) O4Wn+$AN  
{ VSK!Pc.G}  
System.err.println("File is not access!"); v<*ga7'S  
} ICJp-  
else 7*!h:rg  
{ %n^jho5  
for(int i=0;i<nStartPos.length;i++) 6#,VnS)`q  
{ $ BEIG@qG  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); e{ce \  
} EFb1Y{u^\!  
for(int i=0;i<nEndPos.length-1;i++) ,a:!"Z^ f  
{ \S[7-:Lu^  
nEndPos = nStartPos[i+1]; E>/kNl  
} .L,xqd[zC  
nEndPos[nEndPos.length-1] = nFileLength; N36<EHq  
} S,K'y?6  
} ^ -s'Ad3  
i.eu$~F  
U_/sY9gz(  
//启动子线程 7^{M:kYC!  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $6W o$c%  
for(int i=0;i<nStartPos.length;i++) o%!8t_1mR  
{ P1<Y7 +n  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6`KAl rH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), k`LoRqF  
nStartPos,nEndPos,i); W?a{3B   
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j@JhxCe1+R  
fileSplitterFetch.start(); ZnX]Q+w  
} *W'F 6Hpu  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), a3&&7n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 2"31k2H[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", y"|QY!fK  
nEndPos = " + nFileLength); <<43 'N+  
// fileSplitterFetch[nPos.length-1].start(); }y<p_dZI  
#=tWjInm  
&3 QdQ n,  
//等待子线程结束 QJBzv|  
//int count = 0; F9hh- "(Z  
//是否结束while循环 E0;KTcZi  
boolean breakWhile = false; kC =e>v  
orGNza"A  
6$1dd#  
while(!bStop) ohK_~  
{ >^cP]gG Y  
write_nPos(); %SV5 PO@  
Utility.sleep(500); A!([k}@=j  
breakWhile = true; ;Up'+[Vj'C  
~m ,xG  
ZI'MfkEZ*  
for(int i=0;i<nStartPos.length;i++) A]fN~PR  
{ 7j9:s>D  
if(!fileSplitterFetch.bDownOver) Yx- 2ux  
{ 0mJvoz\j8  
breakWhile = false; K;%P_f/KJP  
break; E7A psi4]  
} d(.e%[`  
} Y{6vW-z_<  
if(breakWhile) _l?InNv  
break; (!-gX" <b  
-E6#G[JJ  
(1~d/u?2\  
//count++; SZO$#  
//if(count>4) 8MHYk>O~{G  
// siteStop(); H4s^&--  
} =0te.io)3O  
K[tQ>C@s2  
W|IMnK-  
System.err.println("文件下载结束!"); %LeQpbyOR  
} ' `0kW_'  
catch(Exception e){e.printStackTrace ();} Vej [wY-c  
} `Yk~2t"V  
#cB=] (N  
VO _! +  
//获得文件长度 2V6=F[T  
public long getFileSize() c/l%:!A  
{ LRF_w)^['  
int nFileLength = -1; X<\E 'v`~  
try{ !PQ%h/ix  
URL url = new URL(siteInfoBean.getSSiteURL()); >]6f!;Rt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :n'$Txf  
httpConnection.setRequestProperty("User-Agent","NetFox"); :%[=v (G[  
`6`p~  
#fq%903=  
int responseCode=httpConnection.getResponseCode(); dGxk ql  
if(responseCode>=400) U(lcQC`$  
{ J~=bW\^I  
processErrorCode(responseCode); +_.k\CRms  
return -2; //-2 represent access is error :}QBrd  
} BCDmce`=l  
$XBn:0U  
tUS)1*{_  
String sHeader; ]V|rOtxb  
3 [R<JrO  
H .F-mm  
for(int i=1;;i++) zV)(i<Q  
{ K gN=b  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); RrFq"  
//Utility.log(in.readLine()); Rne#z2Ok  
sHeader=httpConnection.getHeaderFieldKey(i); D?+\"lI  
if(sHeader!=null) ~SI`%^L  
{ !VaKq_W  
if(sHeader.equals("Content-Length")) 'q158x  
{ F.zx]][JV  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _|f1q  
break; qOA+ao  
} K U 2LJ_~Y  
} )?5027^  
else kEQ1&9  
break; _?j66-( Q  
} vNMndo!  
} U3Fa.bC6}  
catch(IOException e){e.printStackTrace ();} 8Ld`$_E  
catch(Exception e){e.printStackTrace ();} jZjWz1+  
o!R.QI^2VT  
,g69?w  
Utility.log(nFileLength); r[doN{%  
t=,ZR}M1`  
b3/@$x<  
return nFileLength; #@ClhpLD  
} ]><K8N3Z  
oRf.34  
zD#$]?@ b  
//保存下载信息(文件指针位置) tcDWx:Q  
private void write_nPos() {e'P* j  
{ se|>P=/  
try{ mf~Joluc J  
output = new DataOutputStream(new FileOutputStream(tmpFile)); j,DF' h  
output.writeInt(nStartPos.length); <x QvS^|[  
for(int i=0;i<nStartPos.length;i++) JD`IPQb~E  
{ l#%qF Db  
// output.writeLong(nPos); !,Ou:E?Bb  
output.writeLong(fileSplitterFetch.nStartPos); sj9j 47y  
output.writeLong(fileSplitterFetch.nEndPos); / @v V^!#1  
} /"(`oe<  
output.close(); =`MxgK +  
} gxKL yZO!  
catch(IOException e){e.printStackTrace ();} tTjadnX  
catch(Exception e){e.printStackTrace ();} x;^DlyyYU  
} ^sF/-/ {?U  
=3h?!$#?  
2X X-  
//读取保存的下载信息(文件指针位置) d4ga6N3'  
private void read_nPos() _i3?;Fds  
{ FT F`-}Hz  
try{ Mb!b0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); C Oc,  
int nCount = input.readInt(); VyMFALSe]h  
nStartPos = new long[nCount]; RJ\'"XQ  
nEndPos = new long[nCount]; o+],L_Ab  
for(int i=0;i<nStartPos.length;i++) <<FBT`Y[  
{ w@![rH6~F  
nStartPos = input.readLong(); +YJpVxYmZ  
nEndPos = input.readLong(); g=gM}`X%  
} WMw|lV r  
input.close(); .4[\%r\i  
} s![Di  
catch(IOException e){e.printStackTrace ();} [ML|, kq!  
catch(Exception e){e.printStackTrace ();} #+"1">l  
} 3wYhDxY1  
[PIh^ DhK  
]/#3 P  
private void processErrorCode(int nErrorCode)  * Cj<Vy  
{ rq#\x{l  
System.err.println("Error Code : " + nErrorCode); ,q K'!  
} [mcER4]}  
e"d-$$'e  
RM3"8J  
//停止文件下载 <#ng"1J  
public void siteStop() WvoJ^{\4N*  
{ : GdLr  
bStop = true; 9Ro7xSeD  
for(int i=0;i<nStartPos.length;i++) O}-+o1  
fileSplitterFetch.splitterStop(); ?mp}_x#=  
,%T sfB  
J1u&Ga  
} B9: i.rQ  
} BhzcimC)  
//负责部分文件的抓取 LOEiV  
**FileSplitterFetch.java 3E-dhSz:i  
*/ 4n0Iw  I  
package NetFox; g QYs,  
;S?ei>Q  
ROr|n]aJj  
import java.io.*; K2qKkV@  
import java.net.*; {+^&7JX  
ZK4d;oa",  
l+#uQo6cqQ  
public class FileSplitterFetch extends Thread { >sGiDK @  
v ;nnr0;  
r'<!wp@  
String sURL; //File URL 8dLK5"_3  
long nStartPos; //File Snippet Start Position _Wtwh0[r*  
long nEndPos; //File Snippet End Position gX~lYdA  
int nThreadID; //Thread's ID ?&JK q^9\I  
boolean bDownOver = false; //Downing is over `sLD>@m  
boolean bStop = false; //Stop identical $}t;c62  
FileAccessI fileAccessI = null; //File Access interface XD%GNZ  
Q%QIr  
?$6(@>`f&t  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException =eQ'^3a  
{ YJF|J2u  
this.sURL = sURL; /^9=2~b  
this.nStartPos = nStart; ?/fC"MJq?  
this.nEndPos = nEnd; ,R}9n@JI^Y  
nThreadID = id; ncpNesB  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 QT4&Ix,4T1  
} sdBB(  
8^pu C  
2f5YkmGc";  
public void run() f&I5bPS7}  
{ iBk1QRdn  
while(nStartPos < nEndPos && !bStop) #'5{ ?Cb  
{ 629ogJo8  
&3|l4R\  
PQrc#dfc |  
try{ "XLFw;o  
URL url = new URL(sURL); 1b<[/g9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t+#vcg,G  
httpConnection.setRequestProperty("User-Agent","NetFox"); mq+x=  
String sProperty = "bytes="+nStartPos+"-"; moCR64n  
httpConnection.setRequestProperty("RANGE",sProperty); Eih6?Lpu  
Utility.log(sProperty); fwi -   
p^s:s-"f\  
pHKc9VC  
InputStream input = httpConnection.getInputStream(); [ZL<Q  
//logResponseHead(httpConnection); FK @Gd)(  
Z3f}'vr  
 V*W H  
byte[] b = new byte[1024]; t{e}3}LEd  
int nRead; m U= 3w  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Pp.] /;  
{ V6&6I  
nStartPos += fileAccessI.write(b,0,nRead); SM4'3d&mf  
//if(nThreadID == 1) F{E`MK~f_  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y?UB?2 VN  
} P1&Irwb`  
Yo\%53w/  
HfEl TC:3f  
Utility.log("Thread " + nThreadID + " is over!"); Zfd `Fu  
bDownOver = true; r` sG!  
//nPos = fileAccessI.write (b,0,nRead); WO*dO9O  
} kBtzJ#j B  
catch(Exception e){e.printStackTrace ();} hX:yn:P~  
} |?v+8QL,;t  
} [*g'Y;W  
h>A~yDT[  
!O4)Y M  
//打印回应的头信息 h#Z~x  
public void logResponseHead(HttpURLConnection con) 1aezlDc*  
{ U.1&'U*  
for(int i=1;;i++) Y?%=6S  
{ 'jYKfq~_cJ  
String header=con.getHeaderFieldKey(i); 'M fVZho{  
if(header!=null) %?J-0  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); @DKph!c r  
Utility.log(header+" : "+con.getHeaderField(header)); +A1xqOB  
else Fnuheb'&m  
break; $\L=RU!c}  
} ctR ^"'u  
} !Y*O0_  
EME}G42KN  
EJ(z]M`f  
public void splitterStop() ,Y@4d79  
{ s qO$ka{  
bStop = true; Kc`#~-`,(  
} [x0*x~1B  
VP^{-mDph  
HBZtg  
} eIbz`|%3  
#KDN  
ue -a/a  
/* ,D'bIk  
**FileAccess.java 2 ;Q|h$ n  
*//文件访问(定位,写) `~1#X  
package NetFox; ;oOv~ YB7H  
import java.io.*; 1%7zCM0s  
{"_V,HmEF+  
.K+5k`kd  
public class FileAccessI implements Serializable{ ,S1'SCwVdJ  
Ll`nO;h  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {<Xl57w-Q  
RandomAccessFile oSavedFile; pEY zB;  
long nPos; |&~);>Cq2  
@1V?94T1  
RA}Y$}^#'  
public FileAccessI() throws IOException c1 1?Kq  
{ uf`/-jY  
this("",0); JQSczE3  
} $HAwd6NI  
O>IG7Ujl  
bK|nxL  
public FileAccessI(String sName,long nPos) throws IOException |^O3~!JP(>  
{ v&xhS yZ  
oSavedFile = new RandomAccessFile(sName,"rw"); 2lxA/.f  
this.nPos = nPos; [k=LX+w@  
oSavedFile.seek(nPos); c  
} JiGS[tR  
g8]$BhRIfr  
V# JuNJ  
public synchronized int write(byte[] b,int nStart,int nLen) -IL' (vx  
{ [L?WM>]%  
int n = -1; I}\`l+  
try{ 1+Bj` ACP  
oSavedFile.write(b,nStart,nLen); ]"i^ VVw  
n = nLen; KXcE@q9  
} muKjeg'b  
catch(IOException e) 7qg. :h  
{ Jg@eGs\*  
e.printStackTrace (); 20)8e!jP  
} RY~m Q  
8e_9u@p+w  
|qb-iXW=  
return n; LP} j0)n  
} '^BTa6W}m  
B &)wJG  
~ \ Udl  
} w=ZK=@  
$3(E0\#O  
CMYkxU  
/* V4|l7  
**SiteInfoBean.java k'K 1zUBj  
*/ W 6CNMI]  
package NetFox; ZV`o: Gd  
$WbfRyXi7'  
ExSy/^4f  
public class SiteInfoBean { sB<y(}u  
xOc&n0}%  
U z MIm  
private String sSiteURL; //Site's URL hFDo{yI  
private String sFilePath; //Saved File's Path `YK#m4gc  
private String sFileName; //Saved File's Name / KxZ+Ww>v  
private int nSplitter; //Count of Splited Downloading File (&qjY I  
3E;<aCG?  
bYy7Ul6]  
public SiteInfoBean() `^ uX`M/  
{//nSplitter的缺省值为5 @BqSu|'Du,  
//default value of nSplitter is 5 Wq*W+7=.  
this("","","",5); &=l aZxe  
} v;IuB  
YJB f~0r  
J\\o# -H  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) u]Dds;~"b  
{ ?yAjxoE~?  
sSiteURL= sURL; +'9eo%3O  
sFilePath = sPath; Q5tx\GE  
sFileName = sName; e",0Er FT  
this.nSplitter = nSpiltter; P>ZIP* Gr  
r~T3Ieb  
q%MLj./?[  
} rTM0[2N  
jUy$aGX  
G!w?\-  
public String getSSiteURL() B0:/7Ld$Ml  
{ /` 4B-Y4M4  
return sSiteURL; [HQ Bx`3TS  
} q%k _C0  
HH'5kE0;d  
_u8d`7$*%  
public void setSSiteURL(String value) ,98`tB0  
{ &BQ%df<y\  
sSiteURL = value; }B2qtb3  
} jW_FaPW(p  
pc/]t^]p  
;.b^A  
public String getSFilePath() :faB7wduW;  
{ !!UQ,yU  
return sFilePath; o'p[G]NQ1o  
} "QCViR  
1<3!   
!<j)D_  
public void setSFilePath(String value) Q)}z$h55  
{ ?\![W5uuXG  
sFilePath = value; |iB svI:  
} F9 C3i  
K!_''Fg  
y,=TB#  
public String getSFileName() V2_I=]p_  
{ jd?NN:7  
return sFileName; -XARew  
} ~3s\Q%   
z+%74O"c  
UJ6zgsD1b?  
public void setSFileName(String value) M[,G#GO  
{ Z;nUS,?om  
sFileName = value; P0XVR_TJf  
} hZNA I  
HVK./y qy  
T&~7*j(|e  
public int getNSplitter() ~TfQuIvQB  
{ 3eP7vy  
return nSplitter; ,Frdi>7 ~  
} >PMLjXK  
R3Ka^l8R|  
TkSeDP  
public void setNSplitter(int nCount) 6b9 &V`  
{ *q |3QHZ  
nSplitter = nCount;  = ~^  
} \]+57^8r  
} (GI]Uyn  
/yS/*ET8  
;(,1pi7|  
/* 2%(RB4+  
**Utility.java 26<Wg7/,  
*/ A%c)=(,  
package NetFox; Y;6%pm$  
58H%#3Fy  
*QT|J6ng  
public class Utility { JOm6Zc  
' 5%`[&  
Jh)K0>R  
public Utility() dT*8I0\+  
{ K{x FhdW  
'4}c1F1T_  
&33.mdBH  
} eq#x~O4  
DTR/.Nr'K  
//线程睡眠 Zc9j_.?*  
public static void sleep(int nSecond) 4]/i0\Vbam  
{ =ap6IVR  
try{ Nu%:7  
Thread.sleep(nSecond); %"> Oy&3  
} GxR, 3  
catch(Exception e) t[-0/-4  
{ (66DKG   
e.printStackTrace (); Udh!%QP%[w  
} wuQ>|\Zs  
} _p`@/[(|  
'o*:~n  
//日志 G]- wN7G  
public static void log(String sMsg) q T pvz  
{ }&mFpc  
System.err.println(sMsg); ;dh8|ujh  
} Jqt&TqX@s  
* (4TasQu  
k v}<u  
public static void log(int sMsg) |_P-  
{ Dxwv\+7]  
System.err.println(sMsg); 9C{\=?e;  
} EdPN=  
} l< y9ue=  
d$G<g78D  
_>moza  
/* T"GuE[?a  
**TestMethod.java `=0J:  
*/ CY4_=  
package NetFox; !j3V'XU#Zn  
f 2#9E+IQ  
BU="BB/[  
public class TestMethod { /~LXY< -(  
w$5N6  
#NVqS5  
public TestMethod() m7XJe[O  
{ ///xx/weblogic60b2_win.exe /Jc?;@{  
try{ q-.e9eoc\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); xmDX1sL**  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); K+` Vn  
SiteFileFetch fileFetch = new SiteFileFetch(bean); lbES9o5  
fileFetch.start(); Te8BFcJG  
} FNDLqf!j  
catch(Exception e){e.printStackTrace ();} %(-YOTDr  
/)i)wxi  
~?}/L'q!b  
} <(JsB'TK  
fJ Ch  
/s%I(iP4  
public static void main(String[] args) oPNYCE  
{ 7[-jr;v  
new TestMethod(); oT5xe[{yj  
} 'D-#,X C  
} ED/-,>[f  
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