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http断点续传简单实现(java)

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/* .FgeAxflP  
**SiteFileFetch.java vo\'ycPv  
*/  R.HvqO  
package NetFox; qCfEv4  
import java.io.*; ht]n*  
import java.net.*; Q[K$f%>  
3ej237~F,L  
]GY8f3~|{  
public class SiteFileFetch extends Thread { ~/-SKGzo-  
;nW;M 4{  
R3lZ|rxv:  
SiteInfoBean siteInfoBean = null; //文件信息Bean wbKJ:eWgt  
long[] nStartPos; //开始位置 [7gz?9VyLF  
long[] nEndPos; //结束位置 % H"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 IE996   
long nFileLength; //文件长度 Oy=0Hsh@x  
boolean bFirst = true; //是否第一次取文件 iJOG"gI&  
boolean bStop = false; //停止标志 f>C+l(  
File tmpFile; //文件下载的临时信息 ]w;t0Bk  
DataOutputStream output; //输出到文件的输出流 5 0-7L,  
tugIOA  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 0[%{YmI{W  
public SiteFileFetch(SiteInfoBean bean) throws IOException Cy6!?Mik  
{ w`f66*@Q1  
siteInfoBean = bean; mHju$d  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Is3Y>oX  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); cyB+(jLHDs  
if(tmpFile.exists ()) XIbxi  
{ #TR!x,Hc  
bFirst = false; *K$a;2WjzG  
read_nPos(); hp2E! Cma  
} bF_0',W  
else $poIWJMc  
{ gAsmPI.K  
nStartPos = new long[bean.getNSplitter()]; Qu=b-9  
nEndPos = new long[bean.getNSplitter()]; }(Fmr7%m  
} =CD6x= l6  
!wpK +.D  
yLfyLyO L  
lV^:2I/  
} ej kUNCKQt  
h;+O96V4.  
> TCit1yD  
public void run() G`0{31us  
{ PDA9.b<q0  
//获得文件长度 E.NfVeq  
//分割文件 RxJbQs$Ph  
//实例FileSplitterFetch XfVdYmii  
//启动FileSplitterFetch线程 YQ d($  
//等待子线程返回 fcF|m5  
try{ NJr)f  
if(bFirst) S>(xx"Ia  
{ H.{Fw j4  
nFileLength = getFileSize(); Ay qs~&{  
if(nFileLength == -1) 4C_1wk('  
{ 5!Y\STn  
System.err.println("File Length is not known!"); IO8 @u;&  
} ,~Xe#e M  
else if(nFileLength == -2) |&WYu,QQ4  
{ h'h8Mm  
System.err.println("File is not access!"); H#hpaP;  
} Hkia&nz'3  
else 86-Rm  
{ ?r&~(<^z  
for(int i=0;i<nStartPos.length;i++) AU`z.Isf  
{ E8sM`2z5  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); I F!xZ6X8  
} L,#YP#O,j  
for(int i=0;i<nEndPos.length-1;i++) rqN+0CT  
{ c)^A|{,G  
nEndPos = nStartPos[i+1]; AhOBbss]q  
} RPeH[M^  
nEndPos[nEndPos.length-1] = nFileLength; v*GS>S  
} Zh;}Q(w  
} t6KKfb  
D60quEe3%  
Eb9h9sjv  
//启动子线程 URm<Ji  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?_AX;z  
for(int i=0;i<nStartPos.length;i++) MDIPoS3BRa  
{ @Nh}^D >j  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), CUpRtE8@[_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0.R3(O  
nStartPos,nEndPos,i); &XCd2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Jf7H;ZM<  
fileSplitterFetch.start(); iN'T^+um=  
} NkBvN\CQ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), iExKi1knx  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ^J7q,tvbJ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ['\R4H!x  
nEndPos = " + nFileLength); 6q>iPK Jt  
// fileSplitterFetch[nPos.length-1].start(); +0ukLc@  
.{8[o[w =  
Pz2Q]}(w  
//等待子线程结束 ~gZ1*8 s`  
//int count = 0; ]JGq{I>%+6  
//是否结束while循环 jsgDJ}  
boolean breakWhile = false; ~s'}_5;VY  
aDX&j2/  
cyWb*Wv  
while(!bStop) GR*sk#{  
{ Hc\@{17   
write_nPos(); h+H+>,N8`  
Utility.sleep(500); zJ8T.+qJ  
breakWhile = true; ,|\\C6s  
ZyNgG9JL]  
O_2o/  
for(int i=0;i<nStartPos.length;i++) I(BJ1 8F$  
{ wY\,b*x  
if(!fileSplitterFetch.bDownOver) H*<E5^#dw  
{ ke W7pN?  
breakWhile = false; r>bgCQ#-n  
break; #| g h  
} _8 K|2$X  
} lj&\F|-i  
if(breakWhile) ol_\ "  
break; t d\gk  
8lqmd1v  
W!XBuk-  
//count++; 3*%+NQIj  
//if(count>4) RfvvX$  
// siteStop(); 5X];?(VTsb  
} Px?"5g#+  
u|$HA>F[  
A~E S{Zkh  
System.err.println("文件下载结束!");  Lhg  
} f&5S`}C  
catch(Exception e){e.printStackTrace ();} & }j;SK5  
} *< fJgc"3  
5W fZd  
CL5^>. }  
//获得文件长度 4PS|  
public long getFileSize() p</t##]3ks  
{ PEjd  
int nFileLength = -1; q*4@d)_&  
try{ #huh!Mn  
URL url = new URL(siteInfoBean.getSSiteURL()); p%bMfi*T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `]GL3cIh:  
httpConnection.setRequestProperty("User-Agent","NetFox"); %|JL=E}%|  
V:5aq.o!  
m$_l{|4z  
int responseCode=httpConnection.getResponseCode(); *tpS6{4=#7  
if(responseCode>=400) jc:=Pe!E  
{ 4<1V  
processErrorCode(responseCode); 0VJHE~Bgi  
return -2; //-2 represent access is error >{Mv+  
} o\it]B  
#H Jlm1d  
@ kv~2m  
String sHeader; 0;`FS /[(f  
o%lxEd r  
h'G  
for(int i=1;;i++) j<Pw0?~s6  
{ [N[4\W!!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0lq?l:/  
//Utility.log(in.readLine()); p_n$}z  
sHeader=httpConnection.getHeaderFieldKey(i); ;QG8@ms|  
if(sHeader!=null) 6_yatq5c  
{ ~n0Exw(  
if(sHeader.equals("Content-Length")) C{l-l`:  
{ Kt]vTn7!9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Z{#3-O<a+n  
break; `]19}GK~xo  
} M!gu`@@}F  
} CUC]-]8  
else DrBkR` a?  
break; jc>B^mqx  
} 9$[MM*r  
} xo ^|d3  
catch(IOException e){e.printStackTrace ();} {s6#h#U  
catch(Exception e){e.printStackTrace ();} }NV<k  
zU0JwZi  
86qQ"=v  
Utility.log(nFileLength); U m`KmM3  
Ik5-ooZ&{  
n2c(x\DA&  
return nFileLength; Ha ZV7  
} v=dN$B5y3  
q:jv9eL.O  
lQ [JA[  
//保存下载信息(文件指针位置) K'"s9b8  
private void write_nPos() =:R${F  
{ dYwEVu6q  
try{ 6+s&%io4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); $j(4FyH\  
output.writeInt(nStartPos.length); r}|)oG,=  
for(int i=0;i<nStartPos.length;i++) 'f %oL/,  
{ 7uv"#mq  
// output.writeLong(nPos); Pq-@waH3  
output.writeLong(fileSplitterFetch.nStartPos); p ~+sk1[.  
output.writeLong(fileSplitterFetch.nEndPos); l% %cU"  
} Zcc7 7dRA  
output.close(); Ew{N 2  
} ~<Wa$~oY  
catch(IOException e){e.printStackTrace ();} +Ezl.O@z  
catch(Exception e){e.printStackTrace ();} I%j]pY4  
} 0f+]I=1\  
oOXJ7 |n  
n*|8 (fD  
//读取保存的下载信息(文件指针位置) /<O9^hA|  
private void read_nPos() !#olG}#[  
{ 5*B'e{C  
try{ n|QA\,=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); QqeF   
int nCount = input.readInt(); xw1,Wbu]  
nStartPos = new long[nCount]; EW)r/Av:,  
nEndPos = new long[nCount]; cZWW[i  
for(int i=0;i<nStartPos.length;i++) 4l/~::y  
{ .Z17X_  
nStartPos = input.readLong(); +@@( C9  
nEndPos = input.readLong(); 5':j=KQE_  
} <P Vmr2Jp"  
input.close(); q}g0-Da  
} lKRp9isn^  
catch(IOException e){e.printStackTrace ();} >M m.MNU  
catch(Exception e){e.printStackTrace ();} zRau/1Y0  
} %uP/v\l  
h{)`W ]~  
n2F*a  
private void processErrorCode(int nErrorCode) &(x>J:b  
{ N=8CVI  
System.err.println("Error Code : " + nErrorCode); p1z^i(  
} lrMkp@ f.  
d;r,?/C  
Z\)P|#L$  
//停止文件下载 7:.!R^5H  
public void siteStop() |IWm:[H3  
{ \/y&l\ k)  
bStop = true; cf_X=;yaqy  
for(int i=0;i<nStartPos.length;i++) .e S* F  
fileSplitterFetch.splitterStop(); )B5U0iIi  
"MOmJYH  
K<u~[^R  
} N,cj[6;T%  
} Tl^)O^/  
//负责部分文件的抓取 <g8{LG0  
**FileSplitterFetch.java <S@2%%W  
*/ ;/^O7KM-  
package NetFox; t{ridA}  
iW? NxP  
JQ\o[t  
import java.io.*; 3ZYrNul"  
import java.net.*; rV I-Yb  
`zcpaE.@  
:\1vy5 _  
public class FileSplitterFetch extends Thread { 34vH+,!u  
-r{]9v2j  
yv5c0G.D  
String sURL; //File URL {JcMJZ3  
long nStartPos; //File Snippet Start Position @Z~0!VY  
long nEndPos; //File Snippet End Position Ti5"a<R4m6  
int nThreadID; //Thread's ID 3SOrM  
boolean bDownOver = false; //Downing is over .noY[P 8i  
boolean bStop = false; //Stop identical )q%DRLD'G  
FileAccessI fileAccessI = null; //File Access interface 9Bu=8P?  
hN1{?PQ  
|Gb~[6u   
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException xSjs+Y;Mu  
{ ^`(3X  
this.sURL = sURL; X*:)]p(R  
this.nStartPos = nStart; )|S!k\^A  
this.nEndPos = nEnd; ~eGtoEY  
nThreadID = id; -EU~ %/=m+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 n yd'79~>G  
} [#2z=Xg  
\88 IFE  
@,q<][q  
public void run() 9kU|?JE  
{ js=w!q0)9  
while(nStartPos < nEndPos && !bStop) *>Zq79TG  
{ XZPq4(,9}  
(K> 4^E8  
D)JI11a<  
try{ 7(5 wP(  
URL url = new URL(sURL); 7:S)J~s*O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _d3/="=  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ml,87fo  
String sProperty = "bytes="+nStartPos+"-"; I[v~nY~l`  
httpConnection.setRequestProperty("RANGE",sProperty); l8!n!sC[,  
Utility.log(sProperty); =ThacZHb8  
_&F*4t!n_  
sMb+4{W&6  
InputStream input = httpConnection.getInputStream(); qVJC O-K|  
//logResponseHead(httpConnection); ^G(+sb[t  
#c2JWDH1F  
uTUkRqtD!  
byte[] b = new byte[1024]; N6S}u@{J~N  
int nRead; qznd '^[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ? $X1X`@  
{ 6imQjtI  
nStartPos += fileAccessI.write(b,0,nRead); e_CgZ  
//if(nThreadID == 1) y+a]?`2  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;jpsH?3g  
} .AHww7  
c ]&|.~2&  
c5tCw3$t  
Utility.log("Thread " + nThreadID + " is over!"); B976{;QvXV  
bDownOver = true; sBu- \P#  
//nPos = fileAccessI.write (b,0,nRead); C+c;UzbD  
} t[^68]  
catch(Exception e){e.printStackTrace ();} @{UtS2L  
} l8ZzKb-  
} &]HY:  
62%=%XD  
tdB<  
//打印回应的头信息 pD%Pg5p`  
public void logResponseHead(HttpURLConnection con) ]W 6!Xw)[  
{ n8>( m,  
for(int i=1;;i++) q:ZF6o`Z83  
{ m]:|j[!*M  
String header=con.getHeaderFieldKey(i); th(<S  
if(header!=null) @phb5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); BDT1qiC  
Utility.log(header+" : "+con.getHeaderField(header)); |Orp:e!  
else [CJr8Qn  
break; ibskce{H  
} 8;]U:tv  
} p_2-(n@  
|\/Y<_)JD  
~!a~ -:#  
public void splitterStop() F2RU7o'f.  
{ |cCrLa2*-  
bStop = true; Aaq!i*y  
} 0SLS;s.GX  
P mgTTI  
s@vHU4  
} 3]1uDgfr  
W-+~r  
%) 8 UyZG  
/* bjEm=4FI;  
**FileAccess.java &]Q\@;]Aq  
*//文件访问(定位,写) !r*Ogv[  
package NetFox; \sZ!F&a~  
import java.io.*; 0(!D1G{ul  
h*9s^`9)  
X8(, ,>_  
public class FileAccessI implements Serializable{ @e_<OU  
=tE7XC3X_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \d#|n u  
RandomAccessFile oSavedFile; jN43vHm\Y9  
long nPos;  &(Ot(.  
u*J,3o} <  
1FiFP5  
public FileAccessI() throws IOException K7H` Yt  
{ Y^-faL7*\  
this("",0); Cj x(Z]  
} NiQ_0Y}  
w(KB=lA2  
WS?"OTH.^\  
public FileAccessI(String sName,long nPos) throws IOException Hjm  
{ MxO0#  
oSavedFile = new RandomAccessFile(sName,"rw"); y BwgLn  
this.nPos = nPos; 'X$2gD3c9  
oSavedFile.seek(nPos); g~JN"ap  
} %4~2  
], HF) 21  
.Bu?=+O~  
public synchronized int write(byte[] b,int nStart,int nLen) ({}JvSn1  
{ eS/4gM7%  
int n = -1; 3"Y |RSy  
try{ N>S_Vgk}  
oSavedFile.write(b,nStart,nLen); nDvj*lZF  
n = nLen; '%$)"g]/#  
} CG(G){u&  
catch(IOException e) bZ.q?Hlfk  
{ P<@V  
e.printStackTrace (); e-dpk^-  
} O%.c%)4Xo  
"[ 091<  
D/1f> sl  
return n; nmn 8Y V1  
} R7 )2@;i  
_S[@d^cY  
jF}u%T)HL  
} spE(s%dgL  
BuE=(v2}  
Tq7cZe"6  
/* u"*@k^}(  
**SiteInfoBean.java '7UW\KEB[}  
*/ yrnIQu*Uu  
package NetFox; %,G&By&,  
ppjS|l*`  
4]F:QS% x  
public class SiteInfoBean { #&A)%Qbg  
%B&y^mZv*\  
U=4tJb  
private String sSiteURL; //Site's URL DRC2U%[  
private String sFilePath; //Saved File's Path -Q6njt&  
private String sFileName; //Saved File's Name ]\y:AkxhJ  
private int nSplitter; //Count of Splited Downloading File b'Scoa7@'  
tp-PE?  
~9N n8g6  
public SiteInfoBean() gi|j ! m  
{//nSplitter的缺省值为5 06FBI?;|=  
//default value of nSplitter is 5 b42"Y,sbB  
this("","","",5); h#ogL-UU  
} mlsM;A d2  
&> Myf@  
tCFXb6Cz  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) "Cz8nG  
{ ~@=*JzP?  
sSiteURL= sURL; G(2(-x"+  
sFilePath = sPath; vKv!{>,v9Z  
sFileName = sName; DM3W99PWA  
this.nSplitter = nSpiltter; A.@S>H'P  
biJ"@dm 4  
'gDhi!h%  
} g q|T:  
dD Qx[  
)*=ds ,  
public String getSSiteURL() .</`#   
{ w%(Ats  
return sSiteURL; G1t{a:  
} /1F5khN  
2UPqn#.3  
6  XZF8W  
public void setSSiteURL(String value) nU{ }R"|  
{ `*5_`^t   
sSiteURL = value; /0PBY-O  
} ^XsIQz[q  
TC7Rw}jF  
j:)"s_  
public String getSFilePath() [YbnpI  
{ MlDWK_y_&  
return sFilePath; hmfO\gc}y  
} 5C}1iZEJ  
~(( '1+  
IkzY   
public void setSFilePath(String value) _O76Aw-@l  
{ Sm@T/+uG:  
sFilePath = value; R!mFMw"  
} Y7TW_[_u  
3 ZZ"mlk*  
'jr\F2  
public String getSFileName() 'G6g yO/K  
{ I\%a<  
return sFileName; ;}iV`)S  
} p ~/  
;7jszs.6%  
}Zs y&K  
public void setSFileName(String value) nH6Ny  
{ ia'eV10  
sFileName = value; u0&QStI  
} i%M6$or  
JDTlzu1hR  
8zDLX,M-  
public int getNSplitter() Fj?gXc5{  
{ ID/=YG@  
return nSplitter; {yo<19kV@  
} !p&[:+qN  
p$mx  
sqtMhUQ?>w  
public void setNSplitter(int nCount) q%g!TFMg  
{ v}vwk8  
nSplitter = nCount; l70a&[W  
} avJ%J"j8z  
} 8`QbUQ6  
,".1![b  
qL;OE.?oA  
/* P2U^%_~  
**Utility.java ""0 cw  
*/ _,,w>q6K  
package NetFox; 2P`Z >_  
:5YL!D/&  
DZ-2Z@{PX  
public class Utility { C;mcb$@  
Pv- i.  
reBAxmt   
public Utility() ~pv|  
{ Y (a0*fh  
>s 5i  
AQx:}PO  
} Y@jO#6R  
v[++"=< o8  
//线程睡眠 J@ CKgE  
public static void sleep(int nSecond) F.]D\"0`  
{ M<nKk#!+h  
try{ ';>]7oT`  
Thread.sleep(nSecond); h83W;s  
} <$ "   
catch(Exception e) U ]o  
{ zJ"`40V*;  
e.printStackTrace (); U=kP xe  
} e7n[NVrX  
} <8 $fo  
r]sN I[  
//日志 S.4gfY  
public static void log(String sMsg) DlMT<ld  
{ | e? :Uq  
System.err.println(sMsg); ^~ 95q0hq:  
} IqA'Vz,lL  
IBT 1If3  
j aU.hASj  
public static void log(int sMsg) rEoMj)~\4&  
{ bgk+PQ#S-  
System.err.println(sMsg); rpB0?h!$  
} X[e:fW[e)  
} [C>>j;q%  
AG Ws>  
xWiR7~E  
/* fk6`DUBV  
**TestMethod.java ^\(<s  
*/ tg R4C#a   
package NetFox; Bu]PNKIi  
a3f- 9LN  
hw @)W  
public class TestMethod { Rj'Tu0l  
(XU( e  
Bn4wr  
public TestMethod() '{ $7Dbo  
{ ///xx/weblogic60b2_win.exe aVE/qXB  
try{ *!m\%*y{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); iaV%*  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~Y_5q)t(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [C0"vOTUb  
fileFetch.start();  X_\$hF  
} PwC9@c%c  
catch(Exception e){e.printStackTrace ();} |7$Q'3V  
B - 1Kfc  
D;Bij=  
} ~WW!P_wI,  
fe3a_gYPz  
\ cr)O^&  
public static void main(String[] args) w$evAPuz^  
{ ['%$vnS5S  
new TestMethod(); pXhN?joe  
} ] >4CBm$  
} Fd1t/B,  
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