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http断点续传简单实现(java)

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/* -|#{V.G3'  
**SiteFileFetch.java xyk%\&"7  
*/ x'x5tg  
package NetFox; bt)C+|i  
import java.io.*; U+x^!{[/  
import java.net.*; %%s)D4sW  
9efey? z  
S9Yzvq!(  
public class SiteFileFetch extends Thread { 3d6z_Yd:  
rC^ 5Z  
:kR>wX  
SiteInfoBean siteInfoBean = null; //文件信息Bean c#{lXS^  
long[] nStartPos; //开始位置 MOaI~xZ  
long[] nEndPos; //结束位置 iF^qbh%%E  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 T:@6(_Z  
long nFileLength; //文件长度 yogavCD9b/  
boolean bFirst = true; //是否第一次取文件 \(i'iC  
boolean bStop = false; //停止标志 N<rq}^qo  
File tmpFile; //文件下载的临时信息 lfHN_fE>Mq  
DataOutputStream output; //输出到文件的输出流 7s?#y=M  
7! >0  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) FAdTm#tgW]  
public SiteFileFetch(SiteInfoBean bean) throws IOException . f ja;aG  
{ e+lun -  
siteInfoBean = bean; M\m:H3[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `CS\"|z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Lxp}o7>K  
if(tmpFile.exists ()) 6~%><C  
{ ? ;CIS$$r  
bFirst = false; RQQ' Wg  
read_nPos(); 'cpm 4mT  
} &>Ve4!i q  
else I2$DlEke  
{ \ T#|<=  
nStartPos = new long[bean.getNSplitter()]; =m2_:&@0x  
nEndPos = new long[bean.getNSplitter()]; W:RjWn@<  
} 2~$S @c  
:lB`K>)iB}  
j J{F0o  
LRu,_2"  
} rH`\UZ{cc  
prj(  
940:NOgm  
public void run() DH?n~qKpC  
{ _gqqPny4$  
//获得文件长度 @FN|=?8%  
//分割文件 nKm# kb  
//实例FileSplitterFetch p [C 9g  
//启动FileSplitterFetch线程 (&SU)Uvu  
//等待子线程返回 ~6t!)QATnp  
try{ $vu*# .w  
if(bFirst) -n9&W  
{ ^\ x'4!W  
nFileLength = getFileSize(); 2X\Pw  
if(nFileLength == -1) -H6[{WVW!  
{ m~ ah!QM  
System.err.println("File Length is not known!"); MTtx|L\4  
} ej-A =avd  
else if(nFileLength == -2) %JE>Z]  
{ xkDK5&V  
System.err.println("File is not access!"); $~b6H]"9  
} i`gM> q&  
else <4Gy~?  
{ $.Tn\4z&  
for(int i=0;i<nStartPos.length;i++) VG 5*17nf5  
{ -rsbSt ?_  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); (Y)2[j  
} OWewV@VXR  
for(int i=0;i<nEndPos.length-1;i++) lk 1\|Q I  
{ 53:~a  
nEndPos = nStartPos[i+1]; <8b1OdA  
} (U&  
nEndPos[nEndPos.length-1] = nFileLength; -SM_JR3<  
} $$m0mK  
} P5?VrZy  
_ARG "  
BF W b0;+  
//启动子线程 Qa_V  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; g:fvg!_v  
for(int i=0;i<nStartPos.length;i++) R#hy2kA  
{ PN93.G(W  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vQ*[tp#qU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0fewMS*  
nStartPos,nEndPos,i); FJZ'P;3  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |;US)B8}*Z  
fileSplitterFetch.start(); Dq<la+VlO  
} \~*<[.8~  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <{cY2cx~3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6 ^3RfF^W  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", QZ&(e2z  
nEndPos = " + nFileLength); [cnu K  
// fileSplitterFetch[nPos.length-1].start(); o>8~rtl  
<Ja&z M  
1+Gq<]@G  
//等待子线程结束 T]wI)  
//int count = 0; kaCN^yQ  
//是否结束while循环 Ge`7`D>L  
boolean breakWhile = false; wL8j i>"  
$L= Dky7  
`*vO8v  
while(!bStop) .JLJ(WM  
{ *gwaW!=  
write_nPos(); "/6#Z>y  
Utility.sleep(500); 1k6asz^T  
breakWhile = true; OY{fxBb  
{C 5:as  
eP]y\S*P  
for(int i=0;i<nStartPos.length;i++) #1haq[Uv7  
{ /iO"4%v  
if(!fileSplitterFetch.bDownOver) DKt98;  
{ C<J*C0vQO  
breakWhile = false; 8S#$'2sT  
break; yDqwz[v b  
} iKaX8c,zI  
} /#Pm'i>B  
if(breakWhile) u"qu!EY2  
break; {*O%A  
0FcDO5ia  
-]0:FKW  
//count++; CBd%}il  
//if(count>4) bBs{PI2(p1  
// siteStop(); O6Py  
} 5&s6(?,Eu  
 9Do75S{(  
p"hO6b%V  
System.err.println("文件下载结束!"); 0;TiNrzg  
} x4v:67_^  
catch(Exception e){e.printStackTrace ();} &)k=ccm  
} 73X*|g  
^}~Q(ji7  
hOB<6Tm[  
//获得文件长度 n' mrLZw  
public long getFileSize() SEI0G_wk$  
{ fsjLD|?|:  
int nFileLength = -1; i[KXkjr  
try{ 9wR D=a  
URL url = new URL(siteInfoBean.getSSiteURL()); z|3v~,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @]n8*n  
httpConnection.setRequestProperty("User-Agent","NetFox"); q.=Q  
H7+z"^s*  
"~ID.G|<  
int responseCode=httpConnection.getResponseCode(); SOR\oZ7  
if(responseCode>=400) nqH[ y0  
{ VvW4!1Dl  
processErrorCode(responseCode); \YzKEYx+  
return -2; //-2 represent access is error qR cSB  
} HjK8y@j  
.fzyA5@l  
7Y@]o=DIc  
String sHeader; Nmx\qJUR(  
` 1+*-g^r  
1K3XNHF  
for(int i=1;;i++) /)TeG]Xg  
{ -E\G3/*51  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); /rZk^/'  
//Utility.log(in.readLine()); /4Wf\ Zu  
sHeader=httpConnection.getHeaderFieldKey(i); $EY[CA E  
if(sHeader!=null) X i"9y @  
{ 0 8L;u7u  
if(sHeader.equals("Content-Length")) tkV[^OeU>  
{ qWW\d' , .  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); K{_~W yRF  
break; H'3 pHb  
} S=P}Jpq?Y;  
}  _:\rB  
else Q(<A Yu  
break; PFpFqJ)Cs"  
} dsw^$R}   
} nq?+b >//  
catch(IOException e){e.printStackTrace ();} RTVU3fw  
catch(Exception e){e.printStackTrace ();} <y?+xZM]#|  
** m8 HD  
2j4202  
Utility.log(nFileLength); TFb7P/g  
9)+!*(D  
4e>f}u 5  
return nFileLength; ?&0CEfa?  
} FMCA~N  
XwEMF5[  
D>jtz2y=D  
//保存下载信息(文件指针位置) Ch?yk^cY  
private void write_nPos() BD]J/o  
{ KLM6#6`  
try{ z#RwgSPw6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); H9jlp.F  
output.writeInt(nStartPos.length); {G=>WAXo  
for(int i=0;i<nStartPos.length;i++) e;=R8i  
{ ^kK")+K  
// output.writeLong(nPos); pWzYC@_W  
output.writeLong(fileSplitterFetch.nStartPos); a`yCPnB(  
output.writeLong(fileSplitterFetch.nEndPos); -ioO8D&!  
} 0*]0#2Z  
output.close(); prO&"t >  
} )Mq4p'*A[  
catch(IOException e){e.printStackTrace ();} VB/75xK_  
catch(Exception e){e.printStackTrace ();} =UO7!vr;[  
} ]z7pa^  
0o7o;eN  
-U> )B  
//读取保存的下载信息(文件指针位置) ,hNs{-*  
private void read_nPos() RoHX0   
{ sifjmNP  
try{ G :+D1J]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); A\mSS  
int nCount = input.readInt();  XU"G  
nStartPos = new long[nCount]; Wx/PD=Sf&  
nEndPos = new long[nCount]; *9KT@"v  
for(int i=0;i<nStartPos.length;i++) H '5zl^8I  
{ -"yma_  
nStartPos = input.readLong(); $n8&5<  
nEndPos = input.readLong(); Dp*:oMATx0  
} @QJPcF"  
input.close(); T^8`ji  
} 68~]_r.a  
catch(IOException e){e.printStackTrace ();} 1| WDbk  
catch(Exception e){e.printStackTrace ();} D {E,XOi  
} Xl$r720ZJr  
E\4ZUGy0  
~]%re9jGW  
private void processErrorCode(int nErrorCode) rr1,Ijh{D  
{ F'<XB~ &o  
System.err.println("Error Code : " + nErrorCode); : [?7,/w  
} D@w&[IF  
p&(z'd  
mtFC H  
//停止文件下载 meB9 :w[m  
public void siteStop() %j2:W\g:  
{ }cW8B"_"  
bStop = true; sn[<Lq  
for(int i=0;i<nStartPos.length;i++) QWm g#2'  
fileSplitterFetch.splitterStop(); Or/YEt}  
aAu%QRq  
(8S+-k?  
}  iU{\a,  
} >PWDo  
//负责部分文件的抓取 V:D?i#%,z  
**FileSplitterFetch.java ,!AYeVq  
*/ KdlUa^}D  
package NetFox; V+' zuX  
!Y^B{bh  
_B 4 N2t$  
import java.io.*; L eUp!  
import java.net.*; gv jy'Rm  
>0N$R|B&  
( F R  
public class FileSplitterFetch extends Thread { K#v@bu:'  
v>hc\H1P  
NCkrf]*F-  
String sURL; //File URL l0!`>Xx[b  
long nStartPos; //File Snippet Start Position !9C]Fs*`?  
long nEndPos; //File Snippet End Position v~^*L iP+  
int nThreadID; //Thread's ID *~#`LO  
boolean bDownOver = false; //Downing is over {R~L7uR @O  
boolean bStop = false; //Stop identical 3gCP?%R  
FileAccessI fileAccessI = null; //File Access interface Kv5 !cll5  
#B$_ily)  
Fvv/#V^R  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException =6'D/| 3  
{ $xcU*?=K  
this.sURL = sURL; ac43d`wpK  
this.nStartPos = nStart; d m83YCdL  
this.nEndPos = nEnd; @`sZV8  
nThreadID = id; z[+pN:47  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *q1sM#;5  
} KH$o X\v  
>va9*pdJ  
OYfP!,+bn  
public void run() _rUsb4r  
{ "y .(E7 6  
while(nStartPos < nEndPos && !bStop) "X1{*  
{ /h!iLun7I  
a^L'-(  
#Nv0d|0\  
try{ @:u2{>Yl  
URL url = new URL(sURL); 5)K?:7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !\Q/~p'jS  
httpConnection.setRequestProperty("User-Agent","NetFox"); Y,%G5X@S<  
String sProperty = "bytes="+nStartPos+"-"; #0M,g  
httpConnection.setRequestProperty("RANGE",sProperty); ra\2BS)X  
Utility.log(sProperty); &2Cu"O'.i  
JR/^Go$^  
yc$8X sns  
InputStream input = httpConnection.getInputStream(); ps]s Tw  
//logResponseHead(httpConnection); 8+~|!)a  
 0c:j wtf  
""F' Nzy  
byte[] b = new byte[1024]; _i&awm/U  
int nRead; e,0Gc-X[B  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) dzc.s8T(0  
{ 5zI I4ukn*  
nStartPos += fileAccessI.write(b,0,nRead); b"#|0d0  
//if(nThreadID == 1) )x&}{k6 %  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); e0u* \b  
} N|WR^MQD  
Y]1b3 9O  
RiAY>:  
Utility.log("Thread " + nThreadID + " is over!"); sJ/?R:  
bDownOver = true; ~%:23mIk  
//nPos = fileAccessI.write (b,0,nRead); DadlCEZv  
} ZTSNM)f  
catch(Exception e){e.printStackTrace ();} WAbt8{$D  
} >/F,Z%! &q  
} (/l9@0Y.t  
=C2,?6!  
TL_8c][.4$  
//打印回应的头信息 ijWn,bj  
public void logResponseHead(HttpURLConnection con) ,U/ZG|=v  
{ j'JNQo;q  
for(int i=1;;i++) DW~< 8  
{ ;GxKPy  
String header=con.getHeaderFieldKey(i); {p(.ck ze+  
if(header!=null) liq9P,(  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 'Sjcm@ILm  
Utility.log(header+" : "+con.getHeaderField(header)); ~I)\d/7o  
else Vg4N7i  
break; 6~0. YZ9  
} /\M3O  
} 0 /JusQ  
:Keek-E`e=  
!pLQRnI}6  
public void splitterStop() Li_ a|dI  
{ 0dgp<  
bStop = true; g"sW_y_O  
} 6muZE1sn  
,.<l^sj5  
;M"JN:J8  
} 8wqHr@}p  
sP5\R#  
QGnBNsAh  
/* ajz%3/R  
**FileAccess.java &iDX+*(  
*//文件访问(定位,写) 9n"D/NZB  
package NetFox; H-o>| C  
import java.io.*; bR!*z  
BHw/~Hd4  
;  u0 MY  
public class FileAccessI implements Serializable{ RE(R5n28,  
k%)QrRnB  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |};P"&  
RandomAccessFile oSavedFile; Jtxwt[  
long nPos; t)O$W   
D f H>UA  
DLv\]\h}L  
public FileAccessI() throws IOException .W<yiB}^  
{ zviEk/:zm  
this("",0); iIoeG_^*Y  
} 4c*?9r@  
EI*B(  
-*u7MFq_  
public FileAccessI(String sName,long nPos) throws IOException J ;=~QYn[  
{ T8 ,?\7)S9  
oSavedFile = new RandomAccessFile(sName,"rw"); !giL~}j(R  
this.nPos = nPos; y pv~F  
oSavedFile.seek(nPos); OFTyN^([@  
} }Zue?!KQ  
I|*w?i*  
emo@&6*  
public synchronized int write(byte[] b,int nStart,int nLen) tN=B9bm3j  
{ R(sPU>`MX  
int n = -1; ?6F\cl0.  
try{ 7Rf${Wv0  
oSavedFile.write(b,nStart,nLen); l#_(suo64  
n = nLen; I]|X6  
} FDA``H~  
catch(IOException e) )Fh+6  
{ B`x rdtW  
e.printStackTrace (); Fcc\hV;  
} |Fk>NX  
90o G+T4  
xG JX~)  
return n; dMw0Aw,2]8  
} ]kQ*t{\  
+,&8U&~`  
0L_ JP9e  
} O9#8%p% )  
_s/ 5oRHA  
v&p|9C@  
/* HrH-e= j  
**SiteInfoBean.java 5J^S-K^r  
*/ 82.::J'e  
package NetFox; J|-X?V;ZW  
IvFxI#.ju  
l&@]   
public class SiteInfoBean { B zmmE2~*  
A{Jp>15AVg  
 $^F L*w  
private String sSiteURL; //Site's URL UMN3.-4K#  
private String sFilePath; //Saved File's Path 3xSt -MA  
private String sFileName; //Saved File's Name -\OvOkr  
private int nSplitter; //Count of Splited Downloading File C:+-T+m[  
\a+.~_iL|  
rz%8V igb  
public SiteInfoBean() xx`xDD  
{//nSplitter的缺省值为5 y3^<rff3Gc  
//default value of nSplitter is 5 mhZ{}~  
this("","","",5); 9?5'>WO  
} b*w@kLLN  
?6;9r[ p  
W_:3Sj l'  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) v803@9@  
{ WZ\bm$  
sSiteURL= sURL; A dNQS  
sFilePath = sPath; ^=f<WKn  
sFileName = sName; WC6yQSnY&  
this.nSplitter = nSpiltter; I d6H~;  
OIpkXM  
*E*= ;BG  
} 'aYUF&GG  
V\$'3(*  
[Yr }:B <  
public String getSSiteURL() Wt|IKCx   
{ By& T59  
return sSiteURL; AgEX,SPP  
} 5L6_W -n{  
PE $sF ]/  
i2]7Bf)oV  
public void setSSiteURL(String value) pZo:\n5o  
{ |]--sUx:  
sSiteURL = value; BG>fLp  
} -MEp0  
|\/`YRg>  
gEghDO_G  
public String getSFilePath() 00jWs@K  
{ Q&j-a;L  
return sFilePath; z TYHwx  
} +ZFw3KEkz  
#m x4pf{  
='!E;  
public void setSFilePath(String value) muh[wo  
{ MI^@p`s  
sFilePath = value; tB S+?N  
} BlwAD  
+,7nsWV  
yx0wR  
public String getSFileName() PIk2mX/D_6  
{ in-|",O`Z  
return sFileName; tu5g> qb  
} " pg5w  
~e|RVY,  
}W2FF  
public void setSFileName(String value) >A5*=@7bY?  
{ 0R2KI,WI  
sFileName = value; WC& V9Yk  
} <{ZDD]UGs0  
ltQo_k  
i}u,_ }  
public int getNSplitter() (AYzN3 ?D  
{ b+=@;0p*6B  
return nSplitter; !wbO:py[8>  
} O*Gg57a  
O`?qnNmc;  
(,nQ7,2EX  
public void setNSplitter(int nCount) k4N_Pa$}\  
{ E?v9c>c  
nSplitter = nCount; &`@S_YLr  
} 6 zyxGJ(  
} ]A? (OA  
o,r72>|  
?04jkq&  
/* 5#275Hyv  
**Utility.java W;Y"J_  
*/ ;$nCQ/ /  
package NetFox; 0P_=Oy"l-  
/penB[ 1i  
NL^;C3u  
public class Utility { kAV4V;ydh  
53X i)  
u~O9"-m !V  
public Utility() ;AH8/M B9  
{ .-Z=Aa>  
ZVX1@p  
B4 k5IS  
} 6o:b(v&Oo  
$?Km3N\?v  
//线程睡眠 fA$2jbGW  
public static void sleep(int nSecond) ltWEA  
{ L`2(u!i J  
try{ t.rlC5 k  
Thread.sleep(nSecond); XY`{F.2h  
} XWq`MwC9  
catch(Exception e) }H Ct=W`  
{ &0*7]Wo*  
e.printStackTrace (); ]D.} /g  
} m~I@ q [  
} q!10 G  
(X?HuWTm  
//日志 !We9T)e  
public static void log(String sMsg) *w#^`yeo  
{ 9kzJ5}  
System.err.println(sMsg); V3S"LJ  
} uQhI)  
`uwSxt  
=L\&} kzB  
public static void log(int sMsg) Kj7 ?_o{  
{ +B '<0  
System.err.println(sMsg); X :#}E7]j  
} N,bH@Q.Ci  
} 7VIfRN{5n  
&q7}HO/ @  
Mdw"^x$7  
/* ~hxW3e  
**TestMethod.java YB+My~fw{l  
*/ 2!)|B ;y  
package NetFox; [-0=ZKH?  
+ Pc2`,pw|  
H73 r3BH  
public class TestMethod { Pk3b#$+E  
:@b=;  
fKbg?  
public TestMethod() j6d{r\!$4  
{ ///xx/weblogic60b2_win.exe *snY|hF  
try{ %$<v:eMAs  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); r0Zj'F_e  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); C14"lB.  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3o2x&v  
fileFetch.start(); 84_Y+_9  
} *kt|CXxAS8  
catch(Exception e){e.printStackTrace ();} *qA:%m3  
<lZVEg  
w5+(A_  
} v =_Ds<6n  
en"\2+{Cg  
}U^iVq*  
public static void main(String[] args) Xf;_r+;  
{ mwMcAUD]2  
new TestMethod(); Sa-" G`  
} F AQx8P  
} k?}y@$[)  
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