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http断点续传简单实现(java)

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/* n |,}   
**SiteFileFetch.java >273V+dy  
*/ NX+ eig</-  
package NetFox; gY=+G6;=<  
import java.io.*; 6B?1d /8V  
import java.net.*; .fW`/BXE  
VKrKA71Z~  
M[T!AO-S$  
public class SiteFileFetch extends Thread { \}qv}hU  
h"nv[0!)  
|@)ij c4i  
SiteInfoBean siteInfoBean = null; //文件信息Bean /%N~$ &wW  
long[] nStartPos; //开始位置 XlNB9\"5  
long[] nEndPos; //结束位置  })w5`?Y  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 &9g#Vq%   
long nFileLength; //文件长度 &jPsdv h  
boolean bFirst = true; //是否第一次取文件 #$fFp  
boolean bStop = false; //停止标志 ma* 9O |v^  
File tmpFile; //文件下载的临时信息 1Kebl  
DataOutputStream output; //输出到文件的输出流 ck<4_?1]  
)ZmE"  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 9k"nx ,"  
public SiteFileFetch(SiteInfoBean bean) throws IOException n#]G!7  
{ 'XQv>J  
siteInfoBean = bean; RMrt4:-DI  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 86} rz  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); z?YGE iR/}  
if(tmpFile.exists ()) x[oYN9O  
{ AU$5"kBE  
bFirst = false; XJ NKM~  
read_nPos(); -s!PO;qm  
} `RzM)ILl  
else O 1X !  
{ F;NZJEy  
nStartPos = new long[bean.getNSplitter()]; 3 \WdA$Wx  
nEndPos = new long[bean.getNSplitter()]; EX5kF  
} IH0^*f  
#5I "M WA  
?^+|V,<  
u1kbWbHu(  
} ?3, *  
UX9o  
|ZKchd8Yq  
public void run() K^vMIoh  
{ sR0nY8@F  
//获得文件长度 5m3sjcp_  
//分割文件 O&0R ~<n  
//实例FileSplitterFetch V!=]a^]:  
//启动FileSplitterFetch线程 eK@Y] !lz  
//等待子线程返回 p5'\< gQ  
try{ Fy@D&j  
if(bFirst) d$Xvax,C  
{ U\z+{]<<  
nFileLength = getFileSize(); ?0<3"2Db~  
if(nFileLength == -1)  t|DYz#]  
{ >y@w-,1he  
System.err.println("File Length is not known!"); K&h|r`W(  
} ^YZ#P0 y  
else if(nFileLength == -2) MG@19R2s  
{ Dx%fW`  
System.err.println("File is not access!"); ;g*6NzdA  
} (^4%Fk&I-  
else 7> QtO  
{ 32Z4&~ I  
for(int i=0;i<nStartPos.length;i++) dA~6{*)  
{  h 2zCX  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Glr.)PA  
} sig_2;  
for(int i=0;i<nEndPos.length-1;i++) 3N21[i2/m  
{ ;vx9xs?6  
nEndPos = nStartPos[i+1]; HTG;'$H^  
} /P%:u0fX,  
nEndPos[nEndPos.length-1] = nFileLength; >JMKEHl.q  
} S'e2~-p0F  
}  Ui.F<,E  
^eRuj)$5A  
WveFB%@`;  
//启动子线程 1,J.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; x@ O:  
for(int i=0;i<nStartPos.length;i++) $b$D[4  
{ }R x%&29&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {%Y7]*D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;sf/tX  
nStartPos,nEndPos,i); +A3 H#'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a*8}~p,  
fileSplitterFetch.start(); (!(bysi9  
} F*=RP$sj  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B+LNDnjO]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); V_kE"W)  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", sFTIRVXN,  
nEndPos = " + nFileLength); Y(f-e,  
// fileSplitterFetch[nPos.length-1].start(); xd3  
2o/`8+eJu  
Fqv5WoYVf  
//等待子线程结束 F8I <4S  
//int count = 0; @n(In$  
//是否结束while循环 ^q` *!B 9@  
boolean breakWhile = false; Vmc)or*#  
ZJ(!jc$"*%  
aBnbu vp  
while(!bStop) ccSSa u5N  
{ v#FUD-Z  
write_nPos(); C(t/:?(y  
Utility.sleep(500); 96avgyc  
breakWhile = true; luT8>9X^:a  
86g+c  
c"ztrKQQ  
for(int i=0;i<nStartPos.length;i++) 'Ap 5Aq  
{ \YS?}! 0  
if(!fileSplitterFetch.bDownOver) nz\fN?q  
{ rWXW}Yg  
breakWhile = false; |9I;`{@  
break; O)R0,OPb  
} B .mV\W  
} M}Mzm2d#`  
if(breakWhile) *@nUas 2"  
break; ?s]`G'=>V`  
JPG!cX%  
4/?Zp4g  
//count++; fna>>  
//if(count>4) g OM`I+CwT  
// siteStop(); pS;dvZ  
} D.b<I79bX  
0 y%R  
}[`?#`sW  
System.err.println("文件下载结束!"); t,,^^ll  
} v"+EBfx  
catch(Exception e){e.printStackTrace ();}  $wTX  
} b3lpNJ J  
f,>i%.  
<4,?lZ  
//获得文件长度 }o- P   
public long getFileSize() 8B/9{8  
{ uw!|G>  
int nFileLength = -1; "S:N- Tf%U  
try{ 8A.7=C' z  
URL url = new URL(siteInfoBean.getSSiteURL()); 'wrpW#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); tqCg<NH.!m  
httpConnection.setRequestProperty("User-Agent","NetFox"); [@Y q^.6t  
C6~dN& q  
bobkT|s^s  
int responseCode=httpConnection.getResponseCode(); I:<R@V<~#  
if(responseCode>=400) m=B0!Z1xx  
{ !++62Lf  
processErrorCode(responseCode); 9K<a}QJP  
return -2; //-2 represent access is error FOi`TZ8  
} ~*[4DQ[\  
5FI>T=QF  
RfG$Px '  
String sHeader; "lf3hWGw  
9G+rxyWMW  
D:tZiS=0  
for(int i=1;;i++) ycD.:w p\'  
{ ZiYzsn  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); V JL;+  
//Utility.log(in.readLine()); d|RmU/)  
sHeader=httpConnection.getHeaderFieldKey(i);  a|uZJ*  
if(sHeader!=null) 1C=P#MU`  
{ FSs$ ] d;  
if(sHeader.equals("Content-Length")) P'9io!Z-s  
{ WI_mJ/2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]_8I_V cQ  
break; }9 2lr87  
} L$ Ar]O)  
} J6D$ i+  
else Ilb |:x"L  
break; Fjt,  
} $ n[7  
} :-" jK w  
catch(IOException e){e.printStackTrace ();} z|)1l`  
catch(Exception e){e.printStackTrace ();} [Od9,XBa  
.fY<"2g  
l>Ja[`X@  
Utility.log(nFileLength); y4rJ-  
':)j@O3-  
PJ:5Lb<  
return nFileLength; $ywh%OEH  
} E=lfg8yb:  
b2%bgs  
]},Q`n>$  
//保存下载信息(文件指针位置) y7EX&  
private void write_nPos() 1e&b;l'*=  
{ ![ID0}MjJ  
try{ 14!a)Ijl  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9k[},MM  
output.writeInt(nStartPos.length); @i-@mxk6<  
for(int i=0;i<nStartPos.length;i++) {<[tYZmj.  
{ b:cK>fh0_  
// output.writeLong(nPos); ~{Rt4o _W  
output.writeLong(fileSplitterFetch.nStartPos); :k(t/*Nl3  
output.writeLong(fileSplitterFetch.nEndPos); Z;SG<  
} R${4Q1  
output.close(); lY9M<8g  
} N%|Vzc  
catch(IOException e){e.printStackTrace ();} xh^ZI6L<  
catch(Exception e){e.printStackTrace ();} /M*\t.[ 46  
} 8;f<qu|w  
PG[O?l  
{)9HS~e T  
//读取保存的下载信息(文件指针位置) @<TZH  
private void read_nPos() {&u7kWD|  
{ !_H8Q}a  
try{ |SukiXJZF  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); f<4q]HCa  
int nCount = input.readInt(); )X!DCL:16  
nStartPos = new long[nCount]; | 4oM+n;Y  
nEndPos = new long[nCount]; J~'Q^O3@  
for(int i=0;i<nStartPos.length;i++) uNZ>oP>  
{ ^ R^N`V   
nStartPos = input.readLong(); B "F`OS[  
nEndPos = input.readLong(); ^ O Xr: P  
} JKi@Kw  
input.close(); s5aOAyb*w  
} (VPM>ndkw  
catch(IOException e){e.printStackTrace ();} 1S]gD&V  
catch(Exception e){e.printStackTrace ();}  [Ro0eH  
} /Q>{YsRRB  
3/IWO4?_  
],}afa!A  
private void processErrorCode(int nErrorCode) wt=>{JM  
{ E(3+o\w  
System.err.println("Error Code : " + nErrorCode); &G|jzXE  
} YEPG[W<kg  
5OW8G][  
b|8>eY  
//停止文件下载 ,#jhKnk2e  
public void siteStop() +9 p`D  
{ #JR,C -w  
bStop = true; &c?hJ8"  
for(int i=0;i<nStartPos.length;i++) Ed0>R<jR9  
fileSplitterFetch.splitterStop(); q|$>H6H4b  
W*rU,F|9  
,{ L;B  
} f'`nx;@X  
} Re,$<9V  
//负责部分文件的抓取 s!;VUr\  
**FileSplitterFetch.java pg}+lYGP  
*/ .UhBvHH  
package NetFox; ZDkD%SCy  
rE{Xo:Cf  
IL[|CB1v  
import java.io.*; E%\7Uo-  
import java.net.*; w]Ko/;;^2  
90h1e7ZcC  
:_QAjU  
public class FileSplitterFetch extends Thread { ['Y+z2k  
|RAQ%VXm  
:CkR4J!m3  
String sURL; //File URL o=RqegL  
long nStartPos; //File Snippet Start Position _`X#c-J  
long nEndPos; //File Snippet End Position 2hwXWTSu  
int nThreadID; //Thread's ID "X{aS}  
boolean bDownOver = false; //Downing is over Y0u'@l_[F  
boolean bStop = false; //Stop identical 7fW=5wc  
FileAccessI fileAccessI = null; //File Access interface )Rhff$  
\abAPo  
|CZnq-,C  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Oz#EGjz  
{ 78a-3){  
this.sURL = sURL; VmOFX:j!,  
this.nStartPos = nStart; bDFCZH-:'O  
this.nEndPos = nEnd; (&P0la 1  
nThreadID = id; gR-Qj  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [#>$k 6F*  
} ZP6 3Alt  
u_6BHsU  
Iz GB  
public void run() R<lNk<  
{ ]zvVY:v  
while(nStartPos < nEndPos && !bStop) +>!B(j\gx  
{ 5e/qgI)M5  
l@tyg7CwY  
MCi`TXr  
try{ ^0s\/qyqm  
URL url = new URL(sURL); J%\~<_2ny  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x'@32gv  
httpConnection.setRequestProperty("User-Agent","NetFox"); Y0 X"Zw  
String sProperty = "bytes="+nStartPos+"-"; >: W-C{%  
httpConnection.setRequestProperty("RANGE",sProperty); 4QjWZ Wl  
Utility.log(sProperty); i#]aV]IT  
HL(U~Q6JQ  
H7yg9zFT N  
InputStream input = httpConnection.getInputStream(); o1#:j?sN  
//logResponseHead(httpConnection); AJ#m6`M+EK  
.W@(nQ-<  
s?@)a,C%k  
byte[] b = new byte[1024]; <nb3~z1  
int nRead; $p0 /6c  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) DD@)z0W  
{ O+E1M=R6h  
nStartPos += fileAccessI.write(b,0,nRead); S}m$,<x  
//if(nThreadID == 1) 1(%>`=R8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1A?\BJ"  
} 5U)ab3 :  
}#ep}h  
#j^('K|  
Utility.log("Thread " + nThreadID + " is over!"); >9.5-5"   
bDownOver = true; Wiq{wxe  
//nPos = fileAccessI.write (b,0,nRead); 0j{F^rph  
} joChML_  
catch(Exception e){e.printStackTrace ();} C?[a3rNH(  
} B|Fl ,55  
} uO ?Od  
]<8B-D?Z  
X/E7o92\  
//打印回应的头信息 Z@uTkqG)  
public void logResponseHead(HttpURLConnection con) %qS]NC  
{ bSrRsgKvT  
for(int i=1;;i++) w\o)bn  
{ + %MO7vL  
String header=con.getHeaderFieldKey(i); (Pk"NEP   
if(header!=null) aJ5H3X}Y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); pK6e/eC  
Utility.log(header+" : "+con.getHeaderField(header)); mfeMmKFu\  
else HBh` 2Q  
break; mFqSD  
} d)04;[=  
} fjIcB+Z  
_e?q4>B)c  
>Lw}KO`  
public void splitterStop() UTDcX  
{ 5!'R'x5e  
bStop = true; WCuzV7tw  
} E\]OySC%C$  
 Y8)E]D  
p~Hvl3SxR  
} =y< ">-  
ET,Q3X\Oe  
y:[BP4H?y  
/* <#+oQ>5s  
**FileAccess.java eeW' [  
*//文件访问(定位,写) L bJtpwz>z  
package NetFox; 0$eyT-:d  
import java.io.*; ~9JW#HHzn  
XJx,9trH  
$nB-ADRu@  
public class FileAccessI implements Serializable{ !;o\5x<'$O  
]ZzoJ7lr  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 uQGz;F x  
RandomAccessFile oSavedFile; AVXX\n\_  
long nPos; `y\*m]:  
ds*m6#1b  
_\ .  
public FileAccessI() throws IOException <u/a`E?  
{ _4P;+Y  
this("",0); v!NB~"LQ  
} uP{; *E3?  
X}oj_zsy;^  
rQ9*J   
public FileAccessI(String sName,long nPos) throws IOException _Kc 1  
{ Dh2:2Rz=#7  
oSavedFile = new RandomAccessFile(sName,"rw"); 2.[_t/T  
this.nPos = nPos; "| K f'/r  
oSavedFile.seek(nPos); s1X]RXX&j  
} n?'d|h  
&EAk z  
[096CK  
public synchronized int write(byte[] b,int nStart,int nLen) )46 0 Ed  
{ rkxW UDl   
int n = -1; :{[<g](  
try{ u5Qp/ag?N  
oSavedFile.write(b,nStart,nLen); `S"W8_m  
n = nLen; M[ x_#m|  
} dCB&c ^  
catch(IOException e) U?bG`. X  
{ 9*#$0Y=  
e.printStackTrace (); _h0-  
} c{1V.  
Da"yZ\4  
nIfN"  
return n; 'UY[ap  
} ]EB6+x!G  
12idM*  
'@'B>7C#  
} vG Y!4@[  
Y4QLs^IdB  
>@^<S_KVh  
/* RnHQq'J|\  
**SiteInfoBean.java as>:\hjP##  
*/ d i!"IQAvK  
package NetFox; |2z}Xm5\  
{tPnj_|n<  
m"n.Dz/S  
public class SiteInfoBean { \CcmePTN#x  
(nGkZ}p  
F[5S(7M 7  
private String sSiteURL; //Site's URL egfi;8]E  
private String sFilePath; //Saved File's Path Osnyd+dJY  
private String sFileName; //Saved File's Name E]NY (1  
private int nSplitter; //Count of Splited Downloading File GGH;Z WSe  
#C4|@7w%  
'<TD6jBs  
public SiteInfoBean() Hw Z^D= A  
{//nSplitter的缺省值为5 0z/h+,  
//default value of nSplitter is 5 IWQ&6SDW$z  
this("","","",5); Bb~5& @M|N  
} d+tj%7  
0f1H8zV  
DB#$~(o  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) g[M]i6h2  
{ hHpx?9O+!  
sSiteURL= sURL; tyB)HF  
sFilePath = sPath; 8$ic~eJ  
sFileName = sName; 1YFeVMc  
this.nSplitter = nSpiltter; (#oYyM]  
2xDQ :=ec  
J==}QEhQ{  
} qmEoqU  
z OtkC3hY  
f3 !n$lj  
public String getSSiteURL() h6g:(3t6m  
{ L/BHexOB  
return sSiteURL; !}ilN 1>  
} {gsW(T>)  
Vc|NL^  
*%X.ym'  
public void setSSiteURL(String value) T8U[xu.>  
{  =^Th[B  
sSiteURL = value; q-YL]PgV  
} 0 sZwdO  
|) O):  
%l,4=TQ[m  
public String getSFilePath() bhYU5I 9  
{ ha5e(Hj?  
return sFilePath; mf}\s]_c  
} >PIPp7C  
8 }-7{  
ABcBEv3  
public void setSFilePath(String value) [m\,+lG?)j  
{ 8'KMxR  
sFilePath = value; iX{H,- C  
} bo1I&I  
vO]J]][  
'*4iqP R;  
public String getSFileName() MI\]IQU  
{ Ir/:d]N*  
return sFileName; \#++s&06  
} Pg Syt  
Atd1qJ  
 ;1@C_5C  
public void setSFileName(String value) ^sV|ck  
{ ZOuR"9]  
sFileName = value; a%E8(ms37y  
} ENq"mwV|  
=:gjz4}_8  
Ir27ZP  
public int getNSplitter() @0|nq9l1  
{ z?kd'j`FG  
return nSplitter; !lhFKb;  
} <GaT|Hhc=  
B9*Sfw%  
&:No}6  
public void setNSplitter(int nCount) t!{x<9  
{ l<xFnj  
nSplitter = nCount; FZp<|t  
} n' ?4.tb  
} ^X &)'H  
c;wA  
)|RZa|`-G  
/* J)*8|E9P  
**Utility.java Hd 0Xx}3&  
*/ VhvTBo<cw  
package NetFox; (B:uc_+  
.!yq@Q|=u  
| ]# +v@  
public class Utility { C_G1P)k  
z h%qS~8Yv  
2ce'fMV  
public Utility() O&V[g>x"U  
{ rz.IoQo  
3]^'  
<Oa9oM},d  
} t8vc@of$c,  
gI{ =0  
//线程睡眠 6vobta^w  
public static void sleep(int nSecond) 6m+W#]^  
{ JNBT^=x  
try{ R hio7C  
Thread.sleep(nSecond); U:n*<l-k}  
} Ek ZjO Ci  
catch(Exception e) fhRjYYGI  
{ F7T E|LZ  
e.printStackTrace (); ]fE3s{y &-  
} p=B?/Sqa  
} y(v_-6b  
o/1JO_41  
//日志 RZh}:  
public static void log(String sMsg) X+iK<F$  
{ <d"Gg/@a  
System.err.println(sMsg); f`|G]da-3o  
} X NE+(Bt  
} 0;Sk(B>  
C[8KlD  
public static void log(int sMsg) \Y e%o}.{  
{ 0T))>.iu#  
System.err.println(sMsg); {eR9 ;2!  
} {|6z+vR  
} gz61FW  
GNU;jSh5  
s;1e0n  
/* z0Xa_w=  
**TestMethod.java ?3jdg]&  
*/ HO5d%85  
package NetFox; a$m_D!b~_  
9m8ee&,  
C:GvP>  
public class TestMethod { f xtxu?A>  
o56kp3b)b  
~@P)tl>  
public TestMethod() j=ihbR^]Tl  
{ ///xx/weblogic60b2_win.exe Q2c*.Y  
try{ S}7>RHe  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); RmOyGSO  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); WZ?!!   
SiteFileFetch fileFetch = new SiteFileFetch(bean); bulboyA&#  
fileFetch.start(); T~J? AKx  
} ]l[2hy= cV  
catch(Exception e){e.printStackTrace ();} l>7r2;  
J]fS({(\I  
|zpx)8Q  
} e{C6by"j{S  
F=}Z51|:~  
2Va4i7"X\  
public static void main(String[] args) c7qwNs*f  
{ % {Q-8w!  
new TestMethod(); RrWNJ&o  
} vg(K$o{BT  
} f&yQhe6q  
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