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http断点续传简单实现(java)

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/* *~t&Ux#hj  
**SiteFileFetch.java <3[,bTIk  
*/ :{(` ;fJ  
package NetFox; aSKLSl't`  
import java.io.*; 0gI^GJN%Y!  
import java.net.*; }67lL~L  
0 e}N{,&Y  
EH*Lw c  
public class SiteFileFetch extends Thread { 7 )2Co[t  
_I"T(2Au  
<6 LpsM}  
SiteInfoBean siteInfoBean = null; //文件信息Bean Qx B0I/ {  
long[] nStartPos; //开始位置 |wnXBKV(  
long[] nEndPos; //结束位置 f.Uvf^T}2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 mHm"QBa!  
long nFileLength; //文件长度 q0Hor   
boolean bFirst = true; //是否第一次取文件 O?6ph4'  
boolean bStop = false; //停止标志 8"fZ>XQ  
File tmpFile; //文件下载的临时信息 b6@(UneVM  
DataOutputStream output; //输出到文件的输出流 Zj(2$9IU  
|;G9K`8  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) jp~C''Sj  
public SiteFileFetch(SiteInfoBean bean) throws IOException #s4v0auK  
{ #- l1(m  
siteInfoBean = bean; +@U}gk;#c  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); zlUXp0W  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); n<}t\<LG^c  
if(tmpFile.exists ()) 1Qc>A8SU  
{ 2|LgUA?<  
bFirst = false; *8ZaG]L  
read_nPos(); e^N6h3WF  
} Kx-s95t  
else C EzTErn  
{ _{eH" ,(  
nStartPos = new long[bean.getNSplitter()]; @v#]+9F  
nEndPos = new long[bean.getNSplitter()];  Uz;z  
} j4!g&F _y  
&!kD81?Mm  
N"tEXb/,  
4RLuv?,)~  
} &<oZl.T  
([mC!d@a  
\:'|4D]'I  
public void run() h{J=Rq  
{ aSN"MTw.  
//获得文件长度 0q@U>#  
//分割文件 Z=L~W,0'  
//实例FileSplitterFetch c" |4'#S  
//启动FileSplitterFetch线程 1<Z~Gw4  
//等待子线程返回 4iDlBs+  
try{ >~nc7j u  
if(bFirst) @@?P\jv~  
{ L.cGt"{  
nFileLength = getFileSize(); %,Pwo{SH  
if(nFileLength == -1) ySS kw7  
{ "_g3{[es!  
System.err.println("File Length is not known!"); 'S[&-D%(3  
} \-Oq/g{j  
else if(nFileLength == -2) Hn- k*Y/P  
{ Po ,zTz   
System.err.println("File is not access!"); X; ~3 U 9  
} -0 e&>H%  
else gbC!>LV  
{ yY 3Mv/R  
for(int i=0;i<nStartPos.length;i++) 6r|BiHP  
{ e=8z,.Xk  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &fyT}M A  
} xE[CNJ%t^,  
for(int i=0;i<nEndPos.length-1;i++) |i}5vT78  
{ _ ?\4k{ET  
nEndPos = nStartPos[i+1]; ;RmL'  
} rA">< pH  
nEndPos[nEndPos.length-1] = nFileLength; P B W.nm  
} ug|'}\LY  
} }'"4q  
v0d<P2ix  
C6!P8qX  
//启动子线程 Q#,j,h  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #fuc`X3:HL  
for(int i=0;i<nStartPos.length;i++) >z,SN  
{ 6F@2:]W  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {m<NPtp910  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), m^9[k,;K  
nStartPos,nEndPos,i); [pc6!qhDG&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); W@T_-pTCjK  
fileSplitterFetch.start(); 7[b]%i  
} m9&MTR D\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #VLO6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); RfZZqe U  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", G;'=#c ^  
nEndPos = " + nFileLength); _(TYR*  
// fileSplitterFetch[nPos.length-1].start(); SviGLv;oR  
#nzVgV]  
 .L vg $d  
//等待子线程结束 " iKX-VIl  
//int count = 0; TqZ&X| G  
//是否结束while循环 ,rO>5$w.  
boolean breakWhile = false; jgkJF[t`  
#Q6.r.3@x  
cc$L56q  
while(!bStop) W,g0n=2V  
{ HZG<aY="  
write_nPos(); .t7mTpi  
Utility.sleep(500); !Q0aKkMfL  
breakWhile = true; '(qVA>S  
,o_Ur.UJ  
Py3Y*YP  
for(int i=0;i<nStartPos.length;i++) 0VA$ Ige  
{ uPp9 UW  
if(!fileSplitterFetch.bDownOver) + pq/:h  
{ 2f=7`1RCD  
breakWhile = false; Y(` # J[  
break; V&j |St[  
} /=|5YxY  
} %)|_&Rh  
if(breakWhile) qM|-2Zl!+  
break; cSkJlhwNn  
}'FNGn.~#  
r2Wx31j{  
//count++; }I Rx$ cKV  
//if(count>4) hZudVBn  
// siteStop(); +( *;F4>  
} itp$c|{  
:Hn*|+'  
^LO`6,   
System.err.println("文件下载结束!"); \k8|3Y~g  
} 9qqzCMrI0e  
catch(Exception e){e.printStackTrace ();} d- wbZ)BR  
} &>0ape  
+mr\AAFn  
@`hnp:  
//获得文件长度 @ZD/y %e  
public long getFileSize() T9c=As_EM  
{ n1Y3b~E?E  
int nFileLength = -1; UT^-!L LB]  
try{ )/:r $n7  
URL url = new URL(siteInfoBean.getSSiteURL()); @ k`^Z5tN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Dn}Wsd=  
httpConnection.setRequestProperty("User-Agent","NetFox"); !JkH$~  
X+: >&&9  
X~H ~k1  
int responseCode=httpConnection.getResponseCode(); 77:s=)   
if(responseCode>=400) TC2gl[  
{ v7L} I[f  
processErrorCode(responseCode); K~?M?sa  
return -2; //-2 represent access is error Tt0:rQ.  
} |&>!"27;w  
'+ 8.nN  
@k~_ w#  
String sHeader; frYPC Irj  
6]#\|lds1  
!A6l\_  
for(int i=1;;i++) c1,dT2:=  
{ !Gphs`YI  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); s`bC?wr5h  
//Utility.log(in.readLine()); A(xCW+h@)  
sHeader=httpConnection.getHeaderFieldKey(i); (4U59<ie  
if(sHeader!=null) Ix"hl0Kh  
{ )ZU=`!4  
if(sHeader.equals("Content-Length")) L 1fK  
{ V?k"BU  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); %/^k r ZD  
break; Xgy)Z:R  
} s 4Mi9h_  
} 05|,-S  
else wc-ll&0Z  
break; ql Uw;{;p  
} 7jb{E+DrG  
} &I[ITp6y 0  
catch(IOException e){e.printStackTrace ();} Qe~2'Hw#9  
catch(Exception e){e.printStackTrace ();} Qoj}]jve  
8Jz/'  
a-`OE"  
Utility.log(nFileLength); .45XS>=z#  
cI5*`LML1  
#&@qmps(T  
return nFileLength; O$><E8q  
} t*fG;YOg  
+3c!.] o;  
x bG'![OX  
//保存下载信息(文件指针位置) %Jrdr`<  
private void write_nPos() NMSpi[dr  
{ a=55bEn  
try{ '.@'^80iQ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3b_tK^|'  
output.writeInt(nStartPos.length); i w,F)O  
for(int i=0;i<nStartPos.length;i++) {(DD~~)D  
{ 3wS{@'  
// output.writeLong(nPos); !  Z e  
output.writeLong(fileSplitterFetch.nStartPos); S;o U'KOY  
output.writeLong(fileSplitterFetch.nEndPos); )$#r6fQO  
} dh7PpuN{  
output.close(); _HT*>-B  
} 0I.9m[<Fc  
catch(IOException e){e.printStackTrace ();} 3X+uJb2  
catch(Exception e){e.printStackTrace ();} !Q,A#N(  
} S=Ihg  
@~!1wPvF`I  
a<.7q1F  
//读取保存的下载信息(文件指针位置) >.D0McQg  
private void read_nPos() ;w(]z  
{ + *YGsM`E9  
try{ BO5gwvyI  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); %j].' ;  
int nCount = input.readInt(); QK5y%bTSA  
nStartPos = new long[nCount]; 728}K^7:  
nEndPos = new long[nCount]; 2$D *~~  
for(int i=0;i<nStartPos.length;i++) 5G~;g  
{ eQk ~YA]K  
nStartPos = input.readLong(); fwy-M:  
nEndPos = input.readLong(); 8ycmvpJ  
} 26fm }QV  
input.close(); Fr%LV#Q  
} &`a$n2ycy  
catch(IOException e){e.printStackTrace ();} W|U!kqU  
catch(Exception e){e.printStackTrace ();} h(,SAY_  
} hT&,5zaWdv  
(D'Z4Y  
wz*QB6QtU  
private void processErrorCode(int nErrorCode) 2a;vLc4  
{ i^{.Q-  
System.err.println("Error Code : " + nErrorCode); c<V.\y0x  
} r<;bArs-u  
W{OlJRX8  
{IeW~S' &  
//停止文件下载 .+G),P)   
public void siteStop() U*Z P>Vv  
{  qO  
bStop = true; ]P TTI\n  
for(int i=0;i<nStartPos.length;i++) PN{l)&K2.  
fileSplitterFetch.splitterStop(); u7u8cVF  
l`2X'sw[/  
I/bED~Z:a  
} 9=&e5Oq}  
} QZBXI3%#s  
//负责部分文件的抓取 Sf}>~z2  
**FileSplitterFetch.java |Xblz1>DF  
*/ IMY?L  
package NetFox; d7A08l{  
gmfux b/  
\s2hep  
import java.io.*; -ob_]CKtJ~  
import java.net.*; ZdEeY|j  
a1p:~;f}[  
DBl.bgf  
public class FileSplitterFetch extends Thread { 0f vQPs!O  
,P^pDrc  
 Z*d8b  
String sURL; //File URL #&.& Uu$  
long nStartPos; //File Snippet Start Position d:0RDK-}s  
long nEndPos; //File Snippet End Position 2}u hPW+  
int nThreadID; //Thread's ID Fzk  
boolean bDownOver = false; //Downing is over Y[gj2vNe4g  
boolean bStop = false; //Stop identical ?JTy+V2t  
FileAccessI fileAccessI = null; //File Access interface f>JuxX\G  
pN<wO1\9  
lgZ3=h  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )5lo^Qb  
{ b=a&!r5M  
this.sURL = sURL; xm>RLx}9  
this.nStartPos = nStart; DCb\ =E  
this.nEndPos = nEnd; ze Qgg|;  
nThreadID = id; c,KT1me  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 YzU(U_g$  
} ;YxQo o >  
&I.UEF2,  
mt7}1s,i[  
public void run() /%Bc*k=ox  
{ sk!v!^\_r  
while(nStartPos < nEndPos && !bStop) Wy%q9x]}  
{ QP|Ou*Qm)  
B^Q\l!r  
zIWw055W  
try{ SsDz>PP  
URL url = new URL(sURL); RqW ZhHI1M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q7$ILW-S  
httpConnection.setRequestProperty("User-Agent","NetFox"); N<+ ><>9  
String sProperty = "bytes="+nStartPos+"-"; %4U;Rdq&Ud  
httpConnection.setRequestProperty("RANGE",sProperty); vm)&WEL!  
Utility.log(sProperty); ?eT^gWX  
]#N2:ych  
~$>l@> xX  
InputStream input = httpConnection.getInputStream(); 9^J8V]X  
//logResponseHead(httpConnection); 80cBLGG  
~C< X~$y&  
WO$PW`k  
byte[] b = new byte[1024]; @L^2VVWk^  
int nRead; ^Sx 0t  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) < pI2}  
{ _3h(R`VdWO  
nStartPos += fileAccessI.write(b,0,nRead); cTm oz.0  
//if(nThreadID == 1) JwbC3 t):@  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xA]CtB*o7  
} |@={:gRJ{x  
-UkP{x)S  
>z6 (fM`i  
Utility.log("Thread " + nThreadID + " is over!"); `h12  
bDownOver = true; {zBf*x  
//nPos = fileAccessI.write (b,0,nRead); r00waw>C\  
} C$\|eC j  
catch(Exception e){e.printStackTrace ();} <OF7:f  
} o:_}=1nh  
} s S8Z5k;  
km'3[}8o&  
S2K_>kvG)~  
//打印回应的头信息 ^AMcZ6!\  
public void logResponseHead(HttpURLConnection con) qSj2=dlW  
{ _*6nTSL  
for(int i=1;;i++) r_T\%  
{ }% JLwN  
String header=con.getHeaderFieldKey(i);  vrdlI^  
if(header!=null) ,"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); jdQ`Y+BC  
Utility.log(header+" : "+con.getHeaderField(header)); -,Cx|Nl  
else 9_[TYzpB!  
break; }6.R.*Imz  
} :kqJ~  
} npg.*I/>  
on $?c  
|\2z w _o  
public void splitterStop() /ZZo`   
{ 33|>u+  
bStop = true; OBi9aFoQ  
} _)Q) tOW  
( =0W[@k  
2}>jq8Y47  
} rH8^Fl&jT  
`GS!$9j  
;oV dkp  
/* ,rc5r3  
**FileAccess.java y.2_5&e/  
*//文件访问(定位,写) +:?-Xd:p  
package NetFox; DCM ,|FE  
import java.io.*; @Z~lM5n$8  
BKfcK>%g  
{<iIL3\mC  
public class FileAccessI implements Serializable{ :j9{n ,F  
[Rw0']i`4  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节  Ek(. ["  
RandomAccessFile oSavedFile; FGu:8`c9  
long nPos; $n& alcU  
Jf@M>BT^A  
$[5ihV$u  
public FileAccessI() throws IOException y7dnXO!g9-  
{ 2 ]5dSXD  
this("",0); [jve |-v=  
} w-};\]I  
YvE$fX=  
2Ch!LS:+  
public FileAccessI(String sName,long nPos) throws IOException g !w7Yv  
{ X|t?{.p  
oSavedFile = new RandomAccessFile(sName,"rw"); h<\o[n7j  
this.nPos = nPos; mm\Jf  
oSavedFile.seek(nPos); `o yz"07m  
} ct=|y(_  
7(^<Z5@  
G!T)V2y  
public synchronized int write(byte[] b,int nStart,int nLen) zg2A$Fd[j  
{ Oyhl*`-*t  
int n = -1; [>::@[  
try{ _,_>B8  
oSavedFile.write(b,nStart,nLen); pa Uh+"y>  
n = nLen; F.ryeOJ  
} PcC9)x  
catch(IOException e) p>h B&h  
{ DtG><g}[]  
e.printStackTrace (); Fh9`8  
} ~Y@(  
e4u$+  
qCOv4b`  
return n; >/nS<y>  
} VS@o_fUx)  
r<cyxR~  
Lw\ANku  
} "12.Bi.O"[  
@4Z>;  
$Ll]h</Z  
/* e5maZ(.;F  
**SiteInfoBean.java ,,S5 8\x  
*/ 'W usEME  
package NetFox; sh[Yu  
\Xc6K!HJM  
{EGiGwpf  
public class SiteInfoBean { %ribxgmd  
, fFB.q"  
\ F#mwl,>"  
private String sSiteURL; //Site's URL Xg?hh 0s  
private String sFilePath; //Saved File's Path .9+"rK}u  
private String sFileName; //Saved File's Name k-xh-&  
private int nSplitter; //Count of Splited Downloading File RoSh|$JF  
o1YX^-<[F  
'x{g P?.  
public SiteInfoBean() <iunDL0  
{//nSplitter的缺省值为5 n( l!T 7  
//default value of nSplitter is 5 G<OC99;8  
this("","","",5); 1VL!0H  
} ~'KymarPU  
LOpn PH`  
qEPvV  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) yjvzA|(YC  
{ 6 /gh_'&  
sSiteURL= sURL; p#hs8xz  
sFilePath = sPath; &!]$#  
sFileName = sName; %&5 !vK  
this.nSplitter = nSpiltter; @B %m,Mx  
`4__X;  
P66{l^  
} !ccKbw)J#  
Re-~C[zwT  
DZ5%-  
public String getSSiteURL() <at/z9b  
{ f@l$52f3D  
return sSiteURL; z(d@!Cd  
} >J^bs &j  
0?  (  
u@5vK2  
public void setSSiteURL(String value) -v .\CtpHv  
{ V.#,dDC@j  
sSiteURL = value; Ls)y.u  
} l-xKfp`  
b|U&{I>TH  
zJWBovT/  
public String getSFilePath() Kj,C 9  
{ h!ZEZ|{  
return sFilePath; EGL1[7It`  
} ojU:RRr4l$  
~Z!!wDHS  
3US}('  
public void setSFilePath(String value) exrsYo!%  
{ - FV$Sne  
sFilePath = value; L ?g|:  
} *`OgwMr)M  
$7eO33Bm  
i71 ,  
public String getSFileName()  hX?L/yf  
{ g^@ Kx5O\  
return sFileName; #3vq+mcn  
} Og[NRd+  
jOj`S%7  
7yo/ sb9h  
public void setSFileName(String value) ,o7aIg&_H  
{ tgK$}#.*  
sFileName = value; uSCF;y=1g,  
} QEK,mc3  
0KO_bF#EB=  
*c4uCI:0t  
public int getNSplitter() gQ4Q h;  
{ HMGby2^+  
return nSplitter; ;SoKX?up5  
} }VxbO8\b(  
P3V=DOG"  
BV,P;T0"D  
public void setNSplitter(int nCount) L&M6s f$N  
{ )k@W 6N  
nSplitter = nCount; /Y@^B,6 \  
} yep`~``_  
} DqyJ]}|  
. [DCL  
/3->TS  
/* _yY(&(]#  
**Utility.java XlIRedZ{  
*/ .r[b!o^VR  
package NetFox; 6}wXNTd  
H~E(~fl  
T.O^40y  
public class Utility { ',j'Hf  
wr{03mQHxp  
f>\OT   
public Utility() w='1uV<6  
{ ktLXL;~X  
T)wc{C9w  
0Ci\(  
} 5Nc~cD%0tK  
M,@\*qlEJ  
//线程睡眠 {;0j9rr  
public static void sleep(int nSecond) 'WK}T)o  
{ Qb}7lm{r  
try{ %"^$$$6%  
Thread.sleep(nSecond); }rf_:  
} tn\Y:  
catch(Exception e) a$ a+3}\  
{ )R$+dPu>  
e.printStackTrace (); 7uG@ hL36  
} #PUvrA2Zl  
} dA >=#/"  
A5-y+   
//日志 OJ8ac6cJ  
public static void log(String sMsg) F{}mlQg  
{ iTsmUq<b]l  
System.err.println(sMsg); Qj: D=j8  
} RG/M-  
h- .V[]<  
3qOq:ZkQ  
public static void log(int sMsg) ~$XbYR-  
{ _[;>V*?zp5  
System.err.println(sMsg); <>$`vuU  
} .,zrr&Po  
} yoa"21E$  
xLX<. z!r  
58\rl G  
/* v#*9rNEj0  
**TestMethod.java lJ.:5$2H  
*/ 'Lu7cb^  
package NetFox; <>/0 ;J1<  
IJHNb_Cku  
@ hH;d\W#  
public class TestMethod { 2[f8"'lUQ  
?dMyhU}  
z{:T~s  
public TestMethod() P#-9{T   
{ ///xx/weblogic60b2_win.exe ZN>oz@j Y  
try{ GJz d4kj  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7=C$*)x  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *i zPLM}+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); K6<@DP+/  
fileFetch.start(); y1R53u`;L  
} K{)N:|y%!$  
catch(Exception e){e.printStackTrace ();} 1}+lL)-!  
5&a4c"fU  
M{I8b<hY  
} ipU,.@~#  
SA_5..  
=au7'i|6  
public static void main(String[] args) kBolDPvBG  
{ 0'y9HE'e  
new TestMethod(); ufF$7@(+  
} OZ 4uk.)  
} xGsg'  
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