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http断点续传简单实现(java)

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/* va!fJ  
**SiteFileFetch.java \\Nt^j3qR  
*/ -'Z-8  
package NetFox; J5}?<Dd:  
import java.io.*; Z*.rv t  
import java.net.*; Q>TNzh  
jV#1d8qm  
R  xc  
public class SiteFileFetch extends Thread { G9CL}=lJ,  
6dYa07  
iAXF;'|W  
SiteInfoBean siteInfoBean = null; //文件信息Bean @QDpw1;V'  
long[] nStartPos; //开始位置 tZ:fh  p  
long[] nEndPos; //结束位置 DN;$ ->>  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9+~1# |  
long nFileLength; //文件长度 kE1k@h#/  
boolean bFirst = true; //是否第一次取文件 +[pJr-k  
boolean bStop = false; //停止标志 U:8cz=#  
File tmpFile; //文件下载的临时信息 "|/q4JN)7d  
DataOutputStream output; //输出到文件的输出流 u\)q.`  
}+F@A`Bm&  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) DO~~  
public SiteFileFetch(SiteInfoBean bean) throws IOException @Suww@<  
{ #,OiZQJC  
siteInfoBean = bean; i"n1E@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); sfsK[c5bm  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5Z13s  
if(tmpFile.exists ()) r(g2&}o\  
{ :d@RN+U  
bFirst = false; \M~uNWv|  
read_nPos(); B XO,  
} iGNZC{  
else )b,FE}YX  
{ hO(A_Bw  
nStartPos = new long[bean.getNSplitter()]; 8*eVP*g  
nEndPos = new long[bean.getNSplitter()]; +>:[irf  
} (lvp-<*  
zvT8r(<n}  
Srrzj-9^)K  
^vTp.7o~5  
} .xtam 8@  
0I*{CVTQj  
Nb\B*=4AR  
public void run() vH6.;j'^  
{ TU9$5l/;g  
//获得文件长度 th+LScOX  
//分割文件 ~2QD.(  
//实例FileSplitterFetch ?*cCn-|  
//启动FileSplitterFetch线程 `r0MQkk  
//等待子线程返回 && WEBQ  
try{ r`PD}6\  
if(bFirst) \_/dfmlIZ  
{ MFqb_q+  
nFileLength = getFileSize(); 3*oZol/  
if(nFileLength == -1) "}:SXAZ5`  
{ K^%ONultv  
System.err.println("File Length is not known!"); 4"Mq]_D  
} LKst QP!I  
else if(nFileLength == -2) 'Kd-A:K2g  
{ dRBWJ/ 1T  
System.err.println("File is not access!"); COA>y?  
} 8/-hODoT_  
else >&Vz/0  
{ Y7 e1%,$v  
for(int i=0;i<nStartPos.length;i++) _]us1  
{ D`)K3;h  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); )yS8(F0  
} 8 LsJ}c  
for(int i=0;i<nEndPos.length-1;i++) OOzXA%<%c  
{ BKu< p<  
nEndPos = nStartPos[i+1]; _hEr,IX=J  
} ]x6r P  
nEndPos[nEndPos.length-1] = nFileLength; c>wn e\(5H  
} v R ! y#  
} @[]#[7  
%4Yq (e  
2FEi-m}  
//启动子线程 w+hpi5OH  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; [f=Y*=u9,  
for(int i=0;i<nStartPos.length;i++) 1/c+ug!y  
{ "FLiSz%ME  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K/8TwB?I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), I\|.WrMNi  
nStartPos,nEndPos,i); cPX^4d~9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >&Y\g?Z6G  
fileSplitterFetch.start(); L!~ap  
} 0_-P~^A  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 'v5q/l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); B\+uRiD8w  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~g*5."-i  
nEndPos = " + nFileLength); ;G*)7fi  
// fileSplitterFetch[nPos.length-1].start(); k!d<2Qp W  
l _zTpyOZ  
2FR 5RG oD  
//等待子线程结束 t_\&LMD  
//int count = 0; H"wIa8A  
//是否结束while循环  Rp6q)  
boolean breakWhile = false; =|H.r9-PK6  
}w{E<C(M  
x}#N?d  
while(!bStop) [x -<O:r=P  
{ {N@Pk[!  
write_nPos(); G}@a]EGm  
Utility.sleep(500); )g`~,3G  
breakWhile = true; ~Sx\>wBlc  
6ck%M#v  
6u{%jSA>D\  
for(int i=0;i<nStartPos.length;i++) ]6,D 9^{;  
{ i$CF*%+t  
if(!fileSplitterFetch.bDownOver) ;dTxQ_:  
{ bl#6B.*=  
breakWhile = false; %Hu.FS5'  
break; rv2;)3/*  
} v(P <_}G  
} m1M6N`f  
if(breakWhile) 6+:;M b_S  
break; 593!;2/@  
z<8VJZd  
Ei89Ngp\}  
//count++; 3Qu-X\  
//if(count>4) T[2<_nn=  
// siteStop(); C{,Vk/D-0  
} T75N0/teS  
4K,S5^`Gx  
ts r{-4V  
System.err.println("文件下载结束!"); o+Q2lO5  
} SUD~@]N1  
catch(Exception e){e.printStackTrace ();} q XB E3  
} ~w}=Oby'y  
<|hrmwk|  
R0-Y2v  
//获得文件长度 SME]C') 7  
public long getFileSize() c,#Nd@  
{ D H:9iX'  
int nFileLength = -1; Ti>}To}B5  
try{ Ho $+[K  
URL url = new URL(siteInfoBean.getSSiteURL()); kH4m6p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); gZ=$bR  
httpConnection.setRequestProperty("User-Agent","NetFox"); R#s_pW{op  
 lHE+o;-  
[C@ Ro,mI  
int responseCode=httpConnection.getResponseCode(); \p!m/2  
if(responseCode>=400) l|M|;5TW  
{ }Ggn2 X  
processErrorCode(responseCode); _WI~b  
return -2; //-2 represent access is error ZHCrKp  
} A>\3FeU>UC  
(R(NEN  
NWj4U3x  
String sHeader; !p_l(@f  
zo@,>'m  
gBZNO! a,d  
for(int i=1;;i++) .I%B$eH  
{ f4 vdJ5pV  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); cG4}daK]d  
//Utility.log(in.readLine()); BRv#`  
sHeader=httpConnection.getHeaderFieldKey(i); Cj J n  
if(sHeader!=null) !$<Kp6  
{ >L$9fn/J  
if(sHeader.equals("Content-Length")) P=X)Ktmv  
{ S KGnx  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !e('T@^u6u  
break; ?\zyeWK0L  
} boZ/*+t  
} bG+Gg*0p  
else IEWl I  
break; ,2P /[ :  
} ^Zlbs goZ  
} m; PTO$--  
catch(IOException e){e.printStackTrace ();} ^BP4l_rO9  
catch(Exception e){e.printStackTrace ();} 'Y]<1M>.g  
n,{  
S5~(3I )v  
Utility.log(nFileLength); GqgJ]m  
D3y4e8+Z'  
MI~Q Xy,  
return nFileLength; %h v-3L#V  
} R9UC0D:-x  
^c| 0?EH  
m~F ~9&  
//保存下载信息(文件指针位置) |RDE/  
private void write_nPos() M`xI N~  
{ 4thPR}DH}  
try{ `R*!GHro  
output = new DataOutputStream(new FileOutputStream(tmpFile)); jEK{47i v  
output.writeInt(nStartPos.length); 2 S2;LB  
for(int i=0;i<nStartPos.length;i++) ,/[1hhP@  
{ OOYdrv,  
// output.writeLong(nPos); Vc+~yh.)  
output.writeLong(fileSplitterFetch.nStartPos); ,,-j5Y  
output.writeLong(fileSplitterFetch.nEndPos); M->#WGl\B  
} ZL9|/ PY  
output.close(); ,.&D{ $1W  
} o@YEd d  
catch(IOException e){e.printStackTrace ();} r$%,k*X^ k  
catch(Exception e){e.printStackTrace ();} Kc+9n%sp  
} 5"D\n B%  
Ef=4yH?\j  
{6F]w_\  
//读取保存的下载信息(文件指针位置) {7Kl #b  
private void read_nPos() '@"A{mrE  
{ RI BB*  
try{ +:u &]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); NSQ)lSW,;  
int nCount = input.readInt(); M* dou_Q  
nStartPos = new long[nCount]; Qd}h:U^  
nEndPos = new long[nCount]; Z-aB[hE  
for(int i=0;i<nStartPos.length;i++) Q|f)Awe$  
{ :kXxxS  
nStartPos = input.readLong(); zF&_9VNk=c  
nEndPos = input.readLong(); q\Z9.T+Qo  
} %@%~<U)W  
input.close(); ;!EEzR.  
} ppO!v?  
catch(IOException e){e.printStackTrace ();} *k0;R[IAV  
catch(Exception e){e.printStackTrace ();} aI\]R:f,  
} Hlj3z3  
qtp-w\#S$  
C(}Kfi@6N  
private void processErrorCode(int nErrorCode) n'@XgUI,  
{ Rtai?  
System.err.println("Error Code : " + nErrorCode); ~P9^4  
} EtDzmpJR>  
O! w&3 p  
`>`{DEDx{5  
//停止文件下载 EHt(! ;?q  
public void siteStop() &y~GTEP  
{ p0HcuB)Y  
bStop = true; # twl  
for(int i=0;i<nStartPos.length;i++) X&,a=#C^  
fileSplitterFetch.splitterStop(); 5WI0[7  
Chtls;Ph[  
ET|4a(x  
} NaeG)u#+  
} S?Uvt?  
//负责部分文件的抓取 jDW$}^ 6  
**FileSplitterFetch.java {!"lHM%  
*/ (@xr/9:i  
package NetFox; S#|5&SR  
|l,0bkY@&  
SuA`F|7?P  
import java.io.*; Gdlx0i  
import java.net.*; r D|Bj(X8  
AaJz3oncJ  
OWmI$_L  
public class FileSplitterFetch extends Thread { QC+BEN$  
58Z,(4:E  
\Qz  
String sURL; //File URL 7[(<t+  
long nStartPos; //File Snippet Start Position G3t\2E9S  
long nEndPos; //File Snippet End Position `R:HMO[ow  
int nThreadID; //Thread's ID 9Oc(Gl5az  
boolean bDownOver = false; //Downing is over - [7S.  
boolean bStop = false; //Stop identical h>n<5{zqM  
FileAccessI fileAccessI = null; //File Access interface k7bfgb {  
3 yM!BTlX  
"C]_pWk  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _^Q =n>G  
{ 1$uO%  
this.sURL = sURL; 9K#U<Q0b'  
this.nStartPos = nStart; )7iYx{n  
this.nEndPos = nEnd; (M,*R v  
nThreadID = id; .p\<niu7  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 C-VkXk  
} }_cX" s  
.T7S1C $HP  
C?PgC~y)  
public void run() +p &$`(  
{ {I QCA-AI  
while(nStartPos < nEndPos && !bStop) WSV% Oy3V  
{ ~`VD}{[,B  
=%d0MZD  
3HB(rTw  
try{ Ndqhc  
URL url = new URL(sURL); W$u/tRF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3?yq*uE}  
httpConnection.setRequestProperty("User-Agent","NetFox");  .KE2sodq  
String sProperty = "bytes="+nStartPos+"-"; c+]5[6  
httpConnection.setRequestProperty("RANGE",sProperty); +q)B4A'J!  
Utility.log(sProperty); EP]OJ$6I  
l1}HJmom  
o%?~9rf]]  
InputStream input = httpConnection.getInputStream(); M\bea  
//logResponseHead(httpConnection); 8f-B-e?k  
RQd5Q.  
~@EBW3>~5  
byte[] b = new byte[1024]; Rs1JCP=d8  
int nRead; "\x\P)j0>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2]-xmS>|b  
{ `Z~\&r=  
nStartPos += fileAccessI.write(b,0,nRead); JJE0q5[  
//if(nThreadID == 1) Dq~D4|  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u[1'Ap  
} FLOSdMYdw  
T~-PT39E  
Z/= HQ8  
Utility.log("Thread " + nThreadID + " is over!"); k[;(@e@c  
bDownOver = true; Ih5F\eM  
//nPos = fileAccessI.write (b,0,nRead); H%`|yUE(  
} /mFa*~dj2  
catch(Exception e){e.printStackTrace ();} mi$*,fz  
} j{;IiVHnR  
} /? HLEX  
ryoD 1OE  
e=EM07z  
//打印回应的头信息 L9(!L$  
public void logResponseHead(HttpURLConnection con) NW@guhK.  
{ .eM A*C~n  
for(int i=1;;i++) @P}!mdH1  
{ s4Y7x.-  
String header=con.getHeaderFieldKey(i); BJ7m3[lz  
if(header!=null) &&{_T4  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); [[9XqD]  
Utility.log(header+" : "+con.getHeaderField(header)); mRC6m K>  
else nXcOFU  
break; d"JI4)%  
} P*sb@y>}O  
} <bxp/#6D  
+UC-  
A]"IQ-  
public void splitterStop() 1r;.r|  
{ <MoKTP-<  
bStop = true; U4$CkTe2Y  
} t(?tPt4zp  
9<S};I;  
:p,DAt}  
} Zp*0%x!e  
K=X13As_  
NKS-G2 Y<P  
/* ^J$?[@qD  
**FileAccess.java q<*UeyE S  
*//文件访问(定位,写) \hT=U*dMR  
package NetFox; # ~T K C|G  
import java.io.*; k->cqtG  
60&4?<lR4  
~J,e^$u  
public class FileAccessI implements Serializable{ ^N_?&pgy  
 [EU \-  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 X7gtR|[  
RandomAccessFile oSavedFile; J`x!c9zg7  
long nPos; t|y`Bl2  
YXWlg%s  
J`4{O:{4  
public FileAccessI() throws IOException KF4}cM=.5  
{ V;-YM W  
this("",0); m^Xq<`e"<  
} ykbTWp$Y4Z  
Me e+bp  
"vG~2J  
public FileAccessI(String sName,long nPos) throws IOException -THU5AB  
{ C [h^bBq  
oSavedFile = new RandomAccessFile(sName,"rw"); +HOHu*D  
this.nPos = nPos; -%#F5br%  
oSavedFile.seek(nPos); "G3zl{?GP  
} 8o4?mhqV  
S;FgS:;  
8h| 9;%  
public synchronized int write(byte[] b,int nStart,int nLen) O'} %Bjl  
{ X0QLT:J b  
int n = -1; %;{R o)03  
try{ A#P]|i  
oSavedFile.write(b,nStart,nLen); oDEvhN T  
n = nLen; YjM_8@ <  
} C%y!)v_x  
catch(IOException e) QL4BD93v  
{ Lw!Q*3c  
e.printStackTrace (); 7 -Yn8Gq  
} RY]Vo8  
;_vo2zl1  
9:tn! <^=I  
return n; #fR~ 7 KR  
} XY1e eB-  
nm597WeZp  
8hx 3pvmk  
} Rg?m$$X`  
[nnX,;  
j[Xc i<m  
/* dW8M^A&  
**SiteInfoBean.java PRE\ 2lLY  
*/ :>'4@{'   
package NetFox; {v>orP?  
~HH6=qjU)  
Q7-d]xJ^  
public class SiteInfoBean { uNn]hl|x  
.}.63T$h9  
5, <:|/r  
private String sSiteURL; //Site's URL ?Q XS?  
private String sFilePath; //Saved File's Path ucVn `  
private String sFileName; //Saved File's Name _(Qec?[^Ps  
private int nSplitter; //Count of Splited Downloading File }.j09[<  
RC| t-(Z  
{tlt5p!4  
public SiteInfoBean() <!r0[bKz@  
{//nSplitter的缺省值为5 /Ky xOb)  
//default value of nSplitter is 5 LT ZoO9O  
this("","","",5); &CEZ+\bA  
} "}jY;d#n  
=(x W7Pt~  
z sZP\  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $stBB  
{ hn bF}AD  
sSiteURL= sURL; C/{tvY /o  
sFilePath = sPath; k5%:L2FO  
sFileName = sName; -:|1>og  
this.nSplitter = nSpiltter; &b#O=LF  
))qOsphN  
C=z7Gk=  
} X_0Ta_u?T  
UmRI! WQl  
U[Pll~m2b  
public String getSSiteURL() `T]1u4^E  
{ rfdT0xfcU  
return sSiteURL; @}{~Ofs  
} vQ/&iAyut  
[aK7v{Wu  
Ew|VDD(.  
public void setSSiteURL(String value) _m+64qG_8'  
{ BrQXSN$i  
sSiteURL = value; (KF=v31_m  
} ?u`TX_OsB  
IC6}s  
+4,v. B@  
public String getSFilePath() b:,S  
{ N<\U$\i  
return sFilePath; ]ctlK'.  
} *0 0K3  
Yb<t~jm  
I<'wZJRRa  
public void setSFilePath(String value) Y GZX}-  
{ FD&"k=p+X  
sFilePath = value; Wy2 pa #Q  
} S]7RGzFe  
x[,HK{U|t  
jJN.(  
public String getSFileName() P1Z+XRWOM  
{ Fj`6v"h  
return sFileName; 7n1@m_7O  
} )K4A-9pC  
HW)4#nLhh  
)4hb%U  
public void setSFileName(String value) )@ /!B`  
{ =3Y:DPMB  
sFileName = value; yX:*TK4  
} O+Zt*jN;  
39w|2%(O.  
GJLlMi  
public int getNSplitter() _IA@X. )?  
{ XL/?v" /  
return nSplitter; ` R;6]/I?  
} gsqpQq7  
.."=  
D=w5Lks  
public void setNSplitter(int nCount) _oB!-#  
{ w+P?JR!)+  
nSplitter = nCount; u'o."J^&'  
} VFZ_Vw  
} a]<y*N?qu  
8u,f<XHi"a  
@w)Vt $+b]  
/* Xgge_`T9  
**Utility.java H0zKL]D'>  
*/ Fu*~{n  
package NetFox; ?F@0"qi  
hcvWf\4'#q  
>i>%@  
public class Utility { rpk )i:k\  
?I6us X9$  
nV|H5i;N7  
public Utility() eB`7C"Z  
{ K[%)_KW  
,DN>aEu1  
;TAf[[P  
} HQ8oOn  
nQ/R,+6h  
//线程睡眠 fh0a "#L{  
public static void sleep(int nSecond) -.8 nEO3  
{ mCa [?  
try{ }{J5)\s9  
Thread.sleep(nSecond); l .8@F  
} 6dG:3n}  
catch(Exception e) ##gq{hgjb$  
{ a&6e~E$K2  
e.printStackTrace (); 9V]\,mD=  
} y#'|=0vTvP  
} V^a] @GK:  
LV4]YC  
//日志 }1ABrbc  
public static void log(String sMsg) @S/jVXA  
{ ;]* %wX  
System.err.println(sMsg); H\OV7=8  
} S H"e x,=  
Iv6(Z>pAB  
os<B}D[  
public static void log(int sMsg) @z8,XW }  
{ wHSas[4k  
System.err.println(sMsg); l-Hp^|3Wq  
} ggr\nY  
} PVGvjc  
pDGX$1O"  
X>C l{.  
/* lg)jc3  
**TestMethod.java 1gEeZ\B-&  
*/ 1m*fkM#  
package NetFox; 01n5]^.p  
+Ar=89  
"~y@rqIba  
public class TestMethod { qNI2+<u)j  
('qu#.'  
(Kl96G<Wej  
public TestMethod() <r_L-  
{ ///xx/weblogic60b2_win.exe F;5S2:a@Z  
try{ g$c\(isY;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 1(z&0Y;  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); t(-`==.R  
SiteFileFetch fileFetch = new SiteFileFetch(bean); J. ;9-  
fileFetch.start(); :wn9bCom?M  
} f%Y'7~9bA  
catch(Exception e){e.printStackTrace ();} a?4'',~  
Nwu,:}T  
(^fiw%#  
} C]ev"Am_)  
W 7k\j&x  
1+1Z]!nG#!  
public static void main(String[] args) _~?N3G  
{ C NDf&dzX8  
new TestMethod(); [89qg+z  
} K3QE>@']  
} 0Q^a*7w`8a  
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