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http断点续传简单实现(java)

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/* &zO3qt6  
**SiteFileFetch.java };i&a%I|  
*/ LG"c8Vv&)~  
package NetFox; mJSK; @w<O  
import java.io.*; nMTLD  
import java.net.*; a|8| @,  
"w(N62z/  
Y]hV-_2+Do  
public class SiteFileFetch extends Thread { ?s1u#'aO  
"xL;(Fqu  
\8=e |a5`  
SiteInfoBean siteInfoBean = null; //文件信息Bean A Z]P+v  
long[] nStartPos; //开始位置 hN Z4v/  
long[] nEndPos; //结束位置 hTlnw[I  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 8f /T!5  
long nFileLength; //文件长度 ^fFtI?.6jI  
boolean bFirst = true; //是否第一次取文件 :D<:N*9i  
boolean bStop = false; //停止标志 x:!C(Ep)  
File tmpFile; //文件下载的临时信息 {E;2&d  
DataOutputStream output; //输出到文件的输出流 ;% /6Y~/  
LvSP #$f  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 0@II &  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,Wz[tYL*  
{ 2N L:\%wz  
siteInfoBean = bean; @SKO~?7T  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,k4z;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 6V.awg,  
if(tmpFile.exists ()) *37LN  
{ Q3N y5G>  
bFirst = false; _#/!s]$d#  
read_nPos(); H.jLGe>  
} 54`bE$:+  
else ${jA+L<J  
{ B, QC -Tn  
nStartPos = new long[bean.getNSplitter()]; +O;OSZ  
nEndPos = new long[bean.getNSplitter()]; I>A^5nk  
} E9L!O.Q  
UgF)J  
!L &=?CX  
O\|C,Ep m  
} O!#L#u53  
1?/5A|?V4+  
n;-x!Gs  
public void run() y8<lp+  
{ NYSj^k;^(z  
//获得文件长度 JxX jDYrU  
//分割文件 ^ I{R[O'8  
//实例FileSplitterFetch 3Ew"[FUs  
//启动FileSplitterFetch线程 gp#bQ  
//等待子线程返回 ^yn[QWFO  
try{ u\Nw:Uu i  
if(bFirst) Ff)~clIK '  
{ {u(}ED#p  
nFileLength = getFileSize(); '<R B  
if(nFileLength == -1) SX_kr^#  
{ ~)! V8  
System.err.println("File Length is not known!"); xWC\954  
} +Op%,,Db  
else if(nFileLength == -2) *3w/`R<\  
{ Ev$-P X  
System.err.println("File is not access!"); 9,iq"dQ  
} .d#G]8suF  
else vOvxQS}dBp  
{ X]+(c_i:hC  
for(int i=0;i<nStartPos.length;i++) Ux%\Y.PPI  
{ Q7 0**qm  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 4e(9@OLP  
} !T#8N7J>  
for(int i=0;i<nEndPos.length-1;i++) #VQGN2bK.  
{ =0@d|LeZ  
nEndPos = nStartPos[i+1]; Hnd9T(UB  
} ?c=R"Yg$  
nEndPos[nEndPos.length-1] = nFileLength; i(&6ys5  
} l ))~&  
} 6]@|7|N>X  
6*(h9!_T1  
RAD4q"}k  
//启动子线程 ery?G-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; `aO@N(  
for(int i=0;i<nStartPos.length;i++) (IoPU+1b  
{ SBN_>;$c5}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bgzT3KZ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), rr07\;  
nStartPos,nEndPos,i); *Lb(urf  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |`)V^e_  
fileSplitterFetch.start(); )L(d$N=Bd  
} J1c&"Oh  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), RV#uy]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); u]]5p[ |S  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", v8'`gY  
nEndPos = " + nFileLength); c@o/Cv  
// fileSplitterFetch[nPos.length-1].start(); EhP&L?EL  
RP@idz  
r/q1&*T  
//等待子线程结束 {z[HNSyRs  
//int count = 0; fssL'DD  
//是否结束while循环 AZ]SRz9mKY  
boolean breakWhile = false; gH{\y5%rO  
i2ml[;*,N  
kDpZnXP  
while(!bStop) (krG0S:0Q  
{ /wxxcq  
write_nPos(); >A'!T'"~  
Utility.sleep(500); CQuvbAo  
breakWhile = true; ubCJZ"!  
n%ArA])_&  
+zdq+<9X  
for(int i=0;i<nStartPos.length;i++) Y`O}]*{>8R  
{ J>|:T  
if(!fileSplitterFetch.bDownOver) eUw;!Du  
{ HG3>RcB  
breakWhile = false; YK+Z0ry  
break; \w_[tPz}  
} 8}0y)aJ  
} rHdP4:n  
if(breakWhile) __n"DLW  
break; ,Y5 4(>>%  
qmyZbo|8&  
3Co>3d_  
//count++; ZU@jtqq  
//if(count>4) knZd}?I*  
// siteStop(); juYt =  
} ghQsS|)p.  
GeT CN  
i1&noRGl  
System.err.println("文件下载结束!"); 'u%;6'y  
} (xJBN?NRO  
catch(Exception e){e.printStackTrace ();} K{h]./%  
} |Qq'_4:  
}4`YdN  
62'0)Cy^  
//获得文件长度 {73DnC~N  
public long getFileSize() `fVA. %  
{ [~JN n  
int nFileLength = -1; r~a}B.pj  
try{ ky"7 ^  
URL url = new URL(siteInfoBean.getSSiteURL()); |'(IWU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :9>nY  
httpConnection.setRequestProperty("User-Agent","NetFox");  %tjEVQa  
wQ95tN  
$(hZw  
int responseCode=httpConnection.getResponseCode(); \EqO;A%<  
if(responseCode>=400) '7%9Sqx  
{ DvKMb-*S  
processErrorCode(responseCode); 4K,&Q/Vdd7  
return -2; //-2 represent access is error |LhuZ_;1xo  
} oOvbel`;  
}zLE*b,  
^ `9OA`2  
String sHeader; WV5R$IqY  
eLWzd_ln  
iWsIc\!+,  
for(int i=1;;i++) E_#&L({|@  
{ 8A=(,)`}9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =Ih_[$1dw  
//Utility.log(in.readLine()); @ZWKs  
sHeader=httpConnection.getHeaderFieldKey(i); 0_)\e  
if(sHeader!=null) D-/A>  
{ ^B>6 !  
if(sHeader.equals("Content-Length")) s4\2lBU?  
{ KA7nncg;,  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5,3h'\ "!  
break; U/;Vge8{  
} >3/<goXk7  
} j  jQ=  
else ?uLqB@!2  
break; %1<|.Dmd  
} j&r5oD;  
} x :s-\>RcA  
catch(IOException e){e.printStackTrace ();} 78kk"9h'  
catch(Exception e){e.printStackTrace ();} 4?cg6WJ'6  
0&)4^->c  
.#SWfAb2h  
Utility.log(nFileLength); gw-l]@;1  
[F e5a  
L=>N#QR7  
return nFileLength; b^1!_1c  
} #gP\q?5Ov  
aO{k-44y  
on~rrSK  
//保存下载信息(文件指针位置) @YRBZ6FH  
private void write_nPos() b=sc2 )3?  
{ iqpy5  
try{ |1EM )zh6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); i4l?q#X  
output.writeInt(nStartPos.length); Y,{Xv  
for(int i=0;i<nStartPos.length;i++) !.!Ervi!N  
{ SI\zW[IL  
// output.writeLong(nPos); MCvjdc3:  
output.writeLong(fileSplitterFetch.nStartPos); 9 ItsK  
output.writeLong(fileSplitterFetch.nEndPos); ey:3F%  
} ~R3@GaL1  
output.close(); rZ<@MV|d  
} XvWUJ6M  
catch(IOException e){e.printStackTrace ();} hl8[A-d(R  
catch(Exception e){e.printStackTrace ();} =MA$xz3  
} ! fY'^Ya?  
ka655O/)&  
PKk_9Xd  
//读取保存的下载信息(文件指针位置) XfharJ_b  
private void read_nPos() S'q (Qo  
{ I;9>$?t[  
try{ V|Smk;G  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); A\YP}sG1  
int nCount = input.readInt(); !CUrpr/*  
nStartPos = new long[nCount]; rF'q\tJDz  
nEndPos = new long[nCount]; ;>bcI).  
for(int i=0;i<nStartPos.length;i++) e~oI0%xl^  
{ cE'MSB  
nStartPos = input.readLong(); \G:\36l  
nEndPos = input.readLong(); |bA\>%~  
} v25]}9/C  
input.close(); N$i!25F`  
} Xgou7x<  
catch(IOException e){e.printStackTrace ();} eT0Yp  
catch(Exception e){e.printStackTrace ();} llN#4D9s  
} VG'M=O{)3  
j&~`H:=E  
(Rj'd>%c  
private void processErrorCode(int nErrorCode) 8`M) r'5  
{ >NDI<9<'0}  
System.err.println("Error Code : " + nErrorCode); j#6@ cO'`  
} /x\{cHAt8J  
Z#+lwZD  
Mwm9{1{  
//停止文件下载 <a_ytSoG1  
public void siteStop() vf^`'  
{ 2Tt^^Lb  
bStop = true; hUR>NUK@8  
for(int i=0;i<nStartPos.length;i++) (@X].oM^y  
fileSplitterFetch.splitterStop(); \+3amkBe  
Ts)ox}rYVm  
H+lBb$  
} 6)5Akyz4V  
} `0)'&HbLY  
//负责部分文件的抓取 S3fyt]pp  
**FileSplitterFetch.java QY7Thnp1  
*/ RvXK?mL4F  
package NetFox; =hAH6C  
)y#~eYn  
og$%`o:{  
import java.io.*; u*"mdL2  
import java.net.*; <h"07.y  
%Eq4>o?D  
9fhgCu]$  
public class FileSplitterFetch extends Thread { 09_5niaz[  
xPp\OuwK  
u#bd*(  
String sURL; //File URL @hVF}ybp  
long nStartPos; //File Snippet Start Position }eLnTi{  
long nEndPos; //File Snippet End Position K3I|d;Y~X!  
int nThreadID; //Thread's ID N*$L#L$*  
boolean bDownOver = false; //Downing is over :=cZ,?PQp1  
boolean bStop = false; //Stop identical +3wVcL  
FileAccessI fileAccessI = null; //File Access interface _VM()n;  
kKlcK_b;  
hH3~O` ~  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7FB aN7l  
{ +BaZl<ZP1s  
this.sURL = sURL; xp68-&  
this.nStartPos = nStart; g q|]t<'  
this.nEndPos = nEnd; QKVFH:"3  
nThreadID = id; {wq~+O  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [gE_\=FSKu  
} pf@H;QS`  
^f?>;,<&  
s%OPoRE  
public void run() lHI ;fR  
{ \.l8]LH  
while(nStartPos < nEndPos && !bStop) zMI_8lNz  
{ ?P>3~3 B  
7,BULs\g  
@SX-=Nr  
try{ tA{B~>  
URL url = new URL(sURL); *rH# k?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [19QpK WM  
httpConnection.setRequestProperty("User-Agent","NetFox"); $AyE6j_1gX  
String sProperty = "bytes="+nStartPos+"-"; 5S/YVRXq  
httpConnection.setRequestProperty("RANGE",sProperty); G.l ~!;  
Utility.log(sProperty); QoBM2Q YO  
\:Vm7Zg  
8{)j"rghah  
InputStream input = httpConnection.getInputStream(); [==x4N b  
//logResponseHead(httpConnection); )z=L^ot  
5'%nLW7;O  
QTLGM-Z  
byte[] b = new byte[1024]; `~;`q  
int nRead; W^8MsdM  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) hztxsvw  
{ Zv|TvlyT"  
nStartPos += fileAccessI.write(b,0,nRead); 1wTPT,k  
//if(nThreadID == 1) AdGDs+at,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :JD*uu  
} sn-P&"q  
!E.CpfaC  
dK d"2+fH  
Utility.log("Thread " + nThreadID + " is over!"); c\DMeYrg  
bDownOver = true; F|bg2)|du8  
//nPos = fileAccessI.write (b,0,nRead); H{U(Rt]K  
} ?)V|L~/  
catch(Exception e){e.printStackTrace ();} W'! I+nh  
} q#_<J1)z  
} %*a%F~Ss  
U%V4@iz~\m  
)uRR!<"~  
//打印回应的头信息 v7b +  
public void logResponseHead(HttpURLConnection con) =Ohro '   
{ S=_*<[W%4  
for(int i=1;;i++) Ev ]oPCeA  
{ b"pN;v  
String header=con.getHeaderFieldKey(i); y"Ios:v@-  
if(header!=null) 9][A1 +"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Vu5Djx'  
Utility.log(header+" : "+con.getHeaderField(header)); `;)op3A'  
else XE($t2x,M  
break; w[]\%`69}Z  
} Vi<6i0  
} IylfMwLC  
<[A;i  
@d_9NOmNT  
public void splitterStop() ->r udRQ  
{ @pN6uDD}R  
bStop = true; &xE+PfX  
} <RCeY(1  
1k!$#1d<  
x \b+B  
} 1 &-%<o  
U[G5<&Z^  
Y/]J0D  
/* yC\!6pg  
**FileAccess.java U-pBat.$'C  
*//文件访问(定位,写) ;nw}x4Y[  
package NetFox; 6F; |x  
import java.io.*; 51'{Jx8  
iJb-F*_y  
^2LqKo\T  
public class FileAccessI implements Serializable{ I<!,_$:  
LX</xI08W  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 M9QxF  
RandomAccessFile oSavedFile; e$N1m:1*  
long nPos; %o_CD>yD  
d(F4-kBd  
UQO?hZ!y/.  
public FileAccessI() throws IOException cv9-ZOxJ  
{ ,lQfsntk'  
this("",0); +m4?a\U  
} "#]V^Rzxh  
N >k,"=N /  
t'*2)U  
public FileAccessI(String sName,long nPos) throws IOException @!mjjeG+1  
{ +t}<e(  
oSavedFile = new RandomAccessFile(sName,"rw"); O4T_p=Xc  
this.nPos = nPos; +?+iVLr!l}  
oSavedFile.seek(nPos); QA#Jx  
} w%eEj.MI|i  
Rip[  
J-W8wCq`  
public synchronized int write(byte[] b,int nStart,int nLen) %i@Jw  
{ 6B@{X^6y  
int n = -1; j]   
try{ J>^KQ  
oSavedFile.write(b,nStart,nLen); 2qPQ3-'  
n = nLen; >qci $  
} Z'_EX7r  
catch(IOException e) T9]:, z  
{ 0ae}!LO  
e.printStackTrace (); +Ec@qP R&  
} s3oQ( wC %  
|1UJKJwX  
i~.9 B7hdE  
return n; W)2ZeH*  
} 5Cl;h^R|m  
ef]60OtP  
b0[H{q-z{X  
} >?ckBU9  
eG%Q 3h  
*"sDsXo- I  
/* G$CI~0Se:  
**SiteInfoBean.java Fo GSCg%  
*/ X XC(R  
package NetFox; *!L it:H  
99?: 9g  
R2dCp|6A  
public class SiteInfoBean { <9aa@c57  
q|kkdK|N/Y  
);*#s~R  
private String sSiteURL; //Site's URL NZt 8L?  
private String sFilePath; //Saved File's Path ]VHO'z\m  
private String sFileName; //Saved File's Name S01 Bc  
private int nSplitter; //Count of Splited Downloading File L=<{tzTc  
Un{9reX5  
^26}8vt  
public SiteInfoBean() "yc@_+"\+  
{//nSplitter的缺省值为5 Ap9 %5:]  
//default value of nSplitter is 5 j$}W%ibj  
this("","","",5); p|VgtQ/ )%  
} 1|3{.Ed  
aDVBi: _  
^fT?(y_= e  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) cA25FD  
{ _U`1BmTC2  
sSiteURL= sURL; 46M?Gfd,X  
sFilePath = sPath; W5zlU2  
sFileName = sName; 7Un5Y[FZo  
this.nSplitter = nSpiltter; Ah1fcXED  
,-_\Y hY>  
h-=lZ~W~  
} (}&O)3)  
6@cT;=W;xj  
2^T`> ?{X  
public String getSSiteURL() 0ZjinWkR[  
{ _Sn7z?  
return sSiteURL; %TA@-tK=  
} ^V;2v? O  
5_= HtM[v]  
3ew`e"s  
public void setSSiteURL(String value) 9ld'SB:#  
{ iK <vr  
sSiteURL = value; I,wgu:}P#  
} >Mc,c(CvU  
sU 5/c|&  
= , ^eQZR:  
public String getSFilePath() L[cl$ pYV  
{ 2'5%EQW;0y  
return sFilePath; 3F|#nq  
} k\`~v$R3  
nK;c@!~pS  
6;vfl*  
public void setSFilePath(String value) \oc*  
{ #JIh-h@  
sFilePath = value; "0#d F:qt  
} O6Jn$'os1#  
si.w1  
y:+4-1  
public String getSFileName() 'o.A8su,  
{ |Wzdu2T  
return sFileName; tNbZ{=I>  
} %`1 p8>n  
M5>cYVG  
BT8L'qEj  
public void setSFileName(String value) 3T7,Y(<V  
{ YdNmnB %J  
sFileName = value; 7lYiufg  
} jizp\%W+  
`X ;2lgL  
POtwT">z  
public int getNSplitter() xgV(0H}Mf  
{ ,/ bv3pE  
return nSplitter; /a:sWmxMT  
} Nn]|#lLP  
L?slIGp%-  
1 /dy@'  
public void setNSplitter(int nCount) u >W:SM  
{ Iurb?  
nSplitter = nCount; lZ![?t}2`  
} ;+-M+9"?O  
} krI@N}OU  
Bc^ MZ~+ip  
>azTAX6L3  
/* 0v/}W(  
**Utility.java 12JmSvD  
*/ "cVJqW  
package NetFox; ;H;c Sn5uL  
Kk?C   
x'IYWo ]  
public class Utility { +M^+qt;]V  
v@^P4cu;  
P UJkC  
public Utility() -0 o1iU7  
{ _)U[c;^6  
O<KOsu1WW  
f;7I{Z\<  
} ljw(cUM  
2LqJ.HH  
//线程睡眠 ?wpS  
public static void sleep(int nSecond) @G&2Tbj[`  
{ pDloew  
try{ `BOG e;pl  
Thread.sleep(nSecond); 9nrmz>es|-  
} n B .?=eUa  
catch(Exception e) 4u.Fy<+@4M  
{ b|'{f?  
e.printStackTrace (); LI`H,2Km  
} h .%)RW?  
} e#/SFI0m  
cFF'ygJ/  
//日志 {/E_l  
public static void log(String sMsg) {I:nza  
{ |Y")$pjz  
System.err.println(sMsg); t<DZW#  
} RP1sQ6$  
BdQ/kXZu+  
 3 UX/  
public static void log(int sMsg) lc8zF5  
{ Fk*C8  
System.err.println(sMsg); r;C BA'Z  
} _Q=h3(ZI  
} 7(W"NF{r  
f(Uo?_as  
u P&<  
/* G%#M17   
**TestMethod.java %%h0 H[5*  
*/ "eb+O  
package NetFox; T_NN.Ol   
W0qn$H  
PC55A1(T  
public class TestMethod { P3op1/Np  
sG K7Uy  
.wvgH i  
public TestMethod() RJ0:O   
{ ///xx/weblogic60b2_win.exe xwjiNJ Gj  
try{ dc=~EG-_rM  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); FNy-&{P2  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); t*dd/a  
SiteFileFetch fileFetch = new SiteFileFetch(bean); E~K5n2CI  
fileFetch.start(); 9>7w1G#  
} 9JBVG~m+  
catch(Exception e){e.printStackTrace ();} \F5d p  
&++tp5  
Q35jJQ$<`  
} %RD%AliO}K  
?j|i|WUD  
GX,)~Syw*  
public static void main(String[] args) ~;D5j) 9I  
{ }]!?t~5*  
new TestMethod(); =Yt)b/0b9  
} g7@.Fa.u'!  
} qku}cWD9/_  
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