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http断点续传简单实现(java)

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/* OK8|w]-A  
**SiteFileFetch.java /k_?S?  
*/ /l6r4aO2=  
package NetFox; r P1FM1"M  
import java.io.*; zLt7jxx  
import java.net.*; SN<Dxa8Iy  
.=`r?#0  
0D==0n  
public class SiteFileFetch extends Thread { SJ0IEPk  
1ZZ}ojq  
AhA4IOG`.  
SiteInfoBean siteInfoBean = null; //文件信息Bean hH.X_X?d%  
long[] nStartPos; //开始位置 D #Ku5~j  
long[] nEndPos; //结束位置 N0mP EF2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #0uD&95<  
long nFileLength; //文件长度 $-*E   
boolean bFirst = true; //是否第一次取文件 ~[*\YN);  
boolean bStop = false; //停止标志 42B_8SK  
File tmpFile; //文件下载的临时信息 6R=dg2tKT  
DataOutputStream output; //输出到文件的输出流 V!&O5T(~  
MGbl-,]  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) +!6dsnr8  
public SiteFileFetch(SiteInfoBean bean) throws IOException #Y>os3]  
{ I7C*P~32{n  
siteInfoBean = bean; N"k IQe*}1  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); IN!,|)8s  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %pd-{KR  
if(tmpFile.exists ()) hW Va4  
{ t^')ST  
bFirst = false; a9%^Jvm"  
read_nPos(); HAca'!p  
} &Cykw$s  
else _$vAitUe4S  
{ 0x1#^dII  
nStartPos = new long[bean.getNSplitter()]; j t6q8  
nEndPos = new long[bean.getNSplitter()]; KEfx2{k b  
} Ex`!C]sQ  
3v?R"2\qS  
v<u`wnt  
|,)=-21&;  
} lO+6|oF0  
\2U FJ  
|A/)b78'u  
public void run() >0c4C< _  
{ :*<UCn""  
//获得文件长度 N*$L#L$*  
//分割文件 [$iKx6\  
//实例FileSplitterFetch "tX=^4   
//启动FileSplitterFetch线程 BXj]]S2  
//等待子线程返回 .?^a|]  
try{ 9]]isE8r  
if(bFirst) %Bf;F;xuB  
{ OF_g0Zu  
nFileLength = getFileSize(); DnI31!+y  
if(nFileLength == -1) G[4$@{  
{ #[LnDU8>9  
System.err.println("File Length is not known!"); yE{(Ebm  
} `{v!|.d<  
else if(nFileLength == -2) ,e93I6  
{ 'Z{_w s  
System.err.println("File is not access!"); }#D+}Mo!,  
} G\4*6iw:  
else l2|[  
{ , b;WCWm  
for(int i=0;i<nStartPos.length;i++) GUH-$rA  
{ yd+.hg&J  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); N)0V6q"  
} PgMU|O7To  
for(int i=0;i<nEndPos.length-1;i++) sCrOdJ6|  
{ s%OPoRE  
nEndPos = nStartPos[i+1]; D.;iz>_}Y  
} VX{9g#y$j  
nEndPos[nEndPos.length-1] = nFileLength; 1RM@~I$0  
} z7$,m#tw  
} PYhRP00}M  
2M`:/shq  
r&0IhE  
//启动子线程 -+)06BqF}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 9Z!|oDP-  
for(int i=0;i<nStartPos.length;i++) 8}_M1w6v  
{ 58>C,+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [19QpK WM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Yn+d!w<3:  
nStartPos,nEndPos,i); /t=Fx94  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5S/YVRXq  
fileSplitterFetch.start(); q37d:Hp  
} x<gP5c>zm  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l'm\ *=3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Z^_-LX:%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \YMe&[C:o  
nEndPos = " + nFileLength); DV5K)m&G  
// fileSplitterFetch[nPos.length-1].start(); +ebmve \+  
aEvW<jHh  
kh5VuXpe  
//等待子线程结束 7AouiL 2-W  
//int count = 0; CA[3 R  
//是否结束while循环 JK=0juv<E  
boolean breakWhile = false; L,7+26XV"B  
(5\VOCT>4%  
JC#M,j2  
while(!bStop) -RKqbfmi=  
{ U_.9H _G  
write_nPos(); P g.j]  
Utility.sleep(500); Bh0hUE  
breakWhile = true; 6t!PHA  
hg Pzx@  
4mM?RGWv  
for(int i=0;i<nStartPos.length;i++) t,,W{M|E(  
{ 6U(M HxY  
if(!fileSplitterFetch.bDownOver) .sBwJZ  
{ W^8MsdM  
breakWhile = false; ,SB5"  
break; =,w(D~ps  
} EZb_8<DH  
} efUa[XO  
if(breakWhile)  {,Z-GJ  
break; TRzL":  
$z \H*  
+ rN&@}Jt.  
//count++; ~Kiu " g  
//if(count>4) 2R=Fc@MXs  
// siteStop(); < ?{ic2j#  
} fMl uVND  
`2l j{N  
b-Xc6f  
System.err.println("文件下载结束!"); J *nWCL  
} /]>8V'e\  
catch(Exception e){e.printStackTrace ();} $ts1XIK%  
} ,(y6XUV~  
HY>zgf,0  
?Jy /]j5fI  
//获得文件长度 9ymx;  
public long getFileSize() W\1V`\gF  
{ =tQ^t4_  
int nFileLength = -1; 0/TP`3$X#"  
try{ ({!S!k  
URL url = new URL(siteInfoBean.getSSiteURL()); ~/l5ys  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y DWV=/  
httpConnection.setRequestProperty("User-Agent","NetFox"); P,W(9&KM  
YQN@;  
,9YgznQ  
int responseCode=httpConnection.getResponseCode(); &qMt07  
if(responseCode>=400) `JzP V/6  
{ >j6"\1E+Dz  
processErrorCode(responseCode); 0 P2lq  
return -2; //-2 represent access is error P+<4w  
} :/XWk %  
N;mJHr3[F  
oa<%R8T?@  
String sHeader; M"!{Dx~  
h,@tfd U^  
5lrjM^E|  
for(int i=1;;i++) H63?Erh>a  
{ 5[0W+W  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ,?oC+9w  
//Utility.log(in.readLine()); /|LQ?n  
sHeader=httpConnection.getHeaderFieldKey(i); h\lyt(.s  
if(sHeader!=null) }/J<#}t  
{ WWgJ !Uz  
if(sHeader.equals("Content-Length")) %*a%F~Ss  
{ (U([T-H  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Lc! t  
break; o>75s#= b=  
} M.u1SB0  
} mPJ@hr%3  
else |YcYWok  
break; !$pnE:K  
} i#K Y'"P  
} *6/OLAkyF  
catch(IOException e){e.printStackTrace ();} 8/"R&yAh  
catch(Exception e){e.printStackTrace ();} WbJ  
(MzThGJK_  
7!PU}[:  
Utility.log(nFileLength); y"Ios:v@-  
5a%i%+;N  
{&uN q^Ch  
return nFileLength; ap wA  
} F#KUu3;B  
r<OqI*7  
p>h}k_s  
//保存下载信息(文件指针位置) W4&Itj  
private void write_nPos() I' 'X\/|  
{ 7Sl"q=>  
try{ {xu~Dx  
output = new DataOutputStream(new FileOutputStream(tmpFile)); IylfMwLC  
output.writeInt(nStartPos.length); #ja6nt8GC  
for(int i=0;i<nStartPos.length;i++) &6&$vF65c  
{ l&{+3aC:  
// output.writeLong(nPos); OICH:(t_  
output.writeLong(fileSplitterFetch.nStartPos); MmH(dp+  
output.writeLong(fileSplitterFetch.nEndPos); 63HtZ=hO7  
} ]FEsN6  
output.close(); [vn"r^P  
} 4|h>.^  
catch(IOException e){e.printStackTrace ();} 8SOfX^;o  
catch(Exception e){e.printStackTrace ();} B4t,@,\O  
} }iRRf_   
/[+qw%>  
=|V[^#V  
//读取保存的下载信息(文件指针位置) vRMGNz_P7[  
private void read_nPos() 4vyJ<b  
{ ) ^ 7- qy  
try{ xp%LXx j  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); m2v'zJd}g  
int nCount = input.readInt(); L*zfZ&  
nStartPos = new long[nCount]; 8d[!"lL  
nEndPos = new long[nCount]; Cig! 3  
for(int i=0;i<nStartPos.length;i++) S9{&.[O  
{ 6F; |x  
nStartPos = input.readLong(); GsiT!OP]y  
nEndPos = input.readLong(); U.c~l,5%"  
} mk[<=k~  
input.close(); ZO& F15$P  
} PMZ*ECIJU  
catch(IOException e){e.printStackTrace ();} H+npe'm_Z  
catch(Exception e){e.printStackTrace ();} 8I<LZ{a10  
} `P jS  
T854}RX[{  
g?{7DI`  
private void processErrorCode(int nErrorCode) FF~VV<a  
{ 3\j3vcuy  
System.err.println("Error Code : " + nErrorCode); '@f#GNRT  
} l 9bg  
PBb'`PV  
DAQozhP8  
//停止文件下载 [E;~Y_l  
public void siteStop() Dpkc9~z  
{ g-<[* nF  
bStop = true; 6. 6x$y3v  
for(int i=0;i<nStartPos.length;i++) CO{AC~  
fileSplitterFetch.splitterStop(); V`xE&BI  
+m4?a\U  
x }i'2   
} qkD9xFp  
} )TOKHN  
//负责部分文件的抓取 'Ooq.jaK;/  
**FileSplitterFetch.java r<pt_Cd  
*/ XL`i9kV?  
package NetFox; # 66vkf*  
j1K?QH=e#{  
NT<}-^  
import java.io.*; i+~H~k}"X  
import java.net.*; T#ehJq 5  
[='<K  
~QU\kZ7Z  
public class FileSplitterFetch extends Thread { LsaRw-4.c  
X;d 1@G  
vg\fBHzn  
String sURL; //File URL ?<~P)aVVj  
long nStartPos; //File Snippet Start Position wj9 Hh  
long nEndPos; //File Snippet End Position LEA^o"NW.  
int nThreadID; //Thread's ID Y*YV/E.  
boolean bDownOver = false; //Downing is over [Y8ot-6  
boolean bStop = false; //Stop identical G&#l3bkQ  
FileAccessI fileAccessI = null; //File Access interface hSXZu?/  
UB7C,:"  
^K[[:7Aem  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException -9yWf8;  
{ PY[!H<tt  
this.sURL = sURL; Vc&xXtm[v  
this.nStartPos = nStart; M4K>/-9X+V  
this.nEndPos = nEnd; NLZUAtx(  
nThreadID = id; _SqUPTb"u  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 85#+_}#  
} ?}<Wmy2A  
{oRR]>  
Gt;U9k|i  
public void run() +?uZ~VSl  
{ Kbcr-89Gv~  
while(nStartPos < nEndPos && !bStop) O>>%lr|  
{ e@L?jBj8m  
8[d6 s  
q@}tv =}  
try{ GL3olKnL  
URL url = new URL(sURL); ..yLtqos  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5 0<  
httpConnection.setRequestProperty("User-Agent","NetFox"); !KLY*bt6  
String sProperty = "bytes="+nStartPos+"-"; A~#w gLGn  
httpConnection.setRequestProperty("RANGE",sProperty); -}P/<cu:  
Utility.log(sProperty); dgW/5g  
kx07Ium  
#RP7?yGM,  
InputStream input = httpConnection.getInputStream(); Df0m  
//logResponseHead(httpConnection); i~.9 B7hdE  
XZ_vbYTj  
qWw{c&{Q],  
byte[] b = new byte[1024]; O],]\M{GL  
int nRead; 7-[^0qS  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;"+]bne~  
{ rB.LG'GG]  
nStartPos += fileAccessI.write(b,0,nRead); W(jP??up  
//if(nThreadID == 1) eG%Q 3h  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); e*pYlm  
} %$zX a%A  
dwmZ_m.  
#i| AE`  
Utility.log("Thread " + nThreadID + " is over!"); o '!WW  
bDownOver = true; 5+Hw @CY3  
//nPos = fileAccessI.write (b,0,nRead); c8M'/{4rH  
} )X5en=[)O  
catch(Exception e){e.printStackTrace ();} (kZ2D  
} R% )7z)~  
} kT4Oal+4  
a'YK1QX  
UYsyVY`Fm|  
//打印回应的头信息 |H4f&& Wd  
public void logResponseHead(HttpURLConnection con) Uf<IXx&;  
{ H1a<&7  
for(int i=1;;i++) Rx.dM_S  
{ |gM@}!DL  
String header=con.getHeaderFieldKey(i); ]VHO'z\m  
if(header!=null) .{66q#.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ugv"A;l  
Utility.log(header+" : "+con.getHeaderField(header)); Lb%:u5X\D@  
else W3Dtt-)E  
break; DeGcS1_?  
} ^:,I #]  
} "[wP1n!G  
T |ZJ$E0  
o7t#yw3  
public void splitterStop() }XIUz|  
{ "78BApjWT6  
bStop = true; rWxQ;bb#  
} 75RQ\_zDu  
Hy#<fKz`!  
w$[ck=  
} .dl4f"k  
`Y.Q{5Y  
\,yX3R3}.~  
/* kac]Rh8vO  
**FileAccess.java 4 X6_p(  
*//文件访问(定位,写) F;<cG `|Rx  
package NetFox; AJR`ohh  
import java.io.*; cj9<!"6  
OjBg$f~0F  
E~'QC  
public class FileAccessI implements Serializable{ >e9xM Gv  
gukKa  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 4: S-  
RandomAccessFile oSavedFile; 3NxwQ,~  
long nPos; +G lb  
Nm,9xq  
88M$mjx  
public FileAccessI() throws IOException 6@cT;=W;xj  
{ Zh 3hCxXa  
this("",0); }pL#C  
} a^.5cJ$]  
ad'C&^o5  
TaE&8;H#N  
public FileAccessI(String sName,long nPos) throws IOException ~t.M!vk  
{ 7&{[Y^R]"  
oSavedFile = new RandomAccessFile(sName,"rw"); i9quP"<9  
this.nPos = nPos; J#jx)K!  
oSavedFile.seek(nPos); &/tGT3)  
} E>3(ff&  
} 2P,Z6L  
2]/[  
public synchronized int write(byte[] b,int nStart,int nLen) !i*bb~  
{ PxiJ R[a  
int n = -1; ( | X?  
try{ )|CF)T-  
oSavedFile.write(b,nStart,nLen); kSH|+K\M4  
n = nLen; ?(P3ZTk?.  
} :igURr  
catch(IOException e) V j"B/@  
{ ;PF!=8dW  
e.printStackTrace (); KI~M.2pk  
} n0< I  
|% xgob  
,]qTJ`J  
return n; Gs)2HR@>  
} `]3A#y)v  
fC^POLn[f  
!;~6nYY  
} ={gfx;  
L>1i~c&V  
FT+[[9i  
/* Mo_(WSs  
**SiteInfoBean.java "0#d F:qt  
*/ H:>i:\J/M9  
package NetFox; *mTx0sQz(J  
1Wy0#?L  
N)N\iad^  
public class SiteInfoBean { Jx_BjkF  
s6| S#  
y?*4SLy  
private String sSiteURL; //Site's URL |ZuS"'3_w  
private String sFilePath; //Saved File's Path ^i!6q9<{e  
private String sFileName; //Saved File's Name "~^ #{q  
private int nSplitter; //Count of Splited Downloading File -=CZhp  
U5x&? n<  
cop \o4ia  
public SiteInfoBean() /R% Xkb  
{//nSplitter的缺省值为5 u?+i5=N9{  
//default value of nSplitter is 5 K,Z_lP_~Vw  
this("","","",5); 3T7,Y(<V  
} ;R8pVj!1f  
"de3S bj@?  
)T26 cT$  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) wtpz ef=  
{ jizp\%W+  
sSiteURL= sURL; B+8B<xZ  
sFilePath = sPath; >p|tIST  
sFileName = sName; mcFJ__3MAV  
this.nSplitter = nSpiltter; x\MzMQ#Bf  
xgV(0H}Mf  
B6gn(w3  
} !w }cKm  
l'0fRQc  
^B`*4  
public String getSSiteURL() FyV)Nmc%t  
{ WfF~\DlrD  
return sSiteURL; B%Vz -t  
} Tz{f 5c&  
{,`)  
Y~%9TC  
public void setSSiteURL(String value) oe*Y(T\G  
{ 27q=~R}  
sSiteURL = value; [~#]p9|L  
} ql_GN[c/  
uiQRRT  
(h3f$  
public String getSFilePath() Oj?  |g_  
{ *8?0vkZZ2  
return sFilePath; O${B)C,  
} N,M[Opm  
LWp#i8,  
]= nM|e  
public void setSFilePath(String value) TCI%Ox|a  
{ 1P[[PvkD6  
sFilePath = value; "cVJqW  
} K~DQUmU@  
] 3UlF'{  
g=5vnY  
public String getSFileName() XV|u!'Ey  
{ 9C_Vb39::$  
return sFileName; ;#jE??E/:  
} {i09e1  
*[SOz)  
P UJkC  
public void setSFileName(String value) 48 n5Y~YS  
{ gc KXda(  
sFileName = value; y.PsC '  
} rE[:j2HF  
i,z^#b7JQ  
B{ptP4As-  
public int getNSplitter() VwKo)zH  
{ rM y(NAo_  
return nSplitter; N&]GP l0  
} /+g9C(['  
?wpS  
)W1tBi  
public void setNSplitter(int nCount) D`e6#1DbJ  
{ Svun RUE-f  
nSplitter = nCount; Ga M:/.  
} j{?ogFfi  
} vl,Ff9  
3{*nG'@Mal  
Q eZg l!  
/* e!hy,O{Pw  
**Utility.java o$%I{}9x  
*/ P/e6b .M  
package NetFox; 7)Y0D@wg  
gf\F%VmSN  
FT$Z8  
public class Utility { (n+FEE<  
V9%!B3Sb  
 ZFH;  
public Utility() 94CHxv  
{ #i1z&b#@  
|Y")$pjz  
"gCqb;^  
} CL)*cu6zG  
P1>?crw  
//线程睡眠 &4R -5i2a  
public static void sleep(int nSecond) ]QJWqY  
{ (G<fvl!~  
try{ 1@"os[ 9  
Thread.sleep(nSecond); alV{| Vf[6  
} Wn kIi,<  
catch(Exception e) i+&o%nK2  
{ =)Z~ w`  
e.printStackTrace (); L63B# H "  
} M?QK4Zxb6U  
} |q+dTy_n  
1X,\:F.-+  
//日志 6Ex 16  
public static void log(String sMsg) f(Uo?_as  
{ RAUD8Z  
System.err.println(sMsg); ~M?^T$5  
} x3L0;:Fx8P  
.2v)x  
VTIRkC wl@  
public static void log(int sMsg) J7Y lmi  
{  Bl1^\[#  
System.err.println(sMsg); 4u}jkd$]*  
} o_@6R"|  
} W#sCvI@   
*Q XUy  
C=zc6C,  
/* XRx^4]c  
**TestMethod.java Yj'/ p  
*/ hvo7T@*'  
package NetFox; u`~,`z^{n  
r0L' mf$  
H2oD0f|  
public class TestMethod { xwjiNJ Gj  
*\"+/   
W6Z3UJ-  
public TestMethod() ;cD&qheDV  
{ ///xx/weblogic60b2_win.exe (\o &Gl  
try{ <#%kmYSL  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4E 0 Y=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); U0fr\kM  
SiteFileFetch fileFetch = new SiteFileFetch(bean); z5q(  
fileFetch.start(); c)B <d#  
} 9JBVG~m+  
catch(Exception e){e.printStackTrace ();} 25wvB@0&  
-?Kd[Ma  
K^f&+`v6_  
} ]rM HO  
S>nf]J`  
B +<i=w  
public static void main(String[] args) gWLhO|y  
{ Dxp.b$0t  
new TestMethod(); *h)|K s  
} s.j6" Q[W  
} ywkyxt  
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