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http断点续传简单实现(java)

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/* L>/$l(  
**SiteFileFetch.java NaoOgZ?  
*/ _`=qc/-0  
package NetFox; 5u9lKno  
import java.io.*; c(Y~5A{TXO  
import java.net.*; m %+'St|qr  
qh>An;:u  
j^#\km B  
public class SiteFileFetch extends Thread { +/$&P3  
^-?^iWQ G  
(BH<\&yHE  
SiteInfoBean siteInfoBean = null; //文件信息Bean n+=7u[AZi  
long[] nStartPos; //开始位置 ).,twf58  
long[] nEndPos; //结束位置 <k1muSe  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Yqh-U%"'  
long nFileLength; //文件长度 ES,JdImZ|  
boolean bFirst = true; //是否第一次取文件 k"[AV2UW1  
boolean bStop = false; //停止标志 ;ja~Q .}4  
File tmpFile; //文件下载的临时信息 W="pu5q$5  
DataOutputStream output; //输出到文件的输出流 a{7*um  
V+sZ;$  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) nO6UlY  
public SiteFileFetch(SiteInfoBean bean) throws IOException 2va[= >_  
{ p?Ux1S  
siteInfoBean = bean; ]{i0?c  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =zAFsRoD_B  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?8grK  
if(tmpFile.exists ()) ecl6>PS$'  
{ M1P;x._n  
bFirst = false; cyd_xB5K  
read_nPos(); A#q.)8  
} lu>G=uCJ  
else R+0fs$s u  
{ h;E.y   
nStartPos = new long[bean.getNSplitter()]; 76[ qFz  
nEndPos = new long[bean.getNSplitter()]; o}waJN`yI  
} 2@_3V_  
vbd ;Je"  
\0}bOHqEH  
u$nmnd`g  
} O '#FVZ.g  
,%/F,O+#  
e 0$m<5  
public void run() B;Z _'.i,d  
{ 1HSt}  
//获得文件长度 xK[ [b  
//分割文件 :1t&>x=T  
//实例FileSplitterFetch p{qA%D  
//启动FileSplitterFetch线程 8M3DG=D  
//等待子线程返回 yp]vDm  
try{ qe1>UfY  
if(bFirst) NV{= tAR  
{ xZq, kP^  
nFileLength = getFileSize(); ?gU - a  
if(nFileLength == -1) Tl_o+jj  
{ #.]W>hN8\  
System.err.println("File Length is not known!"); x=K'Jj  
} a]V#mF |{  
else if(nFileLength == -2) `mZ1!I-T  
{ [G+@[9hn%  
System.err.println("File is not access!"); 0ZL>-  
} [4;_8-[Nv  
else B2BG*xa  
{ OI/]Y7D[Oq  
for(int i=0;i<nStartPos.length;i++) ~ c~j  
{ P-^-~/>n  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Lo[;{A$u  
} ='Oxy  
for(int i=0;i<nEndPos.length-1;i++) (Ww SisC~  
{ 92,@tNQQ}  
nEndPos = nStartPos[i+1]; (ux9"r^g;x  
} ga1b%5]v.  
nEndPos[nEndPos.length-1] = nFileLength; ZS3T1 <z  
} o+^e+ptc  
} +N~{6*@uz,  
 ^LSD_R^N  
\ X6y".|-  
//启动子线程 zuJ` 704  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; GXv2B%i8  
for(int i=0;i<nStartPos.length;i++) h52+f  
{ - 3<&sTR  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Cx) N;x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), h4slQq~K  
nStartPos,nEndPos,i); )=N.z6?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); h_Er$ZT64  
fileSplitterFetch.start(); >9g^-~X;v  
} RHu,t5,  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z&qOu8Jh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Ra~:O\Z  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", el^<M,7!  
nEndPos = " + nFileLength); e [F33%  
// fileSplitterFetch[nPos.length-1].start(); G0r(xP?  
,5sv;  
{5fq4A A6  
//等待子线程结束 w6B`_Z'f  
//int count = 0; iVqF]2 >  
//是否结束while循环 a}Jy o!.  
boolean breakWhile = false; KA`)dMWL  
~vR<UQz  
;ZrFy=Iv  
while(!bStop) 5kv]k?   
{ q 7+|U%!9  
write_nPos(); yg4ILL  
Utility.sleep(500); P_@ty~u  
breakWhile = true; M?$tHA~OX  
52 DSKL  
.9!&x0;  
for(int i=0;i<nStartPos.length;i++) *EtC4sP  
{ 6>EoU-YX}l  
if(!fileSplitterFetch.bDownOver) =\<!kJ\yH  
{ OBPiLCq  
breakWhile = false; twTRw:.!f  
break; cja-MljD  
} lo >:S1  
} 4MgG]  
if(breakWhile) } M\G  
break; wK%x|%R[  
/z(s1G.  
69C ss'  
//count++; qkyYt#4E  
//if(count>4) u-dF ~.x  
// siteStop(); E~Y%x/oX  
} {O[ !*+O  
1`n ZK$  
A5dH*< }  
System.err.println("文件下载结束!"); gm&O-N"= U  
} iB'g7&,L  
catch(Exception e){e.printStackTrace ();} O{G $]FtF  
} k1WyV_3  
]0p*EB=C*  
23UXOY0BW  
//获得文件长度 -| t|w:&  
public long getFileSize() v-Uz,3  
{ bNz2Uo!0K  
int nFileLength = -1; _ID =]NJ_  
try{ /^Lo@672  
URL url = new URL(siteInfoBean.getSSiteURL()); E!>l@ ki  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6HR*)*>z_  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]h&?^L<.  
&[}5yos r  
O`(it %Ho!  
int responseCode=httpConnection.getResponseCode(); Jc9^Hyqu&  
if(responseCode>=400) $2*&\/;-E!  
{ SB!m&;Tb  
processErrorCode(responseCode); L2y{\<JC"  
return -2; //-2 represent access is error mZ t:  
} C;!h4l7L  
P~*v}A  
<Xj ,>2m;  
String sHeader; AqP\g k  
l_*:StyR+  
X`n*M]  
for(int i=1;;i++) g.O? 1bebe  
{ v&ZI<Xt+  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9!6yo  
//Utility.log(in.readLine()); @sb00ad2q  
sHeader=httpConnection.getHeaderFieldKey(i); /B9jmvj`  
if(sHeader!=null) QWxl$%`89<  
{ u&Dd9kMz  
if(sHeader.equals("Content-Length")) !' @  
{ 4K*DEVS  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); CU(W0D  
break; s((_^yf  
} ?GGh )";y  
} nnO@$T  
else g|l|)T.s  
break; +^.Q%b0Xx  
} /T2f~1R  
} x?Oc<CQ-2  
catch(IOException e){e.printStackTrace ();} ( G6N@>V(`  
catch(Exception e){e.printStackTrace ();} TMQu'<?V  
^l/$ 13=  
} u7&SU  
Utility.log(nFileLength); UwxrYouv~@  
6Bm2_B  
#3u471bp  
return nFileLength; -x1O|q69  
} C!" .[3  
4.mbW  
C(*)7| m  
//保存下载信息(文件指针位置) A,s .<TG  
private void write_nPos() x5Ee'G(  
{ T)B1V,2j=  
try{ 8M'6Kcr  
output = new DataOutputStream(new FileOutputStream(tmpFile)); pBu~($%d  
output.writeInt(nStartPos.length); DV~1gr,\  
for(int i=0;i<nStartPos.length;i++) 4==Lt Ep  
{ \ow0Y >  
// output.writeLong(nPos); #TSLgV'U  
output.writeLong(fileSplitterFetch.nStartPos); KGX?\#-  
output.writeLong(fileSplitterFetch.nEndPos); U!x\oLP  
} =<[ZFO~v  
output.close(); p{Gg,.f!HM  
} s2ys>2k  
catch(IOException e){e.printStackTrace ();} WH$ Ls('  
catch(Exception e){e.printStackTrace ();} ^5~[G%G4  
} S.OGLLprp  
$T0|zPK5  
[%8+Fa~Wa  
//读取保存的下载信息(文件指针位置) "]`QQT-{0  
private void read_nPos() ^i^S1h"  
{ 2={ g'k(  
try{ d|sI>6jD  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); BPd]L=,/  
int nCount = input.readInt(); r4qFEFV3%  
nStartPos = new long[nCount]; 8)k.lPoo.  
nEndPos = new long[nCount]; 3?uP$(l  
for(int i=0;i<nStartPos.length;i++) T't^pO-`  
{ v+=_  
nStartPos = input.readLong(); 4.dMNqU  
nEndPos = input.readLong(); XfT6,h7vFL  
} L3~E*\cV  
input.close(); .ODtduURe  
} Cst> 'g-yB  
catch(IOException e){e.printStackTrace ();} }J$PO*Q@'  
catch(Exception e){e.printStackTrace ();} QrPWS-3~!  
}  OkO"t  
fwQ%mU+  
)V}u1C-N  
private void processErrorCode(int nErrorCode) &4DV]9+g  
{ h OboM3_  
System.err.println("Error Code : " + nErrorCode); qwaw\vOA  
} 4p~:(U[q  
LVLh&9  
j{P,(-  
//停止文件下载 :7!/FBd  
public void siteStop() ( |5g`JDG  
{ q#Qr@Jf  
bStop = true; Gf'V68,l$  
for(int i=0;i<nStartPos.length;i++) xI~\15PhG  
fileSplitterFetch.splitterStop(); uj/le0  
ZcO!cR&*'J  
Qzh:*O  
} R/O_*XY  
} %r!  
//负责部分文件的抓取 T+4Musu{V  
**FileSplitterFetch.java >)pwmIn<  
*/ Gz@%UIv  
package NetFox; \aUbBa%!  
dYV)lMJ*  
+uwjZN'9a  
import java.io.*;  "rjJ"u 1  
import java.net.*; -RH ?FJ  
=C\S6bF%  
\^-3)*r  
public class FileSplitterFetch extends Thread { ?\#4`9  
bt&vik _  
Hab9~v ]  
String sURL; //File URL ); |~4#  
long nStartPos; //File Snippet Start Position [bT@Y:X@`  
long nEndPos; //File Snippet End Position <qRw! 'S^  
int nThreadID; //Thread's ID up2%QbN(  
boolean bDownOver = false; //Downing is over ^LC5orO  
boolean bStop = false; //Stop identical .(1$Q6yG  
FileAccessI fileAccessI = null; //File Access interface {2:H`|x  
%r!#  
|k+&we uY  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException T8hQ< \g  
{ BkqIfV%O  
this.sURL = sURL; ln=zGX.e  
this.nStartPos = nStart; nQ(#'9  
this.nEndPos = nEnd; oG*lU h}  
nThreadID = id; Iwn@%?7  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 mc$c!Ax*  
} *BO4"3Z  
3P\I;xM  
b]g.>$[nX  
public void run() @e0 Q+t  
{ $0W0+A$  
while(nStartPos < nEndPos && !bStop) 'b^:"\t'Rh  
{ Io"=X! k  
UU ,)z  
Y+=@5+G  
try{ (wY% $kW4  
URL url = new URL(sURL); [X~X?By>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7e=a D~f  
httpConnection.setRequestProperty("User-Agent","NetFox"); \qTn"1b Q  
String sProperty = "bytes="+nStartPos+"-"; 7R2)Klt  
httpConnection.setRequestProperty("RANGE",sProperty); 9vj:=,TNu  
Utility.log(sProperty); R&alq  
X)&Z{ V>  
wRiP5U,  
InputStream input = httpConnection.getInputStream(); Z?Q2ed*j  
//logResponseHead(httpConnection); Ph%s.YAZ~  
Dps{[3Y+  
TwhK>HN  
byte[] b = new byte[1024]; 8\V-aow  
int nRead; ^LcI6 h  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) YI|G pq  
{ ?\pE#~m  
nStartPos += fileAccessI.write(b,0,nRead); Y3zO7*-@  
//if(nThreadID == 1) ;_SS3q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1Ev+':%  
} +|8Lt[^ux  
E8dp  
D!sSe|sL^  
Utility.log("Thread " + nThreadID + " is over!"); 8|tm`r`*Az  
bDownOver = true; JWn{nJ$]  
//nPos = fileAccessI.write (b,0,nRead); QJE- $ :  
} !S-hv1bE  
catch(Exception e){e.printStackTrace ();} }-Ma ~/  
} dDuA%V0  
} 6b8Klrar!  
pnG8c<  
-*Pt781  
//打印回应的头信息 e S=k 48'U  
public void logResponseHead(HttpURLConnection con) J-ZM1HoB  
{ i|O7nB@  
for(int i=1;;i++) i;xMf5Jz  
{  =*Yc/  
String header=con.getHeaderFieldKey(i); G7202(w <  
if(header!=null) 7r<>^j'  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); w${=dW@K  
Utility.log(header+" : "+con.getHeaderField(header)); C/vLEpP{(/  
else jlP7'xt1%  
break; ,q HG1#^  
} ).S<{zm7  
} y,>m#6hx#  
>V$#Um?AXj  
)/AvWDKvO  
public void splitterStop() Iq=B]oE  
{ 8WGM%n#q  
bStop = true; :V2 Q n-N  
} S- \lN|  
D6oby*_w  
_Kj.  
} 9C 05  
//,'oh~W  
<`*P/V  
/* #]N9/Hij#g  
**FileAccess.java ^k(eRs;K  
*//文件访问(定位,写) . R}y"O\  
package NetFox; bLzuaNa'  
import java.io.*; }"x*xN  
oMe]dK  
%Eh%mMb^  
public class FileAccessI implements Serializable{ u_"h/)C'H  
-YyH"f   
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 r97[!y1gt  
RandomAccessFile oSavedFile; Y fA\#N0;3  
long nPos; X&~Eo  
p4EItRZS  
M\6`2q  
public FileAccessI() throws IOException gc~h!%'.I  
{ uPXqTkod  
this("",0); &s;^q  
} 7qz-RF#s8  
N8q Z{CWn  
~?5m5z O  
public FileAccessI(String sName,long nPos) throws IOException Ve1] ECk  
{ ')-(N um  
oSavedFile = new RandomAccessFile(sName,"rw"); EM/+1 _u  
this.nPos = nPos; z{0;%E  
oSavedFile.seek(nPos); l,L=VDEz,  
} \>`$x:  
Av>j+O ;  
(NC>[  
public synchronized int write(byte[] b,int nStart,int nLen) e:D"_B  
{ vxT"BvN  
int n = -1; DOIWhd5:  
try{ -\$cGIL  
oSavedFile.write(b,nStart,nLen); RbM~E~$  
n = nLen; $)]FCuv  
} gVJ#LJ  
catch(IOException e) z]|[VM?4L  
{ UeMe4$m  
e.printStackTrace (); Kn$1W=B1.  
} ] *VF Ws  
3a}`xCO5  
mZVOf~9E  
return n; 51ebE`  
} U(=9&c@]  
O9X:1>a@i  
D>e\OfTR:  
} l1Q+hz5"*U  
5l/l]  
<^_Vl8%  
/* 6CmFmc,  
**SiteInfoBean.java # pB:LPEsK  
*/ = DTOI  
package NetFox; e=UVsYNx  
cloSJmUlQ  
e@-Mlq)  
public class SiteInfoBean { {/xs9.8:JX  
TK/'=8  
W.D3$  
private String sSiteURL; //Site's URL `A _8nW)  
private String sFilePath; //Saved File's Path ,Z7Z!.TY!  
private String sFileName; //Saved File's Name @dCPa7:>&  
private int nSplitter; //Count of Splited Downloading File _xg VuJ   
,1;8DfVZV  
+Cg"2~  
public SiteInfoBean() G=5t5[KC  
{//nSplitter的缺省值为5 +Z<Q^5w@  
//default value of nSplitter is 5 j~*Z7iu  
this("","","",5); LA`V qJ  
} [ky6E*dV`  
{3(.c, q@  
Z;~[@7`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9Y%?)t.2  
{ zHOE.V2Qo  
sSiteURL= sURL; HU[nN*  
sFilePath = sPath; ou^nzm  
sFileName = sName; n_n|^4 w  
this.nSplitter = nSpiltter; ]z=Vc#+!  
?g;ZbD  
lJzy)ne  
} ^%%5  
>-@ U_p  
CCh8?sM  
public String getSSiteURL() Y0B1xL@  
{ m?VRX .>  
return sSiteURL; YATdGLTeq  
} 9N D+w6"  
2ZG1n#  
_|  
public void setSSiteURL(String value) G P[r^Z  
{ ,;iBeqr5  
sSiteURL = value; @fH&(@  
} ]( =wlq)  
4JZHjf0M6  
 AMD?LjY~  
public String getSFilePath() ki~y@@3I  
{ rt^45~  
return sFilePath; {rvbo1t  
} t0J5v;  
VHT@s7u0"  
/uE^H%9h  
public void setSFilePath(String value) [)SR $/A  
{ 2>}\XKF).  
sFilePath = value; xOL)Pjo /m  
} 8q?;Hg  
fQ36Hd?(5  
<@e+-$  
public String getSFileName() |[37:m  
{ /Fo/_=FE2  
return sFileName; C. Ja;RFq  
} O GFE*  
2yQ}Lxr(  
y2#>c*  
public void setSFileName(String value) E!I  
{ {y^|ET7  
sFileName = value; )jk1S  
} .FKJ yzL  
xEiX<lguyN  
=`1m-   
public int getNSplitter() -N7xO)  
{ k?HrD"k"  
return nSplitter; }PFt  
} &=-e`=qJ'6  
fNqmTRu  
7SK 3  
public void setNSplitter(int nCount) 9fuJJ3L[  
{ .IH@_iX  
nSplitter = nCount; wt}%2x} x  
} MxgLzt Y  
} Sn(l$wk=  
#A3v]'7B  
~n/Aq*  
/* *vRI)>wU  
**Utility.java J`r,_)J"2  
*/ {,Bb"0 \  
package NetFox; L-z ;:Ztk  
\o B'  
M 20Bc,VI  
public class Utility { 6)wy^a|pb  
i-k >U}[%  
t$K@%yU2  
public Utility() SH vaV[C  
{ ;vJ\]T ml  
_V& !4Zd9:  
Ns2,hQFc  
} m4"N+_j  
$U>/i@D  
//线程睡眠 _hy{F%}  
public static void sleep(int nSecond) ut$,?k!M  
{ Hwp{<  
try{ (LRM~5KVg  
Thread.sleep(nSecond); 7$ =Y\ P  
} ~{4n}*  
catch(Exception e) PUP"ky^q"  
{ qX5yN| A4  
e.printStackTrace (); ;}/U+`=D?  
} fVDDYo2\  
} %AG1oWWc>.  
#v4LoNm  
//日志 *K(k Kph  
public static void log(String sMsg) +}^|dkc  
{ W|25t)cJ8h  
System.err.println(sMsg); z.3<{-n}0i  
} ;8ET!&k*>E  
?< cM^$lI>  
^kn ^CI6  
public static void log(int sMsg) s.yq}Q  
{ u^Nxvx3l0  
System.err.println(sMsg); jg [H}  
} D<U 9m3  
} bmOqeUgB  
OXHvT/L`  
C$<"w,  
/* VEj$^bpp5s  
**TestMethod.java S]&8St  
*/ J7BFk ?=  
package NetFox; ryxYcEM0  
+T0op4  
0#oBXu  
public class TestMethod { sM9FE{,mx  
@Od^k#  
bMN@H\Ek  
public TestMethod() /!GKh5|  
{ ///xx/weblogic60b2_win.exe 7%}ay  
try{ *Jvxs R'a1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); FR x6c  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); E *F*nd]K  
SiteFileFetch fileFetch = new SiteFileFetch(bean); w6T[hZ 9  
fileFetch.start(); &{%MjKJ._  
} Ia629gi5s  
catch(Exception e){e.printStackTrace ();} :qKF58W  
} q%jO  
2_;]  
} HH)"]E5  
9W!8gCs  
9!9> ?Z  
public static void main(String[] args) EM=w?T  
{ 0YzsA#yv  
new TestMethod(); ^Q0&.hL@  
} ]3*P:$Rq  
} ha*X6R  
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