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http断点续传简单实现(java)

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/* Cu)%s  
**SiteFileFetch.java S<2CG)K[  
*/ dw{#||  
package NetFox; SoXX}<~E4  
import java.io.*; .g(\B  
import java.net.*; Pq[0vZ_}dN  
NIWI6qCw  
]ut-wqb{p  
public class SiteFileFetch extends Thread { i 5 >J  
E7Gi6w~\  
%>I?'y^  
SiteInfoBean siteInfoBean = null; //文件信息Bean c'TiWZP~  
long[] nStartPos; //开始位置 Y*5@|Q  
long[] nEndPos; //结束位置 M&}oat*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _Vk,&'  
long nFileLength; //文件长度 Z;"4$@|qE  
boolean bFirst = true; //是否第一次取文件 ^w&5@3d  
boolean bStop = false; //停止标志 O3<Y_I^  
File tmpFile; //文件下载的临时信息 c4qp3B_w  
DataOutputStream output; //输出到文件的输出流 ^J#*n;OQ3A  
Ht=6P)  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) m_r@t*  
public SiteFileFetch(SiteInfoBean bean) throws IOException x[.z"$T@  
{ r[UyI3(i^  
siteInfoBean = bean; b. %B;qB  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @kCD.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .JD4gF2N  
if(tmpFile.exists ()) mER8> <  
{ VFO&)E/-  
bFirst = false; "t%1@b*u  
read_nPos(); O0=,&=i  
} z6L>!=  
else %Zv(gI`A  
{ I 1VEm?CQ  
nStartPos = new long[bean.getNSplitter()]; ?-.Ep0/  
nEndPos = new long[bean.getNSplitter()]; TYJnQ2m  
} Ls$g-k%c@Q  
&[W3e3Asra  
*k@0:a(>  
0]2B-o"kI  
} HhY2`P8  
$@:>7Y"  
28UL  
public void run() xP5mL3j  
{ ;+TF3av0zq  
//获得文件长度 g.`t!6Hc  
//分割文件 wCC~tuTpr  
//实例FileSplitterFetch :)+@qxTy  
//启动FileSplitterFetch线程 )kY _"= d  
//等待子线程返回 23u1nU[0  
try{ ffoo^1}1  
if(bFirst) 4MF}FS2)  
{ b/n8UxA  
nFileLength = getFileSize(); ` HE:D2b  
if(nFileLength == -1) b0z{"  
{ eB/hyC1  
System.err.println("File Length is not known!"); W_f"Gk  
} #iqhm,u7D  
else if(nFileLength == -2) yOn2}Z  
{ 8NF;k5   
System.err.println("File is not access!"); ttAVB{kdo  
} beHCEwh  
else G(|(y=ck  
{ Ek B6- nz  
for(int i=0;i<nStartPos.length;i++) `S/1U87  
{ ]\9B?W(#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); OL ]T+6X  
} )zL"r8si  
for(int i=0;i<nEndPos.length-1;i++) XB!`*vZ/<  
{ }r<@o3t  
nEndPos = nStartPos[i+1]; \Q?|gfJH  
} M\.T 0M_  
nEndPos[nEndPos.length-1] = nFileLength; [nPzh Xs  
} h7W%}6Cqkw  
} f'i8Mm4IL  
=Q=&Ucf_  
%6c*dy  
//启动子线程 GZhfA ;O,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3EW f|6RI  
for(int i=0;i<nStartPos.length;i++) UN .[,%<s  
{ 2Fp]S a  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d`],l\o C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {+UNjKQC  
nStartPos,nEndPos,i); 4pTu P /  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _]~ht H  
fileSplitterFetch.start(); 84oW  
} o|*|  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m9<[bEO<$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7s fuju(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 9bcyPN  
nEndPos = " + nFileLength); E[Ws} n.  
// fileSplitterFetch[nPos.length-1].start(); ga1gd~a  
M?4r5R  
j+B5m:ExfI  
//等待子线程结束 6q uWO2x  
//int count = 0; 5t5S{aCDr  
//是否结束while循环 v`ZusHJ1d  
boolean breakWhile = false; uI-7 6  
s3E~X  
m)]fJ_  
while(!bStop) Mb 2 L32  
{ ) }it,<  
write_nPos(); V8U`%/`N  
Utility.sleep(500); Nec(^|[   
breakWhile = true; :_YG/0%I  
a$! {Tob2  
% x*Ec[l  
for(int i=0;i<nStartPos.length;i++) 3 ws(uF9$  
{ Iv|WeSL.  
if(!fileSplitterFetch.bDownOver) "KI,3g _V  
{ 53+rpU_  
breakWhile = false; d_7Xlp@  
break; gjN!_^ _  
} 46?F+,Rzl  
} U#]eN[  
if(breakWhile) r5qx! >  
break; c'Tu,-  
7D~O/#dcc  
=5=Vm[  
//count++; y>cmKE  
//if(count>4) w3bH|VnU8;  
// siteStop(); 5NvyK[w]  
} UV8r&O  
8 W<)c  
&'ETx"  
System.err.println("文件下载结束!"); QKaj4?p$|S  
} ut5!2t$c  
catch(Exception e){e.printStackTrace ();} 6ewOZ,"j"4  
} a&c#* 9t{  
[11-`v0  
1 l*(8!_  
//获得文件长度 q {+poV X  
public long getFileSize() Yg,WdVI&@  
{ 56 kgL;$h  
int nFileLength = -1; FR6I+@ oX~  
try{ ]%Yis=v  
URL url = new URL(siteInfoBean.getSSiteURL()); 5eSTT#[+R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); sv6U%qV  
httpConnection.setRequestProperty("User-Agent","NetFox"); DMxS-hl  
 t-x"(  
Oi[9b  
int responseCode=httpConnection.getResponseCode(); irw 7  
if(responseCode>=400) <^q"31f  
{ =ObtD"  
processErrorCode(responseCode); ~q|e];tA  
return -2; //-2 represent access is error H!>oLui  
} .&}4  
95 .'t}  
3XlnI:w =  
String sHeader; MMr7,?,$  
sPTUGx'  
a<"& RnG(  
for(int i=1;;i++) ?_j6})2zY  
{ c@#zjJhW]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); sCCr%r]zL  
//Utility.log(in.readLine()); xPJJ !mY  
sHeader=httpConnection.getHeaderFieldKey(i); nK'8Mo  
if(sHeader!=null) H1j6.i}q  
{ vG_v89t!ex  
if(sHeader.equals("Content-Length")) <07W&`Dw  
{ sr@XumT  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); K/d &c]  
break; ^W[`##,{Od  
} NE%yv,B  
} C(*@-N pf[  
else W (c\$2`  
break; g+r{>x  
} BCZnF /Zo  
} @=#s~ 3  
catch(IOException e){e.printStackTrace ();} Z*aU2Kr`;  
catch(Exception e){e.printStackTrace ();} ` "":   
St&HE:  
.:!x*v  
Utility.log(nFileLength); -XIvj'u  
y$9 t!cx  
dB/I2uGl>  
return nFileLength; safS>wM]  
} ~I|R}hS  
8[`<u[Iv  
`[:1!I.}-  
//保存下载信息(文件指针位置) YIUmCx0a  
private void write_nPos() &Wz:-G7<n  
{ +pViHOJu&V  
try{ (ai-n,y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |A/_Qe|s2  
output.writeInt(nStartPos.length); PjZvLK@a9)  
for(int i=0;i<nStartPos.length;i++) J*&=J6  
{ /~huTKA}  
// output.writeLong(nPos); LF.~rmPa  
output.writeLong(fileSplitterFetch.nStartPos); HtYR 0J  
output.writeLong(fileSplitterFetch.nEndPos); 4m!3P"$  
} cE>/iZc  
output.close(); }e =GvWGa  
} Pc4c Sw#5  
catch(IOException e){e.printStackTrace ();} 1gej$G@  
catch(Exception e){e.printStackTrace ();} J7^T!7V.  
} (wF$"c3'{  
U9sub6w6  
'?GZ"C2  
//读取保存的下载信息(文件指针位置) @5VZ   
private void read_nPos() kGiw?~t=%  
{  !Ocg  
try{ tU/NwA"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); a(T4WDl^  
int nCount = input.readInt(); }M@Jrq+7  
nStartPos = new long[nCount]; 3v+}YT{>b  
nEndPos = new long[nCount]; L\CM);y  
for(int i=0;i<nStartPos.length;i++) <U`Nb) &  
{ tS|zf,7  
nStartPos = input.readLong(); ^l9 *h  
nEndPos = input.readLong(); jV&W[xKa  
} E?D{/ k,zZ  
input.close(); FGhrf  
} 0M2+?aKif  
catch(IOException e){e.printStackTrace ();} Xtnmh)'K~#  
catch(Exception e){e.printStackTrace ();} 'z!#E!i  
} f|1FqL+T]  
<f{`}drp/  
Cy'W!qH  
private void processErrorCode(int nErrorCode) <%uZwk>#  
{ rWKLxK4oU  
System.err.println("Error Code : " + nErrorCode); \1 D,Kx;Cb  
} S%#Mu|  
h,?Yw+#o"  
u`,R0=<4  
//停止文件下载 A_U0HVx_  
public void siteStop() K :ptfD  
{ Bin&:%|9?  
bStop = true; >.~k?_Of  
for(int i=0;i<nStartPos.length;i++) 5{aQ4H>~tx  
fileSplitterFetch.splitterStop(); 4GA-dtyV&  
c}s3c >`d  
|sM#g1D@  
} [N+ruc?)  
} * xXc$T  
//负责部分文件的抓取 2;r^~:  
**FileSplitterFetch.java urjp&L&  
*/ m|FONQ,@D  
package NetFox; LOkDx2@g  
LgKEg90w(  
R! xc $`N  
import java.io.*; 4>`w9   
import java.net.*; bGO_y]Pc  
y N%Pe:R  
Q 5TyS8  
public class FileSplitterFetch extends Thread { cNC BbOMr  
r T$g^  
-z1o~~  
String sURL; //File URL V t;&2v  
long nStartPos; //File Snippet Start Position >m{-&1Tx  
long nEndPos; //File Snippet End Position v A~hkkj{  
int nThreadID; //Thread's ID 7O :Gi*MA  
boolean bDownOver = false; //Downing is over A1T;9`E  
boolean bStop = false; //Stop identical sJ()ItU5i  
FileAccessI fileAccessI = null; //File Access interface ~3]8f0^%m  
[T|1Qq7  
!gQ(1u|r  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException W7> _nK+g?  
{ %'5wwl  
this.sURL = sURL; ~,1X>N"  
this.nStartPos = nStart; <rxem(PPu  
this.nEndPos = nEnd; 1H@F>}DP  
nThreadID = id; $R36`wk  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 `o'sp9_3  
} nwH|Hs riU  
1uzfV)  
!XceiQu  
public void run() J1MnkxJmpQ  
{ #R| 4(HlL  
while(nStartPos < nEndPos && !bStop) b~echOj  
{ +Q&@2 oY"  
u:?RdB}B_@  
]xs\,}I%  
try{ NKYyMHv6  
URL url = new URL(sURL); n&&y\?n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); g;@PEZk1  
httpConnection.setRequestProperty("User-Agent","NetFox"); Pfy;/}u^c  
String sProperty = "bytes="+nStartPos+"-"; <!$Cvx\U  
httpConnection.setRequestProperty("RANGE",sProperty); wt,N<L  
Utility.log(sProperty); rMloj8O*  
CKgyv%T5m:  
wu'60po  
InputStream input = httpConnection.getInputStream(); izA3INT  
//logResponseHead(httpConnection); ZH :X 4!  
UQr+\ u  
yB[ LO( i  
byte[] b = new byte[1024]; AP@d2{"m}  
int nRead; #}?$mxME*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) F@3,>~[%I  
{ f}3bYF  
nStartPos += fileAccessI.write(b,0,nRead); (avaTUMOqy  
//if(nThreadID == 1) rR;Om1 -,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jL>r*=K)%  
} (>23[;.0  
_bsfM;u.%  
H8U*oLlc  
Utility.log("Thread " + nThreadID + " is over!"); x$sQ .aT  
bDownOver = true; w"J(sVy4  
//nPos = fileAccessI.write (b,0,nRead); ~coG8r"o  
} S?$T=[yY)  
catch(Exception e){e.printStackTrace ();} )I_I?e  
} Kz;VAH  
} c8MNo'h  
G&-h,"yo^  
Stpho4+/y  
//打印回应的头信息 ) 'KHUa9  
public void logResponseHead(HttpURLConnection con) " OtLJ  
{ Dr609(zg^  
for(int i=1;;i++) QB>e(j%  
{ j>zVC;Sj*  
String header=con.getHeaderFieldKey(i); S/aPYrk>6  
if(header!=null) l.! ~t1i  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Oylw,*%  
Utility.log(header+" : "+con.getHeaderField(header)); %yVZ|d*Q  
else NeP1 #  
break; 7)#/I  
} 4B]a8  
} Zup?nP2GkT  
F9" K  
^,gKA\Wli  
public void splitterStop() 5`Z#m:+u  
{ 0fNBy^(K  
bStop = true; IA'AA|v  
} up?8Pq*  
*V}}3Degh  
8wd2\J,]  
} gS ]'^Sr  
dewu@  
# L R[6l  
/* ] $*cmk(Y  
**FileAccess.java &0`L;1R  
*//文件访问(定位,写) q ^?{6}sy  
package NetFox; R<)uvW_@  
import java.io.*; +Xk!)Ge5E*  
9S^-qQH3}  
Z8W<RiR  
public class FileAccessI implements Serializable{ V RL6F2 >6  
O<*iDd`(e  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 (;h\)B!o  
RandomAccessFile oSavedFile; _ U\vHa$#  
long nPos; sQvEUqy9  
KqQrxi?f-  
6pse @x?  
public FileAccessI() throws IOException |bh:x{h  
{ -eya$C  
this("",0); 4^5s\ f B  
} {+MMqJCa  
\BDNF< _  
>=bO@)[  
public FileAccessI(String sName,long nPos) throws IOException li[g =A,  
{ u/AN| y  
oSavedFile = new RandomAccessFile(sName,"rw"); M;OYh  
this.nPos = nPos; T&%>/7I>  
oSavedFile.seek(nPos); Y!H"LI  
} Tm `CA0@  
0=04:.%D  
= ~yh[@R)  
public synchronized int write(byte[] b,int nStart,int nLen) ~kL":C>2  
{ n| %{R|s  
int n = -1; L2N/DB'{  
try{ TBpW/wz/  
oSavedFile.write(b,nStart,nLen); S}+n\pyQ  
n = nLen; LX8vVj8K  
} cX2b:  
catch(IOException e) g8C+j6uR0  
{ 0|cQx VJb  
e.printStackTrace (); 83h6>D b  
} "^\4xI  
D 6(w}W  
~b+>o  
return n; ~_q\?pw<$L  
} g7F>o76M  
w-1CA{"i7  
i^8Zp;O"f  
} 1\BECP+  
rpd3Rp  
22GtTENd1h  
/* gaJS6*P#  
**SiteInfoBean.java h )w<{/p(  
*/ _Nd\Cm  
package NetFox; 7 9Iz,_  
Z?~7#F~Z`  
C][`Dk\D{  
public class SiteInfoBean { CyE.q^Wm  
=(o$1v/k  
(C!fIRY  
private String sSiteURL; //Site's URL (Az^st/_  
private String sFilePath; //Saved File's Path X(8 ]9  
private String sFileName; //Saved File's Name 2/GH5b(  
private int nSplitter; //Count of Splited Downloading File 4CDmq[AVS[  
Qr/?tMALc  
`VHm,g2  
public SiteInfoBean() 2$jY_{B+x  
{//nSplitter的缺省值为5 ZnQnv@{8 l  
//default value of nSplitter is 5 6Cibc .vt  
this("","","",5); }MoCUN)I  
} *yB!^O  
,[A} 86  
JO _a+Yl  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 5~qr+la  
{ `/"z.~8  
sSiteURL= sURL; zdY`c  
sFilePath = sPath; +q3W t|  
sFileName = sName; ).-FuL4Y  
this.nSplitter = nSpiltter; fx*Swv%r  
Z*JZ Ubo-Q  
@wpm;]  
} cewQQ&  
3T_-_5[c  
Ouj5NL  
public String getSSiteURL() $XJe)  
{ |/q*Fg[f  
return sSiteURL; L)Kn8  
} PoC24#vS  
#0weN%  
zj8;ENhEI  
public void setSSiteURL(String value) Y yI|^f8C  
{ BKN]DxJ6  
sSiteURL = value; %bddR;c  
} &vLZj  
Jg7IGU(dct  
,Qp58u2V  
public String getSFilePath() nwz}&nR  
{ r8@:Ko= a  
return sFilePath; {D7!'Rq,  
} pnf3YuB  
}=wSfr9g  
iXBc ~S  
public void setSFilePath(String value) O^LzS&I*  
{ 'A4Lr  
sFilePath = value; ~,ac{%8x  
} :kgwKuhL  
K~[/n<ks  
Qg3 -%i/@  
public String getSFileName() <n0-zCf  
{ }Za[<t BWS  
return sFileName; 3wD6,x-e   
} ?onZ:s2  
T1D7H~ \lG  
N!hp^V<7  
public void setSFileName(String value) zVp|%&  
{ X^"95Ic  
sFileName = value; eGZId v1  
} n}a# b%e  
y9:|}Vh  
e=YvM g  
public int getNSplitter() N-lXC"{)  
{ 8^+Q n/b_%  
return nSplitter; t:W`=^  
} T?Gi;ld7  
U%2pbGU  
^M8\ 3G  
public void setNSplitter(int nCount) Jzh_`jW0l  
{ 89~)nV)  
nSplitter = nCount; KWM.b"WnXr  
} nJrV  
} bD=_44I  
QRx'BY$5  
I/fERnHM/+  
/* h}.0Ne  
**Utility.java 'j>Q7M7q{  
*/ )0!hw|0|  
package NetFox; _bFX(~37z?  
S__+S7]Nr  
XYf;72*  
public class Utility { ?f:FmgQk  
_^Rf*G!  
vfmKYiLp  
public Utility() E+csK*A7  
{ . [*6W.X  
'Ko T8g\b  
2#ypM9  
} aZ- )w  
zPZy#7/A  
//线程睡眠 ?2QssfB  
public static void sleep(int nSecond) J/WPffqD  
{ vA"yy"B+ V  
try{ dfO84Z} 5  
Thread.sleep(nSecond); iw<+rh*C  
} J$@3,=L6V  
catch(Exception e) -&%#R_RV  
{ {'EQ%H $q  
e.printStackTrace (); 0t'WM=W<!8  
} &U!@l)<  
} HSq&'V  
#*XuU8q?  
//日志 Lw1~$rZg  
public static void log(String sMsg) 3/P2&m  
{ 0vf2wBK'T  
System.err.println(sMsg); pv;}Sv$ ]-  
} l. !5/\  
}D{y u+)  
|-=^5q5  
public static void log(int sMsg) dKi+~m'w  
{ HS>Z6|uLY  
System.err.println(sMsg); L-",.U*;  
} D'c, z[  
} szGp<xv_p  
e\tcP  
mi6<;N 2w|  
/* z'XFwk  
**TestMethod.java 8?J\  
*/ yIOoVi\m  
package NetFox; G"3D"7f a  
U_B"B;ng+  
S3A OT  
public class TestMethod { 9g|o17  
tFO86 !ln  
ku&IVr%  
public TestMethod() Ws{2+G~  
{ ///xx/weblogic60b2_win.exe aU4v-9@U8  
try{ 2y`rS _2  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); lt`#or"o  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); BMgiXdv.B  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~f;d3dJ]/  
fileFetch.start(); 58ev (f  
} "O!J6  
catch(Exception e){e.printStackTrace ();} H3nx8R$j](  
VMe~aUd  
IJhJfr0)Oo  
} 2 <y!3OeN  
Rbm"Qz  
~kj1L@gy   
public static void main(String[] args) z|x0s0q?  
{ Gn>#Mvq  
new TestMethod(); =TE6R 0b  
} /n"Ib )M  
} b<u   
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