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http断点续传简单实现(java)

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/* 7v,>sX  
**SiteFileFetch.java -&)^|Atm  
*/ IJ4"X#Q/  
package NetFox; a m<R!(  
import java.io.*; =~=/ dq  
import java.net.*; $elrX-(vL  
Z~?:r  
"rX=G=  
public class SiteFileFetch extends Thread { f{AgKW9"  
,dVCbAS@  
a|nlmH"l  
SiteInfoBean siteInfoBean = null; //文件信息Bean _9z/>e  
long[] nStartPos; //开始位置 +=k?Dp[  
long[] nEndPos; //结束位置 =oQzL  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 rG\m]C3E  
long nFileLength; //文件长度 Czv lZDo  
boolean bFirst = true; //是否第一次取文件 m/eGnv;!  
boolean bStop = false; //停止标志 ZC2C`S\xr  
File tmpFile; //文件下载的临时信息 6km u'vw  
DataOutputStream output; //输出到文件的输出流 Q`vyDoF  
{t=Nnc15K  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) k5/nAaiVE  
public SiteFileFetch(SiteInfoBean bean) throws IOException %+I(S`}  
{ _5`M( ;hL2  
siteInfoBean = bean; K&)a3Z=(.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]#BXaBVMY  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ]Rj"/(X,  
if(tmpFile.exists ()) Q|ik\  
{ UkqLLzL  
bFirst = false; 2#(7,o}Y5  
read_nPos(); mCz6&  
} +XpRkX&-  
else ]UgA z  
{ ~JZ Lfw  
nStartPos = new long[bean.getNSplitter()]; /yykOvUO  
nEndPos = new long[bean.getNSplitter()]; '|d (<.[  
} c%Gz{':+  
dX$])b_Uw  
p9s~WD/K  
6~!YEuA  
} !8L Ql}  
L}21[ N~ky  
KPR{5  
public void run() *z+\yfOO"  
{ 6pLwwZD  
//获得文件长度 :mJM=FeJ  
//分割文件 $U8ap4EXM  
//实例FileSplitterFetch gx6&'${=#  
//启动FileSplitterFetch线程 /GXO2zO  
//等待子线程返回 9{TOFjsF  
try{ ReE3742@  
if(bFirst) X~DXx/9  
{ P9>C!0 -x  
nFileLength = getFileSize(); bv+e'$U3  
if(nFileLength == -1) * QR7t:([  
{ ^LNc  
System.err.println("File Length is not known!"); u}:O[DG  
} XBY"7}  
else if(nFileLength == -2) {30<Vc=  
{ CYn}wkz  
System.err.println("File is not access!"); c|.:J]  
} PaDT)RrEM  
else ZGbZu  
{ ib&qH_r/  
for(int i=0;i<nStartPos.length;i++) >WDpBn:  
{ u!-eP7;7  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); m[bu(qz  
} AO]lXa  
for(int i=0;i<nEndPos.length-1;i++) ]OrFW4tiE  
{ r{TNPa6!  
nEndPos = nStartPos[i+1]; x$Oz0[  
} B.G!7>=  
nEndPos[nEndPos.length-1] = nFileLength; f2u2Ns0Ym  
} \\lC"Z#J`  
} #NE^f2  
"J.jmR;  
Tk!b`9  
//启动子线程 }dHiW:J>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; u#,]>;  
for(int i=0;i<nStartPos.length;i++) O.E0LCABC  
{ :I $2[K  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >'jM8=o*Ax  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), CS{9|FNz  
nStartPos,nEndPos,i); i\ Vpp8<B  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); oTfbx+i/G  
fileSplitterFetch.start(); 8$vH&Hd I  
} S|J8:-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bGJUu#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); D1n2Z :9  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", OKqpc;y:D  
nEndPos = " + nFileLength); PGKXzp'  
// fileSplitterFetch[nPos.length-1].start(); !kcg#+s91  
G8s`<:9*  
YXtGuO\q  
//等待子线程结束 aOHCr>po,  
//int count = 0; x-pMT3m\D#  
//是否结束while循环 qck/b  
boolean breakWhile = false; uJ`&hX  
RI(uG-Y  
TUaK:*x*  
while(!bStop) }$)<k  
{ -!0LIr:"  
write_nPos(); &~%@QC/  
Utility.sleep(500); Wj:QC<5 v  
breakWhile = true; a  98  
(<l2 ^H  
v'!Nt k  
for(int i=0;i<nStartPos.length;i++) 3+-(;>>\  
{ h9I )<_}R  
if(!fileSplitterFetch.bDownOver) X*"K g  
{ nIjQLx  
breakWhile = false; kpH;D=;  
break; //Gvk|O1  
} Oi0;.< kX  
} JY2 F-0t)  
if(breakWhile) cDiz!n*.q  
break; /;rN/ot2o  
'-IT@}  
`I8^QcP  
//count++; .A\\v6@  
//if(count>4) Jg:-TK/  
// siteStop(); XijLS7Aw|  
} Q: O>kCDV  
@vYmkF`  
@q/1m~t  
System.err.println("文件下载结束!"); M0SH-0T;Z  
} XKX,7  
catch(Exception e){e.printStackTrace ();} $NT9LtT@K  
} xLI{=sL  
} 4]<P  
io{H$  x(  
//获得文件长度 BozK!"R_<  
public long getFileSize() s[q4K  
{ Jyci}CU3\Q  
int nFileLength = -1; WrNgV@P  
try{ o#P3lz  
URL url = new URL(siteInfoBean.getSSiteURL()); \( <{)GpBi  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .w_`d'}  
httpConnection.setRequestProperty("User-Agent","NetFox"); ph?0I: eU  
I#X2 UQzP  
J,G9m4Z7  
int responseCode=httpConnection.getResponseCode(); +MZO%4  
if(responseCode>=400) J7ekIQgR  
{ `4.sy +2  
processErrorCode(responseCode); P"h\7V,d%  
return -2; //-2 represent access is error SP*JleQN  
} :6$4K"^1  
n& m?BuG  
rm=~^eB  
String sHeader; Hu9R.[u  
bo;pj$eR3R  
$SzCVWS  
for(int i=1;;i++) @k+G Cf  
{ IR dz(~CP  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); I?Jii8|W9  
//Utility.log(in.readLine()); %HF$  
sHeader=httpConnection.getHeaderFieldKey(i); ' ?G[T28  
if(sHeader!=null) Bdq"6SK>  
{ .x!7  
if(sHeader.equals("Content-Length")) *_<*bhR<  
{ boF4d'g"  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); sRyw\v-=P  
break; 2Z`$  
} G#n^@kc*,  
} g<iwxF  
else ,AbKxT f2  
break; (L0 hS'  
} 7#9'2dI  
} vYSetAd v  
catch(IOException e){e.printStackTrace ();} QR5,_wJ&  
catch(Exception e){e.printStackTrace ();} 5'kTe=  
{1@4}R4  
r$r&4d Y  
Utility.log(nFileLength); *2Vp4  
'!fFI1s  
e.}3OK  
return nFileLength; 5{ 4"JO3  
} YoF\ MT]W  
EK8E  
XJJ[F|k~  
//保存下载信息(文件指针位置) W\>^[c/  
private void write_nPos() (]}x[F9l  
{ [^U;  
try{ 5S\][;u  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5"}y\  
output.writeInt(nStartPos.length); Pv7f _hw  
for(int i=0;i<nStartPos.length;i++)  ?+ -/';  
{ 5xMA~I0c  
// output.writeLong(nPos); z^P* :  
output.writeLong(fileSplitterFetch.nStartPos); AJ>BF.>  
output.writeLong(fileSplitterFetch.nEndPos); 5y(t`Fmt  
} vNC$f(cQ  
output.close(); 5DkK'tCI9Z  
} IYfV~+P  
catch(IOException e){e.printStackTrace ();} )e|$K= D  
catch(Exception e){e.printStackTrace ();} NoJnchiU  
} "$~}'`(]  
iJ`%yg,  
%Ye)8+-  
//读取保存的下载信息(文件指针位置) :jk)(=^  
private void read_nPos() #gX%X~w$F  
{ 6z9R1&~%  
try{ YW?7*go'Z  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); DnNt@e2|  
int nCount = input.readInt(); 60hNCVq%  
nStartPos = new long[nCount]; `7QvwXsH]  
nEndPos = new long[nCount]; 'w`SBYQ5  
for(int i=0;i<nStartPos.length;i++) 9?u9wuH  
{ [Krm .)  
nStartPos = input.readLong(); 'DCKD4@C/  
nEndPos = input.readLong(); Mvy6"Q:  
} ( oQ'4,F  
input.close(); w8 ?Pb$Fe  
} OwG6i|q  
catch(IOException e){e.printStackTrace ();} v%H"_T  
catch(Exception e){e.printStackTrace ();} *F\T}k7  
} mJ0}DJiX$  
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g(-;_j!=  
private void processErrorCode(int nErrorCode) Ci]'G>F@"  
{ 2YL`3cgfb  
System.err.println("Error Code : " + nErrorCode); Q3'fz 9v  
} 0hrCG3k.91  
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r+t ,J|V  
//停止文件下载 Y brx%  
public void siteStop() [NHg&R H  
{ d{QMST2&  
bStop = true; 7))y}N:p  
for(int i=0;i<nStartPos.length;i++) x`]Of r'  
fileSplitterFetch.splitterStop(); /C*~/}  
N7e`6d!  
&?SX4c~?u  
} b->eg 8|  
} lemVP'cn  
//负责部分文件的抓取 h7bPAW=(  
**FileSplitterFetch.java 1S+;ZMk  
*/ Iq)(UfaSve  
package NetFox; xLA~1ZSVJw  
)HEfU31IC  
ki\B!<uv  
import java.io.*; ETM2p1 ru0  
import java.net.*; 8$\Za,)g  
bAdiA2VF'  
0yn[L3x7  
public class FileSplitterFetch extends Thread { >eQbipn  
`-4'/~G  
#":: ' ?,  
String sURL; //File URL wAw42{M  
long nStartPos; //File Snippet Start Position N5m'To]  
long nEndPos; //File Snippet End Position 5gSylts8  
int nThreadID; //Thread's ID #S%4?   
boolean bDownOver = false; //Downing is over E_~x==cb  
boolean bStop = false; //Stop identical N*Yy&[  
FileAccessI fileAccessI = null; //File Access interface Vr 8:nP:  
H#+\nT2m  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException u+m4!`  
{ _l<mu?"  
this.sURL = sURL; ~F;CE"3A  
this.nStartPos = nStart; Kv}k*A% S  
this.nEndPos = nEnd; {-HDkG' 8  
nThreadID = id; @}(SR\~N]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 k=?^){[We  
} Jn=42Q:>  
\]I  
8"x9#kyU<3  
public void run() (_K_`5d;QI  
{ )Ob]T{GY  
while(nStartPos < nEndPos && !bStop) X'f)7RbT  
{ FqwIJ|ct  
\ZMP_UU(  
wFvT0  
try{ Cc!J1)  
URL url = new URL(sURL); bG(x:Py&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |H W( vA  
httpConnection.setRequestProperty("User-Agent","NetFox"); @T ysXx  
String sProperty = "bytes="+nStartPos+"-"; )\>r-g$  
httpConnection.setRequestProperty("RANGE",sProperty); je,c7ZFO  
Utility.log(sProperty); +Qs!Nhsq  
TiyUr [  
=p q:m  
InputStream input = httpConnection.getInputStream(); DVh)w}v  
//logResponseHead(httpConnection); MWs~#ReZ  
hk_g2g  
@ .gPJMA  
byte[] b = new byte[1024]; F}'wH-qp  
int nRead; X'x3esw w  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) v5T`K=qC  
{ \,R!S/R#  
nStartPos += fileAccessI.write(b,0,nRead); MU1E_"Z)  
//if(nThreadID == 1) F;P5D<  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); - IU4#s  
} o\4CoeG  
BxdX WO  
zJY']8ah  
Utility.log("Thread " + nThreadID + " is over!"); w>[T&0-N  
bDownOver = true; $3k "WlRG  
//nPos = fileAccessI.write (b,0,nRead); n(>C'<otj  
}  q>-R3HB  
catch(Exception e){e.printStackTrace ();} 2 z7}+lH  
} t`YWwI.  
} =u=Kw R  
u]M\3V.  
99u/fkL  
//打印回应的头信息 .x-J44i@/  
public void logResponseHead(HttpURLConnection con) $mpO?D J~  
{ ^I`a;  
for(int i=1;;i++) <7'&1= %r  
{ X?/Lz;,&  
String header=con.getHeaderFieldKey(i); xQU"A2{}>  
if(header!=null) 3z3_7XI  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); .'j29 6[u  
Utility.log(header+" : "+con.getHeaderField(header));  $:EG%jl  
else VI_+v[Hk/  
break; ] 8Tzr  
} 6+3$:?  
} jj,r <T  
l5k?De_(x  
{<K=*r rZ  
public void splitterStop() 9x?'}  
{ 8sg|MWSU  
bStop = true; ?:igumeYX  
} E'EcP4eL  
gn)R^  
){P^P!s$  
} _ym"m,,7?  
zkexei4^<  
.'T40=7  
/* ag 8`O&+  
**FileAccess.java {eQWO.C{  
*//文件访问(定位,写) GeV+/^u  
package NetFox; .z-UOyer  
import java.io.*; UpfZi9v?W  
J,5+47b1}R  
6kR\xP]Kr  
public class FileAccessI implements Serializable{ SK R1E];4  
%e? fH.)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Td hTQ  
RandomAccessFile oSavedFile; }mk>!B}=  
long nPos; y=Q!-~5|fF  
E\M-k\cSj  
C:i|-te  
public FileAccessI() throws IOException @i LIU}+  
{ +,5-qm)Gh>  
this("",0); % frfSGf.#  
} Sh&PNJ-*  
g"K>5Cb  
a#[-*ou`  
public FileAccessI(String sName,long nPos) throws IOException 3FNT|QF  
{ |=K_F3aJ  
oSavedFile = new RandomAccessFile(sName,"rw"); "2{%JFE  
this.nPos = nPos; I ~$1Lu`~  
oSavedFile.seek(nPos); 4W;S=#1  
} (Rd$VYuf  
gzdG6"  
h<x4YB5Mj  
public synchronized int write(byte[] b,int nStart,int nLen) wC CV2tk  
{ u0 y 1  
int n = -1; 2@khSWV  
try{ mL yBm  
oSavedFile.write(b,nStart,nLen); i9A~<  
n = nLen; [4Q"#[V&9  
} :O-1rD  
catch(IOException e) +L%IG  
{ }]6f+  
e.printStackTrace (); rv7{Ow_Y  
} z|N3G E(.@  
rHz||jjU  
M 2q"dz   
return n; %,UPJn  
} Vf $Dnu@}z  
T .n4TmF  
1^G{tlA-  
} ,[!LCXp  
DjLL|jF  
 P_Hv%g  
/* ig!7BxM)<h  
**SiteInfoBean.java )rtomp:X  
*/ o:p *_>&  
package NetFox; 1G^#q,%X_v  
GJA`l8`SQ  
cg{AMeW  
public class SiteInfoBean { Log|%P\  
w_wslN,)  
iG<Som  
private String sSiteURL; //Site's URL l"+J c1\X  
private String sFilePath; //Saved File's Path SA"8!soY3  
private String sFileName; //Saved File's Name J'T=q/  
private int nSplitter; //Count of Splited Downloading File @It>*B yB.  
#& ?g %'  
Jkt4@h2Q}  
public SiteInfoBean() 6iA( o*'Yn  
{//nSplitter的缺省值为5 "Cz<d w]D  
//default value of nSplitter is 5 "TOa=Tt{,  
this("","","",5); c&nh>oN  
} d+fSo SjX8  
,,4 GNbBC  
|`/TBQz:r  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .qv'6G  
{ +&=?BC}L9^  
sSiteURL= sURL;  jN*:QI  
sFilePath = sPath; 4JyM7ePND}  
sFileName = sName; 8|^CK|m6*  
this.nSplitter = nSpiltter; {*m?Kc7k  
SPkn 3D6  
ipE ]}0q  
} {KL5GowH  
,  X{>  
Zu*K-ep"  
public String getSSiteURL() sW@krBxMv  
{ s>n(`?@L  
return sSiteURL; T^.Cc--c  
} aM3gRp51cj  
Wr?'$:  
7:E!b=o#  
public void setSSiteURL(String value) K%5"u'  
{ e^1uVN  
sSiteURL = value; r(A.<`\   
} \}0-^(9zd  
f58?5(Dc|  
2{|$T2?e  
public String getSFilePath() V ~{fB~  
{ {R6HG{"IS6  
return sFilePath;  ;q>9W,jy  
} zCaT tb|@  
XzIx:J6  
=n(3o$r(  
public void setSFilePath(String value) TI|/u$SJ<Z  
{ PJ4(}a  
sFilePath = value; @~td`Z?1 y  
} , E )|y4  
0MF}^"R  
c]k*}W3T  
public String getSFileName() _ QOZ sEe  
{ $.%rAa_H  
return sFileName;  AnBJ(h  
} G\d$x4CVGc  
I0'WOV70  
3>M&D20Z  
public void setSFileName(String value) !U%T&?E l  
{ :iWS\G^ U  
sFileName = value; fh8j2S9J  
} ~Ou1WnmO  
,MPB/j^o5!  
o +B:#@9?  
public int getNSplitter() O*6n$dUj3  
{ 1 T<+d5[C  
return nSplitter; DL^o_61  
} _f0C Y"  
0pb '\lA  
OPJ: XbG  
public void setNSplitter(int nCount) Y$K!7Kq  
{ -_OS%ARa  
nSplitter = nCount; ^"\s eS  
} 8 )*2@-Rp  
} jhgX{xc  
*A'FC|\  
SymwAS+  
/* ,i9Byx#TN  
**Utility.java Ga>uFb}W~  
*/ ZzGahtx)Y  
package NetFox; y m,H@~  
)::>q5c  
9# 4Y1LS)  
public class Utility { ?tdd3ai>  
m0w;8uF2UV  
CbBSFKM  
public Utility() e>rRTN  
{ wBj-m  
2| iV,uJ&  
.0 )Y  
} Yj|eji7y  
Vgb *% I  
//线程睡眠 AI vXb\wL  
public static void sleep(int nSecond) 9I7\D8r  
{ }GMbBZ:nKK  
try{ QS.>0i/7l  
Thread.sleep(nSecond); R:-JkV>e:  
} 6d[_G$'nk  
catch(Exception e) @:0ddb71  
{ @!N-RQ&A  
e.printStackTrace (); _ZB\L^j)  
} Gl %3XdU  
} TcTM]ixr  
9h90huyKF  
//日志 #m{{a]zm^  
public static void log(String sMsg) 8M*PML4r  
{ rPNb\Ri  
System.err.println(sMsg); ^efb 5  
} O%~jop7# 6  
`vG,}Pt]  
d,vNem-Z*L  
public static void log(int sMsg) r[(xj n  
{ Lf([dE1  
System.err.println(sMsg); G0 J4O!3  
} c !ZM  
} yq-=],h  
HW4 .zw  
>Iewx Gb>  
/* ,Y?sfp  
**TestMethod.java % }|cb7l  
*/ yH 9!GS#  
package NetFox; L TV{{Z+  
ZoB*0H-  
@$"J|s3M  
public class TestMethod { mffn//QS  
NgCuFL(Ic  
 XY.5Rno4  
public TestMethod() @RFs/'  
{ ///xx/weblogic60b2_win.exe \I-#1M  
try{ uJHu>M}~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ne61}F"E  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -! ;l~#K=  
SiteFileFetch fileFetch = new SiteFileFetch(bean); G&xo1K]  
fileFetch.start(); hv6@Jr3  
} _Y=2/*y^  
catch(Exception e){e.printStackTrace ();} GuZ ( &G6*  
4H5pr  
jN-vY<?h]  
} P7ph}mB  
u<q :$  
X8dR+xd  
public static void main(String[] args) +;g {$da5  
{ JjpRHw8\  
new TestMethod(); "\Egs)\  
} )k&a}u5y  
} \~d";~Y`  
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