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http断点续传简单实现(java)

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/* :<G+)hIK  
**SiteFileFetch.java wA+4:CF @  
*/ -P uVI5L<  
package NetFox; "tbBbEj?d  
import java.io.*; ?O]gFn  
import java.net.*; Z?[J_[ZtR3  
b<MMli  
Z.f<6<gF  
public class SiteFileFetch extends Thread { "[Lp-4A\  
iFT3fP'> 5  
Eu_0n6J  
SiteInfoBean siteInfoBean = null; //文件信息Bean *J- jr8&  
long[] nStartPos; //开始位置 q"vT]=Y}:  
long[] nEndPos; //结束位置 @y%qQe/g  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 {_D'\i(Y_  
long nFileLength; //文件长度 hIHO a  
boolean bFirst = true; //是否第一次取文件 hRiGW_t  
boolean bStop = false; //停止标志 g4932_tC  
File tmpFile; //文件下载的临时信息 :~(^b;yhZ  
DataOutputStream output; //输出到文件的输出流 V3nv5/6  
xpo}YF'5  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) XX+rf  
public SiteFileFetch(SiteInfoBean bean) throws IOException +DDvM;31w  
{ 2^j9m}`  
siteInfoBean = bean; !SNtJi$;v  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Kn]WXc|("  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /FXfu  
if(tmpFile.exists ()) cE#Y,-f  
{ Lf<9GYNy>`  
bFirst = false; Z ISd0hV  
read_nPos(); aesFv)5DK  
} ~nlY8B(  
else |1x,_uyQ%  
{ "R]K!GUU  
nStartPos = new long[bean.getNSplitter()];  vpMv  
nEndPos = new long[bean.getNSplitter()]; ^u<+tV   
} Mqy`j9FbL  
smNr%}_g  
a+Nd%hoe  
{hR23eE)#  
} <>GyG-q  
]YKWa"  
suSIz 7:  
public void run() MS)bhZvO  
{ W>49,A,q  
//获得文件长度 Lr&tpB<  
//分割文件 'LI)6;Yc  
//实例FileSplitterFetch wm4e:&  
//启动FileSplitterFetch线程 K!mgh7Dx  
//等待子线程返回 cPYQ<Y=  
try{ q fe#kF9  
if(bFirst) t$2{U  
{ +cN2 KP  
nFileLength = getFileSize(); `z.#O\@o  
if(nFileLength == -1) |szfup~5es  
{ '` "&RuB  
System.err.println("File Length is not known!"); )}v2Z3:  
} .?TVBbc%5  
else if(nFileLength == -2) !{LwX Kf  
{ `.XU|J*z,  
System.err.println("File is not access!"); ySZ)yT  
} 8'$n|<1X  
else 04TV. /uA  
{ ^S @b*  
for(int i=0;i<nStartPos.length;i++) `x3c},'@k  
{ $Re %+2c  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .#}R$}e+  
} MaM7u:kD#  
for(int i=0;i<nEndPos.length-1;i++) Qp}<8/BM\  
{ :KwYuwYS  
nEndPos = nStartPos[i+1]; 5Ml}m  
} R<U <Y'Y  
nEndPos[nEndPos.length-1] = nFileLength; l0f6Lxfz  
} XR(kR{yo  
} h";sQ'us  
(nm&\b~j  
5{UGSz 1  
//启动子线程 QQJ cvaQ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; MG|NH0k  
for(int i=0;i<nStartPos.length;i++) v?rN;KY#pK  
{ $= gv  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ZZUCwczI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), I`7[0jA~  
nStartPos,nEndPos,i); *!r8HV/<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9j/B3CjW  
fileSplitterFetch.start(); rQF%;  
} Ru/3>n  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), dJk.J9Z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); a"EXR-+8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", JkTL+obu  
nEndPos = " + nFileLength); TSeAC[%pL  
// fileSplitterFetch[nPos.length-1].start(); 3JwmLGj}  
TX;|g1K  
|"arVde  
//等待子线程结束 +-ue={ '  
//int count = 0; LYT0 XB)A  
//是否结束while循环 aX! J0&3  
boolean breakWhile = false; $%/Zm*H  
{az8*MR=X  
&A>J>b  
while(!bStop) RSy1 wp4W  
{ Z|u_DaSrr|  
write_nPos(); ?U&onGy  
Utility.sleep(500); 3=z'Ih`  
breakWhile = true; 9,4a?.*4~  
K/altyj`  
w!Z3EA;`  
for(int i=0;i<nStartPos.length;i++) ,ua]h8  
{ H&I 0\upd  
if(!fileSplitterFetch.bDownOver) I3$v-OiL  
{ ZC05^  
breakWhile = false; :wMZ&xERDZ  
break; ,^/;!ErR$  
} xi^_C!*J  
} K}6}Opr,Tt  
if(breakWhile) zZ kwfF  
break; tP`,Egf"g  
/#blXI  
@>da%cX  
//count++; *M&~R(TMn  
//if(count>4) ?(F~9 V  
// siteStop(); h.PY$W<  
} ${ e{#  
h|wy vYKZ  
S#jE1EN  
System.err.println("文件下载结束!"); {2-w<t  
} V;.=O}Lr  
catch(Exception e){e.printStackTrace ();} vAX %i(4  
} 7z`)1^ M  
By%aTuV$  
6ZX{K1_q  
//获得文件长度 ~Xa >;  
public long getFileSize() :0r@o:H  
{ i9$ -lk  
int nFileLength = -1; lBl`R|Gt  
try{ RxcX\:  
URL url = new URL(siteInfoBean.getSSiteURL()); k |M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); tMC<\e  
httpConnection.setRequestProperty("User-Agent","NetFox"); )%P!<|s:5  
2wikk]Z  
64Q{YuI  
int responseCode=httpConnection.getResponseCode(); zGA#7W2?0  
if(responseCode>=400) (FP- K  
{ S9-FKjU  
processErrorCode(responseCode); z" 4$mh  
return -2; //-2 represent access is error PU[] Nw  
} y3 kXfSe  
4; y*y tY*  
KftZ ^mk+p  
String sHeader; ?$%#y u#.  
ZE#A?5lb  
0;KjP?5  
for(int i=1;;i++) fn;`Vit#  
{ \\xoOA.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [Q6PFdQ_JT  
//Utility.log(in.readLine()); d=yuuS /  
sHeader=httpConnection.getHeaderFieldKey(i); AKu]c-  
if(sHeader!=null) l*^c?lp)  
{ /c6:B5G  
if(sHeader.equals("Content-Length")) w`x4i fZ0q  
{ M*$#j|  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); J4"?D9T3G  
break; v*U OD'tk  
}  ]?M3X_Mq  
} bW-9YXj%  
else c>mTd{Abi  
break; lp+Uox  
} t}w<xe  
} NU"Ld+gw  
catch(IOException e){e.printStackTrace ();} 5bBY[qp  
catch(Exception e){e.printStackTrace ();} Wa.y7S0(@  
C;>!SRCp  
6 b-'Hui+  
Utility.log(nFileLength); 3qggdi  
)&Af[m S  
rrz^LD  
return nFileLength; > >%m,F[  
} @|N{E I  
!-B$WAV  
pV[SY6/  
//保存下载信息(文件指针位置) #:[^T,YD0  
private void write_nPos()  2:GS(%~  
{ >= O5=\`  
try{ p.)IdbC`B  
output = new DataOutputStream(new FileOutputStream(tmpFile)); e>J.r("f  
output.writeInt(nStartPos.length); ` "Lk@  
for(int i=0;i<nStartPos.length;i++) U'*~Ju  
{ r?7tI0  
// output.writeLong(nPos); mM(Z8PA 9-  
output.writeLong(fileSplitterFetch.nStartPos); a1#",%{I  
output.writeLong(fileSplitterFetch.nEndPos); 6 H{G$[2  
} }-/oL+j  
output.close(); ,)?!p_*@:  
} d RIuA)0s  
catch(IOException e){e.printStackTrace ();} dj-/%MU  
catch(Exception e){e.printStackTrace ();} Q{= DLm`  
} ({$>o]<h  
<]Btx;}  
me@k~!e"z  
//读取保存的下载信息(文件指针位置) .VXadgM  
private void read_nPos() s+0n0C  
{ aE(DNeG-H  
try{ U2G[uDa;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); '+&!;Jj,  
int nCount = input.readInt(); .C|dGE?,  
nStartPos = new long[nCount]; ?+_Y!*J2b  
nEndPos = new long[nCount]; GahIR9_2  
for(int i=0;i<nStartPos.length;i++) k 5gvo  
{ VPvQ]}g6k  
nStartPos = input.readLong(); HC!5AJ&+}v  
nEndPos = input.readLong(); W#9A6ir>  
} blx"WVqo  
input.close(); AGhr(\j  
} sq_ yu(  
catch(IOException e){e.printStackTrace ();} 7hlzuZob+y  
catch(Exception e){e.printStackTrace ();} [hJ ASX9  
} OE/r0C<&  
n #PXMD*  
d1}cXSQ1T  
private void processErrorCode(int nErrorCode) |33_="  
{ 8}aSSL]  
System.err.println("Error Code : " + nErrorCode); O:j=L{,d^  
} *#.Ku(C+  
L-`?=- 9`  
Pd+Wb3  
//停止文件下载 RDxvN:v  
public void siteStop() C]a iu  
{ ;"2(e7ir  
bStop = true; \SooIEl@  
for(int i=0;i<nStartPos.length;i++) byHXRA)39  
fileSplitterFetch.splitterStop(); 'tDVSj  
1`2lq~=GV  
b"(bT6XO!  
} +{\b&q_  
} _^h?JTU^  
//负责部分文件的抓取 &UQP9wS4v  
**FileSplitterFetch.java :M$8<03>F  
*/ #]2,1dJ  
package NetFox; .-:@+=(  
8b X?HeYrr  
Na.)!h_Kn'  
import java.io.*; ;F:Qz^=.a  
import java.net.*; 7Ga'FT.F  
\ccCrDz  
k&= iye(  
public class FileSplitterFetch extends Thread { ,#.9^J  
MC_i"P6a  
Vr KFpFd  
String sURL; //File URL s;,ulME  
long nStartPos; //File Snippet Start Position CTZ#QiNP  
long nEndPos; //File Snippet End Position g7r0U6Y  
int nThreadID; //Thread's ID ^}4ysw  
boolean bDownOver = false; //Downing is over 72sBx3 ;  
boolean bStop = false; //Stop identical 9R N ge;*  
FileAccessI fileAccessI = null; //File Access interface J';XAB }  
&!? qSi~V  
6AKT -r.  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException GE#LcCa  
{ -O6\!Wo=-  
this.sURL = sURL; eB5<N?;s  
this.nStartPos = nStart; T2}ccnDi  
this.nEndPos = nEnd; 3&Fqd  
nThreadID = id; W C3b_ia  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 S^ JUQx7  
} *Edr\P  
7WN$ rl5/  
O;RNmiVoq  
public void run() :snn-e0l  
{ l`vr({A  
while(nStartPos < nEndPos && !bStop) &$.x1$%  
{ l]mn4cn3  
`bEum3l\6]  
eo'C)j# U  
try{ &:Sb$+z  
URL url = new URL(sURL); \?NT,t=3J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &>z}u&oF  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3bMUsyJ2  
String sProperty = "bytes="+nStartPos+"-"; Zq>}SR  
httpConnection.setRequestProperty("RANGE",sProperty); i ,g<y  
Utility.log(sProperty); R,ddH[3  
.E0*lem'hE  
ai~JY[  
InputStream input = httpConnection.getInputStream(); f n'N^  
//logResponseHead(httpConnection); ZUUfn~ORc  
!d=Q@oy5  
nwAx47>{  
byte[] b = new byte[1024]; My\  
int nRead; `-)Fx<e  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Jul xFjC  
{ pd X"M>  
nStartPos += fileAccessI.write(b,0,nRead); Ld YaJh~h  
//if(nThreadID == 1) N>_d {=P  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^9I^A!w=  
} }lt]]094,  
%]@K}!)2  
@DYkWivLu  
Utility.log("Thread " + nThreadID + " is over!"); <jRs/?1R  
bDownOver = true;  LYX\#  
//nPos = fileAccessI.write (b,0,nRead); h\^> s$  
} r.;(Kx/M  
catch(Exception e){e.printStackTrace ();} 1MzOHE  
} #] 5|Qhrr+  
} ;j/-ndd&&  
MF^I] 7_  
IRQ3>4hI  
//打印回应的头信息 T4{&@b 0*  
public void logResponseHead(HttpURLConnection con) $MG. I[h  
{ }qOC*k:  
for(int i=1;;i++) q3E_.{t  
{ 3fJwj}wL  
String header=con.getHeaderFieldKey(i); ^y"$k  
if(header!=null) c=p@l<)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); q>q@ztt  
Utility.log(header+" : "+con.getHeaderField(header));  <XxFR  
else = pS\gLQu  
break; S Yvifgp  
} :B'}#;8_  
} RKP->@Gs  
N{G+|WmQ  
[\&Mo]"0  
public void splitterStop() ;pNHT*>u,  
{ :[N[D#/z  
bStop = true; 5!*5mtI  
} 5i$~1ZC  
8D:{05  
G K @]61b  
} 3Ecm Nwr  
_ QM  
<nj[=C4v  
/* #7U,kTj9  
**FileAccess.java '.@R_sj   
*//文件访问(定位,写) 5b[:B~J  
package NetFox; 6Bp{FOj:Ss  
import java.io.*; OR^Wd  
DwZt.*  
@"HR"@pX  
public class FileAccessI implements Serializable{ %1]2+_6  
q9oF8&O,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 T}[W')[s  
RandomAccessFile oSavedFile; |b/J$.R  
long nPos; @X/S h:  
7Yxy2[  
k&DH QvfB  
public FileAccessI() throws IOException jl2nRo  
{ KX)xCR~  
this("",0); ]+ ':=&+:  
} C)z[Blt  
c)SSi@< cv  
NI(`o8fN  
public FileAccessI(String sName,long nPos) throws IOException =,[46 ;q  
{ "\BP+AF  
oSavedFile = new RandomAccessFile(sName,"rw"); :<&}/r  
this.nPos = nPos; _ |TE )h  
oSavedFile.seek(nPos); MQY1he2M  
} Lx?bO`=qg7  
~~zw[#'  
<\^X,,WtO  
public synchronized int write(byte[] b,int nStart,int nLen) .3|9 ~]  
{ ;*W]]4fy  
int n = -1; X_'.@q<!CV  
try{ ;$&-c/]F#  
oSavedFile.write(b,nStart,nLen); BQS9q'u_  
n = nLen; q qzQKN  
} EkSTN  
catch(IOException e) ;wQWt_OtuJ  
{ -'PpY302  
e.printStackTrace (); U-FA^c;  
} N0vd>b  
N^ D/}n  
FOk @W&  
return n; U*&ZQw  
} dWqFP  
J82{PfQ"  
(uG4W|?p  
} ^ Nsl5  
uAvs  
"j a0,%3  
/* "ZyHt HAK  
**SiteInfoBean.java 9)l_(*F  
*/ AVyZ#`,  
package NetFox; ooZ-T>$  
#dpt=  
.897Z|$VB  
public class SiteInfoBean { Q?a"uei[  
y{<#pS.  
{-Y_8@&  
private String sSiteURL; //Site's URL 9wq%Fnt  
private String sFilePath; //Saved File's Path bf74 "  
private String sFileName; //Saved File's Name 4*+EUJ|  
private int nSplitter; //Count of Splited Downloading File Q"Ec7C5eM  
BL8\p_U  
I }/Oi]jA6  
public SiteInfoBean() _"sRL} -Z  
{//nSplitter的缺省值为5 i9xv`Ev=R  
//default value of nSplitter is 5 \W}EyA  
this("","","",5); m_(hCY=Q$  
} tH'VV-!MZ  
gNqV>p  
+ kF[Oh#  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) KvD$`"L/CT  
{ q9 ;\B&  
sSiteURL= sURL;  wi9|  
sFilePath = sPath; 'u3+k.  
sFileName = sName; $1?X%8V  
this.nSplitter = nSpiltter; !X8UP{J)L  
5i^vN"J  
iCK$ o_`?  
} xI<dBg|]+  
`e9uSF:9C  
>1~`tP  
public String getSSiteURL() v$i%>tQ\  
{ od}x7RI%m  
return sSiteURL; O0{  
} YW{V4yW  
rl^LS z  
zrew:5*uZ  
public void setSSiteURL(String value) Yy)a,clZ*$  
{ +lT]s#Fif  
sSiteURL = value; S1zw'!O5  
} c_q+_$t  
f`,Hr?H  
0w['jh|,  
public String getSFilePath() z{g<y^Im+E  
{ G zXP  
return sFilePath; _;q-+"6L;  
} M0zD)@  
\z`d}\3( R  
N ]7a=  
public void setSFilePath(String value) Kk98FI0]  
{ \r%Vgne-g  
sFilePath = value; W{+0iAYnp  
} 6h_k`z  
E E|zY%  
s~$4bN>LD  
public String getSFileName() T+nC>}*jgJ  
{ >ij4z N  
return sFileName; otVyuh  
} dO4#BDn"=  
CDYx/yO  
G^ZkY  
public void setSFileName(String value) ~9 WJrRWB  
{ _O;~ }N4u  
sFileName = value; gqD^Bs'VF  
} /eRtj:9M  
r)5\3j[P  
!(_xu{(DL  
public int getNSplitter()  "$Iw Q  
{ =P;;&j3Z  
return nSplitter; -mHhB(Td'  
} '}`hY1v  
Mto~ /  
n{Qh8"  
public void setNSplitter(int nCount) sHTePEJ_h  
{ Eb[H3v48,  
nSplitter = nCount; <SM&VOiaOz  
} _Q}RElA  
} , q@(L  
C$RAJ  
4EhBpTg  
/* KO]?>>5S6  
**Utility.java y]pN=<*h5  
*/ u4#~ i0@  
package NetFox; eN<pU%7  
'Tf#S@o  
2V2x,!  
public class Utility { %M)oHX1p  
7YXXkdgbd  
ul=a\;3x#|  
public Utility() Fma`Cm.  
{ h GA0F9.U  
aBVEk2 p  
8 1K G1i)  
} @2~O^5[>  
^z%o];  
//线程睡眠 n|mJE,N  
public static void sleep(int nSecond) 4=F]`Lql  
{ (LT\ IJSM  
try{ BtpjQNN  
Thread.sleep(nSecond); Xk&F4BJQk<  
} Fy _<Ui  
catch(Exception e) ok>P [ &!  
{ J<($L}T*$  
e.printStackTrace (); q:- ]d0B+  
} %$Jq t  
} _5U%'\5s  
Ef_F#X0#  
//日志 S1az3VJI\  
public static void log(String sMsg) _Xk03\n6  
{ <(bCz>o|  
System.err.println(sMsg); dp UdFuU"  
} FU (}=5n  
2iR:*}5  
A1|7(Sow  
public static void log(int sMsg) uzVG q!'H  
{ #GY&$8.u*  
System.err.println(sMsg); hP4)8>  
} "%}Gy>;  
} (N*<\6kr  
0V>ESyae5  
s}[A4`EWH  
/* ~E<PtDab  
**TestMethod.java (DG@<K,6  
*/ /jjW/ lr  
package NetFox; #7-kL7 MK]  
yUD_ w  
7z/(V\9B  
public class TestMethod { `'[7~Ew[  
[xZ/ZWb/  
z\Pe{J  
public TestMethod() t?]\M&i&  
{ ///xx/weblogic60b2_win.exe |8DH4*y!  
try{ J$6-c' 8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); r 1l/) ;  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); xZ.~:V03\t  
SiteFileFetch fileFetch = new SiteFileFetch(bean); e(OwS?K  
fileFetch.start(); v+!y;N;Q  
} /-!&k  
catch(Exception e){e.printStackTrace ();} z`emKFbv  
2~G,Ia  
9*}iBs  
} O8K@&V p  
9SRfjS{7  
toS(UM n  
public static void main(String[] args) >\|kJ?h  
{ w+Z--@\  
new TestMethod(); 8iMF8\  
} Vl5SL{+D  
} ~w Zl2I  
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