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http断点续传简单实现(java)

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/* AwWo,Y399h  
**SiteFileFetch.java '9@AhiNV  
*/ : 22)` ;0  
package NetFox; QzVoU |  
import java.io.*; Y T'olk  
import java.net.*; P71] Z  
_f"KB=A_x  
rVZlv3  
public class SiteFileFetch extends Thread { tP4z#0r2  
9xaieR  
REWW(.3o  
SiteInfoBean siteInfoBean = null; //文件信息Bean ;L[N.ZY!  
long[] nStartPos; //开始位置 Q#zU0K*^  
long[] nEndPos; //结束位置 jr/IU=u*v  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "P yG;N!W  
long nFileLength; //文件长度  wWQt  
boolean bFirst = true; //是否第一次取文件 1xjWD30  
boolean bStop = false; //停止标志 z-_$P)[c  
File tmpFile; //文件下载的临时信息 zx7A}rs3oX  
DataOutputStream output; //输出到文件的输出流 PwU<RKAE  
X8y :=k,E  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) m2[]`Ir^@  
public SiteFileFetch(SiteInfoBean bean) throws IOException qyzH*#d=Cf  
{ ko ~D;M:  
siteInfoBean = bean; Egmp8:nZl@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^J'O8G$  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %#TAz7  
if(tmpFile.exists ()) fLZ mQO  
{ u4h.\ul8%  
bFirst = false; = ( 4l  
read_nPos(); ^~^=$fz  
} h?p!uQ  
else {LBL8sG  
{ mC} b>\  
nStartPos = new long[bean.getNSplitter()]; wizLA0W  
nEndPos = new long[bean.getNSplitter()]; eI98J"h%?  
} ~DP5Qi  
IO7cRg'-F  
lC@wCgc  
F0tcVdv  
} OV|n/~  
s*R UYx  
XbIxGL  
public void run() `6<Qb=  
{ <Vl`EfA(  
//获得文件长度 <l5s[  
//分割文件 Cd|rDa  
//实例FileSplitterFetch 80K"u[  
//启动FileSplitterFetch线程 eW;c 3<  
//等待子线程返回 'LYN{  
try{ X@za4d  
if(bFirst) {01^xn.  
{ M[P1hFuna  
nFileLength = getFileSize(); .rQcg.8/B  
if(nFileLength == -1) N?IdaVLj  
{ a fLE9  
System.err.println("File Length is not known!"); Z-3("%_$/  
} Y>x3`f]  
else if(nFileLength == -2) a]!u go}  
{ .|@2Uf  
System.err.println("File is not access!"); 1BSn#Dnj  
} Q-J} :U  
else Q5]rc`} 5  
{ m[ER~]L/C  
for(int i=0;i<nStartPos.length;i++) BmaY&?  
{ hPuF:iiQ4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Z%JAX>v&B  
} x>+sqFd\  
for(int i=0;i<nEndPos.length-1;i++) 2M)E1q|a  
{ `yh][gqVE~  
nEndPos = nStartPos[i+1]; q8MyEoc:n  
} 3gYtu-1  
nEndPos[nEndPos.length-1] = nFileLength; <?h(Dchq  
} 1n[wk'}qf4  
} a:s$[+'Y  
@ 6*eS+t\  
3zv0Nwb,  
//启动子线程 *;T'=u_lR  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &5*t*tI  
for(int i=0;i<nStartPos.length;i++) *Ag3qnY  
{ uK0L>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Nz:p(X!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), vhzz(UPUt  
nStartPos,nEndPos,i); pZ]&M@Ijp  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w$j6!z  
fileSplitterFetch.start(); SNf~%B?`L  
} 89t"2|9 u  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Gn4XVzB`O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9%2h e)Yqc  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", (a"/cH  
nEndPos = " + nFileLength); Jl|^^?  
// fileSplitterFetch[nPos.length-1].start(); jI~$iDdOfs  
c *i,z  
T8^l}Y B  
//等待子线程结束 &'Xgf!x  
//int count = 0; wbI1~/  
//是否结束while循环 ]Bs{9=2  
boolean breakWhile = false; 3 K q /V_  
V9cj  
h-x~:$Z,  
while(!bStop) x4,[5N"}YK  
{ -j1]H"-  
write_nPos(); _Ud!tK*H  
Utility.sleep(500); Df$~=A}  
breakWhile = true; A)&CI6(  
w|NId,#f  
0QyL}y2  
for(int i=0;i<nStartPos.length;i++) *;Cpz[N  
{ 3J8M0W   
if(!fileSplitterFetch.bDownOver) /. H(&  
{ OzR<jCOS  
breakWhile = false; 2`A[<S  
break; RL H!f1cta  
} W$W w/mcl+  
} Fl*<N  
if(breakWhile) nWh f  
break; hZWkw{c  
eU.C<Tv:8  
2B5Ez,'#x  
//count++; o_5[}d  
//if(count>4) n/e,jw  
// siteStop(); $GHi9aj_P  
} FF0~i+5  
Ul3xeu  
8L]Cc!~  
System.err.println("文件下载结束!"); :B\ $7+$v  
} Z~[eG"6zI  
catch(Exception e){e.printStackTrace ();} 4~8-^^  
} TX7dwmt) N  
sHPj_d#  
"<f?.l\+  
//获得文件长度 [+="I &  
public long getFileSize() [.w`r>kZI  
{ 5Zmc3&vRl  
int nFileLength = -1; s#8T46?  
try{ U#<{RqY  
URL url = new URL(siteInfoBean.getSSiteURL()); |?hsMN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8k+k\V{  
httpConnection.setRequestProperty("User-Agent","NetFox"); `b%^_@Fb  
D *IeG>%  
L+eK)Q  
int responseCode=httpConnection.getResponseCode(); @ZrNV*&<  
if(responseCode>=400) Hs{x Z:  
{ tu/4  
processErrorCode(responseCode); j?g#8L;W\w  
return -2; //-2 represent access is error QL2 `X2  
} "xn,'`a  
S~&9DQNj  
8iM:ok  
String sHeader; x(p/9$.#  
m\E=I5*/  
`cIeqp  
for(int i=1;;i++) E,cQ9}/  
{ yU"#2 *C  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); P% 8U  
//Utility.log(in.readLine()); 3,#v0#  
sHeader=httpConnection.getHeaderFieldKey(i); Ndyo)11z  
if(sHeader!=null) E`{DX9^  
{ ]z| 2  
if(sHeader.equals("Content-Length")) MXjN ./  
{ K@/dQV%Z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )-Z*/uF^  
break; Y kvEQ=  
} :nfy=*M#  
} rq\<zx]au  
else UUa@7|x  
break; K$B~vy6E`  
} 66$ hdT$  
} DF'~ #G8  
catch(IOException e){e.printStackTrace ();} 5 +j):_  
catch(Exception e){e.printStackTrace ();} &JD^\+7U:  
Qz_4Ms<o  
s OLjT34  
Utility.log(nFileLength); UIU6rilB  
8@|{n`n]  
\< a^5'  
return nFileLength; T)Q_dF.N  
} "L8Hgwg  
Ekh)l0 l  
G({VK  
//保存下载信息(文件指针位置) TI0=nfj  
private void write_nPos() 4 Lz[bI  
{ ?FEh9l)d\  
try{ oq b(w+<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |KO[[4b ?+  
output.writeInt(nStartPos.length); oa[O~z{~  
for(int i=0;i<nStartPos.length;i++) "?FBbJ  
{ VuN#j<H  
// output.writeLong(nPos); NbCIL8f]  
output.writeLong(fileSplitterFetch.nStartPos); P m&^rC;  
output.writeLong(fileSplitterFetch.nEndPos); 5H|7DVG  
} 6E(..fo:"  
output.close(); _c-(T&u<  
} 0%,?z`UY  
catch(IOException e){e.printStackTrace ();} CkNh3'<wg  
catch(Exception e){e.printStackTrace ();} @W~aoq6  
} I :bT"N  
#&?}h)Jr'  
4r86@^c*  
//读取保存的下载信息(文件指针位置) _'^_9u G  
private void read_nPos() g_?Q3  
{ )n[=)"rf  
try{ DbtkWq%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6\ .LG4@LO  
int nCount = input.readInt(); \'|t>|zhp  
nStartPos = new long[nCount]; n-,mC /4  
nEndPos = new long[nCount]; &qIdT;^=I  
for(int i=0;i<nStartPos.length;i++) fKtlfQG  
{ txQr|\4k  
nStartPos = input.readLong(); B(O6qWsL  
nEndPos = input.readLong(); x5rLGt  
} &l4kwds R  
input.close(); L:Mjd47L  
} -8d z`o}  
catch(IOException e){e.printStackTrace ();} +rhBC V  
catch(Exception e){e.printStackTrace ();} K}GR U)  
} Prc1U)nfo  
/x_AWnU  
F IB)cpo  
private void processErrorCode(int nErrorCode) Y]5MM:mI  
{ `)MKCw$e  
System.err.println("Error Code : " + nErrorCode); q!~DCv df  
} ( )f)  
Y^;izM}  
z\?<j%e!t  
//停止文件下载 rfzzMV  
public void siteStop() +Hp`(^(  
{ hF`<I.z}  
bStop = true; 'tU\~3k  
for(int i=0;i<nStartPos.length;i++) | h+vdE8  
fileSplitterFetch.splitterStop(); `0MQL@B  
!| - U,  
zJ:%iL@  
} xuVc1jJH  
} 17 0r5  
//负责部分文件的抓取 7#7|+%W0  
**FileSplitterFetch.java rp2g./2  
*/ !\O!Du  
package NetFox; FJxb!- 0&  
mAJ'>^`^  
H$pgzNL  
import java.io.*; ?IoA;GBg  
import java.net.*; mZuLwd$0  
,WM-%2z^4I  
lvNi/jk  
public class FileSplitterFetch extends Thread { $xF[j9nM  
_N>#/v)Yi  
_+~&t9A!  
String sURL; //File URL >hV 2p/D  
long nStartPos; //File Snippet Start Position VWzuV&;P  
long nEndPos; //File Snippet End Position b):aqRwP  
int nThreadID; //Thread's ID ;18u02z^  
boolean bDownOver = false; //Downing is over /Ei e5p  
boolean bStop = false; //Stop identical |2rOV&@l9  
FileAccessI fileAccessI = null; //File Access interface 'C#[iRG4  
k2PK4Ua_}q  
Z)@[N 6\?  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >ffC?5+  
{ SZ7; } r8  
this.sURL = sURL; Z+[W@5q  
this.nStartPos = nStart; M-q5Jfm  
this.nEndPos = nEnd; rw0s$~'  
nThreadID = id; .j=mT[N,I  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 'op_GW  
} ]<c\+9  
.~q>e*8AH  
/^bU8E&^M  
public void run() n[# **s  
{ 7VWy1  
while(nStartPos < nEndPos && !bStop) V?p`rrj@  
{ |`{$Ego:  
i XGy*#>V  
OPogH=vf  
try{ rR#wbDr5  
URL url = new URL(sURL); s B^ejH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?FV%e  
httpConnection.setRequestProperty("User-Agent","NetFox"); A4b+:MQ*OX  
String sProperty = "bytes="+nStartPos+"-"; Nw-U*y  
httpConnection.setRequestProperty("RANGE",sProperty); ?1] \3nj  
Utility.log(sProperty); U}5]Vm$]  
D0TFC3.k}  
dxtG3  
InputStream input = httpConnection.getInputStream(); _ sy]k A  
//logResponseHead(httpConnection); up0=Y o@  
>g@@ yR,  
8s-X H  
byte[] b = new byte[1024]; ~,xso0  
int nRead; @U1t~f^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) P97i<pB Y_  
{ *&R|0I{>  
nStartPos += fileAccessI.write(b,0,nRead); aVr=7PeF  
//if(nThreadID == 1) BqA_C W  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |oe  
} <E^;RG  
wx!2/I>  
9- 24c  
Utility.log("Thread " + nThreadID + " is over!"); 3a=\$x@  
bDownOver = true; NmF8BmIj  
//nPos = fileAccessI.write (b,0,nRead); .f>7a;V?}  
} {eQijW2Z3  
catch(Exception e){e.printStackTrace ();} lQm7`+  
} 8LXK3D}?3  
} )V*`(dn'zm  
?U1Nm~'UZ  
T1x67 b u  
//打印回应的头信息 CJs ~!ww  
public void logResponseHead(HttpURLConnection con) {G<1.  
{ [qk c6sqo  
for(int i=1;;i++) (XFF}~>B.  
{ }nO%q6|\V  
String header=con.getHeaderFieldKey(i); 2+ g'ul`  
if(header!=null) }jdmeD:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /~c9'38  
Utility.log(header+" : "+con.getHeaderField(header)); W`TSR?4~t?  
else `gJ$fTi&  
break; RUVrX`u*(  
} <p2\;\?4z  
} l7IF9b$c  
2pP"dX  
k5+ Fxf  
public void splitterStop() t'.:"H8BI  
{ }9;mtMR$  
bStop = true; VRSBf;?  
} bMv[.Z@v(  
\%V !& !'  
S?OCy4dk:  
} Z/4bxO=m  
"s(|pQh;  
~lqNWL^l  
/* j7NOYm5N  
**FileAccess.java Z J1@z.  
*//文件访问(定位,写) >!tfvM2X{  
package NetFox; kV!1k<f  
import java.io.*; 0I2?fz)  
4p6T0II_$  
;z+}|>!  
public class FileAccessI implements Serializable{ R9QW%!:,\2  
-mLu!32I<  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 'UZ i>Ta  
RandomAccessFile oSavedFile; $*Wa A`(U  
long nPos; Y@T$O<*  
'0&HkM{ D  
HsT6 #K  
public FileAccessI() throws IOException %kgT=<E'  
{ j_0l'Saj  
this("",0); m#RMd,'X  
} N$.ls48a4-  
7;] IlR6  
M8y|Lm}o  
public FileAccessI(String sName,long nPos) throws IOException 1(% 6X*z  
{ Ub4)x  
oSavedFile = new RandomAccessFile(sName,"rw"); 8H8Q  
this.nPos = nPos; \]\h,Y8  
oSavedFile.seek(nPos); ?`6Mfpvj96  
} /BhP`a%2Q  
'GO *6$/  
Ke~!1S8=  
public synchronized int write(byte[] b,int nStart,int nLen) ZZfi,0R  
{ N.SV*G @  
int n = -1; #c'}_s2F[  
try{ =2vZqGO30  
oSavedFile.write(b,nStart,nLen); lh!8u<yv*  
n = nLen; [TxvZq*4  
} .SSPJY(  
catch(IOException e) HL:w*8a  
{ Z1;+a+S=z  
e.printStackTrace (); `FX?P`\@I  
} u^x<xw6f  
M*~XpT3  
=CCddLO  
return n; mJH4M9WJ]  
} [[]NnWJ  
+ EKp*Vje  
6{fo.M?  
} z(>:LX"xz  
<7/7+_y  
.t{uzDM  
/* N%u4uLP5k  
**SiteInfoBean.java 7ks!0``  
*/ .E{FD%U  
package NetFox; C/ ]Bx  
;$qc@)Uwp  
AU9:Gu@M/  
public class SiteInfoBean { '[HU!8F  
n:H |=SF{  
%z"$?Iv  
private String sSiteURL; //Site's URL N~S#( .}[  
private String sFilePath; //Saved File's Path 5p3: 8G7  
private String sFileName; //Saved File's Name q>6,g>I  
private int nSplitter; //Count of Splited Downloading File dKw[#(m5v  
%uo#<Ny/ I  
c^5fhmlt  
public SiteInfoBean() twaH20  
{//nSplitter的缺省值为5 2&AX_#P  
//default value of nSplitter is 5 P;|63" U  
this("","","",5); !L/.[:X  
} (+BrC`  
f;&XTF5D^  
6r[pOl:  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) xZloEfv.B  
{ U-{3HHA  
sSiteURL= sURL; '}F9f?  
sFilePath = sPath; m]{/5L  
sFileName = sName; ^lK!tOeO  
this.nSplitter = nSpiltter; yC!>7@m  
D?H|O[  
Us>  
} +|4olK$[  
4~WSIR-  
zXwdU5 8  
public String getSSiteURL() ,.L o)[(  
{ PX?^v8wlqL  
return sSiteURL; ]a:T]x6'  
} i A'p!l |P  
'p%w_VbI  
=H}}dC<)  
public void setSSiteURL(String value) YC*`n3D|'  
{ !Uhcjfq`e  
sSiteURL = value; X-j<fX_  
} y35e3  
CdtwR0  
^6!8)7b  
public String getSFilePath() Lr`Gyl62  
{ wvr`~e  
return sFilePath; |I.5]r-EK  
} GB6(WAmr  
+>% AG&Pc  
oiz]Bd  
public void setSFilePath(String value) ;b_<5S  
{ vgr 5j  
sFilePath = value; \,I{*!hw  
} a3He-76  
Q"oJhxS  
}MM:qR  
public String getSFileName() 1O90 ]c0  
{ fECmELd  
return sFileName; |CBJ8],mT  
} KF`mOSP  
hm1.UE  
;*20b@  
public void setSFileName(String value) #vPk XcP  
{ grJ(z)c  
sFileName = value; w&&)v~Y_  
} 2k`Q+[?{q>  
XKT[8o<L  
M%Q_;\?]  
public int getNSplitter() i \.&8  
{ ^4{{ +G)j  
return nSplitter; 5ai$W`6  
} tZr_{F@  
^j?"0|  
~y ?v  
public void setNSplitter(int nCount) \@6V{y'Zo  
{ \Fu(IuD  
nSplitter = nCount; JS&;7Z$KX  
} 1_G+sDw$  
} |j$$0N  
8: VRq  
~jC$C2A0  
/* &Hl w2^  
**Utility.java ZP.~Y;Ch;-  
*/ +n|@'= ]  
package NetFox; tYUo;V  
. B6mvb\  
2y9$ k\<xV  
public class Utility { qp/nWGj  
P_ b8_ydU  
#5^S@}e  
public Utility() >V&GL{  
{ <?!%dV{z  
z,SNJIsx  
F Zk[w>{  
} 3X1 U  
h;J%Z!Rjw  
//线程睡眠 Oc / i'  
public static void sleep(int nSecond) F[0w*i&u5  
{ z+nq<%"'  
try{ SCq3Kh  
Thread.sleep(nSecond); ZVCa0Km  
} D#X&gE  
catch(Exception e) (i]0IYMXy*  
{ z+Ej`$E{lD  
e.printStackTrace (); {=P}c:i W  
} iDlg>UYd  
} kM(,8j  
0-Wv$o[  
//日志 v&"sTcS|  
public static void log(String sMsg) tSunO-\y  
{ V:1_k"zQ  
System.err.println(sMsg); :U'Oc3l#Y  
} c+UZ UgP  
~fz9PoC  
RM!VAFH   
public static void log(int sMsg) WAb@d=H{+>  
{ e]7J_9t@  
System.err.println(sMsg); ov'C0e+o  
} twql)lbx  
} W0# VDe]>  
R^6^ {q  
K`kWfPwp  
/* .wcKG9u  
**TestMethod.java q>VvXUyK,  
*/ 3O?[Yhk`.  
package NetFox; 51!#m|  
<+ckE 2j  
5Ja[p~^L  
public class TestMethod { G2FD'Sf  
2L7ogyrU/A  
-q DL':  
public TestMethod() W_|7hwr  
{ ///xx/weblogic60b2_win.exe k FE<M6a9@  
try{ J-~:W~Qx4N  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); u%nhQ%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $_ k:{?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); WNiM&iU  
fileFetch.start(); W%K=N-kE_  
} ?qczMck_  
catch(Exception e){e.printStackTrace ();} |Q#CQz  
6b h.5|  
e|.a%,Dcy  
}  *l-F  
++d[YhO  
qk!,:T  
public static void main(String[] args) S~.%G)R  
{ :ZU-Vi.b  
new TestMethod(); tL S$D-  
} -K iI&Q  
} O[HBw~  
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