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http断点续传简单实现(java)

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/* y>R=`A1b  
**SiteFileFetch.java TIx|L  
*/ HpR]q05d  
package NetFox; efSM`!%j  
import java.io.*; o=u3&liBi  
import java.net.*; $[9%QQk5<L  
214Ml0/%  
h&|[eZt?F  
public class SiteFileFetch extends Thread { +cWLjPD/}  
A]y`7jJ  
Jx_cf9{  
SiteInfoBean siteInfoBean = null; //文件信息Bean ".f ;+wH  
long[] nStartPos; //开始位置 Q0$8j-1I  
long[] nEndPos; //结束位置 E^Y#&skXp3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 cy*?&~;  
long nFileLength; //文件长度 32l3vv.j  
boolean bFirst = true; //是否第一次取文件 Pih tf4i  
boolean bStop = false; //停止标志 2^XGGB0  
File tmpFile; //文件下载的临时信息 h}-3\8 >  
DataOutputStream output; //输出到文件的输出流 ?M$.+V{a  
tWo{7)Eb  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 909?_ v  
public SiteFileFetch(SiteInfoBean bean) throws IOException J%8(kWQ|  
{ bf0+DvIB  
siteInfoBean = bean; p$SX  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); H!vax)%-\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (As#^q\>B  
if(tmpFile.exists ()) 8][nmjk0  
{ ?=>+LqP  
bFirst = false; X"MB|N y  
read_nPos(); >AC]#'  
} %el"BSB  
else ~L]|?d"  
{ YTAmgkF\4  
nStartPos = new long[bean.getNSplitter()]; 9s_vL9u  
nEndPos = new long[bean.getNSplitter()]; ]d55m/(   
} so PLA68  
Gb"r|(!  
k- Q%.o  
NIh:D bE  
} hhb?6]Z/  
z MLK7+  
.#wqXRd  
public void run() f6|KN+.  
{ $`APHjijN  
//获得文件长度 _,q)hOI  
//分割文件 UU'|Xz9~  
//实例FileSplitterFetch W8Q|$ZJ88F  
//启动FileSplitterFetch线程 S2n39 3  
//等待子线程返回 `L:CA5sBud  
try{ +U_=*"@|  
if(bFirst) N03G>fZ  
{ l6(-I Tb  
nFileLength = getFileSize(); -r#X~2tPzD  
if(nFileLength == -1) CxGx8*<X  
{  pnMEB,)  
System.err.println("File Length is not known!"); m7&O9?X  
} -<Hu!V`+  
else if(nFileLength == -2) [qdRUV'  
{ ?!wgH9?8  
System.err.println("File is not access!"); K6y :mJYp\  
} U;bK!&Z  
else JBZUv  
{  XEC(P  
for(int i=0;i<nStartPos.length;i++) sBu=e7  
{ )Y]{HQd  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); >a"Z\\dF  
} DKfE.p)  
for(int i=0;i<nEndPos.length-1;i++) :1 (p.q=  
{ @)-sTgn  
nEndPos = nStartPos[i+1]; Bt1p'g(V|  
} .P.z B}0=  
nEndPos[nEndPos.length-1] = nFileLength; !E,A7s  
} {*[\'!d--.  
} j>]nK~[ka  
~ns7O  
76wc,+  
//启动子线程 n"+[ :w4  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $KUo s+%  
for(int i=0;i<nStartPos.length;i++) \ W?R  
{ 53c0 E  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #6AFdNy  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), R+nMy=I%8  
nStartPos,nEndPos,i);  )LJnLo+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hq:&wN 7Q  
fileSplitterFetch.start(); s@z}YH  
} by'DQ 00  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]W Zq^'q.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); y" 6y!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }j2Y5  
nEndPos = " + nFileLength); rC.eyq,105  
// fileSplitterFetch[nPos.length-1].start(); {NPuu?&  
Yk'9U-.mc  
3' ~gvi I  
//等待子线程结束 iT;@bp  
//int count = 0; DHw&+MY  
//是否结束while循环 `+zWu 55;  
boolean breakWhile = false; FuUD 61JHY  
6*qL[m.F[o  
%'xb%`t  
while(!bStop) Y 2Q=rj  
{ *?z0$Kz<,[  
write_nPos(); I=7Y]w=  
Utility.sleep(500);  QV h4  
breakWhile = true; !eAo  
Vo9F  
dWX stb:[  
for(int i=0;i<nStartPos.length;i++) cXR1grz  
{ Q~MC7-n>  
if(!fileSplitterFetch.bDownOver) Q.9qImgN  
{ 5GA\xM-  
breakWhile = false; {ekCQeDo  
break; nI/kw%<  
} j,t#B"hOnp  
} CW)Z[<d8  
if(breakWhile) T;diNfgg  
break; s-Aw<Q)d  
h'i{&mS_b  
AsPx?  
//count++; ;>%~9j1C  
//if(count>4) ui "3ak+F  
// siteStop(); 'DCFezdf3  
} 5jgdbHog]  
j}BHj.YuP  
{ F'Kk\f%:  
System.err.println("文件下载结束!"); ?\U!huu  
} yJsH=5A  
catch(Exception e){e.printStackTrace ();} &f>eQ S=(  
} Gy,u^lkk:  
j7MO'RX`&  
Xt{*N-v\  
//获得文件长度 F,GN[f-  
public long getFileSize() D?~8za`5  
{ lJzl6&  
int nFileLength = -1; f`8OM}un&  
try{ Q\Gq|e*  
URL url = new URL(siteInfoBean.getSSiteURL()); 9Ew7A(BG_3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [xfaj'j=@  
httpConnection.setRequestProperty("User-Agent","NetFox"); ewuXpv%vwW  
~1*A  
`gpQW~*R-;  
int responseCode=httpConnection.getResponseCode(); q8Nn%o=5V  
if(responseCode>=400) \ A%eG&  
{ -/ x W  
processErrorCode(responseCode); .lBgp=!  
return -2; //-2 represent access is error !)qQbk  
} e8h,,:l3j  
aup6?'G;  
dI*'!wK  
String sHeader; 1`LXz3uBe  
0G <hn8>  
KtB!"yy#  
for(int i=1;;i++) 1z*kc)=JF8  
{ 1|ZhPsD.}g  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); <&pKc6+{  
//Utility.log(in.readLine()); &[a Tw{2  
sHeader=httpConnection.getHeaderFieldKey(i); D -IR!js ]  
if(sHeader!=null) ~:lKS;PRuK  
{ o5Y2vmz?9  
if(sHeader.equals("Content-Length")) F52B~@ .  
{ _Mc>W0'5@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); "BVdPSDBk  
break; lFUWV)J\  
} h(B,d,q"  
} 3+xy4 G@L  
else !r+IXuqV,!  
break; S2C]?6cTq  
} p T[gdhc  
} K"<*a"1I  
catch(IOException e){e.printStackTrace ();} JR9$. fGJ  
catch(Exception e){e.printStackTrace ();} (QB+%2v  
!umEyd@ "  
a :HNg  
Utility.log(nFileLength); ;`v% sx#  
}:z5t,u6  
K{cbn1\,H  
return nFileLength; !&] z*t  
} oc{EuW{Ag  
[U\(G  
p" `%  
//保存下载信息(文件指针位置) d"~(T:=r  
private void write_nPos() rrs"N3!aT  
{ 99OD= pxQ  
try{ e kQrW%\3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); BF8"rq}r0  
output.writeInt(nStartPos.length); X6RQqen3:  
for(int i=0;i<nStartPos.length;i++) #\4 b:dv  
{ Qu%D  
// output.writeLong(nPos); Di Or{)a  
output.writeLong(fileSplitterFetch.nStartPos); ?mRE'#  
output.writeLong(fileSplitterFetch.nEndPos); },+~F8B  
} +`bC%\T8?  
output.close(); U3#dT2U  
} {UH9i'y:t  
catch(IOException e){e.printStackTrace ();} :DkAQ-<~  
catch(Exception e){e.printStackTrace ();} ~fzuwz  
} dl l%4Sd  
{<w +3Va  
BH@b1}  
//读取保存的下载信息(文件指针位置) TSo:7&|  
private void read_nPos() (E($3t8  
{ 8 #oR/Nt  
try{ #Ogt(5Sd  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $zkH|] zZ  
int nCount = input.readInt(); Erb Sl  
nStartPos = new long[nCount]; ,#'7)M D8  
nEndPos = new long[nCount]; ;RN8\re  
for(int i=0;i<nStartPos.length;i++) m-1?\bs  
{ _MYx%Z  
nStartPos = input.readLong(); FUeq \Wuo  
nEndPos = input.readLong(); *+lsZ8'^C  
} gs`^~iD]m  
input.close(); LxJ6M/".  
} Ff"gadRXd  
catch(IOException e){e.printStackTrace ();} *M~.3$NN  
catch(Exception e){e.printStackTrace ();} FWPW/oC  
} rhY_|bi4P  
K5ZnS`c;  
uhn%lV]  
private void processErrorCode(int nErrorCode) o;J;*~g  
{ r(uP!n1+  
System.err.println("Error Code : " + nErrorCode); (;6s)z  
} H`<?<ak6'M  
sms1%%~  
WPY8C3XO  
//停止文件下载 #*%fu  
public void siteStop() 17py ).\  
{ x3p9GAd#  
bStop = true; vC9@,[  
for(int i=0;i<nStartPos.length;i++) Q5E:|)G  
fileSplitterFetch.splitterStop(); <jd/t19DB  
hWGZd~L  
gOE_ ]  
} gM_:l  
} {HZS:AV0  
//负责部分文件的抓取 W7!.#b(hU  
**FileSplitterFetch.java ^o%_W0_r  
*/ ^!>.97*   
package NetFox; (5Ky6b9v  
r7X D&Y  
3sC: jIp  
import java.io.*; kfpm=dKL  
import java.net.*; %yw=[]Vjze  
8[\ 79|  
O@`J_9  
public class FileSplitterFetch extends Thread { c2b6B.4  
_:,.yRez  
w yD%x(  
String sURL; //File URL I #l;~a<9z  
long nStartPos; //File Snippet Start Position >_#)3K1y8  
long nEndPos; //File Snippet End Position GAJ~$AiwHH  
int nThreadID; //Thread's ID P06 . 1  
boolean bDownOver = false; //Downing is over (Nt[v;BnO  
boolean bStop = false; //Stop identical |[wyc!nY).  
FileAccessI fileAccessI = null; //File Access interface 3}M \c)  
5!:._TcO  
u&3EPu  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException YeIe\3x!N  
{ ]N\6h(**wy  
this.sURL = sURL; $5/\Z  
this.nStartPos = nStart; >)%#V<{<  
this.nEndPos = nEnd; 7&t~R}&|  
nThreadID = id; &|,s{?z2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %<S7  
} -><QFJ  
O|(o8 VS  
ZKsQ2"8{M  
public void run() tMG@K  
{ JTkCk~bX[z  
while(nStartPos < nEndPos && !bStop) {F)E\)$G  
{ ^fZGX<fH   
D5[VK `4Z  
n `#+L~X  
try{ z\h, SX<U  
URL url = new URL(sURL); W8uVd zQ   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %QE5<2k  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8 DL hk  
String sProperty = "bytes="+nStartPos+"-"; 4^MSX+zt  
httpConnection.setRequestProperty("RANGE",sProperty); ^^Bm$9  
Utility.log(sProperty); Uf[T_  
F(G<* lA  
3#<'[TF00t  
InputStream input = httpConnection.getInputStream(); $nc, ?)i!  
//logResponseHead(httpConnection); oYg/*k7EDX  
^(m0M$Wk*  
{*nEKPq(_*  
byte[] b = new byte[1024]; _3KZME  
int nRead; z qO$  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Lkp&;+  
{ 0i _  
nStartPos += fileAccessI.write(b,0,nRead); b7qnO jC  
//if(nThreadID == 1) m\} =4b  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !a)s`  
} $*aE$O6l  
As p8qHS  
J{^n=X9M0J  
Utility.log("Thread " + nThreadID + " is over!"); q1<Fg.-r  
bDownOver = true; lSs^A@s  
//nPos = fileAccessI.write (b,0,nRead); j$%yw4dsj  
} |#:=\gugh  
catch(Exception e){e.printStackTrace ();} w1.MhA  
} afV P-m4L  
} &Ky3Jb<:Gt  
ax;{MfsK  
T!&jFy*W  
//打印回应的头信息 t3Qm-J}wSB  
public void logResponseHead(HttpURLConnection con) <Q\H  
{ kYmo7  
for(int i=1;;i++) vsw7|  
{ lbG}noqb  
String header=con.getHeaderFieldKey(i); j& <tdORT  
if(header!=null) t{[gKV-b  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,?t}NZY&  
Utility.log(header+" : "+con.getHeaderField(header)); `6n!$Cxo  
else Y+OYoI  
break; _u`B3iG  
} 6S2r  
} lJ("6aT?  
\kfcv  
$]Rl__;  
public void splitterStop() oMz/sL'u  
{ 5_PWGaQa  
bStop = true; s&Z35IM8|  
} p9k4w% ~:  
e2q pJ4i  
.<0=a|IAz  
} 9PUa?Bc`=  
v hR twi  
Ny]'RS-  
/* ;K>{_k f  
**FileAccess.java mQmBf|Rl  
*//文件访问(定位,写) ntDRlX  
package NetFox; %GNUnr$  
import java.io.*; 5#yJK>a7  
HDa~7wE  
RCoeJ|  
public class FileAccessI implements Serializable{ Kp$_0  
D9e+  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9*7Hoi4Ji  
RandomAccessFile oSavedFile; #>MO]  
long nPos; h85 (N  
FLi(#9  
FGV}5L  
public FileAccessI() throws IOException ',L{CQA?c  
{ C+X)">/+L  
this("",0); 7=$+k]U8  
} l6',  
z"G`o"4 V  
NvEm,E\|  
public FileAccessI(String sName,long nPos) throws IOException }C_G0'"F  
{ }R7sj  
oSavedFile = new RandomAccessFile(sName,"rw"); \.K\YAM<  
this.nPos = nPos; Wg}B@:`T  
oSavedFile.seek(nPos); =}B4I  
} P@^z:RS*{  
~uP r]#  
2U=/<3;u  
public synchronized int write(byte[] b,int nStart,int nLen) MLkL.1eGSb  
{ >cGh|_9  
int n = -1; J- @o@!o  
try{ ?/o2#iJx  
oSavedFile.write(b,nStart,nLen); /%N31   
n = nLen; ws*~$x?7  
} L?Kz P.(t+  
catch(IOException e) xn%l  
{ Qx6,>'Qk'  
e.printStackTrace (); /}h71V!  
} GI0x>Z+  
oG4w8+N  
O;"*_Xq(`  
return n; &:!ZT=  
} vjOG?-  
d,GtH)(s  
[u`17hyX  
} \;3B?8wbIl  
 ;'2`M  
w>`h3;,2  
/* T% /xti5$!  
**SiteInfoBean.java >N+bU{s  
*/ 1YF+(fk  
package NetFox; ?.rH;:9To  
,7n;|1`  
i6!T`Kau  
public class SiteInfoBean { F20wf1^  
vF*^xhh  
0?J|C6XM#4  
private String sSiteURL; //Site's URL EI?d(K  
private String sFilePath; //Saved File's Path X/- W8  
private String sFileName; //Saved File's Name fD3jwPL  
private int nSplitter; //Count of Splited Downloading File ,ZzB#\  
)vEHLp.  
a>&;K@  
public SiteInfoBean() % K9; qJ5  
{//nSplitter的缺省值为5 l0:e=q2Ax  
//default value of nSplitter is 5 EPE!V>  
this("","","",5); E3FW*UNg[y  
} lRa 3v Ng  
c&| '3i+  
'%n<MTL  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) w (vE2Y ?  
{ ,w9#%=xE  
sSiteURL= sURL; O X5Co <u  
sFilePath = sPath; t?du+:  
sFileName = sName; .pB8=_e:  
this.nSplitter = nSpiltter; 4."o.:8x  
uI[-P}bSc&  
}rj C_q  
} #x4h_K Y  
oUKBb&&O  
^hl]s?"3  
public String getSSiteURL() g|v1qfK  
{  BdE`p{  
return sSiteURL; cKi^C  
} p,[XT`q^  
(^s&M  
m p|20`go  
public void setSSiteURL(String value) _v~D {H&}  
{ ')~Y  
sSiteURL = value; M<#)D  
} q5'yD;[hE  
OUIUgej  
AihL>a%  
public String getSFilePath()  s>*Q  
{ c5wkzY h  
return sFilePath; 3gV&`>@  
} bCE7hutl  
B:6sVJ  
IQk#  
public void setSFilePath(String value) @sg T[P*ut  
{ H.l,%x&K  
sFilePath = value; :EQme0OW  
} dm/\uE'l  
Hl3XqR  
j J`Zz  
public String getSFileName() +GYI2  
{ Ddm76LS  
return sFileName; ~f]r>jQM  
} syC"eH3{  
2 l[A=Z  
iw~V_y4  
public void setSFileName(String value) VM2@{V/=~  
{ VhH]n yi7D  
sFileName = value; $!l2=^\3  
} <igx[2X  
fw:^Lyn9$  
\@}$Wjsl  
public int getNSplitter() O)RzNfI^`N  
{ JV?RgFy  
return nSplitter; %.Tf u0M  
} {YKMQI^O/  
\9|]  
{Hp}F!X$  
public void setNSplitter(int nCount) NBg>i7KQ  
{ -t~B@%  
nSplitter = nCount; ![P(B0Ct/  
} ~0^,L3M  
} LA=>g/+i.X  
|IcxegE  
{Y* ]Qc  
/* d*\C^:Z  
**Utility.java &TkbnDuYd~  
*/ <v7KE*#  
package NetFox; q@M jeGs%  
.e _D3Xp<  
4QKE{0NE  
public class Utility { ,m?UFRi  
~4~Tcn  
\'LCC-  
public Utility() 4 _U,-%/  
{ I_6` Z 0  
E_' n4@}Cx  
3@cJ=   
} 5KH'|z  
4h_4jqf=pU  
//线程睡眠 CF}Nom)  
public static void sleep(int nSecond) +}-W.H%`0  
{ 7 6i rb!-  
try{ JbC\l  
Thread.sleep(nSecond); BWi 7v  
} [A..<[  
catch(Exception e) |phWK^   
{ (Y.$wMB  
e.printStackTrace (); uQ%HLL-W/  
} P7x?!71?L  
} GY$?^&OO>  
CMG`'gT  
//日志 r4NT`&`g?  
public static void log(String sMsg) 2E ; %=e  
{ ,^IZ[D>u)  
System.err.println(sMsg); HlL@{<  
} 2-E71-J  
{O&liU4  
Lj Q1ar\  
public static void log(int sMsg) +81+4{*  
{ g/X=#!  
System.err.println(sMsg); 33KPo0g7  
} h'y@M+c(  
} [ rQ(ae  
2#:]%y;\  
uF3p1by  
/* HToN+z%w3H  
**TestMethod.java zkMO3w>  
*/ qp_ `Fj:  
package NetFox; /GSI.tO  
JdYF&~  
PKM$*_LcGI  
public class TestMethod { XsN#<"f;i  
ccRk4xR  
4%v+ark8  
public TestMethod() ,WDAcQ8\  
{ ///xx/weblogic60b2_win.exe h7]]F{r5  
try{ 5WJkeG ba  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .9fluAG  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); P[P72WR  
SiteFileFetch fileFetch = new SiteFileFetch(bean); So 6cm|{  
fileFetch.start(); [;#.DH]  
} %^%-h}1  
catch(Exception e){e.printStackTrace ();} g+/U^JIc4l  
*pC -`k  
Q|<?$.FN"8  
} VaI P  
` dUiz5o'  
/~rO2]rZ@  
public static void main(String[] args) ?ZV0   
{ i|,A1c"*  
new TestMethod(); _>m*`:Wb  
} |ShRxE3@'  
} fG$.DvJuK  
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