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http断点续传简单实现(java)

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/* 1n3$V:00  
**SiteFileFetch.java ,"H?hFQ  
*/ 2oB?Dn  
package NetFox; I#c(J  
import java.io.*; 6ZgNHARS  
import java.net.*; 6Ct0hk4  
-tP.S1D  
:uvc\|:s  
public class SiteFileFetch extends Thread { `.8-cz  
8p,>y(o  
=1Sy@MbH3  
SiteInfoBean siteInfoBean = null; //文件信息Bean Zd XKI{b  
long[] nStartPos; //开始位置 g RU-g  
long[] nEndPos; //结束位置 }200g_^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 m3"c (L`B  
long nFileLength; //文件长度 /j %_t  
boolean bFirst = true; //是否第一次取文件 S w "|iBZ@  
boolean bStop = false; //停止标志 .+uVgSN  
File tmpFile; //文件下载的临时信息 *-7fa0<  
DataOutputStream output; //输出到文件的输出流 .b~OMTHuvM  
hXnw..0"  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Rk{$S"8S_  
public SiteFileFetch(SiteInfoBean bean) throws IOException eoL0^cZj  
{ $w`veP  
siteInfoBean = bean; `D"1 gD}{A  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); s kY0\V  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); w(#:PsMo<  
if(tmpFile.exists ()) dcP88!#5-  
{ % &2B  
bFirst = false; )BpIxWd?  
read_nPos(); &m4f1ZO*  
} $~ VcQ  
else b<\GI 7  
{ -G!6U2*#  
nStartPos = new long[bean.getNSplitter()]; pKYLAt+^>  
nEndPos = new long[bean.getNSplitter()]; qw)Key  
} *Ji9%IA  
]%||KC!O  
+>^[W~[2  
F*. /D~K  
} 6T]Q.\5BZ  
9M nem*  
V"BVvSNu  
public void run() |&(H^<+Xp  
{ Ho>p ^p  
//获得文件长度 i(z+a6^@|  
//分割文件 (\tq<h0  
//实例FileSplitterFetch R rxRa[{Z  
//启动FileSplitterFetch线程 ^Jn|*?+l  
//等待子线程返回 t3 K>\ :  
try{ :nt}7Dn'  
if(bFirst) G1A$PR  
{ HoMQt3C  
nFileLength = getFileSize(); g8Ok ^  
if(nFileLength == -1) 5#P: "U  
{ ]m RF[b$  
System.err.println("File Length is not known!"); x}uwWfe3  
} 1RmBtx\<  
else if(nFileLength == -2) p-a]"l+L  
{ i4 P$wlO  
System.err.println("File is not access!"); @f-0X1C."N  
} #T Z!#,q  
else N4' .a=1  
{ p$B)^S%0i  
for(int i=0;i<nStartPos.length;i++) NuHL5C?To  
{ ozT._ C  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); oJhEHx[f  
} [;)~nPjI  
for(int i=0;i<nEndPos.length-1;i++) Z=0iPy,m>  
{ -v;iMEZ)  
nEndPos = nStartPos[i+1]; FW/6{tm  
} 4GEjW4E  
nEndPos[nEndPos.length-1] = nFileLength; R%Kl&c  
} gX/|aG$a!U  
} 7l[t9ON  
)kFme=;  
_.u~)Q`6  
//启动子线程 jY1^+y{  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; hLu&lY  
for(int i=0;i<nStartPos.length;i++) JiG8jB7%}  
{ Kv(Y }  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^Z#<tN;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \xy:6gd:  
nStartPos,nEndPos,i); 4KN0i  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,q{lYX83S  
fileSplitterFetch.start(); T[`QO`\5O  
} hj%}GP{{  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [R roHXdk+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); =f/avGX  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", C6Um6 X9/i  
nEndPos = " + nFileLength); @Z"QA!OK~c  
// fileSplitterFetch[nPos.length-1].start(); 4yJ01s  
89 _&X[X  
Ly@U\%.  
//等待子线程结束 \Qe'?LRu{  
//int count = 0; qdg= Imx  
//是否结束while循环 &QiAM`MbC=  
boolean breakWhile = false; Ke'YM{  
Z3&XTsq  
_p3WE9T  
while(!bStop)  ."$=  
{ O% j,:t'"  
write_nPos(); ;tZ}i4Ud  
Utility.sleep(500); )AZ`R8-A  
breakWhile = true; oZ|{J  
6'3Ey'drH  
*}50q9)/  
for(int i=0;i<nStartPos.length;i++) NpjsZcA  
{ R$~JhcX*l'  
if(!fileSplitterFetch.bDownOver) 4jI*Y6Wkz  
{ ~8S4Kj)%  
breakWhile = false; PDa06(t7  
break; ePFC$kMn  
} )[a?J,  
} .>cL/KaP  
if(breakWhile) i1kh@s~8UC  
break; O;.d4pO(tC  
EV;;N  
[m@e^6F0U  
//count++; iyHp$~,q?t  
//if(count>4) la6e`  
// siteStop(); Q'vIeG"o  
} 0.3[=a4 3  
U7f#Z  
`\}zm~  
System.err.println("文件下载结束!"); cc#_acR  
} ]MBJ"1F  
catch(Exception e){e.printStackTrace ();} *AJezhR  
} tF)k6*+  
p5D3J[?N  
9=sMKc%!-  
//获得文件长度 pNk,jeo  
public long getFileSize() 5}(YMsUb  
{ TbSt {TX  
int nFileLength = -1; c"_H%x<[  
try{ v:so85(S<  
URL url = new URL(siteInfoBean.getSSiteURL()); d%"@#bB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  \1c`)  
httpConnection.setRequestProperty("User-Agent","NetFox"); =Am*$wGI  
Jh hT7\h(  
L< nkI  
int responseCode=httpConnection.getResponseCode(); 2+hfbFu,1  
if(responseCode>=400) )QJU ]G  
{ 67hPQ/S1  
processErrorCode(responseCode); XzTH,7[n  
return -2; //-2 represent access is error uR[PKLh  
} <]SS gQ9/"  
|'>E};D  
,1.([%z+r  
String sHeader; .$T:n[@  
+xu/RY_  
QK/+*hr;  
for(int i=1;;i++) ?5+KHG*)  
{ D -\'P31  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); mk3e^,[A  
//Utility.log(in.readLine()); M#gGD-  
sHeader=httpConnection.getHeaderFieldKey(i); .]d tRH<  
if(sHeader!=null) >ehWjL`8  
{ h,RUL  
if(sHeader.equals("Content-Length")) QR-R5XNT[  
{ 9G\3hL]  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); f4;8?  
break; u:>3j,Cs  
} U=<.P;+f9  
} W1,L>Az^Ts  
else FT?1Q'  
break; UK9MWC5g9  
} It:QXLi;  
} :FgRe,D  
catch(IOException e){e.printStackTrace ();} }\qdow-  
catch(Exception e){e.printStackTrace ();} jm!C^5!  
.mU.eLM  
xbC- ueEj  
Utility.log(nFileLength); |~vQ0D  
<$Kv^Y*  
vCe<-k  
return nFileLength; ? F), 4Q  
} ~;4k UJD  
3e<^-e)+xL  
2A;[Ek6{q  
//保存下载信息(文件指针位置) =id $  
private void write_nPos() CoN/L`.SN  
{ uT t:/gm  
try{ Rm 1`D  
output = new DataOutputStream(new FileOutputStream(tmpFile)); >u[1v  
output.writeInt(nStartPos.length); Yt<PKs#E  
for(int i=0;i<nStartPos.length;i++) sWCm[HpG  
{ 9@a;1Wr/f  
// output.writeLong(nPos); g#2X'%&+  
output.writeLong(fileSplitterFetch.nStartPos); e9~4wt  
output.writeLong(fileSplitterFetch.nEndPos); t'/;Z:  
} ) CTM  
output.close(); :|mkI#P.  
} E"yf!*  
catch(IOException e){e.printStackTrace ();} swgBPJ"?  
catch(Exception e){e.printStackTrace ();} UN4) >\Y  
} D}U<7=\3H  
#C7j|9Ew1]  
PGhZ`nl  
//读取保存的下载信息(文件指针位置) >RnMzH/9  
private void read_nPos() ?YykCJJ ~@  
{ RUtS_Z&  
try{ ~,1q :Kue  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); m =F@CA~C  
int nCount = input.readInt(); 0>MI*fnY"  
nStartPos = new long[nCount]; 'U0I.x(  
nEndPos = new long[nCount]; JB_`lefW,'  
for(int i=0;i<nStartPos.length;i++) Xkm2C)  
{ sYI':UQe  
nStartPos = input.readLong(); dkp[?f)x  
nEndPos = input.readLong(); LkB!:+v |B  
} sB/s17ar  
input.close(); v('d H"Y  
} PCfs6.*5Mf  
catch(IOException e){e.printStackTrace ();}  nGd  
catch(Exception e){e.printStackTrace ();} 1y;zPJ<ntm  
} wKbymmG  
W-QPO  
93DBZqN  
private void processErrorCode(int nErrorCode) wO%:WL$5  
{ ]w_)Spo.  
System.err.println("Error Code : " + nErrorCode); `{_PSzM  
} Rw 8o]  
ZHasDZ8  
Lc?O K"[m  
//停止文件下载 Acv{XnB  
public void siteStop() tY=TY{RY  
{ c10).zZ  
bStop = true; Z?mg1;Q  
for(int i=0;i<nStartPos.length;i++) ;BVhkW A  
fileSplitterFetch.splitterStop(); p2(_YN;s  
LTct0Gh  
db~:5#*  
} /vMyf),2  
} XCriZ|s  
//负责部分文件的抓取 3~la/$?p0  
**FileSplitterFetch.java b15qy?`y  
*/ j #YFwX4.  
package NetFox; J@iN':l-  
3Q)>gh*  
nWu4HFi  
import java.io.*; elgQcJ99  
import java.net.*; `p|vutk)U  
>#|Yoc  
vDvGT<d  
public class FileSplitterFetch extends Thread { ^W'[l al.  
o |iLBh$)  
ulM&kw.4i  
String sURL; //File URL ;~1JbP  
long nStartPos; //File Snippet Start Position w'XgW0j{  
long nEndPos; //File Snippet End Position efR$s{n!  
int nThreadID; //Thread's ID NM.B=<Aw*  
boolean bDownOver = false; //Downing is over `1]9(xwhQ0  
boolean bStop = false; //Stop identical fk1f'M)/8  
FileAccessI fileAccessI = null; //File Access interface >t(@?*ZFT  
%'z3es0  
): C4}&l  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3)SZVME1Z  
{ Q$j48,e  
this.sURL = sURL; ;$< ek(i7  
this.nStartPos = nStart; }wXD%X@)l  
this.nEndPos = nEnd; t7FQ.E,T  
nThreadID = id; mA @+4&  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {[ *_HAy7  
} jF9CTL<  
m)}MkC-  
aM!#  
public void run() G - WJlu  
{ I_7EfAqg(  
while(nStartPos < nEndPos && !bStop) It-*CD9  
{ q2vz#\A?  
He3zV\X[Z  
9zd/5|W  
try{ @x +#ZD(  
URL url = new URL(sURL); / u6$M/Cf>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <Q)}  
httpConnection.setRequestProperty("User-Agent","NetFox"); kELyD(^P`  
String sProperty = "bytes="+nStartPos+"-"; 1A-EP@# J  
httpConnection.setRequestProperty("RANGE",sProperty); #jiqRhm  
Utility.log(sProperty); yTiqG5r  
g1 ,  
&S]v+wF  
InputStream input = httpConnection.getInputStream(); ~7'.{VrU  
//logResponseHead(httpConnection); &Sa~Wtm|*  
rK|&u v*b  
Ya 4$7|(  
byte[] b = new byte[1024]; P^W47 SO  
int nRead; 3=7h+ZgB  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) krc!BK`V  
{ ^#se4qQ  
nStartPos += fileAccessI.write(b,0,nRead); -74T C  
//if(nThreadID == 1) >/bK?yT<  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); DjvgKy=Jr_  
} B)8Hj).@B  
}* JMc+!9@  
8-YrmP2k  
Utility.log("Thread " + nThreadID + " is over!"); WEAXqDjM  
bDownOver = true; +Ob#3PRy  
//nPos = fileAccessI.write (b,0,nRead); );H[lKy  
} >nEnX  
catch(Exception e){e.printStackTrace ();} _!p3M3"$B  
} r0 C6Ww7u  
} cLC7U?-  
NI:N W-!  
^I?y\:.  
//打印回应的头信息 ;NeEgqW "  
public void logResponseHead(HttpURLConnection con) MiM=fIuw@s  
{ 1Z8oN3  
for(int i=1;;i++) ] Nipo'N;  
{ aZ`ags ofk  
String header=con.getHeaderFieldKey(i); ; @~*z4U  
if(header!=null) >Fk `h=Wd  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); T?{9Z  
Utility.log(header+" : "+con.getHeaderField(header)); v=-3 ,C  
else Qp&yS U8  
break; gi@ji-10  
} q.km>XRk~  
} wJ*-K-  
[ {LnE:  
X.9MOdG70  
public void splitterStop() eH/\7)z  
{ AiHf?"EVT  
bStop = true; ?u!AHSr(  
} bKZ#>%|:o  
>I~z7 JS  
^QR'yt3e  
} ;o459L>sW  
w1(06A}/  
v} ;qMceJ  
/* u(WQWsN  
**FileAccess.java >ImM~SR)  
*//文件访问(定位,写) 1t=X: ]0j  
package NetFox; dU^<7 K:S  
import java.io.*; ATp  6-  
C?|3\@7  
,!u@:UBT  
public class FileAccessI implements Serializable{ ?QT"sj64w  
HTyF<K  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ~7WXjVZ  
RandomAccessFile oSavedFile; m>dcb 6B+g  
long nPos; y]f^`2L!8>  
fYM6wYJ  
(H%d]  
public FileAccessI() throws IOException CVG>[~}(9'  
{ EFt`<qwj  
this("",0); <`UG#6z8  
} nYt\e]3  
T&"dBoUq>G  
`G0rF\[  
public FileAccessI(String sName,long nPos) throws IOException @"Fp;Je\bN  
{ w[oQ}5?9'  
oSavedFile = new RandomAccessFile(sName,"rw"); ?i EXFYJG  
this.nPos = nPos; dN/ "1%9)  
oSavedFile.seek(nPos); e0WSHg=6@  
} |aAWW d5  
=C>`}%XT}  
zQ %z "tQ  
public synchronized int write(byte[] b,int nStart,int nLen) 2*wO5v  
{  >fA@tUQB  
int n = -1; \"`>-v"h  
try{ UAXF64w{  
oSavedFile.write(b,nStart,nLen);  `pd   
n = nLen; GKujDx+h  
} giPo;z\c  
catch(IOException e) /uXRZ  
{ [^}>AC*im  
e.printStackTrace (); <*Kh=v  
} t^_{5  
\i;&@Kp.N  
j[J@tM#  
return n; <kXV1@>  
} P[GX}~_k  
Pn'(8bRm  
/.kna4k  
} j YIV^o 0  
m{$tO;c/Q  
h$7Fe +#I#  
/* q?-3^z%u  
**SiteInfoBean.java ncJFB,4  
*/ feI[M;7u  
package NetFox; Z~phOv  
=Q8H]F  
jFNs=D&(  
public class SiteInfoBean { S|q!? /jqj  
1u"*09yZd  
vMZ7uO  
private String sSiteURL; //Site's URL AXh3LA  
private String sFilePath; //Saved File's Path ZkB6bji  
private String sFileName; //Saved File's Name ,8=`*  
private int nSplitter; //Count of Splited Downloading File "?eH=!  
f*T)*R_  
i+X2M-[Ls  
public SiteInfoBean() 29iIG 'N  
{//nSplitter的缺省值为5 a?,[w'7FU  
//default value of nSplitter is 5 >)n4s Mq  
this("","","",5); s@ 2 0#D  
} ~6-"i0k  
u3*NO )O  
Od!F: <  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) iJZ|[jEDV  
{ n-hvh-ZO  
sSiteURL= sURL; ||=[kjG~  
sFilePath = sPath; W%>i$:Qq  
sFileName = sName; =CKuiO.j  
this.nSplitter = nSpiltter; Y%fVt|  
y^d[( c  
z#{ 0;t  
} gv#c~cX]  
:>P4L,Da]  
.|-l+   
public String getSSiteURL() Q&Z4r9+Z  
{ b.R!2]T]i^  
return sSiteURL; SLdN.4idK  
} Qst \b8,  
crJ7pe9  
f2O*8^^Y{Q  
public void setSSiteURL(String value) zNV!@Yr  
{ Np|'7D  
sSiteURL = value; W,HH *!  
} \K?(  
c Pq Dsl3  
X-)RU?  
public String getSFilePath() )D[ "M$ZA^  
{ af<NMgT2s~  
return sFilePath; IpWy)B>Fl3  
} $hjP}- oUX  
OU,PO2xX9  
29Gwv  
public void setSFilePath(String value) ~!]&>n;=G  
{ Ml8 YyF/~  
sFilePath = value; n+{HNr  
} ~K~b`|1  
qIbg 4uE  
rU=b?D)n!w  
public String getSFileName() (C`FicY  
{ O{k89{  
return sFileName; E0"10Qbi  
} I 1b  
$J QWfGwR  
Q_&}^  
public void setSFileName(String value) 0?lp/|K  
{ ~L%Pz0Gg  
sFileName = value; M}Nb|V09  
} $!YKZ0)B'0  
0'?V|V=v  
vKNt$]pm=  
public int getNSplitter() q2x|%H RF  
{  4%g6_KB  
return nSplitter; P%zH>K  
} 1t/dxB;  
W@I 02n2 H  
q>_vE{UB  
public void setNSplitter(int nCount) =n@F$/h  
{ #ZG3|#Q=L  
nSplitter = nCount; -VS9`7k  
} C#MF pT  
} M{`/f@z(  
YfE>Pn'r  
$ A-+E\vQ@  
/* JDLTOLG  
**Utility.java &w+;N5}3  
*/ ;i<$7MR.e  
package NetFox; ic%?uWN  
.6>  hD1'  
3B@y &a#&  
public class Utility { wYZT D*A2h  
0:Ar| to$m  
3gb|x?  
public Utility() U't E^W  
{ M]}l^ m>L  
2Y400  
>(hSW~i~  
} ePf+[pV3  
S8 :"<B)  
//线程睡眠 (+|X<Bl:`  
public static void sleep(int nSecond) LmP qLH'(Q  
{ q5Fs)B  
try{ q`XW5VV{K  
Thread.sleep(nSecond); 7FAIew\r  
}  l B1#  
catch(Exception e) p6`Pp"J_tr  
{ z< z*Wz  
e.printStackTrace (); 0y)}.'  
} o4$Ott%Wm  
} gfi AK%  
KX!i\NHz  
//日志 M70c{s`w5  
public static void log(String sMsg) 94\t1fE  
{ 2ck 4C/ h  
System.err.println(sMsg); pX@Si3G`  
} m23+kj)+VY  
g3Z:{@m  
l :/&E 6 9  
public static void log(int sMsg) ,Du@2w3Cq  
{ N;uUx#z  
System.err.println(sMsg); ?a S%  
} 4t04}vp  
} `>s7M.|X  
mw_ E&v  
-K"4rz  
/* ^$!987"  
**TestMethod.java W4(v6>5l  
*/ sONBQ9  
package NetFox; o/C(4q6d  
g& k58{e  
$[g_=Z  
public class TestMethod { !=3Rg-'d1  
Guh%eR'Wt  
rz6uDJ"  
public TestMethod() :p' VbQZ{  
{ ///xx/weblogic60b2_win.exe qz9tr  
try{ ~3gru>qI&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [QT 1Ju64  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ({4]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ,|+Gls  
fileFetch.start(); vv6?V#{  
} j Fma|y  
catch(Exception e){e.printStackTrace ();} EM@ ;3.IO  
d6`OXTD  
3\AM=`  
} .e @>   
LOr|k8tL%  
,vV ]"f  
public static void main(String[] args) R[LsE^  
{ )t:7_M3  
new TestMethod(); scW'AJJq  
} _d@=nK)  
} Bn?:w\%Ue  
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