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http断点续传简单实现(java)

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/* :/FT>UCL  
**SiteFileFetch.java KJN{p~Q  
*/ e'1}5Ky  
package NetFox; Ra^GbT|Z  
import java.io.*; nn6&`$(Q~  
import java.net.*; Cw&U*H  
0?8{q{ o+  
>TZyax<:  
public class SiteFileFetch extends Thread { =$awUy  
g:CMIe4  
ekhx?rz  
SiteInfoBean siteInfoBean = null; //文件信息Bean X\'+);Z  
long[] nStartPos; //开始位置 W&8)yog.  
long[] nEndPos; //结束位置 cAc>p-y%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <46fk*  
long nFileLength; //文件长度 V<G=pPC'H  
boolean bFirst = true; //是否第一次取文件 U<mFwJ C]  
boolean bStop = false; //停止标志 x6B_5eF  
File tmpFile; //文件下载的临时信息 %oqC5O6  
DataOutputStream output; //输出到文件的输出流 6$*ZH *  
v6`TbIq%  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) T_*R^Ukb5  
public SiteFileFetch(SiteInfoBean bean) throws IOException b)Dzau  
{ @XFy^?  
siteInfoBean = bean; !L_\6;aP,x  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .l(t\BfE~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .YcI .  
if(tmpFile.exists ()) cq \()uF'c  
{ 6Cd% @Q2cr  
bFirst = false; S,~DA3  
read_nPos(); ]S#m o  
} h#!u"'JW  
else ~]&,v|g&  
{ l d4#jV ei  
nStartPos = new long[bean.getNSplitter()]; -<Zs7(  
nEndPos = new long[bean.getNSplitter()]; S8$kxQg  
} p?,:  
R#UcwX}o  
fd} U l  
yDW$v/j.|  
} ^+20e3 ~Y  
1JXa/f+  
_.y0 QkwV  
public void run()  ^q=D!g  
{ _@Le MNv  
//获得文件长度 llP 5  
//分割文件 JD}"_,-  
//实例FileSplitterFetch l.Qv9Ll|b  
//启动FileSplitterFetch线程 ">^O{X\  
//等待子线程返回 w0i v\yIRQ  
try{  B1!b@0^  
if(bFirst) amY\1quD|  
{ KixS)sG  
nFileLength = getFileSize(); ` kG}NJf  
if(nFileLength == -1) ) ]x/3J@  
{ LCMCpEtY*K  
System.err.println("File Length is not known!"); -$js5 Gx1  
} 0+P<1ui  
else if(nFileLength == -2) >u:t2DxE  
{ %8a886;2  
System.err.println("File is not access!"); #}Qzu~  
}  mOkf   
else SuU_psF  
{ z rg#BXj7  
for(int i=0;i<nStartPos.length;i++) [j]3='2}G  
{ U3f a *D  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); G$B( AWL  
} Pgg\(D#X`  
for(int i=0;i<nEndPos.length-1;i++) ub0uxvz  
{ gI SP .  
nEndPos = nStartPos[i+1]; ?4 fXCb]7  
} NlS/PWc6(  
nEndPos[nEndPos.length-1] = nFileLength; ] 3@.)  
} }bxW@(bs  
} 8 ;C_@  
x!08FL)  
lnk`D(>W  
//启动子线程 Gz9w1[t  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 5uU.K3G7  
for(int i=0;i<nStartPos.length;i++) Ikn)XZU^  
{ z!r-g(^G  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7z=zJ4C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3. kP,  
nStartPos,nEndPos,i); gfPht 5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -!k$ Z  
fileSplitterFetch.start(); "#a_--"k9  
} 1b,,uI_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), cx(aMcX6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;QA`2$Ow  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", .%pbKi `  
nEndPos = " + nFileLength); :q xd])-  
// fileSplitterFetch[nPos.length-1].start(); Xo{|m[,  
Gs% cod  
q@}eYQ=P|e  
//等待子线程结束 Gqz<;y  
//int count = 0; ;gC.fpu  
//是否结束while循环 #=G[ ~m\  
boolean breakWhile = false; q-g3!  
+x3T^G  
b`=\<u8  
while(!bStop) %ifq4'?Z   
{ '<A:`V9M}v  
write_nPos(); *P#okwp  
Utility.sleep(500); wap@q6fz<  
breakWhile = true; f<`is+"  
py9HUyr5eZ  
'ow`ej  
for(int i=0;i<nStartPos.length;i++) S|{'.XG  
{ *[-% .=[7  
if(!fileSplitterFetch.bDownOver) >>ncq$  
{ lAxbF  
breakWhile = false; UUf-G0/P  
break; nnV(MB4z1  
} kXmnLxhS/  
} SOq{`~,4B  
if(breakWhile) ~qG`~/7  
break; Jv|uI1V  
F3aOKV^  
0jlwL  
//count++; hpxqL%r  
//if(count>4) E0miX)AG  
// siteStop(); -gWqq7O  
} | Vtd !9  
#sn2Vmi  
Jzg>Y?jN R  
System.err.println("文件下载结束!"); SA| AS<  
} N6"b Ox J(  
catch(Exception e){e.printStackTrace ();} f xWW "B*A  
} "pDwN$c  
FZW)C'j  
FY^[?lj  
//获得文件长度 dU7+rc2,CU  
public long getFileSize() h@5mVTb}i  
{ TsPx"+>7`  
int nFileLength = -1; ^r u1QDT  
try{ fgs){ Ng`  
URL url = new URL(siteInfoBean.getSSiteURL()); 8| 6:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yA8e"$  
httpConnection.setRequestProperty("User-Agent","NetFox"); rNgFsFQ>.  
s<i& q {r  
BM(8+Wj  
int responseCode=httpConnection.getResponseCode(); ]}3AP!:  
if(responseCode>=400) $c!cO" U  
{ %6\e_y%  
processErrorCode(responseCode); BI'}  
return -2; //-2 represent access is error :|s!_G<  
} G8w<^z>pTg  
u7_IO  
U;Iqz1S  
String sHeader; ^^u{W|'CaH  
%nTgrgS(=  
_B@=fY(g!  
for(int i=1;;i++) /'V(F* g  
{ $*035f  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); qno8qF*  
//Utility.log(in.readLine()); 1}moT#  
sHeader=httpConnection.getHeaderFieldKey(i); vtvF)jlX  
if(sHeader!=null) "ooq1 0P  
{ ionFPc].  
if(sHeader.equals("Content-Length")) .Ulrv5wJ  
{ 1@&i ju5  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?onaJ=mT  
break; He#5d!cf:M  
} xz-z" 8d  
} EJM6TI"  
else gWxpGW^eZ~  
break; MZyzc{c,  
} "f/Su(6{0  
} 5'JONw'\  
catch(IOException e){e.printStackTrace ();} Qi 3di  
catch(Exception e){e.printStackTrace ();} or?@Ti;  
Vv"JN?dHi  
aZ[ aZU  
Utility.log(nFileLength); Uxla,CCp-  
~ .}  
82S?@%}#J  
return nFileLength; e)pQh& uD  
} ,_STt)  
{XT3M{`rWL  
^sLnKAN  
//保存下载信息(文件指针位置) :L~{Q>o  
private void write_nPos() Q\pTyNAYn  
{ =Kq/E De  
try{ }ze,6T*z  
output = new DataOutputStream(new FileOutputStream(tmpFile)); cQ= "3M)~r  
output.writeInt(nStartPos.length); RTPxAp+\5  
for(int i=0;i<nStartPos.length;i++) ::k>V\;  
{ FtaO@5pS54  
// output.writeLong(nPos); k<1BE^[V  
output.writeLong(fileSplitterFetch.nStartPos); DB1GW,  
output.writeLong(fileSplitterFetch.nEndPos); 0q|.]:][Eo  
} >/*wlY!E  
output.close(); BoJYP  
} >k:BG{$Kae  
catch(IOException e){e.printStackTrace ();} T7vSp<i/  
catch(Exception e){e.printStackTrace ();} YL(7l|^!  
} 85>WK+=  
9ANC,+0p  
aq'd C=y  
//读取保存的下载信息(文件指针位置) ikr|P&e#u  
private void read_nPos() /%El0X  
{ gk"0r\Eq  
try{ :6~DOvY  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); O}4(v#  
int nCount = input.readInt(); 7MRu=Z.-b  
nStartPos = new long[nCount]; OQ[E-%v1 R  
nEndPos = new long[nCount]; t7A '  
for(int i=0;i<nStartPos.length;i++) KC+C?]~M  
{ qTbY'V5A  
nStartPos = input.readLong(); K"p$ga{  
nEndPos = input.readLong(); >Oary  
} BXNt@%  
input.close(); >d.o1<  
} ``%uq)G=D  
catch(IOException e){e.printStackTrace ();} W<J".2D  
catch(Exception e){e.printStackTrace ();} aBo8?VV]8  
} ]_cBd)3P}  
YeN /J.R  
ttEQgkd`  
private void processErrorCode(int nErrorCode) Z3:M%)e_u$  
{ I6bekOvP  
System.err.println("Error Code : " + nErrorCode); <SiD m-=E  
} 6XVr-ef  
?{bF3Mz=  
-7 GF2 @  
//停止文件下载 ye-o'%{  
public void siteStop() ]SNA2?q  
{ rgQ6/3}qc  
bStop = true; cR; zNS  
for(int i=0;i<nStartPos.length;i++) K<@gU\-!  
fileSplitterFetch.splitterStop(); S@AHI!"h=V  
s%tPGjMq  
%s.hqr,I  
} mL\j^q,Y  
} )` nX~_'p  
//负责部分文件的抓取 _%g}d/v}pO  
**FileSplitterFetch.java W)3IS&;P  
*/ oY!nM%z/  
package NetFox; UlBg6   
]LFY2w<  
Q'f!392|  
import java.io.*; _dCsYI%  
import java.net.*; +Eil:Jz  
A;e[-5@  
[ vU$zZ<  
public class FileSplitterFetch extends Thread {  &Gp~)%  
x+j5vzhG)  
W"9?D  
String sURL; //File URL !V~`e9[rl  
long nStartPos; //File Snippet Start Position al/3$0#U  
long nEndPos; //File Snippet End Position 1}#(4tw)  
int nThreadID; //Thread's ID w(w%~;\kLP  
boolean bDownOver = false; //Downing is over <ex,@{n4  
boolean bStop = false; //Stop identical lO482l_t  
FileAccessI fileAccessI = null; //File Access interface F$ kLft[:  
TGnyN'P|  
s>E u[ uA  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException M8Y\1#~  
{ 2ql7*g?Uq@  
this.sURL = sURL; x`'2oz=,F4  
this.nStartPos = nStart; %|(~k*s4  
this.nEndPos = nEnd; 1tvgM !.  
nThreadID = id; c5_?jKpl  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 >G`=8Ku  
} (k?,+jnR  
4l! ^"=rh  
3c5=>'^F  
public void run() xyO]Evg  
{ ygm4Aj>  
while(nStartPos < nEndPos && !bStop) h.Cr;w,2R  
{ 0{ov LzW  
{7^7)^@  
yteJHaq  
try{ rvT7 5dV0  
URL url = new URL(sURL); MpbH!2J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .pNPC|XU  
httpConnection.setRequestProperty("User-Agent","NetFox"); `Q2 `":  
String sProperty = "bytes="+nStartPos+"-"; iqecm]Z0  
httpConnection.setRequestProperty("RANGE",sProperty); {e,m<mAi  
Utility.log(sProperty); 1Yt;1k'  
f o])=KM  
$KL5Z#K  
InputStream input = httpConnection.getInputStream(); &wj;:f  
//logResponseHead(httpConnection); `Q!|/B  
wI +oG  
p#}38`  
byte[] b = new byte[1024]; YH`/;H=$G/  
int nRead; L2>UA<@mZ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) zn5  
{ v'`9^3(-  
nStartPos += fileAccessI.write(b,0,nRead); )i&9)_ro  
//if(nThreadID == 1) M70Xdn  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A:3bL: ;t  
} +O23@G?x  
'>(R'g42n  
fRo_rj _  
Utility.log("Thread " + nThreadID + " is over!"); T:Dp+m!\{  
bDownOver = true; ]saf<?fzr  
//nPos = fileAccessI.write (b,0,nRead); mLM$dk3  
} ;czMsHu0X  
catch(Exception e){e.printStackTrace ();} <a *X&P  
} 3=xb%Upw  
} Vm]ltiTVk  
S5ka;g  
P/._ tQu6  
//打印回应的头信息 }fw;{&s{z  
public void logResponseHead(HttpURLConnection con) yTw0\yiO  
{ qPdNI1 |  
for(int i=1;;i++) ,)A^3Q*  
{ fclmxTy  
String header=con.getHeaderFieldKey(i); }~dXz?{p8  
if(header!=null) E"iH$NN  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); JsOPI ]  
Utility.log(header+" : "+con.getHeaderField(header)); uf,4GPo,  
else K^AX=B  
break; XtfO;`   
} <Ft6d  
} ^GdU$%aa  
}NPF]P;  
((rk)Q+;v  
public void splitterStop() Nd/iMV6V;  
{ +=%13cA*U  
bStop = true; b3e:F{n ^  
} K g&{ ?&  
ay#cW.,  
9z 5K  -s  
} ")7,ZN;  
Oy[1_qfP  
/h%<e  
/* f&t]O$  
**FileAccess.java 5=Mm=HyI2  
*//文件访问(定位,写) Y-&r_s_~  
package NetFox; 70&v`"  
import java.io.*; (+>~6SE  
Y."ujo#bB  
-yeQQ4b  
public class FileAccessI implements Serializable{ (r`+q[  
evPr~_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 a>`\^>G4  
RandomAccessFile oSavedFile; [8.ufpZ  
long nPos; "|`8mNC  
K|];fd U  
{ yU1db^  
public FileAccessI() throws IOException .Ozfj@ f  
{ gs 8w/  
this("",0); @~fg[)7M  
} MK[l*=\s  
: N ^1T6v  
t$r^'ZN  
public FileAccessI(String sName,long nPos) throws IOException W^0F(9~!(  
{ N+l~r]: &  
oSavedFile = new RandomAccessFile(sName,"rw"); C.s{ &  
this.nPos = nPos; \(.&E`r  
oSavedFile.seek(nPos); `|wH=  
} OYC4iI  
;6t>!2I>C  
SqFya  
public synchronized int write(byte[] b,int nStart,int nLen) b$[_(QUw  
{ ]R}#3(]1  
int n = -1; j>eL&.d  
try{ E!Hq%L!/  
oSavedFile.write(b,nStart,nLen); 28SlFu?  
n = nLen; rui}a=rs  
} [e3|yE6  
catch(IOException e) 9:A>a3KOH  
{ '*!R gbj;  
e.printStackTrace (); *jGB/ y  
} [6 wI22  
[V{JuG;s  
KoiU\r  
return n;  wxsJB2  
} ^j';4'  
%9[GP7?  
PTA;a 0A  
} aRq7x~j )\  
51.F,uY  
a\vf{2  
/* CB_(9T72H  
**SiteInfoBean.java :tdx:  
*/ VbM5]UT/  
package NetFox; /}2 bsiJT  
>?'q P ]  
zJI/j _~W  
public class SiteInfoBean { ,.]e~O4R  
Y:^ =jV7  
!W^2?pqN  
private String sSiteURL; //Site's URL _4o2AS:j  
private String sFilePath; //Saved File's Path vKAHf;1  
private String sFileName; //Saved File's Name IG`~^-}7lR  
private int nSplitter; //Count of Splited Downloading File u A C:&  
p$f#W  
, p1 (0i  
public SiteInfoBean() rRcfZZ~` M  
{//nSplitter的缺省值为5 tt[P{mMQ  
//default value of nSplitter is 5 cLr? B;FS  
this("","","",5); Ms1G&NYP  
} ZyCAl9{p  
Q[J,j+f<  
<B`}18x  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) kjaz{&P  
{ ><LIOFqsS  
sSiteURL= sURL; Z<jRZH*L  
sFilePath = sPath; {N)\It  
sFileName = sName; Ez?vJDd  
this.nSplitter = nSpiltter; :FG}k Y  
H xb{bF  
C>v    
} W{ eu_  
{Hp?rY@  
kjNA~{  
public String getSSiteURL()  cD0  
{ F1M@$S ,  
return sSiteURL; QIi*'21a+  
} pC8(>gV<h  
enG6T  
YL){o$-N"J  
public void setSSiteURL(String value) v^@L?{" }8  
{ y{u6t 3  
sSiteURL = value; yl 0?Y  
} {6 #3`  
x ?^c:`.  
Z6D4VZVF  
public String getSFilePath() ^{6Y7T]  
{ FT|*~_@  
return sFilePath; iM8hGQ`  
} QMtt:f]?i  
{)b`fq  
`yQHPN0/  
public void setSFilePath(String value) dC(6s=4  
{ !ox&`  
sFilePath = value; d[~c-G6  
} |o!<@/iH=  
X[@>1tl  
* uEU9fX  
public String getSFileName() v~jN,f*  
{ 1'aS2vB9  
return sFileName; xR_]^Get  
} 3M%EK2,  
_KZ(Yq>SdY  
="A[*:h C"  
public void setSFileName(String value) N23s{S t  
{ 2~ 'Q#(  
sFileName = value; Q@$1!9m  
} dH`a|SVW9  
 fx;5j;  
+Og O<P  
public int getNSplitter() 20fCWVw}?}  
{ fLD9RZ8_  
return nSplitter; _eO]awsA  
} [w{ZP4d>  
k&~vVx  
s &.Z;X  
public void setNSplitter(int nCount) il#rdJ1@t  
{ e<p$Op  
nSplitter = nCount; ?0?'  
} PN.6BJvu  
} kBONP^xI  
r p @=  
i44:VR|  
/* \6lXsu;I.X  
**Utility.java x _2]G'  
*/ ze 4/XR  
package NetFox; '@fk(~|  
&>s(f-\8  
;zCHEz  
public class Utility { RF;N]A?*  
yjSN;3t71  
`2@-'/$\I|  
public Utility() xS(sRx+A  
{ TWs|lhC7!  
:w];N|48s  
kqyMrZ#  
} t =*K?'ly  
c^bA]l^a  
//线程睡眠 8odVdivh  
public static void sleep(int nSecond) HhpP}9P;  
{ @i`gR%  
try{ w+MdQ@'5  
Thread.sleep(nSecond); )T4L^^`  
} `773& \PK  
catch(Exception e) z)0VP QMT  
{ G{"1  I  
e.printStackTrace (); %b*%'#iK  
} )R|7> 97  
} a>kD G <.A  
i]YQq!B  
//日志 n-=\n6"P  
public static void log(String sMsg) $bo^UYZ6  
{ pP r<8tm[  
System.err.println(sMsg); {10ms_s  
} tS9m8(Hr%Q  
1y@-  
H,I}R  
public static void log(int sMsg) ~FsUK;?  
{ kN^)6  
System.err.println(sMsg); B.WJ6.DkS  
} y H'\<bT  
} ]SPB c  
=&pbh  
G8&'*7Bb  
/* Yn#8uaU  
**TestMethod.java PWmz7*/  
*/ 68!]q(!6F  
package NetFox; SH(kUL5  
N0piL6Js  
Stc\P]%d  
public class TestMethod { - VE#:&  
MCCZh{uo  
ku{aOV%  
public TestMethod() <-?B#  
{ ///xx/weblogic60b2_win.exe 9s!/yiP5  
try{ 4sAshrUf  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); q)~qd$yMS  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); M'HOw)U  
SiteFileFetch fileFetch = new SiteFileFetch(bean); j"V$J8)[  
fileFetch.start(); 35>}$1?-6  
} 6a@~;!GlI  
catch(Exception e){e.printStackTrace ();} BNy"YK$  
6Te}"t>  
Y; w]u_  
} S3_4i;K\  
HDEG/k/~m  
+doT^&2u*  
public static void main(String[] args) \PFx# :-c  
{ |W <:rT  
new TestMethod(); IBqY$K+l  
} /OP*ARoC21  
} 'l:2R,cP  
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