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http断点续传简单实现(java)

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/* W NwJM  
**SiteFileFetch.java ]UX`=+{  
*/ 5q|+p?C  
package NetFox; 5:Yck<  
import java.io.*; c Ndw9?Z  
import java.net.*; hWq. #e 6  
j>0<#SYBu  
?w+ QbT  
public class SiteFileFetch extends Thread { QP6z?j.  
 ?YqJ.F;  
w`c0a&7  
SiteInfoBean siteInfoBean = null; //文件信息Bean r-RCe3%g%  
long[] nStartPos; //开始位置 w=f0*$ue+w  
long[] nEndPos; //结束位置 |Z`M*.d+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 tmO;:n<N  
long nFileLength; //文件长度 )Qh>0T+(  
boolean bFirst = true; //是否第一次取文件 "El^38Ho  
boolean bStop = false; //停止标志 G1kaF/`O  
File tmpFile; //文件下载的临时信息 Z69+yOJI  
DataOutputStream output; //输出到文件的输出流 uP{; *E3?  
X}oj_zsy;^  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) e#>tM  
public SiteFileFetch(SiteInfoBean bean) throws IOException T*h!d(  
{ D 4< -8  
siteInfoBean = bean; )Vwj9WD  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); S5i+vUI8C  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); n K+lE0  
if(tmpFile.exists ()) HQq`pG%m6  
{ R<f#r03@|  
bFirst = false; 1&"-*)  
read_nPos(); %ZujCZn  
} _9D|u<D  
else 9pWi.J  
{ #F_'}?09%  
nStartPos = new long[bean.getNSplitter()]; /Zo~1q  
nEndPos = new long[bean.getNSplitter()]; P3'2IzNw  
} +"]oc{W!  
BJ~ ivT<  
_h0-  
^9&b+u=X  
} Da"yZ\4  
nIfN"  
'UY[ap  
public void run() ]EB6+x!G  
{ 12idM*  
//获得文件长度 '@'B>7C#  
//分割文件 7t'(`A 6t/  
//实例FileSplitterFetch |q3f]T&+>{  
//启动FileSplitterFetch线程 p3g4p  
//等待子线程返回 Xo2^N2I  
try{ hlX>K  
if(bFirst) ($c`s8mp  
{ 9160L qY  
nFileLength = getFileSize(); r=h8oUNEJ*  
if(nFileLength == -1)  cp$.,V  
{ :@.C4oq  
System.err.println("File Length is not known!"); :~yzDk\I"-  
} CE)*qFs  
else if(nFileLength == -2) :`D'jF^S  
{ #nKRTb+{  
System.err.println("File is not access!"); g^1r0.Sp{8  
} j5kA^MTG  
else ^w>&?A'!  
{ f2NA=%\  
for(int i=0;i<nStartPos.length;i++) vCj4;P g  
{ Hw Z^D= A  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0z/h+,  
} g;8M<`qvf  
for(int i=0;i<nEndPos.length-1;i++)  1Yud~[c  
{ cn$5:%IK  
nEndPos = nStartPos[i+1]; ji }#MBac  
} ASR-a't6  
nEndPos[nEndPos.length-1] = nFileLength; +4Q[N;[+*  
} ugno]5Ni  
} pjACFVMFX  
zt?h^zf}  
0A.PD rM:  
//启动子线程 2xDQ :=ec  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; J==}QEhQ{  
for(int i=0;i<nStartPos.length;i++) ?FN9rhAC  
{ j~epbl)pC  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0{Bf9cH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), _74UdD{^o  
nStartPos,nEndPos,i); m=H_?W;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Vn'?3Eb<  
fileSplitterFetch.start(); P@C c]Z  
} `mrCu>7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |"Z-7@/k$i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); D ZVXz|g  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3)Zu[c[%'J  
nEndPos = " + nFileLength); Vb2\/e:k  
// fileSplitterFetch[nPos.length-1].start(); ZW>o5x__b  
4Q;<Q"  
Rs2-94$!5  
//等待子线程结束 M+0x;53nz  
//int count = 0; wazP,9W?  
//是否结束while循环 Wm(:P  
boolean breakWhile = false; 6+iK!&+=  
n'yl)HA~>`  
8)pB_en3sO  
while(!bStop) L?HF'5o  
{ `_GO=QQ  
write_nPos(); ilv_D~|  
Utility.sleep(500); >Fyu@u  
breakWhile = true; vO]J]][  
'*4iqP R;  
MI\]IQU  
for(int i=0;i<nStartPos.length;i++) )A"jVQjI%w  
{ PK+ x6]x  
if(!fileSplitterFetch.bDownOver) &U&Zo@ot"x  
{ (xL :;  
breakWhile = false; ailG./I+  
break; +#~O'r]%GG  
} j{)~QD?  
} jB!W2~Z  
if(breakWhile) ZOuR"9]  
break; eQ<xp A  
OF8WDo`  
HyEa_9  
//count++; "R23Pi  
//if(count>4) i j/o;_  
// siteStop(); _dr*`yXi  
} 3za`>bUN  
E67XPvo1+@  
MKC$;>i  
System.err.println("文件下载结束!"); 7/?DPwbx  
} :G}DAUFN  
catch(Exception e){e.printStackTrace ();} tq&Yek>C  
} vL$|9|W(  
IcFK,y%1  
"y$ qrN-  
//获得文件长度 ^wJEfac  
public long getFileSize() )|RZa|`-G  
{ p![&8i@ym  
int nFileLength = -1; vU}: U)S  
try{ $6!i BX@  
URL url = new URL(siteInfoBean.getSSiteURL()); j=W@P-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C`0%C7  
httpConnection.setRequestProperty("User-Agent","NetFox"); |{f~Ks%  
P>wZ~Hjk  
#h N.=~  
int responseCode=httpConnection.getResponseCode();  2:'lZQ  
if(responseCode>=400) BC({ EE~R)  
{ DWrbp  
processErrorCode(responseCode); g/#~N~&  
return -2; //-2 represent access is error YBvd q1  
} ~KRnr0  
q 5p e~  
E0YU[([G  
String sHeader;  eu9w|g  
X`1p'JD  
Q>=-ext}q  
for(int i=1;;i++) *H" aOT^{  
{ fK_~lGY(  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ;Iq5|rzDn  
//Utility.log(in.readLine()); K_#UZA< Y  
sHeader=httpConnection.getHeaderFieldKey(i); [))JX"a  
if(sHeader!=null) _2OuskL  
{ W 2<3C  
if(sHeader.equals("Content-Length")) K/|  
{ .&iN(Bd  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); A"4@L*QV  
break; #ZWl=z5aBi  
} <KLg0L<W  
} p=B?/Sqa  
else y(v_-6b  
break; ao$):,2*  
} q- :4=vkn  
} yW("G-Nm  
catch(IOException e){e.printStackTrace ();} d}-'<Z#G  
catch(Exception e){e.printStackTrace ();} `W"G!X-  
j#3m|dQ  
7Z0/(V.-  
Utility.log(nFileLength); }g{_AiP rv  
S+ebO/$>  
b_vTGl1_6  
return nFileLength; 3dG4pl~  
} g 1@wf  
bSrZ{l  
jNc<~{/  
//保存下载信息(文件指针位置) GNU;jSh5  
private void write_nPos() s;1e0n  
{ sPCMckt  
try{ |>2: eH  
output = new DataOutputStream(new FileOutputStream(tmpFile)); CH;;V3  
output.writeInt(nStartPos.length); _~A~+S}  
for(int i=0;i<nStartPos.length;i++) DYRE1!  
{ A1-qtAO]  
// output.writeLong(nPos); _z8;lt   
output.writeLong(fileSplitterFetch.nStartPos); 0 d4cE10  
output.writeLong(fileSplitterFetch.nEndPos); 85z;Zt0{  
} Tpzw=bC^  
output.close(); Rd%0\ B  
} KlU qoJ;"  
catch(IOException e){e.printStackTrace ();} 9j#@p   
catch(Exception e){e.printStackTrace ();} 4j3oT)+8  
} ?"j@;/=  
9":2"<'+  
#ElejQ|?  
//读取保存的下载信息(文件指针位置) u D(t`W"  
private void read_nPos() VAKy^nR5j  
{ FkB{ SC J  
try{ 1;Xgc@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); m r4b  
int nCount = input.readInt(); +(mL~td01  
nStartPos = new long[nCount]; dJl^ADX[@  
nEndPos = new long[nCount]; ({M?Q>s  
for(int i=0;i<nStartPos.length;i++) [ H,u)8)  
{ !8$RBD %  
nStartPos = input.readLong();  YqU/\f+  
nEndPos = input.readLong(); JJ5C}`(  
} f1Zt?=  
input.close(); kCA5|u  
} cNj*E =~;  
catch(IOException e){e.printStackTrace ();} wL2XNdo}<  
catch(Exception e){e.printStackTrace ();} 'ere!:GJD  
} ' msmXX@q  
KzVTkDn,  
2OalAY6RS  
private void processErrorCode(int nErrorCode) J#7y< s  
{ @!\K>G >9[  
System.err.println("Error Code : " + nErrorCode); -0 0}if7  
} GZ8:e3ri  
I7mG/  
%-j&e44  
//停止文件下载 gj+3y9  
public void siteStop() I/B1qw;MN  
{ xK;e\^v  
bStop = true; XP;x@I#l  
for(int i=0;i<nStartPos.length;i++) ~>%DKJe  
fileSplitterFetch.splitterStop(); Zq*eX\#C  
3k' .(P|F  
A1A3~9HuK  
} aws"3O% uW  
} .7Kk2Y  
//负责部分文件的抓取 A}G|Yfn  
**FileSplitterFetch.java E*|tOj9`1n  
*/ Q)^g3J  
package NetFox;  .mPg0  
x~/+RF XF  
onl>54M^  
import java.io.*; f0oek{  
import java.net.*; ^\wl2  
inF6M8 A1  
A/ 0qk  
public class FileSplitterFetch extends Thread { J_ J+cRwq  
[xdj6W  
\##`pa(8  
String sURL; //File URL +v15[^F  
long nStartPos; //File Snippet Start Position  Q2\  
long nEndPos; //File Snippet End Position $(q8y/,R*-  
int nThreadID; //Thread's ID G;]:$J  
boolean bDownOver = false; //Downing is over _N'75  
boolean bStop = false; //Stop identical VzwPBQ -  
FileAccessI fileAccessI = null; //File Access interface @2' %o<lF  
(ZPXdr  
jJ++h1 K  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Z$;"8XUM  
{ F~_;o+e;X  
this.sURL = sURL; ^?"^Pmw  
this.nStartPos = nStart; zk=\lp2  
this.nEndPos = nEnd; r4;Bu<PQN1  
nThreadID = id; !T'X 'Q  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 nq;#_Rkr  
} 7Dt"]o"+  
wUp)JI  
P*G+eqX  
public void run() r4eUZ .8R  
{ *gu8-7'  
while(nStartPos < nEndPos && !bStop) RJc%, ]:  
{ X+ f9q0  
i'tp1CI  
SRz&Nb  
try{ TzM=LvA  
URL url = new URL(sURL); 77Q}=80GU;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (0jr;jv  
httpConnection.setRequestProperty("User-Agent","NetFox"); #":a6%0Q  
String sProperty = "bytes="+nStartPos+"-"; 7 g6RiH}  
httpConnection.setRequestProperty("RANGE",sProperty); 59!)j>f  
Utility.log(sProperty); [7W(NeMk  
\&q=@rJp(z  
_CdROo6I  
InputStream input = httpConnection.getInputStream(); {}\CL#~y  
//logResponseHead(httpConnection); GLh]G(  
b!a %YLL  
^M Ey,  
byte[] b = new byte[1024]; BaL]mIx  
int nRead; T1N H eH>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) v>-Y uS  
{ 1dv=xe.  
nStartPos += fileAccessI.write(b,0,nRead); ')o0O9/;  
//if(nThreadID == 1) 3Gd0E;3sk~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I@./${o  
} >XE`h 9  
BGqa-d  
CC8k&u,  
Utility.log("Thread " + nThreadID + " is over!"); aRwnRii  
bDownOver = true; {Y_Nj`#BT  
//nPos = fileAccessI.write (b,0,nRead); (9GbG"   
} ./w{L"E  
catch(Exception e){e.printStackTrace ();} Hj~O49%j&  
} 9<cOYY  
} jXR16|  
^ d\SPZ  
/V^sJ($V$~  
//打印回应的头信息 "ahvNx;x  
public void logResponseHead(HttpURLConnection con) }kPVtSQ  
{ ;CmOsA,1  
for(int i=1;;i++) E`xU m9F  
{ dlD}Ub  
String header=con.getHeaderFieldKey(i); :p-Y7CSSu  
if(header!=null) iJP{|-h  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Z"tQp Jg  
Utility.log(header+" : "+con.getHeaderField(header)); qrDcL>Hrn  
else T[2}p=<%  
break; 3j*'HST  
} 3{3/: 7  
} ` clB43 i  
.~`Y)PON  
! F7:i  
public void splitterStop() )N)ljA3]  
{ rYGRz#:~+  
bStop = true; hKksVi  
} 4vqNule  
C1QWU5c v  
j>!sN`dBj  
} Kbas-</Si  
\"d?=uFe  
?}sOG?{  
/* o#e7,O  
**FileAccess.java j'Wp  
*//文件访问(定位,写) &;v!oe   
package NetFox; ;BI)n]L  
import java.io.*; YzV(nEW  
K0<yvew  
x!?Z *v@I  
public class FileAccessI implements Serializable{ M 9"-WIG@h  
2Xgx*'t\  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 NG9vml  
RandomAccessFile oSavedFile; d@g2k> >  
long nPos; 0w3b~RJ  
0&$xX!]  
Gvn: c/m;  
public FileAccessI() throws IOException =|0/Ynfe  
{ l0`'5>  
this("",0); dS$ji#+d$  
} QymD-A"P  
O71BM@2<  
%fpsc _  
public FileAccessI(String sName,long nPos) throws IOException \!wh[qEQ\  
{ `Bu9Nq  
oSavedFile = new RandomAccessFile(sName,"rw"); EcW1;wH  
this.nPos = nPos; *V|zx#RN  
oSavedFile.seek(nPos); p7UTqKi  
} @L;C_GEa  
XS|mKuMc C  
v3^t/[e~:  
public synchronized int write(byte[] b,int nStart,int nLen) H[BYE  
{ C*G/_`?9  
int n = -1; MPvWCPB  
try{ qGa<@ b  
oSavedFile.write(b,nStart,nLen); KjYDFrR4  
n = nLen; ,?y7 ,nb  
} HRHrSf7  
catch(IOException e) D rTM$)  
{ c[{UI  
e.printStackTrace (); a: IwA9!L  
} ,n5a])Dg  
gj;@?o0  
wOcg4HlW  
return n; )E`+BH  
} oKiD8':  
q?i Cc c  
!4B_$6US  
} o2}N=|&  
xBWx+My  
i+AUQ0Zbf6  
/* [q$e6JwAt  
**SiteInfoBean.java pqq?*\W&[v  
*/ \HG$V>2  
package NetFox; s##Ay{  
]ymC3LV]  
.K7C-Xn=  
public class SiteInfoBean { 6Ahr_{  
7TdQRB  
6 [ _ fD  
private String sSiteURL; //Site's URL Ilef+V^qr  
private String sFilePath; //Saved File's Path p`p?li  
private String sFileName; //Saved File's Name k<O y%+C  
private int nSplitter; //Count of Splited Downloading File %M6 c0d[9-  
C8MWIX}  
jGiw96,Y  
public SiteInfoBean() 4:`[qE3  
{//nSplitter的缺省值为5 raHVkE{<  
//default value of nSplitter is 5 2Oi'E  
this("","","",5); m&cvU>lC  
} >Bx8IO1_\d  
5Hy3\_ +  
>[P%Ty);  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) l/F!Bq[*g  
{ -lnevrl   
sSiteURL= sURL; +"Ub/[J{G1  
sFilePath = sPath; 0BDoBR  
sFileName = sName; cz>mhD  
this.nSplitter = nSpiltter; J {!'f| J  
|h D~6a  
cIZ[[(Db  
} ]b )!YPo  
D O%Pwfkd  
, QA9k$`  
public String getSSiteURL() ifHU|0_=  
{ sW'6} ^Q  
return sSiteURL; )-#i8?y3C  
} `:gYXeR  
yU!GS-  
{\Ys@FF  
public void setSSiteURL(String value) @E(P9zQ/zy  
{ V" }*"P-%  
sSiteURL = value; %r P !  
} WP!il(Gr  
x97H(*  
wo]ks}9  
public String getSFilePath() oX*b<d{\N  
{ Y2D >tpqNw  
return sFilePath; [%? hCc  
} sL8>GtVo  
GVZTDrC  
"?[7#d])  
public void setSFilePath(String value) -U:2H7  
{ {s9<ej~<R  
sFilePath = value; \H[Yyp4  
} d QDLI  
>qn+iI2U  
 RY9. n  
public String getSFileName() Z:TFOnJ  
{ S[ ^nSF  
return sFileName; fOLnK y#  
} W W35&mI)k  
F#KF6)P  
[brkx3h  
public void setSFileName(String value) UT~4Cfb  
{ `xGT_0&ck  
sFileName = value; @Rf^P(  
} tbS#^Y  
_E (x2BS?  
tStJ2-5*t  
public int getNSplitter() V4Qz*z%  
{ DEcGFRgN~  
return nSplitter; ILNXaJ'0a  
} 5E0wn'  
)Z&HuEg{ZR  
_C5nApb  
public void setNSplitter(int nCount) e]Puv)S>{8  
{ x?gQ\ 0S<  
nSplitter = nCount; m'c#uU  
} d#4Wj0x  
} L@+Z)# V  
eq{ [?/  
) u-ns5  
/* py=i!vb&Z%  
**Utility.java xmOM<0T  
*/ 1j+eD:d'  
package NetFox; \:h0w;34O  
4NJVW+:2  
88#N~j~P  
public class Utility { OFp#<o,p  
$8=(I2&TW  
my]P_mE  
public Utility() hj+p`e S  
{ :Fc8S9  
N7a[B>+`  
51z/  
} 3#B@83C0Z  
fH; |Rm  
//线程睡眠 t={poQC~  
public static void sleep(int nSecond) +<z7ds{Z  
{ $Q=$?>4U  
try{ :ET x*c  
Thread.sleep(nSecond); 8pd&3G+  
} k~& o  
catch(Exception e) *XHj)DC;  
{ L-j/R1fTvl  
e.printStackTrace (); G%Y*q(VrEu  
} \_?yzgf  
} pTN%;`) {  
xS-w\vbLV  
//日志 b#e]1Q  
public static void log(String sMsg) @PKAz&0  
{ \6U 2-m'  
System.err.println(sMsg); UC.8DaIPN  
} DhHtz.6  
N-Qu/,~+  
x4@MO|C  
public static void log(int sMsg) 6<#Slw[  
{ Oxpo6G  
System.err.println(sMsg); 58 kv#;j  
} 2lF WW(  
} A(PE  
n&(3o6i'  
0= 2H9v  
/* IcRM4Ib))Q  
**TestMethod.java 87R%ke  
*/ cl ?< 7  
package NetFox; =7#u+*Yr9  
W31LNysH!;  
BEFe~* ~  
public class TestMethod {  PE^eP}O1  
uQO(?nCi  
/@6E3lh S  
public TestMethod() P>>f{3e.  
{ ///xx/weblogic60b2_win.exe y|$vtD%c  
try{ m9 ^m  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); SlR7h$r'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?56~yQF/2  
SiteFileFetch fileFetch = new SiteFileFetch(bean); |C^ c0  
fileFetch.start(); tWcizj;?wK  
} ^ sS>Mts  
catch(Exception e){e.printStackTrace ();} w{RNv%hJ$=  
r4;^c}  
"0!~g/X`rK  
} dBsRm{aS  
*sjj"^'=  
HI}pX{.\  
public static void main(String[] args) Z3OZPxm  
{ ,xm;JXJ  
new TestMethod(); )-MA!\=<  
} }_Tt1iai*  
} IvY,9D  
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