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http断点续传简单实现(java)

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/* rF:l+I]  
**SiteFileFetch.java RX cfd-us  
*/ -nL!#R{e  
package NetFox; Dx*tolF  
import java.io.*; !=B=1th4  
import java.net.*; S4!}7NOh  
tT`{xM  
D3 .$Vl,.  
public class SiteFileFetch extends Thread { G1?m}{D)  
7+c}D>/`:  
EjjW%"C,  
SiteInfoBean siteInfoBean = null; //文件信息Bean 1(4}rB3  
long[] nStartPos; //开始位置 hVLV Mqd  
long[] nEndPos; //结束位置 0V!@*Z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 1m\ihU  
long nFileLength; //文件长度 p8bAz  
boolean bFirst = true; //是否第一次取文件 |3K]>Lio  
boolean bStop = false; //停止标志 y=k!>Y|E  
File tmpFile; //文件下载的临时信息 -q")qNt.  
DataOutputStream output; //输出到文件的输出流 1!"iN~  
_2 Hehw  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) YX,xC-37y  
public SiteFileFetch(SiteInfoBean bean) throws IOException pY"&=I79tb  
{ &3~_9+  
siteInfoBean = bean; zYZ^/7)  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^3 6oqe{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); hI}rW^o^  
if(tmpFile.exists ()) $:!L38[7$  
{ 0WO-+eRB/  
bFirst = false; )>+J`NFa  
read_nPos(); _Y 8RP%  
} {u@w^ hZ$  
else ^>/] Qi  
{ u[b0MNE~  
nStartPos = new long[bean.getNSplitter()]; Hr}pO"%  
nEndPos = new long[bean.getNSplitter()]; zLS=>iLD{  
} rpn&.#KS  
-D^.I  
rd hM#?  
K=Y{iHn  
} 9|5>?'CqP  
*If ]f0?%  
g(-}M`  
public void run() ;: 4PT~\*  
{ |*te69RX  
//获得文件长度 nZP%Z=p7  
//分割文件 3uJ>:,~r  
//实例FileSplitterFetch =c Krp'  
//启动FileSplitterFetch线程 T.B} k`$  
//等待子线程返回 *R8qnvE\()  
try{ I?#B_R#  
if(bFirst) DFN  
{ "Wz74ble  
nFileLength = getFileSize();  FtmI\,  
if(nFileLength == -1) H;kk:s'  
{ @(I)]Ca%O  
System.err.println("File Length is not known!"); snti*e4"V  
} Ua\<oD79]  
else if(nFileLength == -2) yIG*  
{ 0OF]|hH  
System.err.println("File is not access!"); nA 5-P}  
} l~j{i/>  
else OdHl)"#  
{ `bMwt?[*  
for(int i=0;i<nStartPos.length;i++) S/H!a:_5r  
{ QbG`F8dj  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); }v$T1Cw  
} 8B"my\  
for(int i=0;i<nEndPos.length-1;i++) |p"4cG?)  
{ M F_VMAq  
nEndPos = nStartPos[i+1]; 5l,Q=V^@l  
} yE>f.|(  
nEndPos[nEndPos.length-1] = nFileLength; $,DX^I%!  
} 0{zA6Xu  
} +E8}5pDt  
e_z"<yq  
^ e4y:#Nu  
//启动子线程 IP-}J$$1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; jSMs<ox  
for(int i=0;i<nStartPos.length;i++) [X=J]e^D  
{ ;&?l1Vu  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^iz2 =}Q8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), w/Ej>OS  
nStartPos,nEndPos,i); h& Q9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O({vHqN>  
fileSplitterFetch.start(); HS[N]'dc  
} t]PO4GA  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), UCDvN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]CZ&JL  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ZW>?y$C+  
nEndPos = " + nFileLength); {H$m1=S  
// fileSplitterFetch[nPos.length-1].start(); BBUXoz  
i=DoK{`L  
8"2X 8C8  
//等待子线程结束 .p d_SQ~  
//int count = 0; L7 f'  
//是否结束while循环 Wzx Dnd<B  
boolean breakWhile = false; 50J"cGs~  
Q?"-[6[v  
@o6^"  
while(!bStop) 53jtwklA  
{ o;<oXv  
write_nPos(); Xh*p\ $  
Utility.sleep(500); n]]!:jFC  
breakWhile = true; ;zZGV4Qc~  
FdVWj 5 $a  
+5C*i@v  
for(int i=0;i<nStartPos.length;i++) )Og,VXEB  
{ '@Q aeFm  
if(!fileSplitterFetch.bDownOver) oP( Hkp,'  
{ ee5QZ,  
breakWhile = false; 8`j;v>2  
break; l: X]$2;  
} u%`4;|tI  
} 8E9W\@\  
if(breakWhile) 2(Ez H  
break; _O*"_^6  
@vcvte  
Tl ?]K  
//count++; 2~BId&]  
//if(count>4) 3cztMi  
// siteStop(); <u9U%V si  
} %}%vey  
d,0Yi u.p  
Mb#-I GZ  
System.err.println("文件下载结束!"); l<l6Ey(  
} eE'2B."F  
catch(Exception e){e.printStackTrace ();} =5yI>A0  
} kb>/R/,9  
gbJz5EEq  
]\Tcy[5  
//获得文件长度 U]h5Q.<SG  
public long getFileSize() L8zY?v(bG  
{ ?MhY;z`=  
int nFileLength = -1; |Skxa\MI  
try{ #[a+m  
URL url = new URL(siteInfoBean.getSSiteURL()); 8`/nk `;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (!^(74  
httpConnection.setRequestProperty("User-Agent","NetFox"); ua -cX3E  
(8*& 42W  
G()- NJ{  
int responseCode=httpConnection.getResponseCode(); aH1mW;,1u  
if(responseCode>=400) RW@sh9  
{ k 8Swra?j  
processErrorCode(responseCode); k!lz_Y  
return -2; //-2 represent access is error /o19/Pvwm  
} kN)m"}gX  
=os%22*  
UEvRK?mm=  
String sHeader; J}-,!3qxW  
!a[1rQH  
Yy"05V.  
for(int i=1;;i++) ^|(w)Sy  
{ -$]Tn#`Fb  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ?r,lgaw  
//Utility.log(in.readLine()); D%0GXUp  
sHeader=httpConnection.getHeaderFieldKey(i); )D:I@`*  
if(sHeader!=null) N}*|*!6hI  
{ K] ^kUN_  
if(sHeader.equals("Content-Length")) M)U 32gI:  
{ x@I(G "  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); U&D"fM8  
break; _"PT O&E  
} h>6'M  
} $Qv+*%c  
else H?P:;1A]c  
break; C NNyz$  
} mGXjSWsd  
} ^]$x/1I;  
catch(IOException e){e.printStackTrace ();} kphv)a4z=  
catch(Exception e){e.printStackTrace ();} ( *(#;|m  
^fLePsmd  
\wxS~T<&L  
Utility.log(nFileLength); ]Xur/C2A  
R18jju>Zr  
;^Vsd\ac0  
return nFileLength; K>h=  
} 8gv \`  
!`k{Ga  
T'cahkSw'O  
//保存下载信息(文件指针位置) T #&9|  
private void write_nPos() `o 6Hm  
{ ;R E|9GR  
try{ `5[d9z/6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); HXTBxh  
output.writeInt(nStartPos.length); (I d]'w4  
for(int i=0;i<nStartPos.length;i++) af61!?K  
{ ey@]B5  
// output.writeLong(nPos); DHO6&8S  
output.writeLong(fileSplitterFetch.nStartPos); 9=j"kXFf  
output.writeLong(fileSplitterFetch.nEndPos); 2NLD7A  
} ^G+1nY4? J  
output.close(); :!M/9D*}0  
} 2<Tbd"x?  
catch(IOException e){e.printStackTrace ();} z O  
catch(Exception e){e.printStackTrace ();} 8I)66  
} c|lo%[]R!  
; /fZh:V2  
GNzk Vy:u  
//读取保存的下载信息(文件指针位置) yVvO!  
private void read_nPos() [a;U'v*  
{ J~6+zBF  
try{ Vf#X[$pc/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); W>Eee?  
int nCount = input.readInt(); #YM5P  
nStartPos = new long[nCount]; njveZav  
nEndPos = new long[nCount]; r^mP'#  
for(int i=0;i<nStartPos.length;i++) 8,pnm  
{ hBf0kl  
nStartPos = input.readLong(); l+'@y (}Q  
nEndPos = input.readLong(); K14e"w%6rs  
} .(OFYK<  
input.close(); Gpws_ jw  
} $DZ\61  
catch(IOException e){e.printStackTrace ();} 2r2qZ#I}  
catch(Exception e){e.printStackTrace ();} 05mjV6j7m  
} 0b9;v lGq$  
PpD ?TAlA  
nc#}-}`5  
private void processErrorCode(int nErrorCode) vT V'D&x2  
{ 3%Z:B8:<y  
System.err.println("Error Code : " + nErrorCode); tr6<89e(o  
} r#^/qs(~  
{ as#lHn  
PG<tic<?  
//停止文件下载 [R[]&\W  
public void siteStop() n 0_q-8r  
{ R _WP r[P  
bStop = true; C fKvC  
for(int i=0;i<nStartPos.length;i++) (+d7cln  
fileSplitterFetch.splitterStop(); +85i;gO5  
=m.Lw  
FUic7>  
} =T'N6x5@  
} nqNL[w6{  
//负责部分文件的抓取 *HFRG)[V  
**FileSplitterFetch.java q~68)D(  
*/ CM+Nm(|\,  
package NetFox; K,{P b?  
'M>QA"*48E  
LeDty_  
import java.io.*; 3-z; pk  
import java.net.*; ]z EatY  
1*\JqCR  
p R=FH#  
public class FileSplitterFetch extends Thread { 9P;}P! W  
e^)+bmh  
N t]YhO  
String sURL; //File URL k%|7H,7  
long nStartPos; //File Snippet Start Position *Y"Kbn 6  
long nEndPos; //File Snippet End Position o2  
int nThreadID; //Thread's ID XKD0n^L[  
boolean bDownOver = false; //Downing is over h.PVRAwk  
boolean bStop = false; //Stop identical 36mp+}R#  
FileAccessI fileAccessI = null; //File Access interface We&~]-b AW  
(jbHV.]P9  
oc+TsVt  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException h>AK^fX  
{ F?#^wm5TZ  
this.sURL = sURL; 6-8,qk  
this.nStartPos = nStart; K.s\xA5`_  
this.nEndPos = nEnd; qdkhfm2(K  
nThreadID = id; Bw _^"e8X  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 'B dZN  
} &[u%ZL  
U$+EUDFi3_  
77D>;90>?  
public void run() jFbj)!;  
{ H9}z0VI  
while(nStartPos < nEndPos && !bStop) ;}v#hKC~  
{ "M#A `b  
jdz]+Q`jq  
86pujXjc'  
try{ m)l<2 `CM  
URL url = new URL(sURL); B:Y"X:Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O@*^2, 6  
httpConnection.setRequestProperty("User-Agent","NetFox"); oasp/Y.p  
String sProperty = "bytes="+nStartPos+"-"; |>_e& }Y%L  
httpConnection.setRequestProperty("RANGE",sProperty); \*x'7c/qg  
Utility.log(sProperty); rCt8Q&mzf  
i\~@2  
3@#WYvD  
InputStream input = httpConnection.getInputStream(); Er /:iO)_  
//logResponseHead(httpConnection); :;Z?2P5i  
D d['e  
*AK{GfP_  
byte[] b = new byte[1024]; ]fxYS m  
int nRead; !1G6ZC:z  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) L@9@3?  
{ og0su  
nStartPos += fileAccessI.write(b,0,nRead); \ZNUt$\  
//if(nThreadID == 1) `sW+R=  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zt&"K0X|  
} /e|vz^#+1,  
X5[.X()M4  
v\&C]W]  
Utility.log("Thread " + nThreadID + " is over!"); %?<Y&t  
bDownOver = true; D,R"P }G  
//nPos = fileAccessI.write (b,0,nRead); >3aB{[[N  
} \ @XvEx%  
catch(Exception e){e.printStackTrace ();} B^|^hZZ>  
} vndD#/lXq  
} CMu/n]?c  
ckDWY<@v  
t`F<lOKj  
//打印回应的头信息 >|j8j:S[  
public void logResponseHead(HttpURLConnection con) i|N%dl+T=  
{ :$k] ;  
for(int i=1;;i++) l!S}gbM  
{ Bs?B\k=  
String header=con.getHeaderFieldKey(i); eKpWFP 0  
if(header!=null) i&K-|[3{g  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4~8!3JH39  
Utility.log(header+" : "+con.getHeaderField(header)); Dk ^,iY(u  
else su2|x  
break; E4}MU}C#[  
} 2!@ER i  
} hYvWD.c}  
]lQLA IQ  
A^L8"  
public void splitterStop() py-5 :g}d  
{ n1Ic[cM}  
bStop = true; #_(t46  
} @%"+;D  
3lh^maQ]  
M\m6|P  
} ,a6Oi=+>/U  
b=87k  
9nGS"E l{  
/* PiL[&_8g  
**FileAccess.java Hl|EySno  
*//文件访问(定位,写) w'i8yl bZ  
package NetFox; {OIktG2gZ  
import java.io.*; {tKi8O^Rb  
%[l#S*)~  
TyGsSc  
public class FileAccessI implements Serializable{ \I-bZ|^  
n0 q$/Y.  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Jxo#sV-  
RandomAccessFile oSavedFile; U"T>L  
long nPos; s[dq-pc "  
+.3,(l  
a_V.mu6h6p  
public FileAccessI() throws IOException S\jIs[Dz  
{ 9coN >y  
this("",0); }57d3s  
} bVgmjt2&>  
#Y_v0.N  
E9N.b.Q)  
public FileAccessI(String sName,long nPos) throws IOException *B*dWMh  
{ -|cB7 P  
oSavedFile = new RandomAccessFile(sName,"rw"); !'5t(Zw5  
this.nPos = nPos; ^U;r>[T9h  
oSavedFile.seek(nPos); f53WDI6  
} eVvDis  
h 0c&}kM  
-~+Y0\%E  
public synchronized int write(byte[] b,int nStart,int nLen) a +lTAe  
{ @%[ dh@oY  
int n = -1; 0}4FwcCr\  
try{ 8GKqPS+  
oSavedFile.write(b,nStart,nLen); du5|/  
n = nLen; u27*-X 5  
} BpR#3CfW  
catch(IOException e) )4O* D92  
{ <#ZDA/G(  
e.printStackTrace (); A5q%yt I  
} C< B1zgX  
|M$ESj4@  
w+Oo-AGNH  
return n; {8im{]8_  
} J_@`:l0,z  
N*{>8iFo4  
R64/m9  
} 7nl  
;=i$0w9W  
-egu5#d>  
/* VGL!)1b  
**SiteInfoBean.java l(A>Rw|  
*/ @FLa i  
package NetFox; ];U}'&  
JQO%-=t  
) mG  
public class SiteInfoBean { Xxmvg.Nl  
OE8H |?%  
^(.utO  
private String sSiteURL; //Site's URL #- z(]Y,y  
private String sFilePath; //Saved File's Path ;e#bl1%#  
private String sFileName; //Saved File's Name no UXRQ  
private int nSplitter; //Count of Splited Downloading File 8 aC]" C  
qJ5gdID1_  
*<IQ+oat,a  
public SiteInfoBean() U66}nN9  
{//nSplitter的缺省值为5 Y)KO*40c  
//default value of nSplitter is 5 R1/87eB  
this("","","",5); > Du>vlT Y  
} 'i7!"Y6>  
?5Ub&{  
c&>==pI]k  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >XomjU[srQ  
{ V+MhS3VD  
sSiteURL= sURL; 1}DUe. a  
sFilePath = sPath; >G<.^~o  
sFileName = sName; ,].S~6IM  
this.nSplitter = nSpiltter; 1v"r8=Wt  
\*x=q20  
=2tl149m/z  
} uJ_"gPO  
6~y7A<[^  
w@Gk#  
public String getSSiteURL() :d`8:gv?  
{ KGq4tlM6  
return sSiteURL; P6([[mmG  
} 3^%sz!jK+  
h8-'I= ~  
-_xC,dwK  
public void setSSiteURL(String value) ;d{lvKk  
{ h 1 `yW#%  
sSiteURL = value; t1%<l  
} Q"QL#<N  
_>)=c<HL  
z;KUIWg  
public String getSFilePath() v:w $l{7  
{ =^D{ZZw{  
return sFilePath; oEuo@\U05v  
} /`YbHYNF[  
8C4 =f  
O,A}p:Pgs  
public void setSFilePath(String value) l0g`;BI_  
{ Da WzQe=  
sFilePath = value; /c9%|<O%  
} 1WbawiG}  
J"W+9sI0  
J`@#yHL  
public String getSFileName() R$xkcg2(  
{ {V*OYYI`R  
return sFileName; k w]m7 T  
} eH y.<VX  
i<]Y0_?s  
#&jr9RB  
public void setSFileName(String value) 9'S~zG%{  
{ 4t;m^Iv  
sFileName = value; d;c<" +  
} kn1+lF@  
A_\ZY0Xt  
sJ(q.FRM'  
public int getNSplitter() A[.5Bi  
{ ?=lnYD j  
return nSplitter; ;N/=)m  
} !s:v UY58  
H%:u9DlEK/  
<(<19t5.  
public void setNSplitter(int nCount) fqgm`4>  
{ 6opu bI<  
nSplitter = nCount; <0hJo=6a8  
} uY5Gn.Y  
} S.kFs{;1x  
d PfD Pb  
N;BS;W5I  
/* raPUx_$PH  
**Utility.java 9&t!U+  
*/ ;"@FLq(n  
package NetFox; bk#t+tuk  
D@yuldx'/  
8*V8B=q}K  
public class Utility { uVBMI.&w  
l8_TeO  
^"Nsb&  
public Utility() 1q[vNP=g&  
{ ;<yVJox  
.$,.w__m ~  
m#oZu {  
} I;!zZ.\  
jt/ |u=  
//线程睡眠 RL;>1Q,H  
public static void sleep(int nSecond) _Di}={1[.  
{ {lhdropd  
try{ D|Tv`47ntu  
Thread.sleep(nSecond); !"Q8KV  
} `Y`QxU!d%  
catch(Exception e) pdrF/U+  
{ L'JEkji"  
e.printStackTrace (); 7v~\c%1V  
} F ;m1I+;  
} I@f">&^  
Cl+TjmOV\`  
//日志 #VwA?$4g`  
public static void log(String sMsg) q;kN+NK64  
{ Wo^r#iRko  
System.err.println(sMsg); vG<JOxP  
} >iCkvQ  
Qs*6wF  
M!s@w%0?'  
public static void log(int sMsg) rl,6r u  
{ ]o(&J7Z6-  
System.err.println(sMsg); zJfoU*G/B  
} TZ7{cekQ  
}  t : =  
"lp),  
fi[c^e+IX  
/* O_p:`h:;M  
**TestMethod.java "DFj4XKXY9  
*/ tN5brf  
package NetFox; Rp2~d  
FJN,er~T[  
!0g+}  
public class TestMethod { 9K8f ##3  
Ge|& H]W  
1{ -W?n  
public TestMethod() _cZ`7 ]Z  
{ ///xx/weblogic60b2_win.exe s'V8PN+-  
try{ :95wHmk  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %rQ5 <U  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $FgpFxz;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Z:#-4CiP  
fileFetch.start(); C/Ig.KmXF{  
} ({cgak  
catch(Exception e){e.printStackTrace ();} "mA Vkq~  
N>OF tP  
nFl=D=50-  
} AcN~Q/xU  
bl>MD8bzLE  
Qr;es,f  
public static void main(String[] args) "Yn <]Pa_  
{ 62}bs/%  
new TestMethod(); &Z+a (  
} )>ed6A1  
} [|2uu."$  
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