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http断点续传简单实现(java)

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/* z%}"=  
**SiteFileFetch.java Ar%*NxX  
*/ qnP4wRpr  
package NetFox; $QiMA,  
import java.io.*; p{E(RsA  
import java.net.*; U6JD^G=qR,  
?V`-z#y7  
3W'fEh5  
public class SiteFileFetch extends Thread { U&3!=|j  
Y{dSQ|xz^  
C|y^{4 |R  
SiteInfoBean siteInfoBean = null; //文件信息Bean 'iMzp]V;  
long[] nStartPos; //开始位置 9/"&6,  
long[] nEndPos; //结束位置 c!@|y E,  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 x8lBpr  
long nFileLength; //文件长度 ~&:-c v  
boolean bFirst = true; //是否第一次取文件 \3vQXt\dM$  
boolean bStop = false; //停止标志 A!Tl  
File tmpFile; //文件下载的临时信息 v&:[?<6-  
DataOutputStream output; //输出到文件的输出流 'D W|a  
g}~s"Sz  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) bK "I9T #  
public SiteFileFetch(SiteInfoBean bean) throws IOException zlLZ8b+  
{ 3Ei^WDJ  
siteInfoBean = bean; sI\NX$M  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); C6ql,hR^h`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Gs#9'3_U5  
if(tmpFile.exists ()) \J:+Wl.9A  
{ k4#j l<R  
bFirst = false; gj;gl ="3  
read_nPos(); f@sC~A. 9\  
} - ~z@W3\  
else V@0T&#  
{ .XgY&5Qk  
nStartPos = new long[bean.getNSplitter()]; ^E%R5JN  
nEndPos = new long[bean.getNSplitter()]; Y6wr}U  
} $mxG-'x%K  
:{<|,3oNdR  
J_F\cM   
Ry[7PLn]  
} #>yOp *  
D[^K0<-Z  
i~x]!!  
public void run() EG4~[5[YgI  
{ `n,RC2yo  
//获得文件长度 5kqI  
//分割文件 G5hRx@vfrL  
//实例FileSplitterFetch `K VSYC  
//启动FileSplitterFetch线程 QXj#Brp  
//等待子线程返回 n\9IRuYO  
try{ l&\y]ZV={  
if(bFirst) .XpuD,^;@  
{ 6O?zi|J[:  
nFileLength = getFileSize(); x`?>j$  
if(nFileLength == -1) sssw(F  
{ &NF$_*\E  
System.err.println("File Length is not known!"); z*HM_u  
} )4fQ~)  
else if(nFileLength == -2) %nJo:/  
{ dr#%~I  
System.err.println("File is not access!"); *~U*:>hS  
} y ;mk]  
else uznqq}  
{ }#g]qK  
for(int i=0;i<nStartPos.length;i++) OGEe8Z9Jt  
{ <uU<qO;6  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @n qM#  
} O<fy^[r:`  
for(int i=0;i<nEndPos.length-1;i++) ]9_tto!/  
{ bD)"Jy  
nEndPos = nStartPos[i+1]; 0x*1I1(c  
} q1 HJ_y  
nEndPos[nEndPos.length-1] = nFileLength; E$_zBD%  
} 'Rnzu0<lF  
} idHI)6!  
o5/BE`VD5c  
I_#5gq  
//启动子线程 xd `MEOY  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0fj C>AS  
for(int i=0;i<nStartPos.length;i++) o w(9dB&E  
{ wMgF*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), RKrNmD*rk*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), zWPX  
nStartPos,nEndPos,i); ~%lUzabMa  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fAkfN H6  
fileSplitterFetch.start(); %1 RWF6  
} [PXq<ST  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #P!<u Lc%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); OL_#Uu  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", h [Sd3Z*  
nEndPos = " + nFileLength); iWWtL  
// fileSplitterFetch[nPos.length-1].start(); ^EN )}:%Z  
L~/L<Ms  
^$dbyj`  
//等待子线程结束 ElTB{C>u  
//int count = 0; {tYY _BI<  
//是否结束while循环 )cL(()N  
boolean breakWhile = false; lA4-ZQ2Zp[  
.~ uKr^%  
erv94acq  
while(!bStop) nN.Gn+Cl  
{ l(x0d  
write_nPos(); Bi9Q8#lh  
Utility.sleep(500); g/l:q&Q<  
breakWhile = true; XXm7rn  
x?A<X2  
*Dq ++  
for(int i=0;i<nStartPos.length;i++) |) cJ  
{ )Vy0V=  
if(!fileSplitterFetch.bDownOver) dHAT($QG  
{ a:GM|X  
breakWhile = false; Qm7];,  
break; Uufig)6  
} zrSYLG  
} L[:A Ue  
if(breakWhile) 22ySMtxn  
break; PI$i_3N  
9%21Q>Y?b  
g :B4zlKG  
//count++; )^P54_2  
//if(count>4) 2oc18#iG (  
// siteStop(); jLn#%Ia}  
} AMB{Fssz  
J:'_S `J  
z80(+ `   
System.err.println("文件下载结束!"); i@D4bd9lR  
} #?\(l%  
catch(Exception e){e.printStackTrace ();} 7MZH'nO  
} ,j{tGj_  
EF$ASNh"  
UsA fZg8  
//获得文件长度 E,ilJl\  
public long getFileSize() 5|jY  
{ t%e<]2-8  
int nFileLength = -1; ]Hl{(v\H O  
try{ f tl$P[T  
URL url = new URL(siteInfoBean.getSSiteURL()); K@:omT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); IP{$lC  
httpConnection.setRequestProperty("User-Agent","NetFox"); >h:'Z*9  
<7)sS<I  
]Ue aXwaU  
int responseCode=httpConnection.getResponseCode(); IDf\! QGx  
if(responseCode>=400) teb(gUy}L6  
{ 6DU(KYN  
processErrorCode(responseCode); 569p/?  
return -2; //-2 represent access is error }&L%c>  
} ~}{_/8'5  
PP\ bDEPy  
B R  
String sHeader; 4 7mT  
}8YY8|]LI  
/ ~".GZ&29  
for(int i=1;;i++) H)S!%(x4  
{ B#IUSHC  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); hP'4PLK  
//Utility.log(in.readLine()); Tc"J(GWG  
sHeader=httpConnection.getHeaderFieldKey(i); DC/Czkv9  
if(sHeader!=null) {U>N*&_`  
{ qe(gKKA%q  
if(sHeader.equals("Content-Length")) x%k@&d;z  
{ P RUl-v  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); I0H]s/*C%9  
break; qAd=i0{N  
} n8)&1 q?V  
} $nW9VMa  
else \p.yR.  
break; >l%8d'=Jl  
} F_-xp1|  
} 8oI|Z=  
catch(IOException e){e.printStackTrace ();} $aU.M3  
catch(Exception e){e.printStackTrace ();} JvvN>bg  
7BINqVS&  
F7j/Zuj  
Utility.log(nFileLength); dR_6j}  
(_@]-   
sm Ql^ 6a  
return nFileLength; A15Kj#Oy  
} Sx J0Y8#z  
oj{CNa  
\1<|X].jNY  
//保存下载信息(文件指针位置) ^>ir&$  
private void write_nPos() ia_@fQ  
{ \\13n4fAv  
try{ DrioBb@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); sG_/E-%5'  
output.writeInt(nStartPos.length); EN[T3 Y  
for(int i=0;i<nStartPos.length;i++) Ua:@,};  
{ QnP3U  
// output.writeLong(nPos); R@pY+d9qp  
output.writeLong(fileSplitterFetch.nStartPos); 9M($_2,44  
output.writeLong(fileSplitterFetch.nEndPos); :2M&C+f[  
} P%Vq#5  
output.close(); a:l-cZ/!  
} uJH[C>  
catch(IOException e){e.printStackTrace ();} \X\f ~CB  
catch(Exception e){e.printStackTrace ();} | ?vm.zp  
} K,! V _  
Nc4;2~XwRp  
h/|p`MP\1  
//读取保存的下载信息(文件指针位置) Pf,@U'f|  
private void read_nPos() JN9>nC!Zy_  
{ ^vT!24sK  
try{ #| ,cy,v4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); H I_uR$m  
int nCount = input.readInt(); vC@^B)5gb  
nStartPos = new long[nCount]; -L]-u6kC[  
nEndPos = new long[nCount]; 1|"BpX~D  
for(int i=0;i<nStartPos.length;i++) x$o^;2Z  
{ x>##qYT  
nStartPos = input.readLong(); _ {wP:dI "  
nEndPos = input.readLong(); )kI**mI}  
}  3TCRCz  
input.close(); Ic_NQ<8  
} >l AtfN='  
catch(IOException e){e.printStackTrace ();} WG6 0  
catch(Exception e){e.printStackTrace ();} 4P1}XYD-2  
} KgkRs?'z  
2yg6hR  
j:'g*IxM_  
private void processErrorCode(int nErrorCode) M+VWAh#uD  
{ [yk-<}#B  
System.err.println("Error Code : " + nErrorCode); F{a;=h#@Q  
} v ;}s`P\"  
EZ|v,1`e  
pk.\IKlG]  
//停止文件下载 7`A]X,:  
public void siteStop() R Qo a  
{ O8bxd6xb  
bStop = true; Kf BT'6t  
for(int i=0;i<nStartPos.length;i++) =HsE:@  
fileSplitterFetch.splitterStop(); Q*%}w_D6f  
kUS]g r~i  
2 HQ3G~U  
} LYRpd  
} HBOyiIm Q  
//负责部分文件的抓取 D%yY&q;  
**FileSplitterFetch.java h,m 90Hd+  
*/ r <5}& B`  
package NetFox; 1VM2CgRa  
9>9EZ?4m  
fM"*;LN!N  
import java.io.*; $+7uB-KsU  
import java.net.*; '-RacNY  
}}tbOD)t  
Qw'905;(  
public class FileSplitterFetch extends Thread { nDC0^&  
Su2{nNC>  
Wj(#!\ 7F  
String sURL; //File URL 9|}Pf_5]%[  
long nStartPos; //File Snippet Start Position thJ~* 0^  
long nEndPos; //File Snippet End Position 6u+aP  
int nThreadID; //Thread's ID %;dj6):@  
boolean bDownOver = false; //Downing is over m]AT-]*f  
boolean bStop = false; //Stop identical ed q,:  
FileAccessI fileAccessI = null; //File Access interface eyyME c!  
'{jr9Vh  
6ABK)m-y  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException W~ET/h  
{ (n*:LS=0  
this.sURL = sURL; p8!T) ?|  
this.nStartPos = nStart; C{zp8 A(Dh  
this.nEndPos = nEnd; [rT.k5_  
nThreadID = id; [|KvlOvP  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?PT> V,&  
} @ps(3~?7  
{jz`K1  
qt~=47<d  
public void run() :HO5 T  
{ z2uL[deN'"  
while(nStartPos < nEndPos && !bStop) Fa )QDBz)  
{ *$<W"@%^J  
[^5;XD:%&l  
@9B*V~ <  
try{ dg24h7|]  
URL url = new URL(sURL); %A$&9c%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O9sEaVX  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q# B0JT1  
String sProperty = "bytes="+nStartPos+"-"; \c:$ eF  
httpConnection.setRequestProperty("RANGE",sProperty); '*b]$5*p  
Utility.log(sProperty); m|aK_  
VIT|#  
LWF,w7v[L  
InputStream input = httpConnection.getInputStream(); Z]]Ur  
//logResponseHead(httpConnection); !,m  
gQ>kDl^$Ls  
\x}\)m_7M<  
byte[] b = new byte[1024]; cgMF?;V  
int nRead; (h3L=  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) m$W >~  
{ ;XurH%Mg  
nStartPos += fileAccessI.write(b,0,nRead); 4a-JC"  
//if(nThreadID == 1) hF,|()E[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nMyl( kF[  
} #0P_\X`E   
U-I,Q+[C[^  
?Afe }  
Utility.log("Thread " + nThreadID + " is over!"); 3=YpZ\l}  
bDownOver = true; __g k:a>oQ  
//nPos = fileAccessI.write (b,0,nRead); -r={P _E6  
} 4#B'pJMw9  
catch(Exception e){e.printStackTrace ();} Y &C b  
} >[fu&r1  
} ef7{D P  
@KQ.tF*  
gJ \6cZD  
//打印回应的头信息 SMX]JZmH  
public void logResponseHead(HttpURLConnection con) G](4!G&  
{ hO=L|BJ?I  
for(int i=1;;i++) .5(YL8d  
{  K& #il  
String header=con.getHeaderFieldKey(i); I,{YxY[$7  
if(header!=null) SO$Af!S:bB  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); !bE-&c  
Utility.log(header+" : "+con.getHeaderField(header)); 6Wu*zY_+  
else .:$(o&  
break; 8W\yM;'  
} _}R[mr/  
} 4dX{an]Cz  
X7},|cmD_  
mM,HMrgLqK  
public void splitterStop() ).SJ*Re*^I  
{ k QuEG5n.-  
bStop = true; R~\R>\  
} Jb QK$[z"  
ZZY#.  
]M7FIDg  
} (~GQncqa  
C^J<qq &  
Lx0nLJ\  
/* 1M]=Nv  
**FileAccess.java ubcB <=xb  
*//文件访问(定位,写) g+ c*VmY  
package NetFox; ^65I,Z"  
import java.io.*; O3} JOv_  
EwC]%BZP  
%QezC+n  
public class FileAccessI implements Serializable{ 1<YoGm&  
)+G"57p  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 vMTf^V  
RandomAccessFile oSavedFile; Q(bOar5  
long nPos; {R}F4k  
DB/~Z  
q/#e6;x  
public FileAccessI() throws IOException 4q}+8F`0F  
{ @J[@Pu O  
this("",0); X1Yw=t~a  
}  ldA_mj{  
h  d3  
aM}9ZurI  
public FileAccessI(String sName,long nPos) throws IOException V8^la'_j  
{ ~ :ASv>m  
oSavedFile = new RandomAccessFile(sName,"rw"); >JpBX+]5m  
this.nPos = nPos; im<bo Mv  
oSavedFile.seek(nPos); v:t;Uk^Y  
} M3tl4%j  
a:BW*Hy{\  
)1s5vNVa  
public synchronized int write(byte[] b,int nStart,int nLen) )?F&`+  
{ DrJ?bG;[  
int n = -1; d:%b  
try{ K./qu^+k  
oSavedFile.write(b,nStart,nLen); ;TAj;Tf]H  
n = nLen; |N)Ik8  
} *~#I5s\s!  
catch(IOException e) my (@~'  
{ R#T-o,m  
e.printStackTrace (); =zkN63S  
} cQ8[XNa  
~gDYb#p  
F.[%0b E  
return n; lL D#|T3  
} Gv-VDRS  
Q:-T' xk@  
TnF~'RZYb  
} )DgXsT  
pY31qhoZ.  
d GUP|O  
/* 0AQ azhm  
**SiteInfoBean.java 6G8No-#y  
*/  Rb6BY-/J  
package NetFox; Pb5yz-?  
l6  G6H$  
 LA3m,  
public class SiteInfoBean { F>fCp  
w!F>fcm  
s<I)THC  
private String sSiteURL; //Site's URL AO-5>r  
private String sFilePath; //Saved File's Path 4MgN  
private String sFileName; //Saved File's Name 5vx 4F f  
private int nSplitter; //Count of Splited Downloading File msl.{  
W A/dt2D|  
A@A8xn%  
public SiteInfoBean() hA7=:LG  
{//nSplitter的缺省值为5 ;ku>_sG-  
//default value of nSplitter is 5 5YY5t^T  
this("","","",5); :""HyjY!  
} 'RjEdLrI  
n7t}G'*Y!^  
_.5{vGyxr  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 'OY4Q 'Z  
{ E'08'8y  
sSiteURL= sURL; )U&9d  
sFilePath = sPath; 67j kU!  
sFileName = sName; ^ja]e%w#  
this.nSplitter = nSpiltter; yXNr[ 7  
Q]WBH_j  
:?M_U;;z2+  
} H$`U] =s|  
\c_g9Iqa  
qc8Ge\3s  
public String getSSiteURL() x3+ -wv  
{ M':-f3aT%  
return sSiteURL; V:\:[KcL^  
} csP4Oq\g[  
v;,W ^#`  
F2N"aQ&  
public void setSSiteURL(String value) "n%j2"TYJj  
{ )N.3Q1g-  
sSiteURL = value; 0L}`fYf  
} TU|#Pz7n-Z  
2F4<3k! &  
+( LH!\{^  
public String getSFilePath() #-L0.z(  
{ &~:EmLgv  
return sFilePath; de:@/-|  
} +7.|1x;C  
KuR]X``2  
Y@FYo>0O  
public void setSFilePath(String value) \BHZRytQF  
{ ,r B(WKU  
sFilePath = value;  /YJo"\7  
} OyO<A3  
/~,*DH$)  
Ao K9=F}  
public String getSFileName() $kUB%\`  
{ [jgVN w""D  
return sFileName; hK?GIbRZ  
} "r^RfZ;  
w B)y@w4k  
;[y( 14g  
public void setSFileName(String value) gj^)T_E_  
{ F_@B ` ,  
sFileName = value; e{x>u(  
} b|i4me@  
=xk>yw!O)  
FGVw=G{r  
public int getNSplitter() |4+'YgO  
{ m` 1dB%;?  
return nSplitter; z^9oaoTl  
}  [N,+mX  
7$*E0  
j2G^sj"|  
public void setNSplitter(int nCount) ]]|#+$ ~  
{ SdnnXEB7  
nSplitter = nCount; 6wp1jN  
} ]L3U2H`7  
} .gO|=E"  
Kbu>U{'  
&eMd^l}:#  
/* tl dK@!E3  
**Utility.java ,!Wo6{'  
*/ m* 3ipI{h  
package NetFox; ? dJd7+A  
%bw+>:Tr  
[{Wo:c9Qq1  
public class Utility { 6FDj:~  
"](Q2  
)>~ jjR  
public Utility() 3EYEd39E  
{ z</C)ObL  
?NA $<0  
P%R!\i  
} b%l H=u  
!Q\*a-C  
//线程睡眠 (BY 0b%^  
public static void sleep(int nSecond) !/G}vu  
{ V7WL Gy.,  
try{ M6wH$!zRa  
Thread.sleep(nSecond); 4q .;\n  
} 6%V:Z  
catch(Exception e) +2MF#{ tS  
{ EMnz;/dMt  
e.printStackTrace (); l~$)>?ZD  
} ;bwBd:Y  
} nc1~5eo  
<VZ43I  
//日志 %ddH4Q/p  
public static void log(String sMsg) n[>hJ6  
{ zU1D@  
System.err.println(sMsg); > %KEMlKZ  
} GP+=b:C{E  
b'pwRKpx  
_#\Nw0{  
public static void log(int sMsg) lL zR5445)  
{ @PM<pEve  
System.err.println(sMsg); D2VYw<tEA  
} |ru!C(  
} r(S h  
eFsl  
gq?O}gVD  
/* Tu-lc)  
**TestMethod.java g7323m1=  
*/ 0j8fU7~6S  
package NetFox; GyL9}  
qG,h 1  
z uNm !$  
public class TestMethod { kb 74:  
7=G6ao7  
0V6, &rTF  
public TestMethod() q25p3  
{ ///xx/weblogic60b2_win.exe 2|7:`e~h  
try{ {ccc[G?>.Q  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 8b0j rt  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Mq~E'g4#  
SiteFileFetch fileFetch = new SiteFileFetch(bean);  IZrcn  
fileFetch.start(); y9mV6.r  
} <k[_AlCmsg  
catch(Exception e){e.printStackTrace ();} yl?LXc[)  
Q=! lbW  
> 3x^jh  
} $cn8]*Z =  
Q"s6HZ"YI  
[? "hmSJ  
public static void main(String[] args) !Gnm<|.  
{ ^/Hf$tYI!`  
new TestMethod(); hpQ #`rhn  
} 1q;R+65  
}  6 wd  
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