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http断点续传简单实现(java)

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/* =BW9/fG  
**SiteFileFetch.java iE+6UK  
*/ a^/K?lAB8  
package NetFox; a(!3Afi  
import java.io.*; m9b(3  
import java.net.*; o_3*;}k8  
s?+fPOF  
f@*>P_t  
public class SiteFileFetch extends Thread { u7 ~mn l  
cP('@K=p  
M%;"c?g  
SiteInfoBean siteInfoBean = null; //文件信息Bean :5<#X8>d  
long[] nStartPos; //开始位置 HYFN?~G  
long[] nEndPos; //结束位置 g`.{K"N>!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 kpWzMd &RK  
long nFileLength; //文件长度 L B<UC?e  
boolean bFirst = true; //是否第一次取文件 wJ(8}eI  
boolean bStop = false; //停止标志 "_oLe;?$c  
File tmpFile; //文件下载的临时信息 'W+i[Ep5Q  
DataOutputStream output; //输出到文件的输出流 G)4SWu0<t  
m/" J s  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) \3: L Nt  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6.UKB<sV  
{ 1::LN(`<  
siteInfoBean = bean; K /8qB~J*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); J2=*-O:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /6smVz@O  
if(tmpFile.exists ()) A{t"M-<  
{ Fi/jR0]e2  
bFirst = false; [{/$9k-aF?  
read_nPos(); )ZeLaaP  
} Ki63Ox^O  
else TL]bY'%  
{ `_ 0)kdu  
nStartPos = new long[bean.getNSplitter()]; @%%bRY  
nEndPos = new long[bean.getNSplitter()]; e+x*psQ  
} GGp{b>E+ #  
{[N?+ZJD*L  
cPm~` Zd  
>z5Oy  
} y78z>(jV  
h%/ssB  
>0 7shNX  
public void run() >waN;&>/  
{ k5g@myb-  
//获得文件长度 .h a`)@MsZ  
//分割文件 M-vC>u3Y  
//实例FileSplitterFetch bbO+%-(X  
//启动FileSplitterFetch线程 dUZ$wbV%h  
//等待子线程返回 iW":DOdi_  
try{ "W3W:vl!  
if(bFirst) &6Ns7w6*z  
{ q< b"M$  
nFileLength = getFileSize(); HmFNE$k  
if(nFileLength == -1) l-Fmn/V  
{ m_(E(_  
System.err.println("File Length is not known!"); ([1=>Jw"  
} aDXpkG0E  
else if(nFileLength == -2) .byc;9M%  
{ {GAsFnZk  
System.err.println("File is not access!"); eC.w?(RB  
} |iAEDZn  
else e{:86C!d)  
{ \?r$&K]4  
for(int i=0;i<nStartPos.length;i++) AVU7WU{  
{ hl*MUD,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); h<GyplG  
} FF8WTuzB+  
for(int i=0;i<nEndPos.length-1;i++) o}d2N/T  
{ l'W3=,G[?  
nEndPos = nStartPos[i+1]; :l4^iSf  
} 8 H,_vf  
nEndPos[nEndPos.length-1] = nFileLength; vi^z5n  
} >'ie!VW@  
} f(^33k  
^NY+wR5Sn  
<\+Po<)3j  
//启动子线程 fmtuFr^a1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; yY'gx|\  
for(int i=0;i<nStartPos.length;i++) 3Gj(z:)b  
{ /7.wQeL9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), is64)2F](  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #)Ep(2  
nStartPos,nEndPos,i); PpW A f\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); RA! x  
fileSplitterFetch.start(); L,f^mX0<  
} D`1I;Tb#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), XSD"/_xD  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Fp wlV}:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", [SKP|`I>I  
nEndPos = " + nFileLength); $_ST:h&C  
// fileSplitterFetch[nPos.length-1].start(); "vv$%^  
'\Qf,%%.  
-Mr{+pf  
//等待子线程结束 -$xKv4  
//int count = 0; D WsCYo  
//是否结束while循环 GH [ U!J  
boolean breakWhile = false; 8[vl3C  
8''9@xz  
?aP1  
while(!bStop) 1!K !oY  
{ H Jnv'^yn  
write_nPos(); ]!n*V/g  
Utility.sleep(500); hz&^_ G6`  
breakWhile = true; Y+|L 3'H  
r!"CH5dT  
.;]YJy  
for(int i=0;i<nStartPos.length;i++) 9OE_?R0c!  
{ KteZK.+#:  
if(!fileSplitterFetch.bDownOver) L&+% Wd~  
{ 1"mnzbf8*  
breakWhile = false; AaJ,=eQ  
break; %iHyt,0v2  
} [GcA.ABz  
} A}az m>  
if(breakWhile) d,Im&j_Z  
break; !~6'@UYo  
z:0-aDe M  
$}^Rsv(  
//count++; m0dFA<5-  
//if(count>4) gt].rwo"  
// siteStop(); }dV9%0s!  
} uJ2C+$=Ul  
\9&YV;Ct  
:< KSf#O  
System.err.println("文件下载结束!"); p{\qSPK  
} ]w1BJZa36  
catch(Exception e){e.printStackTrace ();} 4WBo ZJ  
} wz*)L (pP  
|H3?ox*  
+z~ !#j4Q  
//获得文件长度 o3kt0NuF,  
public long getFileSize() G_7ks]u-  
{ m-~V+JU;x  
int nFileLength = -1; CDwFVR'_Af  
try{ F[Guy7?O  
URL url = new URL(siteInfoBean.getSSiteURL()); eSQzjR*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); EhmUX@k],  
httpConnection.setRequestProperty("User-Agent","NetFox"); s!nSE  
F$"MFdc[  
'<*CD_2t-  
int responseCode=httpConnection.getResponseCode(); C[Y%=\6'0  
if(responseCode>=400) Z7m GC`>  
{ .(gT+5[  
processErrorCode(responseCode); EU?&  
return -2; //-2 represent access is error i9f7=-[U_  
} `\WcF7  
ai<MsQQ:=  
(50[,:#  
String sHeader; /e j/&x15  
URmAI8fq*M  
mE3SiR "  
for(int i=1;;i++) O>tC]sm%  
{ {GG~E54&B  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0C"PC:h5  
//Utility.log(in.readLine()); 7Y_fF1-wY  
sHeader=httpConnection.getHeaderFieldKey(i); m=("N  
if(sHeader!=null) Sm*Jysy`  
{ x):k#cu[L  
if(sHeader.equals("Content-Length")) 76u/WC>B  
{ N4Fy8qU;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /eU1(oo&`5  
break; =0!\F~  
} X+'^ Sp  
} TCEXa?,L  
else b}}1TnS)  
break; ^R8U-V8:  
} ~_# Y,)S!z  
} {YO%JTQ  
catch(IOException e){e.printStackTrace ();} t^bdi}[  
catch(Exception e){e.printStackTrace ();} XeIUdg4>R  
AD!<%h:  
BC$;b>IUA  
Utility.log(nFileLength); I ]WeZ,E  
[Q.4]K2  
JtrDZ;^@  
return nFileLength; c|!A?>O?i  
} zvK5Zxl  
YKX>@)Dxv  
Wc`J`&#.#  
//保存下载信息(文件指针位置) =|WV^0=S'%  
private void write_nPos() 3A}nNHpN  
{ &xiDG=I#  
try{ f2w=ln  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5M\=+5wB  
output.writeInt(nStartPos.length); y T1Qep  
for(int i=0;i<nStartPos.length;i++) 8.;';[  
{ P9tQS"Rs  
// output.writeLong(nPos); /qz "I-a  
output.writeLong(fileSplitterFetch.nStartPos); |au qj2  
output.writeLong(fileSplitterFetch.nEndPos); >kDdWgRQ  
} 5[j!\d}U  
output.close(); eV {FcJha  
} zcD_}t_K  
catch(IOException e){e.printStackTrace ();} tM PX vE  
catch(Exception e){e.printStackTrace ();} L/iVs`qF  
} % Dr4~7=7a  
a@_Cx  
:C:N]6_{SZ  
//读取保存的下载信息(文件指针位置) >$S,>d_k`  
private void read_nPos() yzM+28}L<I  
{ eE.5zXU3R  
try{ KZ<RDXVT  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )T};Q:  
int nCount = input.readInt(); mP$G9R  
nStartPos = new long[nCount]; Jr>S/]"  
nEndPos = new long[nCount]; Vw;ldEdx  
for(int i=0;i<nStartPos.length;i++) V.gY1   
{  \#+2;L  
nStartPos = input.readLong(); >*t>U8  
nEndPos = input.readLong(); ID)gq_k[8,  
} -C'X4C+  
input.close(); kFIB lPV  
} ng&EGM  
catch(IOException e){e.printStackTrace ();} 8$<AxNR  
catch(Exception e){e.printStackTrace ();} @gqs4cg{f  
} )D@n?qbG  
HT,kx  
h3d\MYO)B  
private void processErrorCode(int nErrorCode) g=YiR/O1QN  
{ zyp"*0zUr  
System.err.println("Error Code : " + nErrorCode); 72`/xryY  
} k'I_,Z<,  
UK <DcM~n  
L5k>;|SA  
//停止文件下载 (8-lDoW  
public void siteStop() 0-~6} r$  
{ o? O,nD 6  
bStop = true; ^B!?;\4IM  
for(int i=0;i<nStartPos.length;i++) C8W`Oly:]  
fileSplitterFetch.splitterStop(); |Q)w3\S$  
6[h$r/GXh"  
xE-c9AH  
} J_[[BJ&}x  
} FPUR0myCU  
//负责部分文件的抓取 ,S0~:c:)  
**FileSplitterFetch.java Mm7n?kb6  
*/ %1?V6&  
package NetFox; kdMS"iN8x  
CygV_q  
v4>"p!_C  
import java.io.*; x^O2Lj,w\  
import java.net.*; +l?ro[#6&.  
73z|'0.  
vwH7/+  
public class FileSplitterFetch extends Thread { .q9|XDqQc  
$E,DxDT  
2SPFjpG8n  
String sURL; //File URL =O'%)Y&  
long nStartPos; //File Snippet Start Position ]|La MMD  
long nEndPos; //File Snippet End Position hCvLwZ?LF  
int nThreadID; //Thread's ID Ufe  
boolean bDownOver = false; //Downing is over :9 iOuu  
boolean bStop = false; //Stop identical Nx (pJp{S  
FileAccessI fileAccessI = null; //File Access interface Fx99"3`3  
n25tr'=  
JX0_UU  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9"lW"lG!  
{ b G5  
this.sURL = sURL; x(zZqOed  
this.nStartPos = nStart; pL/.JzB  
this.nEndPos = nEnd; 9PGR#!!F$  
nThreadID = id; Cbg#Yz~/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 B{UoNm@  
} sAN:C{  
v?TJ!o  
G1^!ej  
public void run() %PdYv _5  
{ MVv^KezD  
while(nStartPos < nEndPos && !bStop) M@X#[w:  
{ |21hY  
RowiSW  
g7LW?Ewr  
try{ ,Ve@=<  
URL url = new URL(sURL); LP-Q'vb<=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z(X6%p0  
httpConnection.setRequestProperty("User-Agent","NetFox"); z slEUTj)  
String sProperty = "bytes="+nStartPos+"-"; u&_U CJCf  
httpConnection.setRequestProperty("RANGE",sProperty); N b[o6AX  
Utility.log(sProperty); ~rX6owBq  
*#^1rKGWK  
qq_,"~  
InputStream input = httpConnection.getInputStream(); ^`MDP`M;  
//logResponseHead(httpConnection); ~d `4W<1a  
;GT)sI   
Jb.u^3R@  
byte[] b = new byte[1024]; UYrzsUjg&  
int nRead; yi;t  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &FF. Ddt{  
{ ?[B[ F  
nStartPos += fileAccessI.write(b,0,nRead); 2\tjeg  
//if(nThreadID == 1) htrj3$q(4  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6SO7iFS  
} 6%INNIyAWa  
+* {5ORq=  
+mOtYf W  
Utility.log("Thread " + nThreadID + " is over!"); [IBk-opap  
bDownOver = true; KL"L65g&  
//nPos = fileAccessI.write (b,0,nRead); G5f57F  
} _:p_#3s$  
catch(Exception e){e.printStackTrace ();} }Y ];ccT  
} tRBK1h  
} l'%R^  
^|;4/=bbs  
PM>XT  
//打印回应的头信息 AHD%6 \$  
public void logResponseHead(HttpURLConnection con) hBE>ea  
{ []!r|R3  
for(int i=1;;i++) "$pg mf2  
{ }/0dfes  
String header=con.getHeaderFieldKey(i); ZKPkx~,U[  
if(header!=null) S)|b%mVwR  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); =T4 w:  
Utility.log(header+" : "+con.getHeaderField(header)); s;WCz  
else X hX'*{3k  
break; $QBUnLOek&  
} z35Rjhj9  
} $-fY8V3[  
1ZFSz{  
"q/M8  
public void splitterStop() AV3,4u  
{ :Ia&,;Gc  
bStop = true; =T}uQ$X  
} J4#]8!A  
xumv I{  
 " 1Aus  
} 8mLU ~P |  
4PM`hc  
q#3X*!)  
/* ^(vd8&71  
**FileAccess.java ?+=|{{l  
*//文件访问(定位,写) yvisoZX  
package NetFox; r!,V_a4n  
import java.io.*; f.^w/ GJO/  
E}&jtMRUt  
i]?xM2(N  
public class FileAccessI implements Serializable{ S`w)b'B!M  
<j3HT"^[D  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C P{h+yCj  
RandomAccessFile oSavedFile; 4:g:$s|SE[  
long nPos; 0*@S-Lj^c  
D+""o"%  
jloyJ@ck  
public FileAccessI() throws IOException .Kwl8xRg  
{ AI;=k  
this("",0); F &}V65  
} mP[u[|]  
26K~m@  
:q1r2&ne  
public FileAccessI(String sName,long nPos) throws IOException $7d"9s\$"  
{ $u"$mg7x  
oSavedFile = new RandomAccessFile(sName,"rw"); ??V["o T  
this.nPos = nPos; ".D +# 2Kl  
oSavedFile.seek(nPos); Q*(o;\s  
} ? d\8Q't*  
Ntiz-qW  
x)L@x Q  
public synchronized int write(byte[] b,int nStart,int nLen) IyP].g1"U  
{ X&Lt?e,&  
int n = -1; /Ql}jSKi  
try{ zUqDX{I8  
oSavedFile.write(b,nStart,nLen); )aSkUytg"  
n = nLen; epyfgg MT  
}  c @fc7  
catch(IOException e) j]&{ @Y  
{ G].KJ5,y  
e.printStackTrace (); 'VEpVo/  
} {hz :[  
o7zfD94I  
6u7wfAf  
return n; lZ_k307  
} (mlc' ]F  
UXHFti/A<  
HXI}f\6x  
} E:k?*l  
6~>k]G  
(Lnh> '2  
/* ] ),' =@  
**SiteInfoBean.java .vMi <U;  
*/ CI{x/ e^(  
package NetFox; GNOC5 E$I  
O]lfs >>x  
 <@u6*]  
public class SiteInfoBean { >k|[U[@  
e_V(G  
p;Kr664  
private String sSiteURL; //Site's URL q?&&:.H"?5  
private String sFilePath; //Saved File's Path 7l3q~dQ  
private String sFileName; //Saved File's Name i;Y^}2   
private int nSplitter; //Count of Splited Downloading File n TG|Isa  
JB<4 m4-  
pdSyx>rJ  
public SiteInfoBean() YSyW '~!b  
{//nSplitter的缺省值为5 PAkW[;GSDh  
//default value of nSplitter is 5 Lt_]3g o  
this("","","",5); l1WVt}  
} >kYyR.p.b  
Je,8{J|e  
;rgsPVbVf  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *en{pR'  
{ 9lv 2  
sSiteURL= sURL; x}d\%* B  
sFilePath = sPath; rej[G!  
sFileName = sName; t ,$)PV  
this.nSplitter = nSpiltter; *Y Ox`z!R  
\`C3;}o:"P  
Ek3O{<  
} x5ia<V>=d  
2+PIZ6=hN  
0P(}e[~Z  
public String getSSiteURL() M_K&x-H0  
{ )f Rh^6  
return sSiteURL; B|v fkX2f  
} h 8s*FI  
t At+5H  
kWFR(J&R  
public void setSSiteURL(String value) Lrq&k40y  
{ V EzIWNV  
sSiteURL = value; o;fQ,r P%  
} ^-ZqS  
o/R-1\Dn  
Wm 61  
public String getSFilePath() s/V[tEC*z  
{ t&_lpffv  
return sFilePath; ^^#A9AM  
} vs~*=d27Pf  
,P^"X5$   
h.nzkp5  
public void setSFilePath(String value) !?{5ET,gtN  
{ N *fN&0r  
sFilePath = value; ?=/l@d  
} VMp6s%m  
+Ji dP  
#u_-TWVt  
public String getSFileName() eC?N>wHH  
{ 4y 'REC  
return sFileName; ScEM#9T|  
} -UO$$)Q  
o&=m]hKpQl  
6o!"$IH4  
public void setSFileName(String value) ^IpS 3y  
{ mYCGGwD  
sFileName = value; \ C Yu;  
} 4"{q|~&=:$  
JmkJ^-A 6  
d=[ .   
public int getNSplitter() @ o]F~x  
{ c c:xT0Y  
return nSplitter; ~1p f ?  
} 3XIxuQwf  
[*fnTy  
t1kD5^  
public void setNSplitter(int nCount) ||qW'kNWM  
{ ?G@%haqn6  
nSplitter = nCount; ;Bm{_$hf=  
} IcB>Hg5  
} \a<E3 <  
AK[c!mzx  
52oR^ |  
/* <iMLM<J<w  
**Utility.java .fgoEB,(  
*/ @Z)&3ss  
package NetFox; T"O!  
'?\Hm'8  
xe d$z  
public class Utility { @_;6 L  
uaiG (O   
PqfH}d0l  
public Utility() ^pn:SV  
{ s:%>H|-  
NFQ0/iuW  
l 1@:&j3h  
} "YivjHa7H  
s;bqUY?LD  
//线程睡眠 kHJjdgV  
public static void sleep(int nSecond) Gb"PMai  
{ H=0Y4 T@)T  
try{ Rc u/ @j{O  
Thread.sleep(nSecond); FK->|  
} 6uDNqq  
catch(Exception e) d6u L;eR  
{ /Z^+K  
e.printStackTrace (); wDn5|F}i&  
} a}6Wo=  
} 'E9\V\bi  
HR4^+x  
//日志 YS/4<QA[  
public static void log(String sMsg) C@xh$(y  
{ #U^@)g6  
System.err.println(sMsg); <=WQs2  
} xand%XNv  
1Eh (U  
*\emRI>  
public static void log(int sMsg)  $///N+B  
{ UtzW5{  
System.err.println(sMsg); nM@S`"  
} w9vqFtj  
} [-Dx)N  
$cc]pJy"}  
Nx~8]h1(  
/* YqYCW}$  
**TestMethod.java l2xM.vR  
*/ *f1MgP*GKF  
package NetFox; tip\vS)  
n<?:!f`   
<~'\~Zd+  
public class TestMethod { L\pe  
<`BUk< uf#  
KATt9ox@  
public TestMethod() TwY]c<t  
{ ///xx/weblogic60b2_win.exe 4~D?F'o  
try{ d&F8nBIM5  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~i(X{ ^,3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); OXI.>9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); oGa8}Vtc  
fileFetch.start(); 8@Pv nOL  
} "+p_{J/P  
catch(Exception e){e.printStackTrace ();} b3W@{je  
< yBZsSj  
PC/Oo~Gx  
} woQYP,  
3s" Rv@  
2}K7(y!?u  
public static void main(String[] args) 0X.pI1jCO  
{ Yz4Q!tL  
new TestMethod(); >IsRd  
} 2]hQ56Yv3  
} 525W; mu{  
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