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http断点续传简单实现(java)

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/* >6ni")Q9  
**SiteFileFetch.java LC,F <>w1  
*/ wT6"U$cV  
package NetFox; pj\u9 L_  
import java.io.*; du<tGsy  
import java.net.*; R5N%e%[  
CuaVb1r  
=6j&4p `  
public class SiteFileFetch extends Thread { R{C(K(5/  
nD_GL  
hE-h`'ha`  
SiteInfoBean siteInfoBean = null; //文件信息Bean @x*c1%wg  
long[] nStartPos; //开始位置 L7n D|  
long[] nEndPos; //结束位置 KoOz#,()  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 rMdt:`  
long nFileLength; //文件长度 vLv@&lMW  
boolean bFirst = true; //是否第一次取文件 kjTduZ/3 "  
boolean bStop = false; //停止标志 {DV_* 5  
File tmpFile; //文件下载的临时信息 UFXaEl}R   
DataOutputStream output; //输出到文件的输出流 B{QBzx1L9c  
%6|nb:Oa  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 5MroNr  
public SiteFileFetch(SiteInfoBean bean) throws IOException TJ10s%,V  
{ 8H%;WU9-  
siteInfoBean = bean; EEEh~6?-e  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =2`[&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); vNyf64)  
if(tmpFile.exists ()) 5#HW2"7  
{ iowTLq!?  
bFirst = false; 4GkWRu1  
read_nPos(); C'>|J9~Gz  
} ()Y~Q(5ji  
else z 9vInf@M  
{ vk}n,ecl  
nStartPos = new long[bean.getNSplitter()]; OSRp0G20k\  
nEndPos = new long[bean.getNSplitter()]; _~'=C#XI)  
} hCi60%g/n  
1$xNUsD2  
h1j!IG  
M92dZ1+6  
} @3>u@  
TJ2=m 9Z  
{0[tNth'h  
public void run() @KXV%a'  
{ oI?3<M^  
//获得文件长度 S(k3 `;K  
//分割文件 .yMEIUm  
//实例FileSplitterFetch OC_+("N  
//启动FileSplitterFetch线程 ~k"=4j9  
//等待子线程返回 piJu+tUy  
try{ ~Q Oe##  
if(bFirst) h){0rX@:&  
{ @D]5civm_  
nFileLength = getFileSize(); ^ sOQi6pL  
if(nFileLength == -1) X1DF*wI  
{ &xU[E!2H%  
System.err.println("File Length is not known!"); ZJnYIK  
} cutuDZ  
else if(nFileLength == -2) Q$a{\*[:+  
{  U'k*_g  
System.err.println("File is not access!"); 6]&OrS[  
} .6ylZ  
else TtJH7  
{ 9)h"-H;5:  
for(int i=0;i<nStartPos.length;i++)  Fe#  1  
{ 9>= ;FY  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9"N~yKa`"K  
} +G$4pt|=  
for(int i=0;i<nEndPos.length-1;i++) >f|||H}Snw  
{ P9/q|>F  
nEndPos = nStartPos[i+1]; "SNn^p59k  
} |'e^QpU5  
nEndPos[nEndPos.length-1] = nFileLength; ^-TE([bW  
} l#g\X'bK  
} WO7z  
8^kGS-+^  
/}((l%UE.  
//启动子线程 IY_iB*T3jt  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]P9l jwR  
for(int i=0;i<nStartPos.length;i++) B |5]Jm]  
{ 4(#'_jS  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1NbG>E#Ol  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), MS nG3]{z  
nStartPos,nEndPos,i); %2}-2}[>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ADz ^\  
fileSplitterFetch.start(); D.r<QO~6B  
} 2+RUTOv/d  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), VRVO-Sk  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .H escg/S  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Rm2yPuOU}A  
nEndPos = " + nFileLength); ~G)S   
// fileSplitterFetch[nPos.length-1].start(); [xK3F+  
B+$%*%b  
!`M,XSp(  
//等待子线程结束 >Ifr [  
//int count = 0; I:E`PZ  
//是否结束while循环 "x#-sZ=  
boolean breakWhile = false; nB_?ckj,  
'<gI8W</  
raW>xOivR  
while(!bStop) g!|=%(G=  
{ k 9_`(nx  
write_nPos(); ^dI424  
Utility.sleep(500); kPKB|kP\  
breakWhile = true; ,j#XOy`mzy  
V"[g.%%Y  
,A9]CQ  
for(int i=0;i<nStartPos.length;i++) hE &xE;  
{ >d(~# Z`  
if(!fileSplitterFetch.bDownOver) EW}Bzh>b  
{ ##q2mm:a9P  
breakWhile = false; zU,9T  
break; 3Lfqdqj  
} 0^v`T%|fTX  
} KsddA  
if(breakWhile) Lt2u,9  
break; kT|dUw9G  
_1!7V3|^  
xn?a. 3b'  
//count++; bc*X/).  
//if(count>4) <NHH^M\N  
// siteStop(); R$EW4]j  
} XP`Nf)3{Yd  
9,c(y sv"  
j9m_jv  
System.err.println("文件下载结束!"); ~Q*%DRd&Z-  
} 7( #:GD  
catch(Exception e){e.printStackTrace ();} T*I{WW  
} #./fY;:cj  
-Sq z5lo  
|a8iZ9/D6  
//获得文件长度 B=U 3  
public long getFileSize() +[Dx?XM  
{ u :}%xD6  
int nFileLength = -1; Y`KqEjsC*  
try{ QfmJn((  
URL url = new URL(siteInfoBean.getSSiteURL()); ZVW'>M7.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @MoKWfc  
httpConnection.setRequestProperty("User-Agent","NetFox"); "H2EL}3/]  
WEAT01  
mR!1DQ.\<  
int responseCode=httpConnection.getResponseCode(); e*sfPHt  
if(responseCode>=400) HsxVZ.dS  
{ =WyDp97@+  
processErrorCode(responseCode); %Wg'i!?cB  
return -2; //-2 represent access is error C:GK,?!Jn'  
} u+dLaVlLJ  
} F E>|1  
wDw[RW3  
String sHeader; N[?N5~jG  
pD(j'[  
Fzm*Pz3  
for(int i=1;;i++) ;:iY)}  
{ 8bxfj<O,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); O8^A5,2@3>  
//Utility.log(in.readLine()); PoNi "Pv  
sHeader=httpConnection.getHeaderFieldKey(i); 9q)Kfz  
if(sHeader!=null) 6 o^,@~:R  
{ `34zkPB??  
if(sHeader.equals("Content-Length")) 5sdn[Tt##  
{ "<6G6?sz  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); P)"noG_'i  
break; C^s^D:   
} a,Sw4yJ!Q  
} |U~<3.:m:  
else lVd^ ^T*fh  
break; *F WMn.  
} +2(I1  
} '-QwssE  
catch(IOException e){e.printStackTrace ();} 02Y]`CXj  
catch(Exception e){e.printStackTrace ();} M\vwI"  
Cmu@4j&  
MvuQz7M#d  
Utility.log(nFileLength); % BVs47g  
Y$o< 6[7  
z__EYh  
return nFileLength; 4Xgg%@C  
} FSP+?((  
eP.wOl  
0;hqIJcE:\  
//保存下载信息(文件指针位置) +00b)TF  
private void write_nPos() UMv.{iEj  
{ wrviR  
try{ DP[IZ C  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ,aOl_o -&  
output.writeInt(nStartPos.length); _> f`!PlB|  
for(int i=0;i<nStartPos.length;i++) a Ve'ry  
{ >~#yu&*D  
// output.writeLong(nPos); B`YTl~4  
output.writeLong(fileSplitterFetch.nStartPos); 9Q.rMs>qj  
output.writeLong(fileSplitterFetch.nEndPos); S O4u9V  
} \@Ts+7%  
output.close(); b`(}.r?W  
} vN Vox0V  
catch(IOException e){e.printStackTrace ();} ?fiIwF)  
catch(Exception e){e.printStackTrace ();} Amp#GR1CA  
} y?rPlA_  
\j+1V1t9  
0\H\lKcK  
//读取保存的下载信息(文件指针位置) |<HPn4 ,X  
private void read_nPos() :Hn6b$Vy8  
{ :uP,f<=)K  
try{ kh!FR u h  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); [O$Wa:< 0x  
int nCount = input.readInt(); VdPtPq1  
nStartPos = new long[nCount]; ?OId\'q  
nEndPos = new long[nCount]; \?w2a$?6w  
for(int i=0;i<nStartPos.length;i++) !6n_}I-W  
{ rTM}})81  
nStartPos = input.readLong(); hmvfw:Nq4  
nEndPos = input.readLong(); N c1"g1JR  
} &@G:G(  
input.close(); +"x,x  
} wHzEMwY_  
catch(IOException e){e.printStackTrace ();} !-ok"k0,u  
catch(Exception e){e.printStackTrace ();} f6EZ( v  
} \"qY"V  
Vl5`U'^qx  
) dn(G@5  
private void processErrorCode(int nErrorCode) T m,b,hi$  
{ oin$-i|Xp!  
System.err.println("Error Code : " + nErrorCode); hM@ HA  
} G(Lzf(  
T{Gj+7bQ~  
!_"@^?,q  
//停止文件下载 ]}*R|1  
public void siteStop() BYpG  
{ _?<|{O  
bStop = true; 7OC#8,  
for(int i=0;i<nStartPos.length;i++) jDKO} bQ  
fileSplitterFetch.splitterStop(); W_||6LbZy  
a!ud{Dx  
4Z1ST;  
} vY4\59]P  
} %WSo b@f8  
//负责部分文件的抓取 s&A} h  
**FileSplitterFetch.java BD68$y  
*/ @"hb) 8ng  
package NetFox; (gEBOol  
N< |@ymi  
b+,' ;bW  
import java.io.*; Mxe}B'  
import java.net.*; N+++4;  
! _f9NK  
gaQdG=G8$  
public class FileSplitterFetch extends Thread { 48c1gUw oP  
s2teym,uG  
0x'#_G65y  
String sURL; //File URL :S.9eFfa  
long nStartPos; //File Snippet Start Position (XeE2l2M  
long nEndPos; //File Snippet End Position %Da8{%{`Pc  
int nThreadID; //Thread's ID Mx&&0#;r  
boolean bDownOver = false; //Downing is over 6tB+JF  
boolean bStop = false; //Stop identical E;,u2[3  
FileAccessI fileAccessI = null; //File Access interface Ci?Ss+|  
t|a2;aq_  
GU4'&#  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4P'*umJi  
{ q_TR q:&.  
this.sURL = sURL; MTsM]o  
this.nStartPos = nStart; OSlvwH%(EE  
this.nEndPos = nEnd; M}d_I+  
nThreadID = id; %Qc La//  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Hcl(3> Jn2  
} >v:y?A,  
5Ec6),+&  
%oq{L]C(rf  
public void run() |*:'TKzNS  
{ TX$r `~  
while(nStartPos < nEndPos && !bStop) JM=JH 51`  
{ GYJ80k|  
MJOz.=CbhR  
 ;hY S6  
try{ cU;iUf  
URL url = new URL(sURL); }M1`di4e  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '3_]Gu-D  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ge2q%  
String sProperty = "bytes="+nStartPos+"-"; *-MM<|Qt  
httpConnection.setRequestProperty("RANGE",sProperty); O/,aJCe  
Utility.log(sProperty); Ai:BEPKe  
{/"2Vk<H8  
@HQ`~C#Z'  
InputStream input = httpConnection.getInputStream(); )#P; x "  
//logResponseHead(httpConnection); 1>*#%R?W  
L0* nm.1X  
u\ #"L  
byte[] b = new byte[1024]; wLmhy,  
int nRead; "7!;KHc  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5Y.vJz  
{ 1xD=ffM>8N  
nStartPos += fileAccessI.write(b,0,nRead); WfWN(:dF  
//if(nThreadID == 1) b6}H$Sx~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t?q@H8  
} `!XY]PI+e  
iJ~Zkd  
uZc`jNc\  
Utility.log("Thread " + nThreadID + " is over!"); .l>77zM6  
bDownOver = true; {)"iiJ  
//nPos = fileAccessI.write (b,0,nRead); '>&^zgr  
} H18Tn!RDS  
catch(Exception e){e.printStackTrace ();} d p2F  
} #1`-*.u  
} C 'v+f=  
TatpXN\  
_&N2'hG=sn  
//打印回应的头信息 [K9'<Qnu  
public void logResponseHead(HttpURLConnection con) KAC6Snu1  
{ IOb*GTb  
for(int i=1;;i++) :E_g"_  
{ z*kutZ:6Y  
String header=con.getHeaderFieldKey(i); MNC*Glj=  
if(header!=null) x97 j  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0uWR<,]  
Utility.log(header+" : "+con.getHeaderField(header)); 3{""58  
else b?TO=~k,  
break; _z'u pb&  
} i 7_ _  
} /e7O$L)   
^.#jF#u~  
Qj,]N@7  
public void splitterStop() 7[I}*3Q'  
{ 4kG,*3 &2  
bStop = true; S/^"@?z,vE  
} y=`2\L" O  
N$h{Yvbn  
&0NFb^8+  
} 'XZ) !1N  
O$IEn/%+  
F{EnOr`,m=  
/* \]=7!RQ\  
**FileAccess.java kB/D!1 "  
*//文件访问(定位,写) ,=tD8@a<  
package NetFox; |p><'Q% *  
import java.io.*; dik:4;  
@n(Z$)8tR  
D[^m{ 9_  
public class FileAccessI implements Serializable{ K@#(*."  
)Z(TCJ~~!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 (@t(?Js  
RandomAccessFile oSavedFile; o>/YAX:.!T  
long nPos; 'f[T&o&L/  
&$]v h  
C!Rs^/  
public FileAccessI() throws IOException {P{bOe  
{ V>R8GSx  
this("",0); --HF8_8;'  
} c.,2GwW  
NXNY"r7~  
_h X]%  
public FileAccessI(String sName,long nPos) throws IOException ;cPy1  
{ >)spqu]  
oSavedFile = new RandomAccessFile(sName,"rw"); AI,(z;{P  
this.nPos = nPos; Sg6"WV{<  
oSavedFile.seek(nPos); V#cqRE3XNi  
} x/;buW-  
DTa N"{  
89\n;5'f4  
public synchronized int write(byte[] b,int nStart,int nLen) Ytz)d/3T  
{ bty/  
int n = -1; #bl6sa{E  
try{ #;%JT   
oSavedFile.write(b,nStart,nLen); kMtwiB|7j  
n = nLen; x9;gT&@H  
} EGZb7:Y?  
catch(IOException e) dgA-MQ5{  
{ JcbwDlUb  
e.printStackTrace (); -TM 0]{  
} Eo#u#IY  
Q(<)KZIK  
%kB8'a3  
return n; 0JlZs]  
} r:F  
/ C>wd   
t?9v^vFR  
} Q\cjPc0y  
~.UrL(l=  
4eikLRD,  
/* 0%m)@ukb  
**SiteInfoBean.java $% 1vW=d  
*/ <Wp QbQM  
package NetFox; ow_djv:,  
Bx/L<J@  
{@tv>!WW  
public class SiteInfoBean { 4?-.Z UT-1  
iMs5zf <M  
N 5i+3&  
private String sSiteURL; //Site's URL hO';{Nl/$  
private String sFilePath; //Saved File's Path 9(6I<]#  
private String sFileName; //Saved File's Name \T <$9aNb  
private int nSplitter; //Count of Splited Downloading File 2I&o69x?  
>y[oP!-|P  
 ^}:#  
public SiteInfoBean() 3'^k$;^  
{//nSplitter的缺省值为5 6xZ=^;H  
//default value of nSplitter is 5 tQ H+)*  
this("","","",5); %*&UJpbA  
} P#fM:z@[  
,4ei2`wV  
sO.`x*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) L2, 1Kt7  
{ z .Y$7bf)  
sSiteURL= sURL; `;)\u  
sFilePath = sPath; E;1Jh(58)b  
sFileName = sName; tkXEHsRT  
this.nSplitter = nSpiltter; ;$a@J&  
mZx&Xez_G  
cZT({uYGL  
} RTv qls  
lWqrU1Sjl  
# g_Bx  
public String getSSiteURL() RB+N IoQQ|  
{ hWKJ,r%9;  
return sSiteURL;  nv0]05.4  
} t`+'r}=d  
h}]fn A  
~M\I;8ne  
public void setSSiteURL(String value) J,zO2572u  
{ 4"xPr[=iG  
sSiteURL = value; Rr!Y3)f;  
} 7^Ns&Q  
v{9t]s>B  
V^\8BVw  
public String getSFilePath() [-)r5Dsdq  
{ i} N8(B(  
return sFilePath; HO[wTB|D]  
} ' 4E R00  
om]4BRe  
<0S,Q+&  
public void setSFilePath(String value) SF5@Vg  
{ 1!.(4gV  
sFilePath = value; hs?sGr  
} +e-G,%>9  
JqMDqPIQ  
ZKXo-~=>  
public String getSFileName() !>>f(t4  
{ .VkbYK  
return sFileName; Dgx8\~(E'  
} 'w14sr%  
1*dRK6  
kWNV%RlSx  
public void setSFileName(String value) 3q`)*  
{ SL,p36N  
sFileName = value; 2e|N@j &  
} BSkDpr1C  
1y lk4@`  
M4d47<'*~  
public int getNSplitter() {U84 _Pi  
{ &R$CZU  
return nSplitter; @fa@s-wb  
} 4T?h  
sYdRh?Hq  
3LfC{ER  
public void setNSplitter(int nCount) in(U:04  
{ zLF?P3^  
nSplitter = nCount; KL ?@@7  
} :Dd$i_3=  
} +n7?S~R$  
l27\diKPJ  
~u.T-0F  
/* .S%0   
**Utility.java JkGnKm9G  
*/ ;A'":vXmc  
package NetFox; rY p3(k3  
}=v)Js  
f}L*uw  
public class Utility { Uz7^1.-g4  
7^M9qTEHp  
m~>Y{F2  
public Utility() #BQ.R,  
{ 3( ]M{4j  
7c;9$j  
jr)7kP@  
} Ed:eGm }  
0x9x@gF  
//线程睡眠 iA,kX\nK  
public static void sleep(int nSecond) >OP+^^oZ<  
{ f"( X(1F  
try{ c5Q<$86  
Thread.sleep(nSecond); ^{\<N()R  
} (708H_  
catch(Exception e) c)Ic#<e(  
{ DaH?@Q  
e.printStackTrace (); NWd<+-pC6  
} 4Td{;Y="yF  
} :aG#~-Q  
3&x-}y~sg  
//日志 af |5n><~A  
public static void log(String sMsg) ]7Fs$y.  
{ NO] 3*  
System.err.println(sMsg); siTX_`0  
} St<mDTi  
.@"q$\  
g!i45-n3gt  
public static void log(int sMsg) *FfMI  
{ up2+ s#  
System.err.println(sMsg); unJ R=~E  
} U#n#7G6fRp  
} KK,Z"){  
zFQ&5@43  
[Px'\ nVf  
/* {T'GQz+R"  
**TestMethod.java KI]wm  
*/ 4 V1bLm  
package NetFox; ,+;:3gRk9  
@R m-CWa  
D{v8q)5r  
public class TestMethod { `p'Q7m2y/b  
!WkIi^T  
3@n>*7/E  
public TestMethod() +m}Pmi$  
{ ///xx/weblogic60b2_win.exe __@zTSVb  
try{ < pTTo  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =H8 xSJLh  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 4gSH(*}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); b.O9ITR  
fileFetch.start(); J4=_w  
} CU:o*;jP  
catch(Exception e){e.printStackTrace ();} dx,=Rd5'  
&ff&Y.q~  
WhBpv(q}.  
} 8SmnMt  
hSGb-$~F  
7B3w\  
public static void main(String[] args) *[eL~oN.c  
{  ySbqnw'  
new TestMethod(); 39 Y(!q  
} @>x pYV  
} mfny4R1_  
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