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http断点续传简单实现(java)

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/* %i-lx`U  
**SiteFileFetch.java N+M&d3H`  
*/ [-t> G!)  
package NetFox; '95E;RV&  
import java.io.*; )6>|bmpU  
import java.net.*; MpA;cw]cI/  
z g7l>9Sc  
R==cz^#  
public class SiteFileFetch extends Thread { Ejms)JK+  
I\upnEKKzZ  
>_`D3@Rz  
SiteInfoBean siteInfoBean = null; //文件信息Bean [DxefYyI  
long[] nStartPos; //开始位置 nheU~jb  
long[] nEndPos; //结束位置 M> jBm .  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ls24ccOs  
long nFileLength; //文件长度 t\pK`DM-[  
boolean bFirst = true; //是否第一次取文件 XU_,Z/Yw_  
boolean bStop = false; //停止标志 <.WM-Z  
File tmpFile; //文件下载的临时信息 zNny\Z  
DataOutputStream output; //输出到文件的输出流 M7DLs;sD  
FGwnESCC  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) :5S |x/  
public SiteFileFetch(SiteInfoBean bean) throws IOException x$n~f:1Y  
{ 7<:Wq=e!r  
siteInfoBean = bean; 3_MS'&M  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); V[Rrst0yo  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); qEJ8o.D-=  
if(tmpFile.exists ()) u\XkXS`  
{ 8pPC 9ew\=  
bFirst = false; ^.#X<8hr  
read_nPos(); 3kiE3*H  
} x_<bK$OU  
else a_{io`h3&  
{ 0TO_1 0D  
nStartPos = new long[bean.getNSplitter()]; eOehgU5x  
nEndPos = new long[bean.getNSplitter()]; )[^y t0%  
} {jhmp\PN  
"%E-X:Il#  
VyWYfPK  
ov`^o25f  
} q#99iiG1  
JOrELrMx  
=_RcoG/^~  
public void run() N^\2 _T  
{ @VC .>  
//获得文件长度 LZr0]g{Pu/  
//分割文件 F gWkcV6B  
//实例FileSplitterFetch 0+}EA[  
//启动FileSplitterFetch线程 a|QE *s.  
//等待子线程返回 /o~qC<7  
try{ *BLe3dok(  
if(bFirst) 3vdu;W=Sz  
{ )'[x)q  
nFileLength = getFileSize(); "{A*(.  
if(nFileLength == -1) ;8*XOC;[  
{ h `\$sT!Z  
System.err.println("File Length is not known!"); nn@^K6  
} 7m:|u*ij2~  
else if(nFileLength == -2) UzgA26;  
{ v /R[?H)  
System.err.println("File is not access!"); b0@>xT  
} b4Z`y8=  
else  R"U/RS  
{ &yx NvyA[u  
for(int i=0;i<nStartPos.length;i++) Zc'|!pT _  
{ /m `}f]u  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); s\'y-UITi1  
} p)B33Z zC  
for(int i=0;i<nEndPos.length-1;i++) 6a4'xq7  
{ *Y85DEA  
nEndPos = nStartPos[i+1]; )jyq{Jb  
} O^9CV*]!n  
nEndPos[nEndPos.length-1] = nFileLength; zL:&Q<  
} jR{-  
} Rx6l|'e  
TB7>s~)47E  
gq'>6vOj  
//启动子线程 _wf5%(~b  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; j G-  
for(int i=0;i<nStartPos.length;i++) I|,pE**T  
{ Y5dD|]F|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]} 61vV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), q$r&4s)To  
nStartPos,nEndPos,i); sl/=g   
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #D+7TWDwNt  
fileSplitterFetch.start(); U;xu/xDRi  
} @#RuSc  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Rn`ld@=p[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 'lJEHz\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ?X\3&Ujy$  
nEndPos = " + nFileLength); `|$'g^eCL  
// fileSplitterFetch[nPos.length-1].start(); {5^K Xj$B  
\6{krn|  
qysTjGwa]  
//等待子线程结束 9-0<*)"b>  
//int count = 0; *~ p (GC  
//是否结束while循环 :e*DTVv8  
boolean breakWhile = false; 8b|OXWl  
u!Xb?:3uj  
& _; y.!  
while(!bStop) 2w+U$6e C  
{ lnS(&`oh\=  
write_nPos(); xfjd5J7'  
Utility.sleep(500); #/Ruz'H1>  
breakWhile = true; vr=~M?  
l DN"atSf  
A)tP()+)  
for(int i=0;i<nStartPos.length;i++) w|IjQ1{  
{ ! Tx&vtq  
if(!fileSplitterFetch.bDownOver) TZ[Zm  
{ bS.s?a  
breakWhile = false; 33Jd!orXU  
break; JVtQ ,oZ  
} =#qZ3 Qz_  
} &FSmqE;@^  
if(breakWhile) "~F3*lk#E  
break; <5S@ORN  
k<a;[_S  
.evbE O5  
//count++; |EKu2We*  
//if(count>4) E<tK4?i"  
// siteStop(); =; 0wFwSz  
} !b8uLjd;  
YEv%C| l  
<$%X<sDkq  
System.err.println("文件下载结束!"); -$(Jk<  
} jMM$d,7B  
catch(Exception e){e.printStackTrace ();} E@-ta):  
} bLzs?eos  
8WL8/  
+#2)kg 9_  
//获得文件长度 ~ 3^='o  
public long getFileSize() ]hA,LY f  
{ LxLy+yC#p  
int nFileLength = -1; `K*b?:0lp  
try{ B z^|SkEit  
URL url = new URL(siteInfoBean.getSSiteURL()); q2hFOm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %SrM|&[  
httpConnection.setRequestProperty("User-Agent","NetFox"); M|q~6oM  
#]CFA9 z  
+Y}V3(w9X  
int responseCode=httpConnection.getResponseCode(); `ltN,?/  
if(responseCode>=400) <Mx0\b!  
{ [}OgSP9i  
processErrorCode(responseCode); nd ink$  
return -2; //-2 represent access is error F>zl9Vi<  
} rYY$wA@  
LCs__.  
$Az^Y0[D  
String sHeader; 'fx UV<K&  
9i5tVOhE  
K{@3\5<  
for(int i=1;;i++) N|mJg[j@7  
{ (hB?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); "9IYB)Js  
//Utility.log(in.readLine()); (-0ePSOG  
sHeader=httpConnection.getHeaderFieldKey(i); ZrO!L_/  
if(sHeader!=null) +x=)/;:  
{ ?^i1_v7 Bi  
if(sHeader.equals("Content-Length")) 0V$k7H$Z  
{ k'T^dY&c  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); :Zt2'vcGpf  
break; +-<}+8G;  
} z0%\OhuCcf  
} iYJZvN  
else F(5hmr  
break; /P:.qtT(  
} -`b8T0?oK  
} `Out(Hn  
catch(IOException e){e.printStackTrace ();} IvHh4DU3Z  
catch(Exception e){e.printStackTrace ();} =-KMb`xT  
8j5<6Cv_  
/ASaB  
Utility.log(nFileLength); E<E3&;qD  
HDVW0QaMu  
Z(u5$<up  
return nFileLength; ~YP Jez  
} X(A.X:"  
#m<tJnEO  
M;w?[yEZ  
//保存下载信息(文件指针位置) :~F:/5  
private void write_nPos() 59r_#(uo  
{ K+Y^>N4m  
try{ -d+aV1n  
output = new DataOutputStream(new FileOutputStream(tmpFile)); oVvc?P  
output.writeInt(nStartPos.length); h.eM RdlO  
for(int i=0;i<nStartPos.length;i++) @L/o\pvc  
{ @I`C#~  
// output.writeLong(nPos); vI1i, x#i  
output.writeLong(fileSplitterFetch.nStartPos); ^EELaG  
output.writeLong(fileSplitterFetch.nEndPos); "9!d]2.-Vk  
} 2I/xJ+  
output.close(); $e1=xSQp4  
} S4UM|`  
catch(IOException e){e.printStackTrace ();} t5B7I59  
catch(Exception e){e.printStackTrace ();} 1'.7_EQ4T  
} 2P#=a?~[  
#KxbM-1=  
g.py+ ZFJ  
//读取保存的下载信息(文件指针位置) [XVEBA4GI  
private void read_nPos() wh6yPVVF/  
{ Q=mI 9  
try{ _"@CGXu  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); `x8J  
int nCount = input.readInt(); 'e)^m}:?D  
nStartPos = new long[nCount]; j/`94'Y  
nEndPos = new long[nCount]; dU)]:>Uz  
for(int i=0;i<nStartPos.length;i++) H}hFFI)#Oo  
{ :bu>],d-8'  
nStartPos = input.readLong(); &;yH@@Z  
nEndPos = input.readLong(); b[9&l|y^  
} /X"/ha!=&D  
input.close(); qfY5Ww$8  
} o+w;PP)+=  
catch(IOException e){e.printStackTrace ();} Zxr!:t7  
catch(Exception e){e.printStackTrace ();} Fm\"{)V:b  
} in+}/mwfC  
b-ll  
fmqb` %  
private void processErrorCode(int nErrorCode) v ^[39*8  
{ F{06 _T  
System.err.println("Error Code : " + nErrorCode); sUZX }  
} ;~fT,7qBah  
[.se|]t7X  
Od+6 -J  
//停止文件下载 PZxAH9 S?  
public void siteStop() <+MyZM(z>  
{ -fhN"B)  
bStop = true; L`f^y;Y.  
for(int i=0;i<nStartPos.length;i++) 5oEV-6  
fileSplitterFetch.splitterStop(); o#) {1<0vg  
}En  
!+>v[(OzM  
} qm/Q65>E  
} :NJ_n6E  
//负责部分文件的抓取 pl@O N"=[  
**FileSplitterFetch.java NBl+_/2'w  
*/ )?+$x[f!*  
package NetFox; 1b=lpw 1}  
oSiMpQu08  
|4$M]Mf0  
import java.io.*; b@RHc!,>jV  
import java.net.*; `&\Q +W  
X%z }VA  
+$4(zP s@  
public class FileSplitterFetch extends Thread { L,y6^J!  
8n1'x;  
! cKz7?w  
String sURL; //File URL =q N2Xg/  
long nStartPos; //File Snippet Start Position rpeJkG@+  
long nEndPos; //File Snippet End Position SJD@&m%?[  
int nThreadID; //Thread's ID u\&b4=nL  
boolean bDownOver = false; //Downing is over P96pm6H_;  
boolean bStop = false; //Stop identical +]=e;LN$0  
FileAccessI fileAccessI = null; //File Access interface zvABU+{jD  
fYKOJ5f  
`:N# 'i  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException .MO\uh0N  
{ B8E'ddUw  
this.sURL = sURL; 4iSa7YqhBT  
this.nStartPos = nStart; n]8<DX99Q0  
this.nEndPos = nEnd; %X#zj"  
nThreadID = id; :#dE:L;T  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 2,ECYie^  
} \RNg|G  
/Mb"V5S(W  
_|h8q-[3  
public void run() oIUy-|  
{ U(~+o  
while(nStartPos < nEndPos && !bStop) 8r3A~  
{ Ol4+_n8xj  
2WUT/{:X  
Uj&W<'I  
try{ xsWur(>]  
URL url = new URL(sURL); ~?B;!Csk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'SQG>F Uy  
httpConnection.setRequestProperty("User-Agent","NetFox"); (sVi\R  
String sProperty = "bytes="+nStartPos+"-"; nUkaz*4qU  
httpConnection.setRequestProperty("RANGE",sProperty); f~ }H  
Utility.log(sProperty); !i=nSqW  
9UvXC)R1  
eQQ>  
InputStream input = httpConnection.getInputStream(); ^CwR!I.D}4  
//logResponseHead(httpConnection); wAnb Di{W  
!w&kyW?e  
2^?:&1:  
byte[] b = new byte[1024]; apE   
int nRead; n3J53| %v  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) cwGbSW$t  
{ NcY608C  
nStartPos += fileAccessI.write(b,0,nRead); }9nDo*A"}  
//if(nThreadID == 1) AT5aDEb^^  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c-.t>r &  
} $-[CG7VgX%  
M'_9A  
Tw +  
Utility.log("Thread " + nThreadID + " is over!"); `xrmT t X  
bDownOver = true; 5dZ|!  
//nPos = fileAccessI.write (b,0,nRead); 1sYEZO;  
} odIZo|dv  
catch(Exception e){e.printStackTrace ();} 42]pYm(jk3  
} ?-1r$31p  
} &=4(l|wcg  
DBLO|&2!z[  
JEE{QjTh  
//打印回应的头信息 fGmT_C0t  
public void logResponseHead(HttpURLConnection con) CbN!1E6).  
{ *Q1~S]g  
for(int i=1;;i++) ]9\!;Bz^J  
{ P./VmY'  
String header=con.getHeaderFieldKey(i); c6Y\n%d&  
if(header!=null) ;NNe!}C  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); kI%%i>Y}  
Utility.log(header+" : "+con.getHeaderField(header));  \>Efd  
else (Vo>e =q  
break; 7Pa@1']  
} A&>.74}p  
} V2N_8)s9W  
L/"0ws_  
LzYO$Ir:g  
public void splitterStop() >0l"P"]  
{ !ti6  
bStop = true; id$Ul?z8  
} 02Ia2e.f  
L\;6y*K  
&N3Y|2  
} VN%INUi@  
gzeQ|m2]  
>MPr=W%E  
/* g[w,!F  
**FileAccess.java Z}-Vf$O~  
*//文件访问(定位,写) JMTvSXr  
package NetFox; -j&Tc` j_  
import java.io.*; ['ksP-=  
KoS*0U<g6  
5O`dO9g}$  
public class FileAccessI implements Serializable{ Hk|0HL  
$-On~u0g  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8XsguC  
RandomAccessFile oSavedFile; &d'Awvy0  
long nPos; &N;-J2M  
0q&'(-{s1  
><=gV~7lx  
public FileAccessI() throws IOException 1 E22R  
{ eAqz3#_My  
this("",0); l&}y/t4%  
} v(p mI b{  
]^6c8sgnR  
;U_QvN|  
public FileAccessI(String sName,long nPos) throws IOException +S=Rn,  
{ w^]6w\p  
oSavedFile = new RandomAccessFile(sName,"rw"); UQ4% Xp  
this.nPos = nPos; nJ" '  
oSavedFile.seek(nPos); w4fW<ISg  
} ;*,f<  
not YeY7wR  
~,2/JDVJ5-  
public synchronized int write(byte[] b,int nStart,int nLen) wfjnA~1h  
{ fK(}Ce  
int n = -1; #0Tq=:AE>  
try{ Bphof0{<}  
oSavedFile.write(b,nStart,nLen); #Z5}2soA  
n = nLen; Iuh/I +[7  
} c*R/]Dn   
catch(IOException e) ?Mee 6  
{ 'FYJMIs  
e.printStackTrace (); *s;|T?~i  
} O2"gj"D  
vp.ZK[/`  
O-4C+?V  
return n; ){Ob,LEU&  
} "kc/J*u-3  
M|] "W  
Ka`=WeJ|  
} Yf[Qtmh]I  
M5x U9]B  
>fIk;6<{  
/* mJM _2Ab  
**SiteInfoBean.java B7z -7&TE  
*/ ^H6<Km l/V  
package NetFox; V= 1Bo~  
hxS 6:5Uc  
R-P-i0 ~  
public class SiteInfoBean { K+6e?5t  
:g.46dp4  
Sua[O$  
private String sSiteURL; //Site's URL +\r+n~w  
private String sFilePath; //Saved File's Path 1J' 3g  
private String sFileName; //Saved File's Name "al `$%(  
private int nSplitter; //Count of Splited Downloading File }E_#k]#*  
\8uIER5)  
)+Oujt  
public SiteInfoBean() U#1bp}y  
{//nSplitter的缺省值为5 0T>H)c6:\  
//default value of nSplitter is 5 72veLB  
this("","","",5); 5 B=^v#m  
} P#:?ok  
wRrnniqf8  
3T&6opaF  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?^j^K-rx  
{ $u/E\l  
sSiteURL= sURL; +NFzSal  
sFilePath = sPath; z ;u  
sFileName = sName; %4W$Lq}  
this.nSplitter = nSpiltter; V:G>G'Eh0  
P<fnLQ9  
Q%-di=  
} R-:fd!3oQ  
lb:/EUd5  
RNQK  
public String getSSiteURL() hTbI -u7BF  
{ !'Q -yoHKD  
return sSiteURL; |A8/FU2{  
} WF\)fc#;_o  
ZR\VCVH\^  
21(p|`X  
public void setSSiteURL(String value) sFBneBub  
{ &[hLzlrg  
sSiteURL = value; vp(;W,ba:|  
} #b7$TV  
wR{'y)$  
wW"z  
public String getSFilePath() ,<:!NF9  
{ 3R&lqxhg  
return sFilePath; _`#3f1F@[  
} 1xc~`~  
yObuWDA9  
b}Zd)2G  
public void setSFilePath(String value) ".dZn6"mI  
{ z%/N!RLW  
sFilePath = value; smm]6  
} ]!IVz)<E&  
}(<%`G6N  
hb{ u'=  
public String getSFileName() 1EyL#;k  
{ N 75:5  
return sFileName; `EtS!zD~b  
} V_Wwrhua  
# 6!5 2  
V#jWege  
public void setSFileName(String value) F_bF  
{ .I@CS>j  
sFileName = value; H}LS??P  
} .6OgO{P:  
!d&C>7nb  
.SWt3|Pi5  
public int getNSplitter() 2y%,p{="  
{ fBQ?|~:n  
return nSplitter; 7u[j/l,  
} s[gKc'  
phE &7*!Q  
FW"^99mrnb  
public void setNSplitter(int nCount) "6a8s;  
{ W(hMft%  
nSplitter = nCount; vLxQ *50v$  
} r",]Voibd  
} c/ 5W4_J  
xm6EKp:  
F:#J:x'  
/* oDcKtB+2  
**Utility.java ?:Y#Tbi3  
*/ S!{t6'8K  
package NetFox; 8?Z4-6!{V,  
+w8R!jdA  
x3rlJs`$;  
public class Utility { 8t=(,^c  
_ %%Z6x(  
*6 U&Qy-M  
public Utility() IHp_A  
{ A6oq.I0  
G Xt4j  
uGs; }<<8  
} ~r{5`;c  
}Yv\0\~'W|  
//线程睡眠 Bb{!Yh].:A  
public static void sleep(int nSecond) {_U Kttp  
{ it2 a  
try{ 0[<~?`:)  
Thread.sleep(nSecond); oQ=>'w  
} c)&>$S8*  
catch(Exception e) 4'p=p#o  
{ )f dE6  
e.printStackTrace (); VGqa)ri"  
} irk*~k ?  
} IcIOC8WC  
*1@:'rJ  
//日志 C>Is1i^9  
public static void log(String sMsg) |Oag,o"  
{ dO7;}>F$n  
System.err.println(sMsg); _ IeU+tS  
} ?GBkqQ  
joul<t-  
gh6d&ucQ^  
public static void log(int sMsg) !AJ]j|@VBd  
{ Npn=cLC&  
System.err.println(sMsg); H.G!A6bd  
} KLC{7"6e)  
} TzBzEiANn  
2l5KJlfj>k  
c<#<k}y  
/* nY $tp  
**TestMethod.java iq*A("pU  
*/ UofTll)  
package NetFox; ^zEE6i  
7~M<cD  
eo^/c +FG  
public class TestMethod { $j)hNWI  
2AVc? 9@  
XN,,cU  
public TestMethod() F^!mI7Z|(2  
{ ///xx/weblogic60b2_win.exe mKq"3 4F  
try{ *^ \FIUd  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2i|B=D(  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ]IJv-(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); mDFlz1J,e  
fileFetch.start(); Ri>?KrQF%  
} `:M^8SYrL  
catch(Exception e){e.printStackTrace ();} "8V{5e!%j'  
V,%L ~dI  
djT5 X  
} d77r9  
-v?hqWMp#  
7t-Lz| $"  
public static void main(String[] args) }%{MPqg  
{ NN 0Q`r,8}  
new TestMethod(); r+<{S\ Q  
} si(;y](  
} uHNpfKnZ  
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