http断点续传简单实现（java)

/* (ke<^sv7!  
**SiteFileFetch.java dt>!=<|k  
*/ =Y3
d~~  
package NetFox; jd+HIR  
import java.io.*; !wrAD"l*@  
import java.net.*; 9I|Q`j?p`  
{#{nU NW  
% e70*;  
public class SiteFileFetch extends Thread { $i `@0+:  
2[Qzx%Vp  
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SiteInfoBean siteInfoBean = null; //文件信息Bean (ub
K i[)  
long[] nStartPos; //开始位置 A_6Dol=J@  
long[] nEndPos; //结束位置 /#xYy^`  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 lFgE{;z@  
long nFileLength; //文件长度 .9!&x0;  
boolean bFirst = true; //是否第一次取文件 4vH.B)S-  
boolean bStop = false; //停止标志 6>EoU-YX}l  
File tmpFile; //文件下载的临时信息 Pb :6nH=  
DataOutputStream output; //输出到文件的输出流 =gB{(   
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ht5:kt`F  
public SiteFileFetch(SiteInfoBean bean) throws IOException 7nPm{=BG  
{ wi:d!,P`e  
siteInfoBean = bean; Rk{2ZUeg  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #|e5i9l*B  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 9+>%U~U<  
if(tmpFile.exists ()) KEr?&e  
{ k.F(*kh  
bFirst = false; IZ_ B $mo  
read_nPos(); 9l7 youZ]  
} Q[Tbdc%1EG  
else Nk>6:Ho{G  
{ Z
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nStartPos = new long[bean.getNSplitter()]; rmnnV[@o  
nEndPos = new long[bean.getNSplitter()]; 5YiBw|Z7 "  
} N<lf,zGw  
"\1V^2kMr  
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} 3j$,x(ua9  
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dU"C=c(w\  
public void run() _k W:FB  
{ xJ|Z]m=d   
//获得文件长度 iwEHEi%  
//分割文件 YpbJoHiSH  
//实例FileSplitterFetch `JG7Pl/ih  
//启动FileSplitterFetch线程 yz=6 V%  
//等待子线程返回 ]GHx<5Q:\  
try{ i0&]Ig|;  
if(bFirst) [6Nzz]yy  
{ 3nkO+qQ  
nFileLength = getFileSize(); 'P)[=+O?t  
if(nFileLength == -1) CQ%yki  
{ >qIZ  
System.err.println("File Length is not known!"); KT
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} a<V* )  
else if(nFileLength == -2) V-9z{  
{ qS2]|7q?Tc  
System.err.println("File is not access!"); xZ&S7G1  
} qT_E=)
1  
else ?B,B<@='%  
{ s}Sxl0  
for(int i=0;i<nStartPos.length;i++) x1*@PiO,.  
{ Z{.L_]$I  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \U'TL_Ql  
} ,}42]%$G  
for(int i=0;i<nEndPos.length-1;i++) 9]/ju  
{ W.U|mNJ$
 
nEndPos = nStartPos[i+1]; \~q cYp  
} o!t1EPJE*  
nEndPos[nEndPos.length-1] = nFileLength; -wV0Nv(V8  
} z15QFVm  
} O0<GFL$)&  
ZZl4|  
EC|b7  
//启动子线程 Z})n%l8J]p  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \\~4$Ai[  
for(int i=0;i<nStartPos.length;i++) t]%!vXo  
{ kOuQR$9s  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^l/$ 13=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }u7&SU  
nStartPos,nEndPos,i); q&wXs/$a  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mJ5LRpXN  
fileSplitterFetch.start(); h?:Y\DlU'  
} p
NzGpCk  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), gb0ZGnI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); OECXN
x  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", X{riI^(  
nEndPos = " + nFileLength); <ByDT$E_  
// fileSplitterFetch[nPos.length-1].start(); IN9o$CZ:  
MRHkQE+K@8  

P1l@K2r  
//等待子线程结束 #[#dc]D  
//int count = 0; KBFAV&  
//是否结束while循环 DWH)<\?  
boolean breakWhile = false; Uyyw'Ni  
k||DcwO  
+#<"o#gZ  
while(!bStop) RsDI7v  
{ #8d$%F))  
write_nPos(); p{Gg,.f!HM  
Utility.sleep(500); s2ys>2k  
breakWhile = true; i(c'94M  
DP_bB(  
N6<23kYM  
for(int i=0;i<nStartPos.length;i++) K\ \UF  
{ uNY]%[AnJ  
if(!fileSplitterFetch.bDownOver) ]H[FZY  
{ MY[
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breakWhile = false; 8)k.lPoo.  
break; w,.Hdd6  
} tgYIM`f  
} :PaFC{O)*  
if(breakWhile) O_PC/=m1@  
break; $mOK|=tI_  
g%<7Px[W  
{:enoV"  
//count++; 6A/|XwfE/v  
//if(count>4) K~WwV8c9;  
// siteStop(); Ja#idF[V  
} Z [5HI;  
n{Mj<\kL  
(Qq$ql27  
System.err.println("文件下载结束！"); c(AjM9s  
} {w^flizY  
catch(Exception e){e.printStackTrace ();} h OboM3_  
} qwaw\vO
A  
4p~:(U[q  
(<.1o_Q-LU  
//获得文件长度 +T^m  
public long getFileSize() WiviH#hF  
{ Ahq^dx#o  
int nFileLength = -1; tZXtt=M w  
try{ MOmp{@  
URL url = new URL(siteInfoBean.getSSiteURL()); aTs_5
q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^HL#)fK2I  
httpConnection.setRequestProperty("User-Agent","NetFox"); XfsCu>  
}wkBa]  
]3QQ"HLcp  
int responseCode=httpConnection.getResponseCode(); _L!"3  
if(responseCode>=400) D\V}Eo';6  
{ Krq^|DY  
processErrorCode(responseCode); .+B)@?  
return -2; //-2 represent access is error g%=\Wiit]  
} j4}aK2[<  
t7A.b~#  
I"JT3[*s  
String sHeader; ESASsRzk  
$@&bK2@.(  
($W9 ?
  
for(int i=1;;i++) ccm <rZ7  
{ Ruk6+U  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); SqTm/ t  
//Utility.log(in.readLine()); 3nK'yC  
sHeader=httpConnection.getHeaderFieldKey(i); );|~4#  
if(sHeader!=null) [bT@Y:X@`  
{ <qRw! 'S^  
if(sHeader.equals("Content-Length")) `g :<$3}  
{ u%[*;@;9+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); jv|IV  
break; kxUGd)S  
}  BW\R  
} LL6f40hC  
else esu6iU@  
break; WD?V1:>+  
} mmKrmM*1  
} .$OInh  
catch(IOException e){e.printStackTrace ();} 1)PR]s:-m@  
catch(Exception e){e.printStackTrace ();} ntkinbbD  
bA^a@ lv a  
z vYDE]  
Utility.log(nFileLength); ' R@<4Ib|  
*/+s^{W7  
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return nFileLength; ;_SS3q  
} 1Ev+':%  
{Jy%h8n*  
\rN_CBM  
//保存下载信息（文件指针位置） UQdQtj1'  
private void write_nPos() Cg|uHI*  
{ 88*RlxU  
try{ d!LV@</  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <V8i>LBlz  
output.writeInt(nStartPos.length); 7S7!  
for(int i=0;i<nStartPos.length;i++) Y}#^n7*w~  
{ f:Ja  
// output.writeLong(nPos); 'q^Gg;c>+  
output.writeLong(fileSplitterFetch.nStartPos); D8#q.OR]  
output.writeLong(fileSplitterFetch.nEndPos); &Egn`QU  
} %7@H7^s}9  
output.close(); m{5$4v,[
 
} RQ'c~D)X  
catch(IOException e){e.printStackTrace ();} dB,#`tc=,  
catch(Exception e){e.printStackTrace ();} w:LCm `d  
} 4>Y\2O?**  
).boe& .  
>>8w(PdTn%  
//读取保存的下载信息（文件指针位置） C}kJGi  
private void read_nPos() ppD~xg]  
{ A X#!9-m3  
try{ U`Ag|R  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); A-u5  
int nCount = input.readInt(); =iQm_g  
nStartPos = new long[nCount]; 0EB'!  
nEndPos = new long[nCount]; 8{l=`y"nB  
for(int i=0;i<nStartPos.length;i++) .0-m=3mp2  
{ yy74>K  
nStartPos = input.readLong(); ? 7EVmF  
nEndPos = input.readLong(); d&u/7rm  
} 4a|Fx  
input.close(); '9dtIW6E  
} Om"3Q/&  
catch(IOException e){e.printStackTrace ();} Mfr#IzNHN  
catch(Exception e){e.printStackTrace ();} Ny'v/+nQ  
} c+{4C3z  
K{P#[X*5  
;X6y.1N~  
private void processErrorCode(int nErrorCode) [Z+,)-ke  
{ #dt2'V- ,  
System.err.println("Error Code : " + nErrorCode); b?NeSiswn  
} -}sya1(<8  
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7jbmw<d)9  
//停止文件下载 I`kp5lGD2  
public void siteStop() mwCnP8:K  
{ e;
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bStop = true; T!A}ipqb  
for(int i=0;i<nStartPos.length;i++) F?ebYk1  
fileSplitterFetch.splitterStop(); 9GwsQ \  

>[: 2  
j*`!o/=LI  
} nQHd\/B  
} =k7\g /  
//负责部分文件的抓取 mX?{2[  
**FileSplitterFetch.java Kx+Bc&X  
*/
49$4  
package NetFox; fEc_r:|\6  
cZzZNGY^ts  
r3_gPK  
import java.io.*; 4Z<l>!  
import java.net.*; ({VBp[Mh  
K-C,+eI  
g0OS<,:
 
public class FileSplitterFetch extends Thread { ,b(S=r  
vxT"BvN  
DOIWhd5:  
String sURL; //File URL -\$cGIL  
long nStartPos; //File Snippet Start Position RbM~E~$  
long nEndPos; //File Snippet End Position $)]FCuv  
int nThreadID; //Thread's ID kw:D~E(  
boolean bDownOver = false; //Downing is over j/pQSlV  
boolean bStop = false; //Stop identical Le JlTWotC  
FileAccessI fileAccessI = null; //File Access interface f{c[_OR  
kte.E%.PE  
:+Ax3  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException I 47GQho  
{ 6CmFmc,  
this.sURL = sURL; # pB:LPEsK  
this.nStartPos = nStart; =DTOI  
this.nEndPos = nEnd; e=UVsYNx  
nThreadID = id; cloSJmUlQ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 e@-Mlq)  
} {/xs9.8:JX  
TK/'
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public void run() `A _8nW)  
{ ,Z7Z!.TY!  
while(nStartPos < nEndPos && !bStop) s [F' h-y  
{ =G F  
7XWBI\SW  
$,,>R[;w  
try{ }lTZq|;A  
URL url = new URL(sURL); +Z<Q^5w@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j~*Z7iu  
httpConnection.setRequestProperty("User-Agent","NetFox"); e=z_+gVm  
String sProperty = "bytes="+nStartPos+"-"; x0h3jw+6  
httpConnection.setRequestProperty("RANGE",sProperty); ![]I%'s  
Utility.log(sProperty); )c >B2
3D  

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E5
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InputStream input = httpConnection.getInputStream(); '
b?.\Bm;  
//logResponseHead(httpConnection); |z]2KjF&w-  
:t{vgi D9  
}R&5qpl  
byte[] b = new byte[1024]; %s@S|< W  
int nRead; N[<`6dpE  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) X/8iJ-KB  
{ ?wf+{x-dPP  
nStartPos += fileAccessI.write(b,0,nRead); _6UAeZ*M  
//if(nThreadID == 1) <I%9O:R  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8{<[fZyC  
} ?5v5:U(A  
1uS-Tx  
)Ct*G= N  
Utility.log("Thread " + nThreadID + " is over!"); GP[r^Z  
bDownOver = true; ,;iBeqr5  
//nPos = fileAccessI.write (b,0,nRead); @fH&(@  
} c\MsVH2|  
catch(Exception e){e.printStackTrace ();} A$%!9Cma  
} CTkN8{2S  
} )ozcr^  
Pb8Z))9j  
1!(%<R  
//打印回应的头信息 uo4$rf7  
public void logResponseHead(HttpURLConnection con) d[]p_oIQq  
{ n1>,#|#  
for(int i=1;;i++) v^c<`i;  
{ \;*}zX  
String header=con.getHeaderFieldKey(i); d$_q=ywc  
if(header!=null) |^PLZ>  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); MFH"$t+  
Utility.log(header+" : "+con.getHeaderField(header)); [+l  
else 6Z7pz
tk  
break; N~$Zeq=  
} ~kYqGH  
} 2yQ}Lxr(  
xe6_RO%  
%+xwk=%*  
public void splitterStop() r[v-?W'  
{ },fo+vRM  
bStop = true; u.
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} G?ugMl}  
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U$A7EFK'  
} 2b#(X'ob  
wVp4c?s  
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/* E./__Mz@  
**FileAccess.java \POnsM)+l  
*//文件访问(定位，写) \|~?x#aA  
package NetFox; !FB \h<6  
import java.io.*; L8dU(P  
~n/Aq*  
Be{/2jU%  
public class FileAccessI implements Serializable{ Jh\:X<q  
j6e}7  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 7rdw`  
RandomAccessFile oSavedFile; {x[;5TM  
long nPos; fK'.wX9  
7<3U?]0  
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public FileAccessI() throws IOException GOf`Z'\xt  
{ {Vxc6,=  
this("",0); &"[)s[m+t  
} _hy{F%}  
x7.QL?qR.  
5pM&h~M
 
public FileAccessI(String sName,long nPos) throws IOException `V&1]C8x  
{ CZyz;Jtk  
oSavedFile = new RandomAccessFile(sName,"rw"); W-z90k4Z5  
this.nPos = nPos; i,#k}CNu  
oSavedFile.seek(nPos); h`5YA89  
} J%\
- 1  
AfRW=&xdT  
3I"NI.>*  
public synchronized int write(byte[] b,int nStart,int nLen) *K(k Kph
 
{ +}^|dkc  
int n = -1; 1yBt/
U2  
try{ :xFu_%7  
oSavedFile.write(b,nStart,nLen); hIuMHq7h  
n = nLen; iiX\it$s  
} %kh#{*q$  
catch(IOException e) Q(510)  
{ GIm " )}W  
e.printStackTrace (); 46bl>yk9<  
} \.H9$C$  
+Qh[sGDdY  
F$Im9T6  
return n; bVoU|`c  
} V@D]bV@4  
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} M18qa,fK{  
+Edzjf~Tt  
/gz:zThf{  
/* bLgL0}=n  
**SiteInfoBean.java YijMF/Uyb  
*/ S&4+ e:K  
package NetFox; /!3ZWXY\  
/!GKh5|  
 7%}a
y  
public class SiteInfoBean { e~{^oM  
FR x6c  
ZFS7{:  
private String sSiteURL; //Site's URL
nbI=r+  
private String sFilePath; //Saved File's Path AGOx@;w  
private String sFileName; //Saved File's Name 7}be>(  
private int nSplitter; //Count of Splited Downloading File UJz#QkAio  
J["H[T*  
^GMJ~
[]  
public SiteInfoBean() gmh5 %2M  
{//nSplitter的缺省值为5 KRYcCn  
//default value of nSplitter is 5 [X,A'Q  
this("","","",5); AR%hf  
} "8N"Udu  
TQP+>nS,  
Q%ruQ#  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) vUNisVA  
{ #s"851e  
sSiteURL= sURL; q|5Q?t:,r  
sFilePath = sPath; 5|ic3  
sFileName = sName; ?c!:81+\  
this.nSplitter = nSpiltter; Dv&>*0B  
w |_GV}#_  
\6sqyWI %  
} v:KX9A.  
b'i'GJBQ+$  
.~3kGf":  
public String getSSiteURL() bpCNho$  
{ #(C/Cx54  
return sSiteURL; ;UYc  
} `} =yG_!A  
! ja[4.  
V vu(`9u]  
public void setSSiteURL(String value) |h}B{D  
{ !tEe\K\e  
sSiteURL = value; uWjN2#&,  
} @%1IkvJV  
;+ azeW^  
0VN7/=n|  
public String getSFilePath() ,_jC$  
{ @x1%)1  
return sFilePath; !Xj#@e  
} qI%&ay"/  
V1B(|P  
_qn?2u3mnR  
public void setSFilePath(String value) \M{[f=6llh  
{ @w\I qr  
sFilePath = value; 3e%nA8?  
} FJeiY#us  
2Il8f  
AF}gSNX  
public String getSFileName() s~^}F+n  
{ ~.^AL}zm_  
return sFileName; ?cKZ_c  
} VWx]1\  
%MZP)k,&U  
` #
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public void setSFileName(String value) Xc*U+M>U  
{ %'bJ:  
sFileName = value; VfSj E.|  
} e_.Gw"/Yl  
:^i^0dC  
eQUe >*  
public int getNSplitter() nirDMw[  
{ VT\"q1)p  
return nSplitter; X|}2_B  
} _Mk7U@j+9  
b[I8iSkfi  
$pyOn2}  
public void setNSplitter(int nCount) [P~hjm
J(y  
{ OsqNB'X  
nSplitter = nCount; `=UWqb(K_  
} @-HG`c ct  
} pav'1d%  
i,IB!x  
H/+B%2Zj  
/* W,XTF  
**Utility.java Djq!P  
*/ q_kdCO{:df  
package NetFox; q1?&Ev^  
s{0aBeq  
IQZ#-)[T"  
public class Utility { zCv"]%  
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_8,()t'"  
public Utility() |`TgX@,#9  
{ En{`@JsM  
U;N:j8  
8[vc?+>&  
} @$9'@")  
zcrY>t#l  
//线程睡眠 |`Or'%|PR  
public static void sleep(int nSecond) J(DN!  
{ aJ Z"D8C  
try{ Gg Jf7ie4  
Thread.sleep(nSecond); +M' H0-[  
} _{<seA  
catch(Exception e) :cB=SYcC%  
{ oVFnlA  
e.printStackTrace (); ^9Qy/Er'  
} =X\^J  
} ApBWuXp|u  
F8-?dpf'  
//日志 -Eu6U`"(  
public static void log(String sMsg) ~5FW[_  
{ 4}+/F}TbJ5  
System.err.println(sMsg); Od f[*  
} 7xRl9  
&xRo^iV?  
Q></`QWpoB  
public static void log(int sMsg) L:XC  
{ X+UJzR90  
System.err.println(sMsg); *na?n2Yzt  
} A,sr[Pa@  
} V|(H|9  
8J$|NYv_b  
9mA{K   
/* .X# `k  
**TestMethod.java vz.>~HBP  
*/ Po%
LE]v,  
package NetFox; [sB 9gY(  
n]E?3UGD@W  
Cj~'Lhmv'T  
public class TestMethod { }=c85f~i  
AbZKYF P  
/|* Y2ETOr  
public TestMethod() .L'
.c/ s  
{ ///xx/weblogic60b2_win.exe yw];P
o,  
try{ }zhGS!fO  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); wgCa58H76  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Fu!RhsW5j  
SiteFileFetch fileFetch = new SiteFileFetch(bean); J8mdoVt  
fileFetch.start(); SkmT`*v@  
} :POj6j/  
catch(Exception e){e.printStackTrace ();} `BlI@6th  
x)(|[  
u~A6bK*  
} ,l<6GB2\  
'Lu__NfN  
'7XIhN9  
public static void main(String[] args) z`:lcF{V  
{ 1t)il^p4[;  
new TestMethod(); `@nl  
} Q ]}Hd-  
} Lhqz\o  
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