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http断点续传简单实现(java)

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/* 2)W~7GED  
**SiteFileFetch.java @An "ClDa  
*/ "c'K8,+?  
package NetFox; p%?VW  
import java.io.*; /&T"w,D  
import java.net.*; vz^w %67&  
)ld !(d=  
Gv$}>YJ  
public class SiteFileFetch extends Thread { :SUU)jLq  
p1mY@  
@ff83Bg  
SiteInfoBean siteInfoBean = null; //文件信息Bean vT&xM  
long[] nStartPos; //开始位置 c!2j+ORz  
long[] nEndPos; //结束位置 L'KgB=5K&i  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 k`u:Cz#aB  
long nFileLength; //文件长度 X (0`"rjg  
boolean bFirst = true; //是否第一次取文件 L{i,.aE/nO  
boolean bStop = false; //停止标志 [=otgVteN"  
File tmpFile; //文件下载的临时信息 |Nfi y  
DataOutputStream output; //输出到文件的输出流 U`-]U2 "  
qFpRY7eq  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) B(z?IW&  
public SiteFileFetch(SiteInfoBean bean) throws IOException o`EL)K{  
{ :VB{@ED  
siteInfoBean = bean; tt%lDr1A)  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); a2vZ'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); U> @st="  
if(tmpFile.exists ()) h M/:zC:  
{ hG8 !aJo  
bFirst = false; +)cjW"9  
read_nPos(); >E:V7Fa  
} Af V a[{E  
else I8%2tLVY  
{ bt2`elH|  
nStartPos = new long[bean.getNSplitter()]; [og_0;  
nEndPos = new long[bean.getNSplitter()]; p^yuz (  
} W  :qQ  
1(;_1@P  
F^xhhz&e  
#+ <"`}]N  
} Sj`GP p  
;n"Nv }<C  
$7~T+fmF  
public void run() 3EHn}#+U  
{ 2/coa+Qkv]  
//获得文件长度 (n>gC  
//分割文件 F6vN{ FI  
//实例FileSplitterFetch C@$!'^ 61  
//启动FileSplitterFetch线程 ~dpU D F  
//等待子线程返回 7w_cKR1;  
try{ bL)7 /E  
if(bFirst) T`?{Is['(  
{ |;[%ZE"  
nFileLength = getFileSize(); 5VXI/Lw#  
if(nFileLength == -1) m&36$>r=  
{ oU`J~6.&S  
System.err.println("File Length is not known!"); l^ Q-KUI  
} (C=.&',P  
else if(nFileLength == -2) a'U}.w}  
{ T/b%,!N)  
System.err.println("File is not access!"); oOj7y>Nm  
} aSy^( WN8  
else wk'12r6=(-  
{ M y vyp  
for(int i=0;i<nStartPos.length;i++) ;]/emw=a  
{ GW[g!6 6^  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); t[yu3U  
} f=f8) +5  
for(int i=0;i<nEndPos.length-1;i++) pm.Zc'23  
{ ioZ{2kK  
nEndPos = nStartPos[i+1]; YKk*QcAn  
} VPAi[<FzOG  
nEndPos[nEndPos.length-1] = nFileLength; ("+J*u*kq_  
} Kpx(x0^2  
} RF,[1O-\O  
!pwY@} oL  
bIR&e E  
//启动子线程 }\s\fNSQ/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; E5H0Yo.Wi  
for(int i=0;i<nStartPos.length;i++) h yPVt6Gkj  
{ v*pN~}5  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &ml7368@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {&bjjM  
nStartPos,nEndPos,i); V2&O]bR  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zK5/0zMZ  
fileSplitterFetch.start(); A5A4*.C  
} +;ILj<!Z7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), C1V@\mRi  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); _(R1En1  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", a(qij&>  
nEndPos = " + nFileLength); ;nDCyn4i]  
// fileSplitterFetch[nPos.length-1].start(); 3kc.U  
zOEdFU{x  
R;6$lO8C&  
//等待子线程结束 m4=[e!  
//int count = 0; sX :)g>b   
//是否结束while循环 ?hXeZB+b4  
boolean breakWhile = false; VX;br1$X  
g$(<wWsU  
 3 )bC,  
while(!bStop) ,?OWwm&J  
{ O :'ENoQ:&  
write_nPos(); \9Z1'W  
Utility.sleep(500); pr;z>|FgA>  
breakWhile = true; &N`s@Ka  
K ]  
mw[  
for(int i=0;i<nStartPos.length;i++) HVq02 Z  
{ ;AjY-w  
if(!fileSplitterFetch.bDownOver) 2!7)7wlj0  
{ sghQ!ux  
breakWhile = false; s"7$SxMT  
break; q$<M2  
} KliMw*5(  
} !ULU#2'1  
if(breakWhile) nz?jNdyz  
break; pKnM=N1f  
3>+9Rru  
Tx+Bkfj  
//count++; aLWNqe&1  
//if(count>4) swfcA\7R  
// siteStop(); 3Y L  
} Hju7gP=y}  
lU}y%J@  
QO-R>  
System.err.println("文件下载结束!"); >R9_ ;  
} Zs(I]^w;d  
catch(Exception e){e.printStackTrace ();} 6r x%>\UkS  
} `2B,+ytW8  
QXQ'QEG  
e1EFZ,EcaO  
//获得文件长度 kPt] [1jo  
public long getFileSize() y,i ~w |4  
{ 5 aT>8@$Z^  
int nFileLength = -1; o `]o(OP  
try{ ZSBa+3;z  
URL url = new URL(siteInfoBean.getSSiteURL()); l\?HeVk^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o/;kzi  
httpConnection.setRequestProperty("User-Agent","NetFox"); w`N|e0G@  
B;3lF ;3`  
|SO?UIWp  
int responseCode=httpConnection.getResponseCode(); 'R{Xq HP  
if(responseCode>=400) sW53g$`v  
{ H(JgqbFB*  
processErrorCode(responseCode); &gNb+z+  
return -2; //-2 represent access is error nO ^m  
} R.Plfm06Ue  
i>]1E^yF  
 wfecM(  
String sHeader; 7M|!N_ $  
$RFy9(>  
R>r@I_  
for(int i=1;;i++) t,YnweH  
{ ^tw\F7  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3!&PI  
//Utility.log(in.readLine()); o!\Q,  
sHeader=httpConnection.getHeaderFieldKey(i); ')bas#=uP  
if(sHeader!=null) HFtl4P  
{ ed=pRb  
if(sHeader.equals("Content-Length")) s!vvAD;\  
{ O!,WH?r  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); go6XUe  
break; {pV\]E\]  
} SRUg2)d  
} /8)-j}gZa  
else 4/z K3%J  
break; xla64Qld  
} !mM`+XH  
} H/rJ:3  
catch(IOException e){e.printStackTrace ();} aB=&XGV9  
catch(Exception e){e.printStackTrace ();} n]15 ~GO.  
MHuQGc"e+4  
Xscm>.di  
Utility.log(nFileLength); WDM^rjA|j  
JlM0]__v  
4*)a3jI?  
return nFileLength; ^ B>BA  
} 4TP AD)C  
d){o#@  
YqJ `eLu  
//保存下载信息(文件指针位置) w,6zbI/  
private void write_nPos() W N5`zD$  
{ b3h3$kIYN  
try{ p4Wy2.&Q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8)NQt$lWp  
output.writeInt(nStartPos.length); lBYc(cr  
for(int i=0;i<nStartPos.length;i++) feSj3,<!  
{ \V1geSoE  
// output.writeLong(nPos); 4 8}\  
output.writeLong(fileSplitterFetch.nStartPos); $N}nO:`t  
output.writeLong(fileSplitterFetch.nEndPos); ZFJ qI  
} xT]|78h$   
output.close(); )jS9p~FS  
} hk +@ngh%  
catch(IOException e){e.printStackTrace ();} ]c Or$O*  
catch(Exception e){e.printStackTrace ();} b3zxiq x  
} s`Y8 &e.Yr  
-msfiO  
']x`d  
//读取保存的下载信息(文件指针位置) ' )0eB:  
private void read_nPos() F*0rpQ,*  
{ qwERy{]Sp;  
try{ [110[i^  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); %u)niY-g  
int nCount = input.readInt(); 1+{V^) V?  
nStartPos = new long[nCount]; JKXb$  
nEndPos = new long[nCount]; ,>AA2@6zMT  
for(int i=0;i<nStartPos.length;i++) N084k}io  
{ "1-gMob  
nStartPos = input.readLong(); q2 pq~LI  
nEndPos = input.readLong(); +(pFU\&U3H  
} HW@r1[Y  
input.close(); `veq/!  
} ]ZbZ]  
catch(IOException e){e.printStackTrace ();} mZ[tB/  
catch(Exception e){e.printStackTrace ();} .$rt>u,8<  
} e2}5< 7  
Os5Xejh`I  
@[s+5_9nk  
private void processErrorCode(int nErrorCode) %xJ6t 5.-  
{ *!wBn  
System.err.println("Error Code : " + nErrorCode); Jn+k$'6 %#  
} 3jJd)C R  
RyN}Gz/YN  
/_?y]Ly[r  
//停止文件下载 d4r@Gx%BE  
public void siteStop() gQ0W>\xz  
{ Cb1fTl%  
bStop = true; KiaQ^[/q  
for(int i=0;i<nStartPos.length;i++) *%(BE*C}  
fileSplitterFetch.splitterStop(); [8h~:.d`  
QrX 5Kwq  
B< 6E'  
} 8 etNS~^  
} U.kTdNSp  
//负责部分文件的抓取 "h84D&V  
**FileSplitterFetch.java G(*7hs  
*/ S+LS!b  
package NetFox; O^_$cq  
fPj*qi  
9P)28\4  
import java.io.*; W,53|9b@  
import java.net.*; Wb;x eG  
k/`WfSM\.  
<jk.9$\$A  
public class FileSplitterFetch extends Thread { 0c,)T1NG>  
Vi5&%/Y  
pAY[XN  
String sURL; //File URL %z_L}L  
long nStartPos; //File Snippet Start Position  yf/c  
long nEndPos; //File Snippet End Position vr$zYdV>  
int nThreadID; //Thread's ID M#5*gWfq9  
boolean bDownOver = false; //Downing is over !ot$Q  
boolean bStop = false; //Stop identical ?%]?#4bkc  
FileAccessI fileAccessI = null; //File Access interface mD]^a;U[X  
Cbq|<p# #o  
Z4ZR]eD  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _ l$1@  
{ pn._u`xMV  
this.sURL = sURL; Fb^Ae6/i  
this.nStartPos = nStart; $YPQi.  
this.nEndPos = nEnd; x392uS$#  
nThreadID = id; jWX^h^n7K  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 G^6\OOSy  
} D$vP&7pOr4  
fN-y8  
XVRtfo  
public void run() AgU 7U/yk  
{ B|zVq=l~  
while(nStartPos < nEndPos && !bStop) h]w5N2$}?  
{ _XP3|E;I/  
pRTdP/(OQ  
.o"FT~}z  
try{ xtN=?WjVe0  
URL url = new URL(sURL); 3v:c".O2O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J_tI]?jrU  
httpConnection.setRequestProperty("User-Agent","NetFox"); OM1pyt  
String sProperty = "bytes="+nStartPos+"-"; % QKlvmI"  
httpConnection.setRequestProperty("RANGE",sProperty); uTq)Ets3  
Utility.log(sProperty); M?FbBJ`sF  
`B GU  
n@e[5f9?x  
InputStream input = httpConnection.getInputStream(); oKlOcws}  
//logResponseHead(httpConnection); zB@@Gs>  
$At,D.mGkb  
}aJK^>^>A  
byte[] b = new byte[1024]; xdV $dDCT  
int nRead; WER\04%D\m  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 8>(DQ"h  
{ zm9_[0  
nStartPos += fileAccessI.write(b,0,nRead); DP-euz  
//if(nThreadID == 1) *K}j>A  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L3 VyW8Y  
} HHMv%H]M  
YYiT,Xp<A  
P:3%#d~q  
Utility.log("Thread " + nThreadID + " is over!"); \NN5'DBx  
bDownOver = true; |AS`MsbI9  
//nPos = fileAccessI.write (b,0,nRead); `J}-U\4F{  
} 320g!r  
catch(Exception e){e.printStackTrace ();} ?->&)oAh  
} "v9i;Ba>+  
} YJ[Jo3M@j0  
c~=yD:$  
0s%rd>3  
//打印回应的头信息 R8K ?! Z  
public void logResponseHead(HttpURLConnection con) ~H+W[r}  
{ GSh~j-C'  
for(int i=1;;i++) 4-dV%DgC  
{ {k#RWDespy  
String header=con.getHeaderFieldKey(i); 4\?GA`@  
if(header!=null) C $r]]MSj  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?{bAyh/  
Utility.log(header+" : "+con.getHeaderField(header)); *wY { ~zh  
else nOE 1bf^l  
break; kpU-//lk+  
} ti}g?\VT  
} 5 Y|(i1  
Ksu_4dE  
/t<C_lLM  
public void splitterStop() m@W\Pic,j.  
{ HxXCxI3  
bStop = true; nP+]WUnY  
} zs_^m1t1s  
,aLdW,<6  
0k7kmDW  
} ~=pAy>oV  
_H (:$=$Q  
@jp}WwC/  
/* eK]$8l|LI  
**FileAccess.java IUJRP  
*//文件访问(定位,写) fsxZQ=-PW  
package NetFox; ]PI|Xl  
import java.io.*; !KEnr`O2u  
xqA XfJ.  
e#uk+]  
public class FileAccessI implements Serializable{ z12c9k%s  
i7RW8*  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 R Wd#)3  
RandomAccessFile oSavedFile; J|Xu]fg0  
long nPos; \B<A.,i4  
.eSMI!Y=  
nU6WT|  
public FileAccessI() throws IOException <X{hW^??)  
{ }?vc1%w  
this("",0); NIQX?|;b{  
} YyZ>w2_MTi  
3X,SCG  
=?, dX  
public FileAccessI(String sName,long nPos) throws IOException ]DaC??%w  
{ \~YyY'J  
oSavedFile = new RandomAccessFile(sName,"rw"); G\S>H  
this.nPos = nPos;  xlH?J;$  
oSavedFile.seek(nPos); q[}[w!to  
} b)eKa40Z  
A`D^}F6  
rLfhm Ds%u  
public synchronized int write(byte[] b,int nStart,int nLen) .$k2.-k  
{ mR? } gR  
int n = -1; V(Dn!Nz  
try{ >;;tX3(  
oSavedFile.write(b,nStart,nLen); _cW (R,i  
n = nLen; 6.!3g(w   
} 9b0M'x'W5  
catch(IOException e) M_4:~&N$  
{ $2M dxw5  
e.printStackTrace (); WG_20JdJY  
} N!`8-ap\^  
}#rdMh  
4G%!t`? q  
return n; <Rl:=(]i~  
} *FwHZZ~U  
LQnkpy3A  
SnhB$DG  
} kUdl2["MZ  
/cy'% .!  
7sQw&yUL)  
/* Vo\RtM/6{  
**SiteInfoBean.java [;Q8xvVZ'  
*/ kJJUu  
package NetFox; G2nL#l~@)  
xF+a.gAIb  
sh6F-g  
public class SiteInfoBean { 6PS #Zydb  
^Fl6-|^~  
Y]5\%JR  
private String sSiteURL; //Site's URL *hHy> (*  
private String sFilePath; //Saved File's Path l @hXQ/  
private String sFileName; //Saved File's Name Dm=Em-ST6  
private int nSplitter; //Count of Splited Downloading File _d$0(  
P~)ndaQ  
? 9.V@+i  
public SiteInfoBean() ERW>G {+  
{//nSplitter的缺省值为5 )TceNH  
//default value of nSplitter is 5 G36}4  
this("","","",5); N F[v/S  
} OAc*W<Q0  
b[^=GF>e  
yn0OPjH  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >b |TaQ  
{ x9#>0 4s  
sSiteURL= sURL; o@`& h} $  
sFilePath = sPath; sOJH$G3O  
sFileName = sName; w$9aTL7  
this.nSplitter = nSpiltter; C^@.GA  
7L[HtwI  
nb:J"  
} }57wE$9K  
t5z6{`  
sW~Z?PFP  
public String getSSiteURL() ! af35WF  
{ qAsZ,ik  
return sSiteURL; g1Q^x/  
} OC zWP,  
# E'g{.N  
G 1{F_  
public void setSSiteURL(String value) eH2.,wY1  
{ rl^_RI  
sSiteURL = value;  J9oGw P  
} #&G^%1!  
b;&J2:`  
#,O<E@E  
public String getSFilePath() |X9YVZC  
{ B.&ly/d  
return sFilePath; oJK]oVX9i  
} . `lcxC  
p+ymt P F  
[R j=k)aBm  
public void setSFilePath(String value) ,UQ4`Mh^L  
{ 0X\,!FL  
sFilePath = value; +XU*NAD,!  
} EA 4a Z6%  
,MwwA@,9-  
JBdZ]  
public String getSFileName() !!ZNemXct$  
{ "k\W2,q[  
return sFileName; }io9Hk>|  
} R|h9ilc  
lY_E=K]  
*k'oP~:fT  
public void setSFileName(String value) XpWqL9s_E  
{ VAc-RaA  
sFileName = value; CD(2A,u)/  
} 6OMywGI[Z  
$=n|MbFl  
/Cr0jWu _  
public int getNSplitter() j_SRCm~:  
{ pi? q<p%  
return nSplitter; ;$(a+?  
} +bvY*^i  
Q"CZ}B1<  
MP?9k)f  
public void setNSplitter(int nCount) \cvui^^n  
{ @* L^Jgn  
nSplitter = nCount; G*e/Ft.wf8  
} +Ij>\;vM"  
} ghJ81  
uk_?2?>-5  
BCF- lrZ&  
/* aT"q}UTK  
**Utility.java =-{+y(<"r  
*/ v')Fq[H  
package NetFox; $k*E^~qT  
!1!;}uzt  
]i\D*,FfU  
public class Utility { I(/W+ o  
A\lnH5A  
.Xh^L  
public Utility() mgX0@#wFn  
{ 0U ?1Yh7 m  
4(2}O-~  
p+#J;.  
} +"Ek? )?  
X1!m ]s(I  
//线程睡眠 Lie\3W  
public static void sleep(int nSecond) +ww paR`  
{ =(K;z9OR  
try{ tTe\#o`  
Thread.sleep(nSecond); {w}PV5<  
} \TkBV?W  
catch(Exception e) ,g@U *06  
{ %Y:'5\^lC  
e.printStackTrace (); ~d?7\:n  
} bSU9sg\  
} /!oi`8D  
KWCA9.w4q  
//日志 o5mt7/5[i  
public static void log(String sMsg) S%-L!V ,  
{ 6cVaO@/(  
System.err.println(sMsg); c^}gJ  
} h" Yi'  
j\f;zb?F  
jY$Bns&.w  
public static void log(int sMsg) ;$&&tEh)  
{ ik_Ll|  
System.err.println(sMsg); 724E(?>J  
} }E[S%W[  
} tx}{E<\>$  
}:5r#Cd  
&`Q0&8d5  
/* DoX#+ 07u4  
**TestMethod.java =et=X_3-  
*/ ]zmY] 5  
package NetFox; G#@o6r  
v)!Rir5  
'h%)@q)J)  
public class TestMethod { &!2 4l=!  
ae{% * \J  
0Q_AF`"  
public TestMethod() #JYv1F  
{ ///xx/weblogic60b2_win.exe %L}9nc%~eP  
try{ [?)}0cd0  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #q9jFW8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); zPWG^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >1T=Aw2Z.  
fileFetch.start(); <<6i6b  
} 5'?K(Jdmp  
catch(Exception e){e.printStackTrace ();} bT,]=h"0  
U P GS  
acdaDY  
} M'$n".,p  
WM*[+8h  
eEb(TG~,Y  
public static void main(String[] args) A &~G  
{ i*#Gq6qZq  
new TestMethod(); h35x'`g7+r  
} 2Y\,[$z  
} B<xBuW  
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