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http断点续传简单实现(java)

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/* b+Sq[  
**SiteFileFetch.java `@TWZ%f6  
*/ ]^:sV)  
package NetFox; QxS] 6hA  
import java.io.*; w"ZngrwBl  
import java.net.*; 8?LsV<  
E)sC:oO  
J=7.-R|t  
public class SiteFileFetch extends Thread { h K;9XJAf  
-LzkM"  
C# zYZ JZ  
SiteInfoBean siteInfoBean = null; //文件信息Bean )l?1 dR:sP  
long[] nStartPos; //开始位置 QTr) r;Tro  
long[] nEndPos; //结束位置 VaP9&tWXj  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4PK/8^@7)>  
long nFileLength; //文件长度 uDD{O~wF,  
boolean bFirst = true; //是否第一次取文件 f#mNx  
boolean bStop = false; //停止标志 xB-\yWDZe  
File tmpFile; //文件下载的临时信息 Q\Wh]=}  
DataOutputStream output; //输出到文件的输出流 mxD]`F  
QiH>!Ssw  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) dhrh "x_?:  
public SiteFileFetch(SiteInfoBean bean) throws IOException b3.  
{ [l44,!Z&  
siteInfoBean = bean; E$SYXe[,  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2_T2?weD5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Ig&H0S  
if(tmpFile.exists ()) WbJ|]}hJ\  
{ Nm$B a.Rg  
bFirst = false; abMB-  
read_nPos(); @}; vl  
} \ SCi\j/a(  
else >AK9F. _z  
{ )j,Y(V$P  
nStartPos = new long[bean.getNSplitter()]; de=){.7Y  
nEndPos = new long[bean.getNSplitter()]; f/xQy}4+~E  
} i4T=4q  
n( RQre  
`PY=B$?{4  
FEY_(70  
} |\.:h":!0~  
Me 5Xd|  
RN^<bt{_U  
public void run() [nc-~T+Mo  
{ hgg 8r#4q  
//获得文件长度 `D/<*e,#  
//分割文件 W&~\@j]!D  
//实例FileSplitterFetch =[JstiT?E  
//启动FileSplitterFetch线程 lXpbAW  
//等待子线程返回 uB=DC'lkg  
try{ t=nZ1GZyM  
if(bFirst) 8k{KnH  
{ Mi~x(W@}3  
nFileLength = getFileSize(); :$6mS[@|  
if(nFileLength == -1) QmgO00{  
{ lA{JpH_Y8s  
System.err.println("File Length is not known!"); h;Hg/jv  
} [KQ#b  
else if(nFileLength == -2) MO^Q 8v  
{ ^>wlj  
System.err.println("File is not access!"); &x?m5%^l  
} _D 9/,n$  
else :6gRoMb]  
{ h+rW%`B  
for(int i=0;i<nStartPos.length;i++) C5Vlqc;  
{ d`gKF  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); aD^jlt  
} ^(kmFUV,Z  
for(int i=0;i<nEndPos.length-1;i++) w#v-h3XcF  
{ }j$tFFVi~  
nEndPos = nStartPos[i+1]; MgO_gFr  
} < ]"Uy p  
nEndPos[nEndPos.length-1] = nFileLength; p[Zk;AT~  
} 3AcS$.G  
} Rp+Lu  
?;]Xc~  
,(i`gH{D  
//启动子线程 q2 b>Z6!5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8vkCmV  
for(int i=0;i<nStartPos.length;i++) >,x&L[3  
{ 'yo-`nNFD  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $^e(?P q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), WA6reZ  
nStartPos,nEndPos,i); P5KpFL`B  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); '4Drs}j5  
fileSplitterFetch.start(); P3!JA)p6a  
} `pb=y}  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D\^mh{q(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `]`S"W7&  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", H Y~[/H+:  
nEndPos = " + nFileLength); -zg 6^f_pW  
// fileSplitterFetch[nPos.length-1].start(); iNs@8<=$T  
f AY(ro9Q(  
(gRTSd T ?  
//等待子线程结束 mEmgr(W  
//int count = 0; Cxd^i  
//是否结束while循环 h ,\5C/  
boolean breakWhile = false; aX,6y1  
q eDXG  
5O(U1 *  
while(!bStop) %I=/ y  
{ wRdN(`;v  
write_nPos(); EK.n $  
Utility.sleep(500); EfB.K}b^  
breakWhile = true; !hFzIp  
qZdA%  
j[Jwa*GQP  
for(int i=0;i<nStartPos.length;i++) : HM~!7e  
{ .6!cHL3ln  
if(!fileSplitterFetch.bDownOver) bt*  
{ o@m7@$7  
breakWhile = false; !K-qoBqKM  
break; X$Shi *U[  
} N\"Hf=Y(~  
} mBxMDnh  
if(breakWhile) =Fc}T%  
break; q[Tl#*P?y  
:-_"[:t 5Z  
-_xTs(;|8  
//count++; SP\s{,'F-b  
//if(count>4) ;VzdlCZ@  
// siteStop();  wh#IQ.E-  
} I<Cm$8O?  
9n49p?  
GkxQEL  
System.err.println("文件下载结束!"); "Lyb4#M  
} PWeWz(]0Z4  
catch(Exception e){e.printStackTrace ();} j u&v4]  
} <*I*#WI&B  
A{dqB  
bk0<i*ju7(  
//获得文件长度 r $[{sW  
public long getFileSize() iGSF5S  
{ Es- =0gpK  
int nFileLength = -1; vmv6y*qU  
try{ 0 . UN  
URL url = new URL(siteInfoBean.getSSiteURL()); baBPf{<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q;ZV`D/FA  
httpConnection.setRequestProperty("User-Agent","NetFox"); e7y,zcbv  
SQ*%d.1  
c'XSs  
int responseCode=httpConnection.getResponseCode(); xU2i&il^!  
if(responseCode>=400) Jz4;7/  
{ odDVdVx0  
processErrorCode(responseCode); 8>G5VhCm~o  
return -2; //-2 represent access is error ex#-,;T  
} <`WDNi$Y  
l9]nrT1Hy  
V$w bmz  
String sHeader; g:.LCF  
^I9U<iNIL  
^F qs,^~W  
for(int i=1;;i++) \PD%=~  
{ ?VCp_Ji  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); @HTs.4  
//Utility.log(in.readLine()); /eT9W[a  
sHeader=httpConnection.getHeaderFieldKey(i); ]heVR&bQ  
if(sHeader!=null) xi=0 kO  
{ vT MCZ+^g  
if(sHeader.equals("Content-Length")) OLWn0  
{ S(Z\h_m(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); :fDzMD  
break; q6hH]Q>w*  
} U# IPYyV  
} v-8{mK`9\  
else ([|^3tM  
break; LN) yQ-  
} ~c5 5LlO>  
} ~Y{]yBGoF  
catch(IOException e){e.printStackTrace ();} Lr20xm  
catch(Exception e){e.printStackTrace ();} 8QMMKO ui\  
<Qr*!-Kc6  
elR1NhB|p  
Utility.log(nFileLength); -]-0]*oAp  
&> _aY #  
j+>[~c;0)  
return nFileLength; 9ei<ou_s  
} c (29JZ  
I %sw(uoE  
"$b{EYq6  
//保存下载信息(文件指针位置) N A_8<B^  
private void write_nPos() c6 .j$6t  
{ Zl>wWJ3y  
try{ -GCU6U|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); R5mb4  
output.writeInt(nStartPos.length); V6+:g=@U-l  
for(int i=0;i<nStartPos.length;i++) 4jlwu0L+  
{ BpGyjo J2  
// output.writeLong(nPos); tk)}4b^\%j  
output.writeLong(fileSplitterFetch.nStartPos); V3T.EW  
output.writeLong(fileSplitterFetch.nEndPos); h#Mx(q  
} C?MKb D=K  
output.close(); zlB[Eg^X  
} v9!] /]U^  
catch(IOException e){e.printStackTrace ();} *>!-t   
catch(Exception e){e.printStackTrace ();} 8Ht=B,7T  
} J*zQ8\f=}  
uhv_'Q  
Z"KrirZ  
//读取保存的下载信息(文件指针位置) :^qUr`)  
private void read_nPos() tR 4+]K  
{ >p#_ L^oZ%  
try{ OlptO60{ ]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); D+N@l"U{  
int nCount = input.readInt(); _RS CyV  
nStartPos = new long[nCount]; fGW~xul_  
nEndPos = new long[nCount]; Ic^ (6  
for(int i=0;i<nStartPos.length;i++) .Wi%V"  
{ [w-# !X2y  
nStartPos = input.readLong(); ?!$Dr0r  
nEndPos = input.readLong(); 0'Qvis[kt  
} !s ! el;G  
input.close(); @ *uZ+$  
} Z^Wv(:Nr  
catch(IOException e){e.printStackTrace ();} ]zj&U#{  
catch(Exception e){e.printStackTrace ();} FW)~e*@8=  
} {d0 rUHP  
I)9 ,  
VV#'d  
private void processErrorCode(int nErrorCode) #)i+'L8  
{ ' QjJ^3A  
System.err.println("Error Code : " + nErrorCode); #s#BYbF  
} *5\'$;Rg  
B/mfm 7  
~0o>B$xJ  
//停止文件下载 IFZw54  
public void siteStop() 56u_viZ=8  
{ ~9,Fc6w4`+  
bStop = true; sHV?njZd  
for(int i=0;i<nStartPos.length;i++) loHMQKy@  
fileSplitterFetch.splitterStop(); \4 +HNy3  
`,Y3(=3Xe?  
90-s@a3B-j  
} R:ecLbC  
} knfmJUT  
//负责部分文件的抓取 JV8*;n%}-  
**FileSplitterFetch.java g&Uu~;jq]  
*/ g $^Yv4  
package NetFox; )cL`$h4DD  
8A/rkoht*  
^ 4p$@5zH  
import java.io.*; " YOl6n  
import java.net.*; U7e2NES  
'Q=(1a11  
b/\l\\$-  
public class FileSplitterFetch extends Thread { U'~]^F%eyu  
m( %PZ*s  
(/9erfuJ  
String sURL; //File URL J/,m'wH  
long nStartPos; //File Snippet Start Position I>6zX  
long nEndPos; //File Snippet End Position I47sqz7  
int nThreadID; //Thread's ID 5^CWF|  
boolean bDownOver = false; //Downing is over gR_Exs'K  
boolean bStop = false; //Stop identical w'y,$gtX/  
FileAccessI fileAccessI = null; //File Access interface k! x`cp  
aWP9i &  
M"msLz  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <(xro/  
{ 'F:Tv[qx  
this.sURL = sURL; gNkBHwv  
this.nStartPos = nStart; w4&\-S#  
this.nEndPos = nEnd; b `}hw"f  
nThreadID = id; Z Y5Pf 1  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !t{  
} JW=q'ibR  
pX$ X8z%  
"`4M4`'  
public void run() ,% .)mf  
{ v`Ja Bn  
while(nStartPos < nEndPos && !bStop) ^X"x,8}&V  
{ A!uiM*"W  
I*g[Y=  
/YvwQ  
try{ Adfnd  
URL url = new URL(sURL); *Uf>Xr&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;E!] /oY<  
httpConnection.setRequestProperty("User-Agent","NetFox"); YM.  
String sProperty = "bytes="+nStartPos+"-"; G c ,  
httpConnection.setRequestProperty("RANGE",sProperty);  aN6HO  
Utility.log(sProperty); :o~ ]d  
SP>&+5AydX  
N-Bw&hEZ  
InputStream input = httpConnection.getInputStream(); )wdd"*hv  
//logResponseHead(httpConnection); 5)0'$Xxqa0  
|0X~D}r|J  
!\OX}kHX5  
byte[] b = new byte[1024]; *_HF%JYMZ  
int nRead; # $'H?lO  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) QBfo=9[=e  
{ /#q6.du  
nStartPos += fileAccessI.write(b,0,nRead); FJ{&R Ld  
//if(nThreadID == 1) hx4c`fOs  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X+N8r^&  
} k @gQY_  
LW9F%?e!>  
&]A0=h2{P*  
Utility.log("Thread " + nThreadID + " is over!"); qagR?)N)u  
bDownOver = true; ]mC5Z6,1s  
//nPos = fileAccessI.write (b,0,nRead); >McEuoZx9  
} 5dbj{r)s6i  
catch(Exception e){e.printStackTrace ();} ov >5+"q)  
} K*p3#iB  
} 3BF3$_u)o  
C AN1~  
`joyHKZI.  
//打印回应的头信息 Wd ga(8t  
public void logResponseHead(HttpURLConnection con) b d C  
{ 8,e%=7h_e  
for(int i=1;;i++) dOKe}?}==  
{ Q|U [|U  
String header=con.getHeaderFieldKey(i); kQn}lD  
if(header!=null) Lzcea+*uw  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9g.5:  
Utility.log(header+" : "+con.getHeaderField(header)); H!l 9a  
else wLvM<p7OX  
break; IABF_GwF  
} CT'#~~QB  
} XPnHi@x  
!!cN4X  
[h8macx  
public void splitterStop() vY,D02 EMw  
{ \]dvwN3x  
bStop = true; Z.s0ddM s  
} (CJx Y(1K  
A5_r(Z-5  
.kgt? r  
} K}'?#a(aX=  
+Y$EZL.A  
IA`Lp3Z  
/* SDs#w  
**FileAccess.java nU isC5HW  
*//文件访问(定位,写) azO7C*_  
package NetFox; *55unc  
import java.io.*; n8`WU3&  
D#^euNiWd  
iqN?'8  
public class FileAccessI implements Serializable{ N:Ir63X*#  
 P.mlk>r  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 k^zU;  
RandomAccessFile oSavedFile; ^uPg71r:  
long nPos; WF2t{<]^e  
Dt iM}=:  
0]^gT'  
public FileAccessI() throws IOException o%0To{MAF-  
{ iO2jT+i  
this("",0); wrsr U  
} JC;&]S.  
K6|R ;r5e{  
8NTE`l=>/  
public FileAccessI(String sName,long nPos) throws IOException Qd>\{$N  
{ /!`xqG#  
oSavedFile = new RandomAccessFile(sName,"rw"); uf"(b"N0  
this.nPos = nPos; 432]yhQ  
oSavedFile.seek(nPos); yD@eT:lyi  
} 5du xW>D  
fVdu9 l  
eo.B0NZsF  
public synchronized int write(byte[] b,int nStart,int nLen) ,zxv>8Nt  
{ \Pe+]4R-Xo  
int n = -1; P4+PY 8  
try{ oArJ%Y>  
oSavedFile.write(b,nStart,nLen); w6pXF5ur>  
n = nLen; ff~1>=^  
} ~qK/w0=j  
catch(IOException e) K_!:oe7%  
{ 9}H]4"f7  
e.printStackTrace (); $ +$l?2  
} p+d O w #  
0Q)YZ2  
k|U2Mp  
return n; H6U 5-  
} \xQu*M:!  
7:<A_OLi  
+oL@pp0  
} \1QY=}  
*kEzGgTzoS  
8DM! ]L  
/* ?nq%'<^^  
**SiteInfoBean.java @[Q`k=h$  
*/ ydAiH*>  
package NetFox; syI|gANT/r  
'g3T'2"`5  
+(^H L3  
public class SiteInfoBean { 9[sOh<W  
u(\O@5a  
-Zp BYX5e_  
private String sSiteURL; //Site's URL gYe6(l7m  
private String sFilePath; //Saved File's Path O~Bh(_R&  
private String sFileName; //Saved File's Name W!Fc60>p@f  
private int nSplitter; //Count of Splited Downloading File 6Rmdf>a  
[AA}P/iW  
(t@ :dW  
public SiteInfoBean() n 8 K6m(  
{//nSplitter的缺省值为5 cLw|[!5:  
//default value of nSplitter is 5 =%c\<<]aV  
this("","","",5); K9y~ e  
} )4m`Ya,E3  
V Ew| N)  
%%zlqd"0  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) k+vfZ9bD(J  
{ m/ID3_  
sSiteURL= sURL; A7|L|+ ?  
sFilePath = sPath; "F6gV;{Bt  
sFileName = sName; /bPs0>5  
this.nSplitter = nSpiltter; KSHq0A6/q%  
S4'<kF0z  
e `OQ6|.k8  
} tw&v@HUP  
5$+ssR_?k  
iRbe$v&N  
public String getSSiteURL() *>1^q9M  
{ 0/9]T Ic  
return sSiteURL; ivyaGAF}+o  
} _x|.\j  
3!vzkBr  
?~!9\dek,  
public void setSSiteURL(String value) &;=/^~EG  
{ _A] )q  
sSiteURL = value; ic"8'Rwb  
} tC5-^5[y  
UGj |)/  
fc9@l a  
public String getSFilePath() ]5Dh<QY&.  
{ ~QDM .5  
return sFilePath; C+[)^ 2M{  
} aB?usVoS  
aT(_c/t.  
R n]xxa'  
public void setSFilePath(String value) +jyGRSo  
{ X6 N&:<  
sFilePath = value; 7 nFOV Z  
} a^pbBDi W  
Jazgn5  
A.dbb'^  
public String getSFileName() 'W yWO^Bdk  
{ akU2ToP  
return sFileName; 4^M"V5tDx  
} :O$bsw:3w<  
OZnKJ<  
^YropzHZ4E  
public void setSFileName(String value) &i.sSqSI5  
{ 7GWOJ^)  
sFileName = value; 7CvBE;i  
} TEMxjowr  
~!!| #A)W  
_B&Lyg !J  
public int getNSplitter() /of K7/  
{ 2J8:_Ql3I  
return nSplitter; u+KZ. n/  
} J9p4\=9  
H;l_;c`  
-Ou.C7ol  
public void setNSplitter(int nCount) tiHR&v  
{ q$mc{F($D  
nSplitter = nCount; ]z/R?SM  
} "\KBF  
} IA({RE  
mbGma  
kFV, Fg  
/* . R/y`:1:W  
**Utility.java j)6p>6  
*/ yxo=eSOM  
package NetFox; m<#12#D  
/:' >-253  
n2hV}t9O  
public class Utility { >([,yMIY  
3m` >D e  
~IS8DW$;  
public Utility() fyA-*)oHv  
{ kMMgY?  
$i5J}  
W>)0=8#\  
} mpMAhm:  
R]iV;j|  
//线程睡眠 ,1$F #Eh  
public static void sleep(int nSecond) uMS+,dXy  
{ u0 t lf  
try{ gJ'pwSA  
Thread.sleep(nSecond); eY5mwJ0K  
} Xa?O)Bq.  
catch(Exception e) 4n@lrcq(  
{ J5I@*f)l  
e.printStackTrace (); cN8Fn4gq  
} HdJ g  
} |uqI}6h.  
 pUb1#=  
//日志 ^hmV?a:Y  
public static void log(String sMsg) U`mX f#D  
{ bIAE?D  
System.err.println(sMsg); P<<+;']  
} ,0.kg  
]A'{DKR  
D3X4@sM  
public static void log(int sMsg) L ,dh$F  
{ d*0 RBgn  
System.err.println(sMsg); VNHce H  
} : ~vodh  
} At4\D+J{Vs  
1x:W 3.  
\}s/<Q  
/* !i^"3!.l,]  
**TestMethod.java 2Lf,~EV  
*/ D=TS IJ@  
package NetFox; 5mD8$% \8  
7"!b5(4=  
'bi;Y1:  
public class TestMethod { dm4Q'u  
` 3qf}=Z`  
<m]0!ii  
public TestMethod() d-D,Gx]>$  
{ ///xx/weblogic60b2_win.exe yx :^*/  
try{ fY[Fwjj3  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); m9DFnk<D  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }kqh[`:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .ybmJU*Hg  
fileFetch.start(); w`)5(~b  
} W2 -%/  
catch(Exception e){e.printStackTrace ();} nn_O"fZi  
]?tRO  
=9GA LoGL  
} Q&eyqk   
o utJ/~9;  
?,>3uD#  
public static void main(String[] args) lFjz*g2'  
{ dFy$w=  
new TestMethod(); s5nw<V9$]  
} -3{Q`@F  
} )!2@v@SQ  
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