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http断点续传简单实现(java)

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/* (" +clb`  
**SiteFileFetch.java :yTr:FoF  
*/ F'CJN$6Mw/  
package NetFox; uG/'9C6Z  
import java.io.*; &[SFl{fx>-  
import java.net.*; brG!TJ   
KzQFG)q,  
y:_>R=sw  
public class SiteFileFetch extends Thread { d c/^  
RJKi98xwJ  
rITA-W O  
SiteInfoBean siteInfoBean = null; //文件信息Bean R~eLEjezm  
long[] nStartPos; //开始位置 kU#k#4X4g  
long[] nEndPos; //结束位置 6:AEg  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Af r*'  
long nFileLength; //文件长度 O*Y?: t  
boolean bFirst = true; //是否第一次取文件 ].2t7{64  
boolean bStop = false; //停止标志 :4\%a4{Ie  
File tmpFile; //文件下载的临时信息 k7j[tB#  
DataOutputStream output; //输出到文件的输出流 CD5% iFy  
My Ky*wD  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 6uKP BL@,  
public SiteFileFetch(SiteInfoBean bean) throws IOException ; 6PRi/@  
{ BoOuN94  
siteInfoBean = bean; u~>G8y)k9O  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); gXU(0(Gq  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); |Y?<58[!)  
if(tmpFile.exists ()) 5<Uh2c  
{ W*Ow%$%2  
bFirst = false; %I{>H%CjE  
read_nPos(); 6J@,bB jVz  
} A&M(a  
else 78 ]Kv^l^_  
{ ;?q}98-2  
nStartPos = new long[bean.getNSplitter()]; < Wp)Y  
nEndPos = new long[bean.getNSplitter()]; \3"B$Sp|=  
} Vw.)T/B_D  
G B"Orm.  
 \m+=|  
#`!mQSK  
} agE-,  
|=KzQY|u  
f=VlO d  
public void run() <Q"G aqZ  
{ fK *l?Hr  
//获得文件长度 s:_a.4&Y  
//分割文件 g$zGiqzMK  
//实例FileSplitterFetch H=w):kL|  
//启动FileSplitterFetch线程 vVIN D  
//等待子线程返回 g'{?j~g  
try{ Ryh 0r  
if(bFirst) (:O6sTx-hE  
{ <&gs)BY  
nFileLength = getFileSize(); &328pOT4  
if(nFileLength == -1) "6U@e0ht  
{ <QC7HR  
System.err.println("File Length is not known!"); uPapINj  
} sINf/mv+  
else if(nFileLength == -2) LI&E.(:  
{ W7gY$\1<&  
System.err.println("File is not access!"); /xcXd+k]  
} KLj=M;$:K  
else jSH.e?  
{ nRu %0Op  
for(int i=0;i<nStartPos.length;i++) ~WORC\kCW  
{ AzSu_  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); IG{Me  
} f6Lc"b3s1  
for(int i=0;i<nEndPos.length-1;i++) G-|c%g!ejf  
{ *uf)t,%  
nEndPos = nStartPos[i+1]; >;R`Q9s7  
} .MRN)p  
nEndPos[nEndPos.length-1] = nFileLength; { Ie~MW  
} Di27=_J  
} )UpVGT)  
u[PG/ploc  
aXG|IN5 *m  
//启动子线程 JM?__b7g2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; aG#d41O  
for(int i=0;i<nStartPos.length;i++) VzIZT{  
{ HY1K(T  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1]5k l J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), J/E''*  
nStartPos,nEndPos,i); Ea][:3  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); g/ShC8@=u  
fileSplitterFetch.start(); 9 nY|S{L  
} J~4mp\4b  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rx 74v!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 'DNxc  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", IVZUB*wv)b  
nEndPos = " + nFileLength); @$ Nti>  
// fileSplitterFetch[nPos.length-1].start(); <66%(J>  
(aC=,5N  
j|`lOH8  
//等待子线程结束 kX`m( N$  
//int count = 0; N*6~$zl&  
//是否结束while循环 o|vL:| 8Q  
boolean breakWhile = false; .-![ ra  
],[<^=|  
SZLugyZ2Y  
while(!bStop) m@+QC$6S  
{ @: =vK?8L  
write_nPos(); 8~t8^eBg  
Utility.sleep(500); 27+faR  
breakWhile = true; 0^nF : F  
0Z]HH+Z;  
 s!  
for(int i=0;i<nStartPos.length;i++) &A.0(s  
{ lMh>eX  
if(!fileSplitterFetch.bDownOver) LyNmn.nN  
{ Ok@`<6v  
breakWhile = false;  E>i<2  
break; FG{,l=Z0  
} xV`l6QS  
} s8 MQ:eAP  
if(breakWhile) ` - P1Y  
break; 1KGf @u%-1  
,!alNNY  
00f'G2n  
//count++; .5!`wwVi  
//if(count>4) ,7:-V<'Yv  
// siteStop(); ]s^+/8d=  
} Vy[xu$y  
!.q99DB  
}F/w34+;  
System.err.println("文件下载结束!"); >B~? }@^Gk  
} 53ZbtEwhwr  
catch(Exception e){e.printStackTrace ();}  <82&F  
} e1E_$oJP  
F=w:!tqA  
kZ)}tA7j  
//获得文件长度 WFV'^-4  
public long getFileSize() *`wz  
{ nw+^@|4  
int nFileLength = -1; xP9h$!  
try{ p=A, yGDV  
URL url = new URL(siteInfoBean.getSSiteURL()); 7RBEEE`)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (3D&GY!/  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ab/JCZNn  
D}X6I#U'/  
wd<{%qK`{  
int responseCode=httpConnection.getResponseCode(); g[t paQ  
if(responseCode>=400) R) dP=W*  
{ r)Lm| S  
processErrorCode(responseCode); & fWC-|  
return -2; //-2 represent access is error f(blqO.@l  
} kSc~gJrne  
_izjvg  
\xl$z *zI  
String sHeader; tJ6Q7 J;n  
#}@8(>T  
^,^MW  
for(int i=1;;i++) DUl+Jqn4B  
{ "M-';;  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); NziCN*6  
//Utility.log(in.readLine()); 7=u Gf$/  
sHeader=httpConnection.getHeaderFieldKey(i); [)jNy_4  
if(sHeader!=null) Ri_2@U-  
{ _6,\;"it?8  
if(sHeader.equals("Content-Length")) ( >ze{T|  
{ (7b9irL&cn  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); F:P2:s<d-  
break; rb4;@&  
} `o }+2Cb  
} PMbZv%.,-  
else oOvQA W8`  
break; un~`|   
} u*I'c2m  
} Q8h0.(#-  
catch(IOException e){e.printStackTrace ();} =. \hCgq  
catch(Exception e){e.printStackTrace ();} %dW ;P[0  
uQx/o ^  
T* 0;3&sA  
Utility.log(nFileLength); 3T0-RP*  
fR@Cg sw  
%CvVu)tc  
return nFileLength; *w _o8!3-  
} f sh9-iY8e  
lkJxb~S  
,K\7y2/  
//保存下载信息(文件指针位置) %]0?vw:;j  
private void write_nPos() `|Di?4+6%  
{ #|Lsi`]+  
try{ *'A*!=5(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 'SlZ-SdR  
output.writeInt(nStartPos.length); = <Sn&uL  
for(int i=0;i<nStartPos.length;i++) 3~3tjhw;]9  
{ 9oGcbD4*  
// output.writeLong(nPos); s K+uwt  
output.writeLong(fileSplitterFetch.nStartPos); 9U.Ctx:F  
output.writeLong(fileSplitterFetch.nEndPos); !i (V.A  
} fi*b]a\'  
output.close(); < B]qqqP  
} &QfEDDJ  
catch(IOException e){e.printStackTrace ();} ,'`yh|}G\  
catch(Exception e){e.printStackTrace ();} 'V:MppQVZ.  
} B?-w<":!  
KU(BY}/ ^  
'5$@ I{z  
//读取保存的下载信息(文件指针位置) k]r4b`x`  
private void read_nPos() C^4,L \E  
{ 3fQ`}OcNr  
try{ }cCIYt\RK  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &Lt$~}*&6  
int nCount = input.readInt(); #'> )?]tn  
nStartPos = new long[nCount]; Bx5xtJ|!  
nEndPos = new long[nCount]; #9[>  
for(int i=0;i<nStartPos.length;i++) +3-5\t`  
{ X,3\c:  
nStartPos = input.readLong(); FA{Q6fi:2  
nEndPos = input.readLong(); :X'B K4EN  
} 9^n0<(99b  
input.close(); ]*k ~jY,  
} .4"BN<9  
catch(IOException e){e.printStackTrace ();} D>W&#A8&y  
catch(Exception e){e.printStackTrace ();} fUWrR1  
} JmR2skoV,  
>I~Q[  
d1c+Ii%  
private void processErrorCode(int nErrorCode) X=m^+%iD  
{ |3B<;/v5  
System.err.println("Error Code : " + nErrorCode); 7~Inxk;  
} W =Bw*o-  
l\V1c90m  
BRY/[QRqZ  
//停止文件下载 -o"b$[sf=Z  
public void siteStop() WUz69o be  
{ 3>L5TYa  
bStop = true; }MMKOr(  
for(int i=0;i<nStartPos.length;i++) [efU)O&  
fileSplitterFetch.splitterStop(); b?iPQ$NyQ  
DDGDj)=`  
U7n#TPet  
} >Q@y8*E\F  
} Os>&:{D4!  
//负责部分文件的抓取 Myg;2.  
**FileSplitterFetch.java g7hI9(8+  
*/ m`8{arz2  
package NetFox; J>T98y/))  
JS m7-p|E  
0H4|}+e  
import java.io.*; qCrpc=  
import java.net.*; lv!j  
Y(1?uVYW\d  
Tb2#y]27  
public class FileSplitterFetch extends Thread { psIo[.$rTk  
j96}E/gF  
4V,p\$;  
String sURL; //File URL }qp)VF  
long nStartPos; //File Snippet Start Position 7Rtjm  
long nEndPos; //File Snippet End Position V 1d#7rP  
int nThreadID; //Thread's ID ?b(wZ-/  
boolean bDownOver = false; //Downing is over s Y1@~v  
boolean bStop = false; //Stop identical s=jH1^  
FileAccessI fileAccessI = null; //File Access interface ZaY|v-  
w$iPFZC'  
tF/Ni*\^rV  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ;g#nGs>  
{ 7w9'x Y  
this.sURL = sURL; /2=9i84  
this.nStartPos = nStart; `.~S/$a.&  
this.nEndPos = nEnd; P(@Q[XQ2  
nThreadID = id; ' #=n>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 U%@C<o "  
} S`  U,  
3D@3jyo:  
5p~5-_JX  
public void run() d ]|K%<+(  
{ _>`9]6\&  
while(nStartPos < nEndPos && !bStop) /]J\/Z>  
{ zTMLE~w  
T&6>Eb0{  
yLCMu | +  
try{ Dl0{pGK~  
URL url = new URL(sURL); Z~94<*LEp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C"5P7F{  
httpConnection.setRequestProperty("User-Agent","NetFox"); fHZ9wK>  
String sProperty = "bytes="+nStartPos+"-"; i qxMTH#!  
httpConnection.setRequestProperty("RANGE",sProperty); xa]yq%  
Utility.log(sProperty); OYWHiXE6]  
V73/q  
PeiRe  
InputStream input = httpConnection.getInputStream(); *mj=kJ7(  
//logResponseHead(httpConnection); 6l4=  
YGQ/zB^Pj  
Io IhQ  
byte[] b = new byte[1024]; G^h:#T  
int nRead; "S'Yn-  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +$>aT (q  
{ ->;2CcpHB  
nStartPos += fileAccessI.write(b,0,nRead); (AjgLNB  
//if(nThreadID == 1) t%^&b'/Z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,']CqhL6=R  
} NA0Z~Ug>  
Q{=r9&&  
D{7^y>8_Y-  
Utility.log("Thread " + nThreadID + " is over!"); <a_ (qh@B  
bDownOver = true; _(:$ :*@  
//nPos = fileAccessI.write (b,0,nRead); &D-z|ZjgHi  
} U&*%KPy`  
catch(Exception e){e.printStackTrace ();} 9L-jlAo<  
} VR"le&'z"  
} \X(*JNQ  
K@[Hej6d  
}JQy&V%  
//打印回应的头信息 b[:m[^  
public void logResponseHead(HttpURLConnection con) 7p!f+\kM  
{ C`qV+pV  
for(int i=1;;i++) b=sY%(2s  
{ r~QE}00@^  
String header=con.getHeaderFieldKey(i); HWFTI /]  
if(header!=null) *(vh|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); '/loJz 1  
Utility.log(header+" : "+con.getHeaderField(header)); 862rol  
else ]i,o+xBKH  
break; [P~7kNFOh  
} |XQ_4{  
} m-~3c]pA  
,vMAX?c  
Oop6o $k  
public void splitterStop() wmR~e  
{ %{V7 |Azt  
bStop = true; Fo ;J3<U)  
} Qof%j@  
RSB+Saf.8  
bxO/FrwTj{  
} hCgk78O?  
4=y&}3om(0  
as/PM"  
/* _~umE/tz  
**FileAccess.java `h :!^"G  
*//文件访问(定位,写) 2Rwd\e.z  
package NetFox; `) ],FE*:  
import java.io.*; sieC7raO  
9qGba=}Ey  
w9"~NK8xzM  
public class FileAccessI implements Serializable{ y}={S,z%22  
ZO<\rX (  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 OA}; pQ9QN  
RandomAccessFile oSavedFile; g__s(  IJ  
long nPos; dOaCdnd~  
j bT{K|d-  
6v%ePFul  
public FileAccessI() throws IOException $7Z-Nn38  
{ 6#jql  
this("",0); %B1TN#KoT  
} < 0~1   
[x=(:soEqC  
sHPeAa22  
public FileAccessI(String sName,long nPos) throws IOException d>MDC . j  
{ 74 )G.!  
oSavedFile = new RandomAccessFile(sName,"rw"); Tu}EAr  
this.nPos = nPos; \=|=(kt)  
oSavedFile.seek(nPos); vQ2{ +5!|  
} Rq?t=7fX)  
H!"TS-s`  
g;[t1~oF  
public synchronized int write(byte[] b,int nStart,int nLen) ofz?L#:2  
{ 1.8"N&s  
int n = -1; %8Y+Df;ax  
try{ CHO_3QIz  
oSavedFile.write(b,nStart,nLen); >@?mP$;=  
n = nLen; ~g#/q~UE  
} suWO:]FR  
catch(IOException e) fY78  
{ HSU?4=Q  
e.printStackTrace (); HFyQ$pbBU  
} !OPHS^L  
%yfl-c(u  
b *0uxvLu  
return n; !:esdJH  
} L0=`1q  
LLzxCMc9*  
UpSJ%%.n  
} Ijz*wq\s;  
*M#L)c;6  
-,g.39u  
/* .YB/7-%M[  
**SiteInfoBean.java c\ ZnGI\|  
*/ Ml?KnSb  
package NetFox; S&[9Vb  
'?_~{\9<  
gzW{h0iRr  
public class SiteInfoBean { 4 eSFpy1  
DaGny0|BB  
&{qKoI]  
private String sSiteURL; //Site's URL >RJ&b  
private String sFilePath; //Saved File's Path eFA,xzp  
private String sFileName; //Saved File's Name yQ<h>J>  
private int nSplitter; //Count of Splited Downloading File B *6 ncj  
p_JWklg^  
"j8=%J{  
public SiteInfoBean() l1L8a I,8  
{//nSplitter的缺省值为5 `e3$jy@  
//default value of nSplitter is 5 JwWxM3(%t  
this("","","",5); Y8lZ]IB  
} SH8zkAA7u}  
8s[1-l  
-lv(@7o~  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $XkO\6kh  
{ /yY}.S  
sSiteURL= sURL; +NvpYz  
sFilePath = sPath; L=HnVgBs  
sFileName = sName; x`IWo:j  
this.nSplitter = nSpiltter; 7D'D7=Z.  
q j9q   
QSM3qke  
} ! jDopE0L  
9pS:#hg  
yn<J>e  
public String getSSiteURL() j]R[;8g  
{ Q^05n$ tI  
return sSiteURL; BYa#<jXtAT  
} a +~b3  
$o$WFV+h  
w2('75$J  
public void setSSiteURL(String value) UH\{:@GjNO  
{ 4"!kCUB  
sSiteURL = value; B J I N  
} C"s-ttP   
EymSrZw  
w5/6+@}  
public String getSFilePath() [>3dhj[;  
{ b9-3  
return sFilePath; Y}Y~?kE>M|  
} lHTr7uF(  
oZl%0Uy?9I  
15aPoxo>  
public void setSFilePath(String value) ?q2Yk/P  
{ BTG_c_ ?]e  
sFilePath = value; V+l7W  
} y; <}`  
'<1Cta`  
ORWi+H|  
public String getSFileName() ]A#:Uc5  
{ MOp "kA  
return sFileName; >NV1#\5_R@  
} oEFo7X`t  
)<_qTd0`  
:^>&t^E  
public void setSFileName(String value) u5KAwMw%Q  
{ Iij$ce`nx  
sFileName = value; O2="'w'kR  
} :7dc;WdM  
'}bmDb*  
&o1k_!25  
public int getNSplitter() 8xh x*A  
{ A2A_F|f  
return nSplitter; v.u 5%  
} e+VE FWz  
C>,> _  
! R3P@,j  
public void setNSplitter(int nCount) R?- zJ ;  
{ qcQq.cS_'N  
nSplitter = nCount; X{6a  
} BB(v,W  
} DVKb`KJ"  
`R.Pz _oe  
hk S:_e=  
/* UTN[! 0[  
**Utility.java .P?n<n#  
*/ 2Yd@ V}  
package NetFox; k"/Rjd(;  
9e vQQN6D|  
)N1iGJO)  
public class Utility { v '^}zO  
c813NHW  
<X1 lq9 lW  
public Utility() _p'@.P  
{ -"H0Qafm  
w1VYU>  
"5sA&^_#_  
} T.-tV[2  
zn_#}}e;G  
//线程睡眠 9$C?)XKXB  
public static void sleep(int nSecond) X')l04P@%  
{ 8Djki]  
try{ DQ[7p(  
Thread.sleep(nSecond); d&f!\n_~  
} 3?L[ohKH?:  
catch(Exception e) -!li,&,A1  
{ >+Iph2]  
e.printStackTrace (); nLv~)IQ}:  
} Fpeokr"i  
} de.f?y  
n4}e!  
//日志 khD)x0'b  
public static void log(String sMsg) g#7Q-n3^  
{ }&2,!;"">3  
System.err.println(sMsg); v9S=$Aj  
} `8Ych@f]  
uwZ,l-6T  
<o*b6 m%  
public static void log(int sMsg) RO%M9LISI  
{ P B5h5eX  
System.err.println(sMsg); |JHNFs  
} T{"Ur :p  
} n~}[/ly  
k)X\z@I'  
$N;J)  
/* d%epM5  
**TestMethod.java cs9h\]ZA  
*/ -/0\_zq7  
package NetFox; Q4a7g$^  
e#mqerpJ  
2k^rZ^^"  
public class TestMethod { V3r)u\ o'  
MuP>#Vk  
3]9Rmx  
public TestMethod() ,9_O4O%  
{ ///xx/weblogic60b2_win.exe wAX;)PLg  
try{ dGkw%3[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); !IO\g"y~|%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); b09xf"D  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [{)Z^  
fileFetch.start(); /`DKX }  
} 1@h8.ym<"  
catch(Exception e){e.printStackTrace ();} 2/uZ2N |S  
K9p<PLy+  
-zqpjxU:  
} \0_jmX]p  
;Oqf{em];  
' ]+!i a  
public static void main(String[] args) CmBgay  
{ >P\eHR,{-  
new TestMethod(); c_M[>#`  
} jWi~Q o+  
} gTOx|bx  
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