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http断点续传简单实现(java)

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/* L_rKVoKjt  
**SiteFileFetch.java 7^J-5lY3S  
*/ J dDP  
package NetFox; df7z& {R  
import java.io.*; THmX=K4=?  
import java.net.*; h,V#V1>Hu  
Cu\A[6g,  
o?J>mpC  
public class SiteFileFetch extends Thread { 4{\h53j$  
z.[ Ok  
m dC.M$  
SiteInfoBean siteInfoBean = null; //文件信息Bean ntSPHK|'  
long[] nStartPos; //开始位置 F=hfbCF5x  
long[] nEndPos; //结束位置 uj-q@IKe  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 o " x& F  
long nFileLength; //文件长度 [D H@>:"dd  
boolean bFirst = true; //是否第一次取文件 {O,Cc$_  
boolean bStop = false; //停止标志 8P3EQY -  
File tmpFile; //文件下载的临时信息 d*lnXzQor  
DataOutputStream output; //输出到文件的输出流 <oS k!6*  
1b'1vp  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) qu[x=LZ_  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,diV;d  
{ U jC$Mi`O  
siteInfoBean = bean; BV&}(9z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); LTY@}o]\U  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >Tld:  
if(tmpFile.exists ()) 0=8.8LnN(  
{ V\kf6E  
bFirst = false; qb ^4G  
read_nPos(); ]*^mT&$7  
} 5|-(Ic  
else G2kr~FG  
{ $2^V#GWo  
nStartPos = new long[bean.getNSplitter()]; *Df|D/,WE  
nEndPos = new long[bean.getNSplitter()]; (0qdU;  
} 0n_Cuh\  
O4&/g-  
 IjDG  
'7W?VipU  
} m4n J9<-  
xnu|?;.}!  
+MQf2|--  
public void run() cmu5KeH  
{ Fa9]!bW  
//获得文件长度 XQk9 U  
//分割文件 0X)'8N  
//实例FileSplitterFetch sf?D4UdIH  
//启动FileSplitterFetch线程 ;1cX|N=  
//等待子线程返回 `ge{KB;*n#  
try{ r! 5C3  
if(bFirst) CD^_>sya  
{ 79a{Zwdd9j  
nFileLength = getFileSize(); Ah &D5,3  
if(nFileLength == -1) 0}Xkj)R,  
{ COj50t/  
System.err.println("File Length is not known!"); 5jg^12EP  
} @)m+O#a  
else if(nFileLength == -2) U$pHfNTH  
{ awXL}m[_!  
System.err.println("File is not access!"); {P(Z{9u%  
} -?!Z/#i4  
else /+J?Ep(_  
{ F#iLMO&Q  
for(int i=0;i<nStartPos.length;i++) ha'oLm#  
{ @yB!?x  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); g B<p  
} tGD$cBE  
for(int i=0;i<nEndPos.length-1;i++) ;'pEzz?k"  
{ g?i_10Xlp  
nEndPos = nStartPos[i+1]; `a2Oj@jP  
} 0pu])[P]_[  
nEndPos[nEndPos.length-1] = nFileLength; -2tX 15,  
} ^#S  
} A A<9 XC  
:%A1k2  
ix]3t^  
//启动子线程 @^;WC+\0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; r[M]2h  
for(int i=0;i<nStartPos.length;i++) '8k\a{t_z  
{ (1(3:)@S6  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mw`%xID*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \J-O b  
nStartPos,nEndPos,i); ?i(Tc!  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); pp#Kb 2*  
fileSplitterFetch.start(); w])bQ7)  
} 4I^6[{_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F)_Rs5V:(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?Yg K]IxD  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4\2p8__  
nEndPos = " + nFileLength); +]CKu$,8  
// fileSplitterFetch[nPos.length-1].start(); IVkKmO(qO  
bR*T}w$<  
$z{HNY* 2  
//等待子线程结束 QD<^VY6  
//int count = 0; !V@Y \M d  
//是否结束while循环 cWp n/.a  
boolean breakWhile = false; Iu(T@",Q#  
YT, 1E>rd  
>H5BY9]I  
while(!bStop) v>)[NAY9  
{ Y#{KGVT<  
write_nPos(); ',6QL4qV/  
Utility.sleep(500); <W/-[ M  
breakWhile = true; =t&B8+6  
*xU^e`P  
n1uJQt  
for(int i=0;i<nStartPos.length;i++) v2EM| Q xp  
{ w>H!H6Q  
if(!fileSplitterFetch.bDownOver) 6l [T Q  
{ lbT<HWzNH  
breakWhile = false; %MbjKw  
break; ,$vc*}yI0  
} 4VaUa8 D  
} +2B{"Czm  
if(breakWhile) k%:]PQjYT  
break; Tr/wG  
Q-O:L  
qJ"dkT*  
//count++; 9qwVBu ;  
//if(count>4) $NG}YOP)@  
// siteStop(); `z5j  
} ;-^WUf |  
%'4dg k  
jDgiH}  
System.err.println("文件下载结束!"); na  $z\C\  
} vT%rg r  
catch(Exception e){e.printStackTrace ();} p5)A"p8"9,  
} y @Y@"y  
s.C-II?e  
!S%XIq}FX  
//获得文件长度 yql+N[  
public long getFileSize() og. dYs7W4  
{ : [aUpX=  
int nFileLength = -1; A+Y>1-=JO  
try{ I g-VSQ  
URL url = new URL(siteInfoBean.getSSiteURL()); Ao`9fI#q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;n7k_K#0z!  
httpConnection.setRequestProperty("User-Agent","NetFox"); F2oY_mA  
&E {/s  
-Q 6W`*8  
int responseCode=httpConnection.getResponseCode(); cy^6g? ew  
if(responseCode>=400) ;c:vz F~Q  
{ 4^70r9hV9  
processErrorCode(responseCode); fgn*3 pg  
return -2; //-2 represent access is error .yi.GRk  
} xE;fM\7pu  
9N=Dls  
X_Y$-I$qd  
String sHeader; ,!%[CpM3  
$3Wl~ G}  
X[NsdD?w1+  
for(int i=1;;i++) kfm8F8sxl  
{ jW2z3.w  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); pl q$t/.U;  
//Utility.log(in.readLine()); VC>KW{&J0  
sHeader=httpConnection.getHeaderFieldKey(i); OYG8%L  
if(sHeader!=null) 7gD$Q  
{ W1r-uR  
if(sHeader.equals("Content-Length")) @U5 +1Hjc  
{ _jU6[y|XLh  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /o8`I m   
break; )u\"xxcV  
} <&l3bL  
} \e'>$8%T  
else V%e'H>EC  
break; YaSwn3i/@S  
} v[m/>l2[P  
} Z9=Cw0( w?  
catch(IOException e){e.printStackTrace ();} Lk#u^|Eq7=  
catch(Exception e){e.printStackTrace ();} e *;"$7o9  
mtmBL 2?  
_a15R/S  
Utility.log(nFileLength); j]Rl1~+M  
m>zUwGYEu  
us`hR!_  
return nFileLength; JguE#ob2  
} IO^O9IEx,  
oPzt1Y  
-BQM i0  
//保存下载信息(文件指针位置) d<7xSRC   
private void write_nPos() x-y=Jor  
{ QhpE2ICU  
try{ 0lmoI4bW}s  
output = new DataOutputStream(new FileOutputStream(tmpFile)); YfxZ<  
output.writeInt(nStartPos.length); UvQxtT]  
for(int i=0;i<nStartPos.length;i++) A "_;.e`  
{ ;M"hX  
// output.writeLong(nPos); ;EF s2-{K  
output.writeLong(fileSplitterFetch.nStartPos); O_F<VV*MFQ  
output.writeLong(fileSplitterFetch.nEndPos); `Ph4!-6#  
} ]7dm`XV  
output.close(); {r'#(\  
} /Pg66H#RUf  
catch(IOException e){e.printStackTrace ();} Sw'DS  
catch(Exception e){e.printStackTrace ();} $`l- cSH;  
} #Y`U8n2F  
tTWYlbDFN  
c/T]=S[  
//读取保存的下载信息(文件指针位置) Z33w A?9  
private void read_nPos() apGf@b  
{ VWLou jB  
try{ bmt2~!  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); c?<FMb3]  
int nCount = input.readInt(); rf)\:75  
nStartPos = new long[nCount]; 5"XcVH4g  
nEndPos = new long[nCount]; oh& P Q{  
for(int i=0;i<nStartPos.length;i++) {T:2+iS9:  
{ aeH 9:GQ6  
nStartPos = input.readLong(); 7|,5;  
nEndPos = input.readLong(); InPq1AH  
} UnW,|n8  
input.close(); R['qBHQ?  
} _4%+TN6z  
catch(IOException e){e.printStackTrace ();} V\ARe=IWM  
catch(Exception e){e.printStackTrace ();} og2]B\mN4  
} Fo;xA  
I"T_<  
Vs{|:L+  
private void processErrorCode(int nErrorCode) /:U\U_j  
{ sFCoRH|"c  
System.err.println("Error Code : " + nErrorCode); lQ! 6n  
} !u\X,.h  
Wv(VV[?/&  
YM1@B`yWE  
//停止文件下载 $[FO(w@f  
public void siteStop() hz\7Z+$L_  
{ #@y4/JS&2  
bStop = true; ^P&y9dC.  
for(int i=0;i<nStartPos.length;i++) p(U' c}@2  
fileSplitterFetch.splitterStop(); 'Ur$jW  
)W*S6}A  
8#7z5:_  
} !\?? [1_e  
} v9M ;W+J  
//负责部分文件的抓取 "hs`Y4U  
**FileSplitterFetch.java #{ `(;83  
*/ Nv #vfh9}P  
package NetFox; #G9S[J=xe  
Q3z-v&^E9  
QabF(}61  
import java.io.*; fS!%qr  
import java.net.*; #\t?`\L3  
RUO,tB|(_;  
6I_W4`<VeZ  
public class FileSplitterFetch extends Thread { LRB#|PW  
(kb^=kw#0  
?N$  
String sURL; //File URL ~p oy`h'  
long nStartPos; //File Snippet Start Position O v?k4kJ  
long nEndPos; //File Snippet End Position e[R364K  
int nThreadID; //Thread's ID #XC\= pZX  
boolean bDownOver = false; //Downing is over Zr oj-3-X~  
boolean bStop = false; //Stop identical qjUQ2d  
FileAccessI fileAccessI = null; //File Access interface + s1mm c  
Z$HYXm  
j6IWdqXe  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Et`z7Q*e  
{ bnUd !/;  
this.sURL = sURL; =3/||b4c  
this.nStartPos = nStart; *PZNZ{|m  
this.nEndPos = nEnd; ` [@ F3x  
nThreadID = id; ur*1I/v  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 d;;]+%  
} R2t5T-8`c  
#Du1(R  
7c4\'dt#  
public void run() cq@8!Eu w]  
{ h7I_{v8  
while(nStartPos < nEndPos && !bStop) IY,&/MCh  
{ *>S\i7RET  
\gj@O5rGP  
}2V|B4  
try{ s?E7tmaM  
URL url = new URL(sURL); V><5N;w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -b r/  
httpConnection.setRequestProperty("User-Agent","NetFox"); e[w)U{|40  
String sProperty = "bytes="+nStartPos+"-"; "E 8-76n  
httpConnection.setRequestProperty("RANGE",sProperty); 'iUfr@  
Utility.log(sProperty); V:My1R0  
<E$5LP;:  
A[=)Zw "  
InputStream input = httpConnection.getInputStream(); S37Bl5W  
//logResponseHead(httpConnection); 65s|gfu/  
)}n`MRDB  
J%3S3C2*m  
byte[] b = new byte[1024]; /e#_Yg  
int nRead; u -CY-  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ,j9}VnW)  
{ R;'Pe>  
nStartPos += fileAccessI.write(b,0,nRead); UiaY0 .D  
//if(nThreadID == 1) 3EF|1B/5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [g_f`ZJ=  
} p4HX83y{  
q9icj  
'$q'Wl)  
Utility.log("Thread " + nThreadID + " is over!"); jo{GPp}  
bDownOver = true; RK"dPr  
//nPos = fileAccessI.write (b,0,nRead); (#LV*&K%IC  
} YX!%R]c%  
catch(Exception e){e.printStackTrace ();} Aw9^}k}UfD  
} 1&Nk  
} 4vp,izNW  
f>-OwL($P  
73 D|gF*  
//打印回应的头信息 QjF.U8  
public void logResponseHead(HttpURLConnection con) " 0K5 /9  
{ F}2U8O  
for(int i=1;;i++) 5NBc8h7 V  
{ @6}c\z@AxM  
String header=con.getHeaderFieldKey(i); 0@^YxU[YN  
if(header!=null) kM]?  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); XvZg!<*OH  
Utility.log(header+" : "+con.getHeaderField(header)); Q5{i#F7nJm  
else C4TJS,!1rH  
break; 7cY_=X-?Y  
} :}e*3={4  
} T~=NY,n  
2vu"PeU9  
]0V~|<0c  
public void splitterStop() !)_80O1  
{ :=UeYm @  
bStop = true; Lt|k}p@]  
} UH.M)br  
!|!:MYn  
}oj$w?Ex  
} Wi hQj  
qRTxg%  
)MmMs"Um  
/* $zyY"yWRZ  
**FileAccess.java < yE(p  
*//文件访问(定位,写) 0[);v/@Ho  
package NetFox; s|%mGt &L  
import java.io.*; b3<<4Vf  
g9'50<|J  
l3b$b%0'  
public class FileAccessI implements Serializable{ k]ptk^  
tJbOn$]2"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 CPF d 3 3  
RandomAccessFile oSavedFile; -O^b  
long nPos; ZTM zL%i  
EX=+TOkAf  
6=MejT  
public FileAccessI() throws IOException P[% W[E<  
{ 86vk"  
this("",0); Rfeiv  
} k "'q   
!gW$A-XD  
 ZRsDn  
public FileAccessI(String sName,long nPos) throws IOException $9M>B<]  
{ 8/ZJkI  
oSavedFile = new RandomAccessFile(sName,"rw"); leg@ia  
this.nPos = nPos; TW:vL~L  
oSavedFile.seek(nPos); k2,n:7  
} V.: a6>]  
DUM,dFIlvF  
}\OLBg/  
public synchronized int write(byte[] b,int nStart,int nLen) +\\*Iy'xK  
{ Apa)qRJd  
int n = -1; :&#hjeltt  
try{ -r/#20Y  
oSavedFile.write(b,nStart,nLen); el;^cMY  
n = nLen; Ajs<a(,6  
} -TjYQ  
catch(IOException e) eLL> ThMyW  
{ yL_-w/a  
e.printStackTrace (); $6Nm`[V  
}  ]i=-/  
2fFNJ  
_+wv3? c"  
return n; R]m`v: 9  
} 3@XCP-`  
9kH~+  
C>:F4"0  
} }8fxCW*|  
rs=wEMq/  
3!Rb {  
/* &s\$&%|  
**SiteInfoBean.java #fzvK+  
*/ rRYP~ $c  
package NetFox; ` {k>I^Pg  
G0^23j  
Y^2`)':  
public class SiteInfoBean { {!o-y=  
D 7 [n^WtL  
hG2btmBht  
private String sSiteURL; //Site's URL |\XjA4j  
private String sFilePath; //Saved File's Path /-8v]nRB  
private String sFileName; //Saved File's Name DN&ZRA  
private int nSplitter; //Count of Splited Downloading File 5R{ {FD`h  
>Y1?`  
7h&$^  
public SiteInfoBean() 9c=Y+=<  
{//nSplitter的缺省值为5 8}{';k  
//default value of nSplitter is 5 agM.-MK  
this("","","",5); slOki|p;  
} %+Z 0 $Q  
(+>+@G~o  
C ])Q#!D|  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {5#P1jlT  
{ dY;^JPT  
sSiteURL= sURL; `[jQn;  
sFilePath = sPath; dV<M$+;s]  
sFileName = sName; InH R> ,  
this.nSplitter = nSpiltter; cx_[Y  
-l`@pklQ  
6IctW5b  
} QKwWX_3%Z]  
J= ia  
x +q"%9.c  
public String getSSiteURL() *O)_D bj  
{ 8v*>~E/0  
return sSiteURL; >#$( M5&}-  
} HvKueTQ  
p<Ah50!B  
p27A#Uu2}  
public void setSSiteURL(String value) i74^J+xk  
{ C$"jZcm,I  
sSiteURL = value; v|?hc'Fj  
} nxsQDw\hy  
3+EJ%  
2^ ^;Q:  
public String getSFilePath() P>)-uLc~W  
{ _ZzN}!Mye  
return sFilePath; ,au64sH  
} &VY;Al  
= <O{t#]  
+y6|Nq  
public void setSFilePath(String value) tmRD$O%:  
{ ojs&W]r0Z  
sFilePath = value; i\3BA"ZX  
} -102W{V/T  
<^~Xnstl  
j+Y4>fL$  
public String getSFileName() u5H#(&Om  
{ }<2F]UuR  
return sFileName; Eh!%Ne O  
} p$?c>lim  
$- =aqUU  
HoH3.AY X  
public void setSFileName(String value) @Sq=#f/=  
{ 7@fd[  
sFileName = value; !Ya +  
} ~_8Ve\Y^/  
B 0 K2Uw  
Y@9L8XNP>  
public int getNSplitter() TbIM{X  
{ nd3]&occ  
return nSplitter; x^+ C[%  
} ~e 6yaX8S  
O.& 6J/  
yZ0;\Tr*J  
public void setNSplitter(int nCount) @ RTQJ+ms  
{ Pu/0<Orp7  
nSplitter = nCount; }td+F&l($V  
} sx*1D9s_  
} Jgtv ia  
2mu~hJ  
f#eTi&w  
/* wS``Q8K+dM  
**Utility.java ~q4DePVE  
*/ *VHBTO9  
package NetFox; 4TwU0N+>  
_q6+]  
ua|qL!L+  
public class Utility { h,FP,w;G  
+}mj6I  
6Wc eDY  
public Utility() j"94hWb  
{ 4fzq C)  
QAygr4\X^  
2-j|q6m5  
} Qi=rhN`  
T2Y`q'  
//线程睡眠 R&ou4Y:DG  
public static void sleep(int nSecond) lmH!I )5  
{ rt^z#2$  
try{ &sS k~:  
Thread.sleep(nSecond); _j%Rm:m;<  
} ,J}lyvkd  
catch(Exception e) M8KfC!  
{ / sH*if  
e.printStackTrace (); Sw5H+!  
} lz{>c.Ll[  
} 1 _5[5K^  
C>T6{$xkC  
//日志 !~ -^s  
public static void log(String sMsg) x-tA {_:  
{ v|{*y  
System.err.println(sMsg); X){F^1CT{  
} {dMa&r|lp  
f\r$T Nd6  
HoRLy*nU  
public static void log(int sMsg) 2mU}"gf[  
{ _x UhDu%  
System.err.println(sMsg); ]"/ *7NM  
} ,l0s(Cg  
} GExG1n-  
,P auP~L  
NA/+bgyuT>  
/* * +OAc `8  
**TestMethod.java zh/+1  
*/ Bj@&c>  
package NetFox;  }Ecm  
l\$C)q6O  
QRdb~f;<hj  
public class TestMethod {  n8:2Z>  
y:2o-SJn  
q8kt_&Ij  
public TestMethod() "hy#L 0\t  
{ ///xx/weblogic60b2_win.exe "H G:by  
try{ e}K;5o=I  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); P]6pPS  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); c$e~O-OVD?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =WO{h48]  
fileFetch.start(); xHD!8 B)  
} 3J(STIxg  
catch(Exception e){e.printStackTrace ();} kY_UY~E  
qZ1fQN1yG  
0 ?2#SM  
} j<l>+., U  
E>4 \9  
)$th${pd#v  
public static void main(String[] args) Uj!L:u2b  
{ 4 Qw;r  
new TestMethod(); %+pXzw`B  
} m|f|u3'z$  
} 9R ugkGy  
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