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http断点续传简单实现(java)

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/* PXk?aJ  
**SiteFileFetch.java bt/ =Kq#  
*/ y2|R.EU\m<  
package NetFox; A1i!F?X  
import java.io.*; DAO]uh{6  
import java.net.*; %)(Cp-b!  
z-T{~{q  
$8~e}8dt|  
public class SiteFileFetch extends Thread { v]VWDT `  
1iBP,:>*  
}} ZY  
SiteInfoBean siteInfoBean = null; //文件信息Bean rS8 w\`_  
long[] nStartPos; //开始位置 ~O6\6$3b5E  
long[] nEndPos; //结束位置 nH-V{=**  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 $XnPwOj  
long nFileLength; //文件长度 # Su~`]  
boolean bFirst = true; //是否第一次取文件 Zjh2{ :  
boolean bStop = false; //停止标志 cr;`Tl~}s  
File tmpFile; //文件下载的临时信息 +^|iZbZKx  
DataOutputStream output; //输出到文件的输出流 jp2Q 9Z  
r'7LR  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) S<wj*"|.s  
public SiteFileFetch(SiteInfoBean bean) throws IOException PoSpkJH  
{ a;AzY'R  
siteInfoBean = bean; Dt|)=a  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); EHf\L  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); *%5{'  
if(tmpFile.exists ()) 6<76H  
{ /~p+j{0L3W  
bFirst = false; mN_Z7n;^eh  
read_nPos(); q(M:QWA q  
} 4Y\wnwI  
else TFQ!7'xk)  
{ GX{XdJD  
nStartPos = new long[bean.getNSplitter()]; *# {z3{+  
nEndPos = new long[bean.getNSplitter()]; eOT+'[3"  
} gb|Q%LS9R  
/iaf ^ >  
5VW|fI  
, E )|y4  
} ?#A]{l  
ne}+E  
 AnBJ(h  
public void run() O[@ q%&_  
{ 0#o/^Ah  
//获得文件长度 /b#l^x:j  
//分割文件 5&Ts7& .  
//实例FileSplitterFetch bpAv1udX-W  
//启动FileSplitterFetch线程 $tqJ/:I  
//等待子线程返回 !A3-0zN!  
try{ _f0C Y"  
if(bFirst) nuQ]8 -,  
{ O Wp%v_y]  
nFileLength = getFileSize(); jhgX{xc  
if(nFileLength == -1) 0 fXLcal  
{ ,8'>R@o  
System.err.println("File Length is not known!"); @D^^_1~  
} u^Ku;RQo  
else if(nFileLength == -2) Uh eC  
{ oTjyN\?H  
System.err.println("File is not access!"); 2NGe C0=  
} p/Sbt/R  
else uQ$^;Pr  
{ :'L2J  
for(int i=0;i<nStartPos.length;i++) CbBSFKM  
{ e>rRTN  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); wBj-m  
} 2| iV,uJ&  
for(int i=0;i<nEndPos.length-1;i++) \2-@'^i  
{ Yj|eji7y  
nEndPos = nStartPos[i+1]; Vgb *% I  
} AI vXb\wL  
nEndPos[nEndPos.length-1] = nFileLength; 1+;C`bnA  
} Xl7aGlH  
} M,5j5<7  
d$ACDX2  
g1E~+@  
//启动子线程 *.-.iY.a]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 1F8 W9b^D  
for(int i=0;i<nStartPos.length;i++) f"u *D,/sS  
{ <:>SGSE9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &GTI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3f Xv4R;!:  
nStartPos,nEndPos,i); \`V$ 'B{.  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); '7Nr8D4L  
fileSplitterFetch.start(); Cb t{ H}I3  
} ]M>9ULQ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F7L&=K$2y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); d6{Gt"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", f*{ YFg?*&  
nEndPos = " + nFileLength); sxKf&p;  
// fileSplitterFetch[nPos.length-1].start(); ?^mi3VM  
`nXVE+E@  
/^{BUo  
//等待子线程结束 7\z ZpPDV  
//int count = 0; c\6+=\  
//是否结束while循环 b i y4 d  
boolean breakWhile = false; =h6 sPJ  
lE8&..~l$+  
qSqI7ptA\  
while(!bStop) 1 2++RkL#  
{ up3O|lj4  
write_nPos(); V-I(WzR9y  
Utility.sleep(500); XfE?C:v   
breakWhile = true; lU^;Z 6f  
{CG_P,FO  
3nZ9m  
for(int i=0;i<nStartPos.length;i++) ev0oO+u  
{ f %lD08Sl  
if(!fileSplitterFetch.bDownOver) Sd/?&  
{ "vYE+   
breakWhile = false; @l1  
break; +x? #DH-  
} $8USyGi3J  
} m=AqV:%|  
if(breakWhile) *%w6 9#D  
break; Ut-B^x)gl  
{qW~"z*  
P&d"V<  
//count++; b*;"q9u5  
//if(count>4) 2$_9cF Wm  
// siteStop(); w;}@'GgL  
} `~eX55W  
b `2|I {  
;4M><OS!  
System.err.println("文件下载结束!"); a07@C  
} +uWDP .  
catch(Exception e){e.printStackTrace ();} "'8KV\/D  
} .@-9'<K?~  
ML-)I&>tT  
|4mpohX  
//获得文件长度 !Fw?H3X!"q  
public long getFileSize() KfBTL!0#  
{ _rV5E  
int nFileLength = -1; S-31-Zjw  
try{ >-_d CNZ  
URL url = new URL(siteInfoBean.getSSiteURL()); id<:p*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); BR^7_q4q  
httpConnection.setRequestProperty("User-Agent","NetFox"); y-p70.'{U  
x\&`>>uA  
^_5L"F]sP  
int responseCode=httpConnection.getResponseCode(); ihh4pD27g  
if(responseCode>=400) Q9d`zR]  
{ MS(JR  
processErrorCode(responseCode); k4qp u=@U  
return -2; //-2 represent access is error \Gm-MpW  
} %p^.\ch9  
>e2<!#er|  
R(P%Csbqh  
String sHeader;  $Y=T&O  
:+{ ?  
-U<Upn)2  
for(int i=1;;i++) e{;OSk`x  
{ 1:NrP'W^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =NbI%  
//Utility.log(in.readLine()); a9n^WOJ6  
sHeader=httpConnection.getHeaderFieldKey(i); qQpnLV4  
if(sHeader!=null) (>mI'!4d  
{ t E` cau  
if(sHeader.equals("Content-Length")) /&u<TJ4  
{ N=:5eAza  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0JgL2ayIVI  
break; ^mAYBOE  
} ]0;864X0  
} 2j(h+?N7k  
else ] 2DH;  
break; ZYf2XI(_"  
} U. AjYez  
} -",=G\XZ  
catch(IOException e){e.printStackTrace ();} y%sroI('y  
catch(Exception e){e.printStackTrace ();} {k4CEt;  
UA[,2MBp  
r1ws1 rr=  
Utility.log(nFileLength); wU#F_De)R:  
k>dsw:  
V`adWXu  
return nFileLength; h8\  T  
} th6+2&B6  
Qn ^bVhG+  
iv phlw  
//保存下载信息(文件指针位置) n~g)I&  
private void write_nPos() 0Io'bF  
{ LPG`^SA  
try{ #jAqra._b  
output = new DataOutputStream(new FileOutputStream(tmpFile)); UgWs{y2SE.  
output.writeInt(nStartPos.length); nR4y`oP+  
for(int i=0;i<nStartPos.length;i++) :{NC-%4o0  
{ }SIGPVM  
// output.writeLong(nPos); =9kN_:-  
output.writeLong(fileSplitterFetch.nStartPos); h._nK\  
output.writeLong(fileSplitterFetch.nEndPos); k{gLMl  
} :K\mN/ x  
output.close(); O62b+%~F  
} pV6d Id  
catch(IOException e){e.printStackTrace ();} K1V#cB WO  
catch(Exception e){e.printStackTrace ();} Z/^  u  
} &a/__c/l  
5Z4- Z  
zEZLKWm9-  
//读取保存的下载信息(文件指针位置) LZ@|9!KDw  
private void read_nPos() &z"krM]G  
{ j CTAKaq  
try{ +0),xu  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;['[?wk  
int nCount = input.readInt(); d:G]1k;z  
nStartPos = new long[nCount]; I@Xn3oN  
nEndPos = new long[nCount]; O]f/r,4@  
for(int i=0;i<nStartPos.length;i++) \rykBxs  
{ 0Z|FZGRP  
nStartPos = input.readLong(); pZ#ap<|>I  
nEndPos = input.readLong(); v/*Y#(X  
} 2<mW\$  
input.close(); sH[ -W-  
} I\qYkWg7  
catch(IOException e){e.printStackTrace ();} @aQ1khEd  
catch(Exception e){e.printStackTrace ();} y~IuPc  
} yL;M"L  
c9R 5w.t:  
UpXz&k  
private void processErrorCode(int nErrorCode) \7"@RHcihB  
{ y7KzW*>g :  
System.err.println("Error Code : " + nErrorCode); ~2EHOO{  
} e!fqXVEVR  
65ly2gl  
(M =Y&M'f  
//停止文件下载 m]*Bx%-1c  
public void siteStop() vK$"# F~  
{ 9dMrgz&'  
bStop = true; :';L/x>  
for(int i=0;i<nStartPos.length;i++) cI]WrI2CQa  
fileSplitterFetch.splitterStop(); ?Qb<-~~ j1  
l{w#H|]  
smG>sEp2  
} _2btfY1U  
} LQnkcV  
//负责部分文件的抓取 10#oG{ 9  
**FileSplitterFetch.java +.y .Mp  
*/ \D>$aLO*?  
package NetFox; MxzLK%am  
Knhp*V?  
?^:h\C^a"  
import java.io.*; vpPl$ga5bY  
import java.net.*; E,n}HiAz7V  
Y^%T}yTtq  
n;R#,!<P  
public class FileSplitterFetch extends Thread { `si#aU  
Oi"a:bCU  
7FN<iI&7\  
String sURL; //File URL W4;m H}#0  
long nStartPos; //File Snippet Start Position /v095H@  
long nEndPos; //File Snippet End Position .oEmU+  
int nThreadID; //Thread's ID X0{/ydG F8  
boolean bDownOver = false; //Downing is over k`".  
boolean bStop = false; //Stop identical nN$Y(2ZN  
FileAccessI fileAccessI = null; //File Access interface 8Ry74|`=R  
Ax oD8|  
M5T9JWbN  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @DW[Z`X  
{ OL7_'2_z.  
this.sURL = sURL; HE<1v@jW  
this.nStartPos = nStart; ,:+d g(\r  
this.nEndPos = nEnd; +.RKi !  
nThreadID = id; ] 4+s$rG  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9;yn}\N `  
} 6io, uh!  
UZ8?[  
-st7_3  
public void run() _ >` X]I;  
{ Hn,:`mj4-6  
while(nStartPos < nEndPos && !bStop) K.gEj*@  
{ @?C#r.vgp  
* y^OV_n-8  
,2oF:H  
try{ R~bC,`Bh  
URL url = new URL(sURL); , n !vsIN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a:~@CUD >I  
httpConnection.setRequestProperty("User-Agent","NetFox"); )hwV`2>l  
String sProperty = "bytes="+nStartPos+"-"; 7j5f ;O^+  
httpConnection.setRequestProperty("RANGE",sProperty); s=?aox7  
Utility.log(sProperty); Bh&Ew   
W"L&fV+3  
JcJmds  
InputStream input = httpConnection.getInputStream(); %iJ%{{f`  
//logResponseHead(httpConnection); (2?G:+C 7  
W:i?t8y\y  
P7B:%HiAx  
byte[] b = new byte[1024]; Qy#)Gxp  
int nRead; wV?,Z!\Z  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 3M5#4n\v$  
{ }U@m*dEG  
nStartPos += fileAccessI.write(b,0,nRead); UDf9FnG}L  
//if(nThreadID == 1) c= UU"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bg|!'1bD`5  
} f[gqT yiP  
\Mv":Lm1  
dQezd-y*  
Utility.log("Thread " + nThreadID + " is over!"); Y}6n]n;uR  
bDownOver = true; }awzO#  
//nPos = fileAccessI.write (b,0,nRead); ? _\$  
} (3\Xy   
catch(Exception e){e.printStackTrace ();} 7dihVvL $  
} QbhW!9(,  
} H* !EP  
%/kyT%1  
G;gJNK"e  
//打印回应的头信息 /R X1UQ.s  
public void logResponseHead(HttpURLConnection con) DOm[*1@^  
{ 3+MB5 T  
for(int i=1;;i++) `ir3YnT+  
{ Ql?^ B SqG  
String header=con.getHeaderFieldKey(i); y0v]N  
if(header!=null) Oc9#e+_&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ct$82J  
Utility.log(header+" : "+con.getHeaderField(header)); -6Tk<W  
else @|bP+8oU  
break; l2b{u GE  
} R)!`JKeO/  
} F{k+7Ftc  
Dj-s5pAW  
[%HIbw J  
public void splitterStop() ,]R8(bD)  
{ 3E} An%  
bStop = true; 8:ggECD  
} us?&:L|!=  
ba@ax3  
%IL6ix  
} kfC0zd+  
>KG E-Yzj  
B1N)9%  
/* ^[TV;9I*  
**FileAccess.java !- C' }  
*//文件访问(定位,写) b hjZ7=  
package NetFox; "$p#&W69"J  
import java.io.*; H;<!TX.zD  
HU B|bKy  
#nyv+x;  
public class FileAccessI implements Serializable{ ~WVO  
gL$&@NY  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]/]ju$l9Z  
RandomAccessFile oSavedFile; ,S[K{y<  
long nPos; Bt^K]F\  
~>ME'D~  
%@& a7JOL  
public FileAccessI() throws IOException OQ_stE2i  
{ +2cs#i  
this("",0); bggusK<  
} WoL9V"]  
B_3QQ tjAl  
pL oy  
public FileAccessI(String sName,long nPos) throws IOException "5DJu ~  
{ V7CoZnz  
oSavedFile = new RandomAccessFile(sName,"rw"); vTr34n  
this.nPos = nPos; A,i()R'I  
oSavedFile.seek(nPos);  vfvlB[  
} <FFJzNc+  
lH BI  
O]u",J5  
public synchronized int write(byte[] b,int nStart,int nLen) 7r{qJ7$%  
{ kL{;.WsB  
int n = -1; 4dhqLVgL{  
try{ 2iXoj&3e  
oSavedFile.write(b,nStart,nLen); K6\` __mLf  
n = nLen; 34C``i  
} u7]<=*V]  
catch(IOException e) _45cH{$sA  
{ O@U?IF$  
e.printStackTrace (); ,^T]UHRO  
} $B\E.ml.  
|:iEfi]j  
N} />rD  
return n; 8q_0,>w%  
} 1/j$I~B   
T@+ClZi  
1 0N,?a  
} u?Hb(xZtg=  
nW;kcS*A  
3_ 2hC!u!K  
/* VAj<E0>  
**SiteInfoBean.java &/F_*=VE  
*/ 3l:QeZ  
package NetFox; B#N7qoi  
 .Oo/y0E^  
&{^eU5  
public class SiteInfoBean { XDmbm*~i  
P[gO85  
v+q<BYq  
private String sSiteURL; //Site's URL hYt7kq!"  
private String sFilePath; //Saved File's Path >S&U.  
private String sFileName; //Saved File's Name 4 \Di,PPu  
private int nSplitter; //Count of Splited Downloading File ?9?4p@  
e9@(/+  
R8sck)k'}  
public SiteInfoBean() tW6#e(^l6  
{//nSplitter的缺省值为5 u*R7zY  
//default value of nSplitter is 5 K^ D82tP  
this("","","",5); a|x8=H  
} A!HK~yk~Q  
V:^H4WvL\W  
9`X&,S~e  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }""p)Y&  
{ W7e4pR?w  
sSiteURL= sURL; O k(47nC  
sFilePath = sPath; c>MY$-PD  
sFileName = sName; )mD \d|7f  
this.nSplitter = nSpiltter; pDDG_4E>  
!RMS+Mm?  
h%b hrkD  
} fGO*% )  
g5}7y\  
FN{/.?w(  
public String getSSiteURL() >ZCo 8aK  
{ cIZc:   
return sSiteURL; FLbZ9pX}  
} Baq ~}B<  
[}k|  
x`2pr  
public void setSSiteURL(String value) x70N8TQ_gK  
{ -uR{X G. D  
sSiteURL = value; mTd<2Hy  
} NG-`ag`s  
YRa4W.&Yn  
[t}):}~F|  
public String getSFilePath() 2]Fu 1  
{  GVp  
return sFilePath; hmzair3X  
} -Op@y2+c  
c,BAa*]K  
j;0ih_Z@4W  
public void setSFilePath(String value) iPFL"v<#J  
{ |0w~P s  
sFilePath = value; 7 6*hc   
} m+$/DD^-zl  
&!#2ZJ}{  
[f(uqLdeM  
public String getSFileName() 1Zq   
{ $~hdm$  
return sFileName; /,t| !)\]  
} '}zT1F* p=  
*^6k[3VY  
nOuN|q=C  
public void setSFileName(String value) TAAR'Jz S  
{ >C^/,/%v  
sFileName = value; 0# UAjT3  
} P%jkKE?B4  
?1DUNZ6  
wz@/5c/u  
public int getNSplitter() +9~ZA3DiP  
{ !h/dZ`#  
return nSplitter; % &+|==-  
} qa;EI ;8  
Xa*?<(^`  
'Aet{A=9  
public void setNSplitter(int nCount) A?sNXhh  
{ g\j>qUjs%Q  
nSplitter = nCount; C&oxi$J:p+  
} V%o#AfMI_  
} 6NSO>/E  
*vXDuhQ  
<tU :U<ea]  
/* ZU^Q1}</5  
**Utility.java A ' )(SGSc  
*/ 5 2fO)!  
package NetFox; m^Rd Iy)  
o] S`+ZcV  
Lqq*Nr  
public class Utility { B,:23[v  
-MUQ \pZ  
k$?&]! <o  
public Utility() K.r!?cfv  
{ mR6E]TuM  
P69>gBZYD  
s|KfC>#  
} D~7%};D[  
y#nSk% "t"  
//线程睡眠 w0\4Wa  
public static void sleep(int nSecond) n<+~ zQ  
{ iF+S%aPd#  
try{ M Yu?&}%^  
Thread.sleep(nSecond); WY3_7k8u  
} %!D_q ~"H  
catch(Exception e) &F9OZMK=  
{ 0rGj|@+;  
e.printStackTrace (); yCZ2^P!a  
} ]~ >@%v&  
} ?<g|.HY/  
@ > cdHv  
//日志 @t "~   
public static void log(String sMsg) Y9/{0TArG  
{ S]tkz*w0*  
System.err.println(sMsg); &~42T}GTWG  
} =CGD ~p`  
EOofa6f&l  
6@i|Kw(:  
public static void log(int sMsg) SG1&a:c+.  
{ es{cn=\ s  
System.err.println(sMsg); <)=3XEcb  
} `f2W;@V0  
} j #4+-  
Cbazwq  
eR(\s_`  
/* sf<Q#ieTxY  
**TestMethod.java Ixyvn#ux )  
*/ Bd/} %4V\@  
package NetFox; N,h1$)\B#  
VM=hQYe  
{_?T:`  
public class TestMethod { qAnA=/k`  
PjiNu.>2(  
t00\yb^vJ8  
public TestMethod() |C&%S"*+D  
{ ///xx/weblogic60b2_win.exe U#OWUZ  
try{ BYkVg2D(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Qo]vpp^[#  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); X v`2hf  
SiteFileFetch fileFetch = new SiteFileFetch(bean); XPGL3[w\V  
fileFetch.start(); 0EcC  
} .G7]&5s  
catch(Exception e){e.printStackTrace ();} &?}kL= h  
5B8V$ X  
TW'E99wG  
} dcV,_  
{d&X/tT  
)er?*^9Z  
public static void main(String[] args) hP,b-R9\  
{ j;$6F/g  
new TestMethod(); ]J8KCjq@  
} G5y]^P  
} 82G lbd)  
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