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http断点续传简单实现(java)

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/* %kU'hzLg  
**SiteFileFetch.java XY+y}D %  
*/ `EMi0hm&H  
package NetFox; *i<\iMoW  
import java.io.*; (%< 'A  
import java.net.*; ]re'LC!d  
%c6E-4b  
"<l<& qp  
public class SiteFileFetch extends Thread { G5'_a$  
W."f 8ow  
-)w]a{F  
SiteInfoBean siteInfoBean = null; //文件信息Bean .`C V^\  
long[] nStartPos; //开始位置 8V5a%2eV  
long[] nEndPos; //结束位置 ;6DnId2Zh  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 xX@FWAj  
long nFileLength; //文件长度 N?23 m`3  
boolean bFirst = true; //是否第一次取文件 -p# ,5}  
boolean bStop = false; //停止标志 z \?UGxu}  
File tmpFile; //文件下载的临时信息 t%+$" nP  
DataOutputStream output; //输出到文件的输出流 G?V"SU.  
Dl;d33  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) KAb(NZK  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,{<p  
{ d\]O'U)s  
siteInfoBean = bean; Bh`IXu  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); R,Ml&4pZ}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); if~rp-\P  
if(tmpFile.exists ()) XT||M)#  
{ j Selop>N  
bFirst = false; L0&S0HG   
read_nPos(); ^,7=X8Su  
} *_)E6Y?9  
else d\Jji 6W  
{ lfS;?~W0k  
nStartPos = new long[bean.getNSplitter()]; 9 qH[o?]  
nEndPos = new long[bean.getNSplitter()]; 3ps,uozj  
} D@vMAW  
#@_ 1fE  
^Rmoz1d  
ndOfbu;mf  
}  Tb#  
w:Q|?30  
2a[9h #  
public void run() AMk~dzNt  
{ pT=2e&  
//获得文件长度 xv0M  
//分割文件 $!`L"szqD*  
//实例FileSplitterFetch 5G? .T?  
//启动FileSplitterFetch线程 W/v|8-gcK  
//等待子线程返回 `s}BXKIv}  
try{ "T*I|  
if(bFirst) F!~l MpuE  
{ )vHi|~(   
nFileLength = getFileSize(); *ro.mQ_  
if(nFileLength == -1) 3A R%&:-  
{ ){tPP$-i=  
System.err.println("File Length is not known!"); |s`Kd-'|q  
} \GHOg.P  
else if(nFileLength == -2) ~ hD{coVTI  
{ C ktX0  
System.err.println("File is not access!"); .;slrg(5F  
} Ed=}PrE  
else & s-VSu7  
{ $,P\)</ VR  
for(int i=0;i<nStartPos.length;i++) =>YvA>izE  
{ !`C%Fkq  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); e\~l!f'z  
} {8ECNQ[]  
for(int i=0;i<nEndPos.length-1;i++) Uh\]?G[G  
{ ;o >WXw  
nEndPos = nStartPos[i+1]; @ta?&Qf)  
} 6z]`7`G   
nEndPos[nEndPos.length-1] = nFileLength; 1NGyaI  
} ~'[jBn)  
} 3M$X:$b  
X2P``YFV{  
{_as!5l  
//启动子线程 b_ JWnh  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; I{<;;;a  
for(int i=0;i<nStartPos.length;i++) F '#^`G9  
{ uRGB/ju^E  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *+~D+_,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;o%:7 &  
nStartPos,nEndPos,i); "GLYyC  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J=P;W2L  
fileSplitterFetch.start(); 6JWGu/A  
} D1! {S7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b_mWu@$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); k -]xSKG  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", y&3TQ]f\  
nEndPos = " + nFileLength); -3`Isv  
// fileSplitterFetch[nPos.length-1].start(); V7n >,k5  
uOb2npPj  
vo H4  
//等待子线程结束 4)E|&)-fu8  
//int count = 0; &*ZC0V3  
//是否结束while循环 #!Ze\fOC  
boolean breakWhile = false; -Y2&A$cM  
Q~h6J*  
ny~W]1  
while(!bStop) pr)K{~m]{<  
{ oX#9RW/ >I  
write_nPos(); { $X X  
Utility.sleep(500); !rz)bd3$  
breakWhile = true; @F~0p5I  
Q{8qm<0g  
?U$}Rsk{#  
for(int i=0;i<nStartPos.length;i++) bt0djJRw  
{ U* 4{"  
if(!fileSplitterFetch.bDownOver) *|sxa#  
{ xdCs5ko  
breakWhile = false; U~Xf=f_Q$  
break; bD  d_}  
} $}V7(wu 6@  
} I>d I[U  
if(breakWhile) #fO*ROe  
break; ~.iA`${y%  
2(hvv-  
l#p }{  
//count++; |x*{fXdMhr  
//if(count>4) dG" K/|  
// siteStop(); _F3KFQ4,S-  
} K* 0 aXr?  
d\\r_ bGW  
S!u6dz^[$X  
System.err.println("文件下载结束!");  dD:  
} 9/FG,9  
catch(Exception e){e.printStackTrace ();} keqr%:E8  
} :EYu 4Y  
yi sF5`+  
xGwTk  
//获得文件长度 poTl|y @  
public long getFileSize()  bkxk i@t  
{ ?rky6  
int nFileLength = -1; ]Jja  
try{ vU?b"n  
URL url = new URL(siteInfoBean.getSSiteURL()); GJ.kkTMT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); OiYNH~hv  
httpConnection.setRequestProperty("User-Agent","NetFox"); P\Ai|"=&]  
~6\& y  
nMTLD  
int responseCode=httpConnection.getResponseCode(); \FIa,5k8  
if(responseCode>=400) Gv!BB=ir(  
{ #4Dn@Gqh.Y  
processErrorCode(responseCode); |if~i;VKL  
return -2; //-2 represent access is error w:ORmR .p  
} KuIBYaK, g  
<j{0!J@:  
w/?nUp  
String sHeader; aytq4Ts  
X!HDj<  
q-A`/9  
for(int i=1;;i++) fEx+gQW_  
{ <jpeu^7  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Rrh<mo(yj#  
//Utility.log(in.readLine()); m(8jSGV  
sHeader=httpConnection.getHeaderFieldKey(i); cBg,k[,  
if(sHeader!=null) JZW gr&O<  
{ (y-x01H  
if(sHeader.equals("Content-Length")) <WZ1-  
{ -q'xC:m  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); x:!C(Ep)  
break; SPfD2%jjC  
} &oon'q5;  
} T@%;0Ro~  
else R;0W+!fE  
break; ZM dM_i?  
} UOn!Y@  
} 7(yXsVq  
catch(IOException e){e.printStackTrace ();} }f<fgY  
catch(Exception e){e.printStackTrace ();} [?Mc4uT{  
+vSCR (n  
6{b%Jfo  
Utility.log(nFileLength); Wv6z%r<  
CPc"  
,`ZPtnH+  
return nFileLength; X_vI0YX9  
} 3*CzXK>`M&  
7 JxE |G  
#[gcg]6c  
//保存下载信息(文件指针位置) B rez&3[  
private void write_nPos() [$hptQv  
{ ~a|^?7@p  
try{ ZAI1p+  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2neF<H?^o  
output.writeInt(nStartPos.length); >P<k[vF  
for(int i=0;i<nStartPos.length;i++) Ymwx (Pm  
{ Sf+(1_^`t  
// output.writeLong(nPos); zF[3%qZE:T  
output.writeLong(fileSplitterFetch.nStartPos); 4]Un=?)I  
output.writeLong(fileSplitterFetch.nEndPos); Paae-EmC  
} U@o2gjGN  
output.close(); OVDMC4K2z!  
} :6 Hxxh  
catch(IOException e){e.printStackTrace ();} o8~f   
catch(Exception e){e.printStackTrace ();} I ybl;u  
} &*jxI[  
dAu^{1+2  
Q\&AlV  
//读取保存的下载信息(文件指针位置) ki[;ZmQq Y  
private void read_nPos() r~S!<9f  
{ mp&Le YYn  
try{ w,M1`RsK  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); JxX jDYrU  
int nCount = input.readInt(); 0C7thl{Dms  
nStartPos = new long[nCount]; ;']vY  
nEndPos = new long[nCount]; .fio<mqi  
for(int i=0;i<nStartPos.length;i++) n4ds;N3Hd  
{ X";QA":  
nStartPos = input.readLong(); ^yn[QWFO  
nEndPos = input.readLong(); '0'"k2"vC  
} hW0,5>[7%  
input.close(); Ff)~clIK '  
} H3 A]m~=3  
catch(IOException e){e.printStackTrace ();} C$N4   
catch(Exception e){e.printStackTrace ();} [oQ`HX1g  
} /7UovKKbz  
q;1VF;<"vH  
oiTMP`Y  
private void processErrorCode(int nErrorCode) )z ?&" I  
{ 902!M65[rG  
System.err.println("Error Code : " + nErrorCode); +Op%,,Db  
} >)AE |j`  
/tId#/Y  
Ev$-P X  
//停止文件下载 ;[WSf{k  
public void siteStop() O4b-A3:  
{ 9E->;0-  
bStop = true; <2o.,2?G  
for(int i=0;i<nStartPos.length;i++) g(@$uJ  
fileSplitterFetch.splitterStop(); X]+(c_i:hC  
*sc0,'0  
f^[{k {t  
} bMK#^ZoH  
} =\ti<  
//负责部分文件的抓取 "6I-]:K-  
**FileSplitterFetch.java P-E'cb%ub  
*/ h-?q6O/|  
package NetFox; 0I(GB;E  
(/9.+V_  
aIn)']  
import java.io.*; 4y]:Gq z~  
import java.net.*; 'b=eC  
< tu[cA>  
]AFM Y<mB  
public class FileSplitterFetch extends Thread { /VhE<}OtH  
_Cv[`e.  
 MrKU,-  
String sURL; //File URL |mQtjo  
long nStartPos; //File Snippet Start Position :o.x=c B  
long nEndPos; //File Snippet End Position <6}f2^  
int nThreadID; //Thread's ID ZZ]OR;8  
boolean bDownOver = false; //Downing is over @MlU!oR&  
boolean bStop = false; //Stop identical <WHs  
FileAccessI fileAccessI = null; //File Access interface "a0u-}/D  
~kSnXJv  
f}9PEpa,Z  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ig.6[5a\  
{ .^)C:XiW  
this.sURL = sURL; LAK-!!0X  
this.nStartPos = nStart; @??c<]9F  
this.nEndPos = nEnd; ^?K?\   
nThreadID = id; 2 d>d(^  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :YRzI(4J  
} U!;aM*67  
"dLMBY~  
lkSz7dr@  
public void run() ,/w852|ub  
{ u]]5p[ |S  
while(nStartPos < nEndPos && !bStop) Oc"'ay(g  
{ :~0^ib<v;  
9(N)MT5F  
li 3PR$W V  
try{ v'bd.eqw  
URL url = new URL(sURL); "zeJ4f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {-v\&w  
httpConnection.setRequestProperty("User-Agent","NetFox"); >jrz;r  
String sProperty = "bytes="+nStartPos+"-"; Vhbj.eX.)  
httpConnection.setRequestProperty("RANGE",sProperty); x^='pEt{  
Utility.log(sProperty); [:R P9r}  
q~g&hR}K  
[! dnm1   
InputStream input = httpConnection.getInputStream(); +SuUI-.  
//logResponseHead(httpConnection); yZ?_q$4kEI  
|S>J<]H p  
cO=UswIkwO  
byte[] b = new byte[1024]; 8x^H<y=O  
int nRead; %)6 :eIS  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) zfr(dQ  
{ 3R:7bex  
nStartPos += fileAccessI.write(b,0,nRead); QqFfR#  
//if(nThreadID == 1) xV n]m9i  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !s[j1=y  
} 6(<~1{ X%  
]=86[A-2N  
UTK.tg  
Utility.log("Thread " + nThreadID + " is over!"); ;qVEI/  
bDownOver = true; "-j@GCme  
//nPos = fileAccessI.write (b,0,nRead); I 3zitI;  
} ,QHx*~9  
catch(Exception e){e.printStackTrace ();} M#lVPXS  
} 5rHnU<H@y  
} &J&w4"0N'  
'/yx_R K2?  
\")YKN=W  
//打印回应的头信息 v4k=NH+w  
public void logResponseHead(HttpURLConnection con) 0JZq:hUd  
{ Bn#HJ17/#  
for(int i=1;;i++) ]N(zom_0d  
{ Dpp52UnT E  
String header=con.getHeaderFieldKey(i); Ng;b!S  
if(header!=null) ?D )qgH  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 1TxhEXB  
Utility.log(header+" : "+con.getHeaderField(header)); AZ]SRz9mKY  
else ]-s`#  
break; _9O }d  
} 4Utx 9^  
} #;*ai\6>vD  
A^Hp#b @  
9 K /  
public void splitterStop() %wjU^Urya  
{ TNPGw!  
bStop = true; FO'. a  
} ZV<y=F*~f  
M4hN#0("4  
%C E@}  
} o2e h)rtB  
Ko]h r  
tv=FFfQ  
/* E?q'|f  
**FileAccess.java 1'U%7#;E  
*//文件访问(定位,写) 98%tws`  
package NetFox; (B/F6 X;o.  
import java.io.*; IO&#)Ft  
,cO)Sxj  
g-V\ s&}  
public class FileAccessI implements Serializable{ dBq,O%$oq  
2|NyAtPb5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 QsF<=b~  
RandomAccessFile oSavedFile; \FY De  
long nPos; XOU-8;d  
x#gmliF  
AO7qs:+  
public FileAccessI() throws IOException oJp_c  
{ (PrPH/$  
this("",0); <ZvPtW  
} BLH3$*,H  
,l? 76g  
fUWm7>6VA>  
public FileAccessI(String sName,long nPos) throws IOException G-i_s6Wu  
{ a5~C:EU0  
oSavedFile = new RandomAccessFile(sName,"rw"); AA& dZjz  
this.nPos = nPos; +VW]%6 +  
oSavedFile.seek(nPos); 2Ku#j ('  
} N8(x),  
.Zt/e>K&  
/sC[5G%  
public synchronized int write(byte[] b,int nStart,int nLen) v*]Xur6e}  
{ YK+Z0ry  
int n = -1; .6/p4OR|  
try{ |2&mvjk@H  
oSavedFile.write(b,nStart,nLen); gLxy RbVI  
n = nLen; hE#8_34%s  
} rHdP4:n  
catch(IOException e) WI 4_4  
{ S"A_TH  
e.printStackTrace (); .p0n\ $r  
} d\Z4?@T<5  
lR K ?%~  
sF3 l##Wv  
return n; @dKf]&h%%  
} }N9a!,{P=b  
]~M {@h!<  
z iGL4c0p  
} l45F*v]^  
i&Cqw~.H  
tJ_@AcF  
/* n$0)gKN7  
**SiteInfoBean.java z'K7J'(R  
*/ G}xBYc0b  
package NetFox; N)y;owgo  
K:50?r_-6  
%t|2GIu  
public class SiteInfoBean { zw9ULQ$#  
;S27m]Q?  
XN%D`tbvJ  
private String sSiteURL; //Site's URL 3:Egqw  
private String sFilePath; //Saved File's Path $/#)  
private String sFileName; //Saved File's Name uOUw8  
private int nSplitter; //Count of Splited Downloading File CrX-?$  
?iO^b.'I#  
7IW7'klkvD  
public SiteInfoBean() \mit&EUh}  
{//nSplitter的缺省值为5 A_ z:^9  
//default value of nSplitter is 5 ,^66`C[G  
this("","","",5); ywtDz8!^u  
} +Ws}a  
EMH}VigR  
tl^;iE!-  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .z7f_KX^  
{ [c%}L 3B  
sSiteURL= sURL; GuDD7~qxY  
sFilePath = sPath; 'N/%SRk  
sFileName = sName; uH h2>Px  
this.nSplitter = nSpiltter; -xEg"dY/  
mYRR==iDL  
r~a}B.pj  
} [/^g) ^s:  
^w}Ib']X  
o"CqVRR  
public String getSSiteURL() yf>,oNIAg  
{ w8Vzx8  
return sSiteURL; md_s2d  
} \aRB   
;G&O"S><]c  
Raqr VC  
public void setSSiteURL(String value) {lw ec"{  
{ udr'~,R  
sSiteURL = value; U.)eJ1a  
} u-cC}DP  
tXGcwoOB  
> _) a7%  
public String getSFilePath() \05C'z3]  
{ KA[Su0  
return sFilePath; 8u23@?  
} ]qQB+]WN  
Fd0FG A&L  
,FPgs0rrS  
public void setSFilePath(String value) cW>`Z:6{K  
{ :9>nY  
sFilePath = value; a[#BlH  
} tjL#?j  
wQ95tN  
yZ6X$I:C  
public String getSFileName() PSvRO% &  
{ nI` 1@ vB&  
return sFileName; @72G*u\Wz  
} Jx,s.Z0@7,  
VAz+J  
!1]xKNp ]  
public void setSFileName(String value) eVJL|uI|  
{ P=g+6-1  
sFileName = value; KJ |1zCM  
} *V+fRN4 W  
!b Km}1T  
<Z wEdq  
public int getNSplitter()  yw^, @'  
{ _z< q9:  
return nSplitter; Cr"hu;  
} svII =JB  
Xp@OIn  
.- o,_eg1f  
public void setNSplitter(int nCount) p_5+L@%Gb  
{ B!lw>rUMQ  
nSplitter = nCount; >m46tfoM  
} 06r cW `  
} IrK )N  
ENr&k(>0HQ  
e hGC N=  
/* : DP{YL|x  
**Utility.java QX/`s3N  
*/ Y"U&3e,  
package NetFox; 3J{'|3x  
z5zm,Jw  
n$K_KU v  
public class Utility { $~l :l[Zs  
\>Q,AyL  
ZGBcy}U(k  
public Utility() _=p|"~rN$  
{ gqamGLK  
_;+&'=6.[  
:2+:(^l  
} owB)+  
pQ JZE7S  
//线程睡眠 W@LR!EW)  
public static void sleep(int nSecond) @A%`\Ea%  
{ iWEYSi\)n  
try{ `W=JX2I  
Thread.sleep(nSecond); 5VS<I\o}  
} R8]bi|e)  
catch(Exception e) t `oP;  
{ ]y/:#^M+  
e.printStackTrace (); %r!-*p<i|  
} <7+.5iB3  
} e wR0e.g  
bL<cg tz7)  
//日志 [DviN  
public static void log(String sMsg) mE1*F'0a  
{ .FyC4"b=c  
System.err.println(sMsg); U/;Vge8{  
} 1>LquZ+Kj  
scmb DaOn  
-rBj-4|"  
public static void log(int sMsg) c_ i;'  
{ _`_$U MK;  
System.err.println(sMsg); od>.5{o  
} XooAL0w  
} z'o+3 zq^  
p;HZA}p \  
6\L,L &  
/* VEk|lX;2  
**TestMethod.java .)Q'j94Q  
*/ >jIc/yEYKI  
package NetFox; e~1??k.;=  
Z~ (QV0}  
j&r5oD;  
public class TestMethod { ofV{SeD67  
^B7Aam  
)deuB5kz  
public TestMethod() (uE_mEIsv  
{ ///xx/weblogic60b2_win.exe yWy9IWI["  
try{ }_S]!AWz  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); E^G=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .#SWfAb2h  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +|N"i~f>j  
fileFetch.start(); rx<fjA%  
} xo}hu %XL  
catch(Exception e){e.printStackTrace ();} +Aq}BjD#  
te_D  ,  
.$rcTZ  
} B7 T+a  
W#$rC<Jh]  
asb") NfIm  
public static void main(String[] args) R[6&{&E:  
{ sSxra!tv4  
new TestMethod(); wiZK-#\x  
} {chl+au*l  
} g~]FI  
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