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http断点续传简单实现(java)

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/* _~m@ SI  
**SiteFileFetch.java `usX(snY  
*/ sdq8wn  
package NetFox; X) lzBM  
import java.io.*; ,v;P@RL|g  
import java.net.*; 6 /8?:  
VUF^ r7e  
PqFK*^)s  
public class SiteFileFetch extends Thread { Gni<@;}  
#QdBI{2  
@y,pf Wh`  
SiteInfoBean siteInfoBean = null; //文件信息Bean d_CY=DHF%`  
long[] nStartPos; //开始位置 5c?1JH62o8  
long[] nEndPos; //结束位置 O)g\/uRy  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 D/1{v  
long nFileLength; //文件长度 , VT&  
boolean bFirst = true; //是否第一次取文件 ml=tS,  
boolean bStop = false; //停止标志 -nP y?>p"|  
File tmpFile; //文件下载的临时信息 AS[yNCsjC  
DataOutputStream output; //输出到文件的输出流 ^O_E T$  
5 rpX"(  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) feOX]g#  
public SiteFileFetch(SiteInfoBean bean) throws IOException qx3@]9  
{ w0n.Y-v4i  
siteInfoBean = bean;  b,] QfC  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @.Pd3CB0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1-`Il]@?8  
if(tmpFile.exists ()) Y%AVC9(  
{ &S/@i|_  
bFirst = false; ?kfLOJQ:I  
read_nPos(); v8Ga@*  
} ,tt]C~\u  
else tOx)t$ix  
{ V=%j ]`Os  
nStartPos = new long[bean.getNSplitter()]; `w@8i[2J  
nEndPos = new long[bean.getNSplitter()]; &)4#0L4  
} 5;{Q >n  
p^u;]~J O  
:77dl/d%  
K.k%Tg[ ~  
} G:'hT=8  
xVOoYr>O  
IKT3T_\-I  
public void run() $n |)M+d  
{ ,,_$r7H`  
//获得文件长度 r+6=b"  
//分割文件 B%P g:|  
//实例FileSplitterFetch I<p- o/TP  
//启动FileSplitterFetch线程 Z(F`M;1>xI  
//等待子线程返回 JHN{vB  
try{ b4o`eR  
if(bFirst) `acX1YWh5  
{ Z_iVOctP  
nFileLength = getFileSize(); G.CkceWRn  
if(nFileLength == -1) ] B ZSW  
{ \.m"u14[b  
System.err.println("File Length is not known!"); 6_KO6O7g  
} {9>LF  
else if(nFileLength == -2) n#F:(MSOp  
{ E0 ~\ A;  
System.err.println("File is not access!"); luNEgCq  
} kzq3-NTV  
else Yyl(<,Yi  
{ x+niY;Z E  
for(int i=0;i<nStartPos.length;i++) `;?`XC"m  
{ WvV!F?uqZ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); %Z T@&  
} 8_yhV{  
for(int i=0;i<nEndPos.length-1;i++) W dM?{; #  
{ v(5zSo  
nEndPos = nStartPos[i+1]; ^! ?wh  
} ma__LWKM,  
nEndPos[nEndPos.length-1] = nFileLength; b#XY.+ *0  
} WX@ a2c.'  
} v?\Z4Z|f  
NJ 6* 7Cd  
C t-^-XD  
//启动子线程 :Kc9k(3&r  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8R G U^&  
for(int i=0;i<nStartPos.length;i++) JL[xrK0  
{ jIpc^iu`,  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ei TG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), kkvG=  
nStartPos,nEndPos,i); [FhFeW>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b/>L}/^PM  
fileSplitterFetch.start(); ){~]-VK  
} %d3KE|&u  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (e,5 b  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <d&9`e1Hc  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", E'_3U5U  
nEndPos = " + nFileLength); &w4~0J>v!  
// fileSplitterFetch[nPos.length-1].start(); bq+ Q$#F2X  
{3s=U"\  
(RhGBgp  
//等待子线程结束 QzV Q}  
//int count = 0; VV'K$v3'N8  
//是否结束while循环 NT3Ti ?J,  
boolean breakWhile = false; tv,Z>&OM  
s48 { R4  
tQTVP2:Y  
while(!bStop)  nIWZo ~  
{ tCoT-\Q  
write_nPos(); [^rMM1^,OB  
Utility.sleep(500); (P=q&]l[  
breakWhile = true; j>D[iHrH  
wtm=  
j,:vK  
for(int i=0;i<nStartPos.length;i++) B)^uGS W  
{ J 'qhY'te  
if(!fileSplitterFetch.bDownOver) o3=2`BvJ  
{ 1MVzu7  
breakWhile = false; 3rRN~$  
break; +;@p'af!9  
} f9ziSD#  
} P LHiQ:  
if(breakWhile) -UTTJnu^  
break; h_xHQf&#  
 9hbn<Y  
i.~*G8!DM  
//count++; fWutB5?P  
//if(count>4) #.Q8q  
// siteStop(); /*$B  
} N^Bjw?3  
)p?p39>h  
 ,m"0Bu2  
System.err.println("文件下载结束!"); #KFpT__F  
} 5:" zs  
catch(Exception e){e.printStackTrace ();} @'D ,T^I  
} -D?-ctFYj^  
CVa?L"lK  
VZ o,AP~  
//获得文件长度 U/p|X)  
public long getFileSize() ke~S[bL%-  
{ W.|r=   
int nFileLength = -1; p  K=  
try{ zJxO\  
URL url = new URL(siteInfoBean.getSSiteURL()); &@&0n)VTd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |mHxkd  
httpConnection.setRequestProperty("User-Agent","NetFox"); X3# AYn,  
G/y@`A)  
Y\Grf$e  
int responseCode=httpConnection.getResponseCode(); @U)k~z2Hk  
if(responseCode>=400) jE.yT(+lW  
{ @ +iO0?f  
processErrorCode(responseCode); v +$3Z5  
return -2; //-2 represent access is error :<"b"{X"  
} 62YT)/i3  
q-k~L\Ys  
}\-"L/D?+  
String sHeader; w%Bo7 'o)V  
I7[F,xci  
JsDugn ,B  
for(int i=1;;i++) MhaoD5*9  
{ c;M&;'#x  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Pl9Ky(Q`V  
//Utility.log(in.readLine()); "{1SDbwmMo  
sHeader=httpConnection.getHeaderFieldKey(i); Ho_ 2zx:8b  
if(sHeader!=null) Z` ;.62S  
{ 6Z:swgi6&  
if(sHeader.equals("Content-Length")) s\Zp/-Q  
{ :)PAj  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); L2N O_N  
break; +^@;J?O  
} cW|M4`  
} cD!y d^QE  
else [0lu&ak[&  
break; @/DHfs4O  
} Q+r8qnL'  
} .5ItH^  
catch(IOException e){e.printStackTrace ();} eG F{.]  
catch(Exception e){e.printStackTrace ();} 0}:wM':G  
u`j9m @`  
8B|qNf `Yi  
Utility.log(nFileLength); eHt |O~  
uFXu9f+  
Gl@-RLo  
return nFileLength; /-mo8]J#2~  
} `g~T #U\>d  
!.^%*6f  
~"t33U6  
//保存下载信息(文件指针位置) s .xJ},E9  
private void write_nPos() L<` p;?   
{ ;O Td<  
try{ 3WTNWz#h  
output = new DataOutputStream(new FileOutputStream(tmpFile)); {,Py%.vvR  
output.writeInt(nStartPos.length); 0>aAI3E  
for(int i=0;i<nStartPos.length;i++) lY,dyNFHV  
{ en1NFP  
// output.writeLong(nPos); x9lG$0k:V  
output.writeLong(fileSplitterFetch.nStartPos); n}T;q1  
output.writeLong(fileSplitterFetch.nEndPos); =Eimbk  
} 3r]m8Hp  
output.close(); 8}A+{xVp8  
} %YhM?jMW  
catch(IOException e){e.printStackTrace ();} 0IP5 &[-P  
catch(Exception e){e.printStackTrace ();} *fIb|r  
} *It`<F|  
R{X@@t9@  
tsqkV7?  
//读取保存的下载信息(文件指针位置) XXe?@w2{  
private void read_nPos() FVw4BUOmi  
{ :v(fgS2\  
try{ -9(9LU2  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0~;Owu  
int nCount = input.readInt(); VD).UdUn  
nStartPos = new long[nCount]; WF!u2E+  
nEndPos = new long[nCount]; yM}Wg~:D:  
for(int i=0;i<nStartPos.length;i++) /3>5ex>PN  
{ ]'%Z&1 w  
nStartPos = input.readLong(); iFi6,V*PRt  
nEndPos = input.readLong(); /xu#ZZ?8F_  
} 1X7tN2tQ  
input.close(); -*QxZiKD  
} th 9I]g^=t  
catch(IOException e){e.printStackTrace ();} g`69 0  
catch(Exception e){e.printStackTrace ();} ~dpU D F  
} 7w_cKR1;  
lJR  
T`?{Is['(  
private void processErrorCode(int nErrorCode) a7_&;  
{ ZtFOIb*  
System.err.println("Error Code : " + nErrorCode); 6')pM&`t  
} ;@&mR <5j  
TS~>9h\;  
b_p/ 1W:  
//停止文件下载 yN4K^#  
public void siteStop() Uql|32j  
{ U11bQ4ak  
bStop = true;  r*gQGvc  
for(int i=0;i<nStartPos.length;i++) (/oHj^>3N`  
fileSplitterFetch.splitterStop(); y!,Ly_x$@  
O6gl[aZN  
%( tu<  
} 2L!wbeTb;  
} c[h{C!d1  
//负责部分文件的抓取 DviRD[+q"  
**FileSplitterFetch.java ;#goC N.  
*/ 3a_=e B  
package NetFox; Rb8wq.LqD  
:|P[u+v  
tt=JvI9>  
import java.io.*; j-% vLL/  
import java.net.*; :zW I"  
>&mNC \PA  
$}*bZ~  
public class FileSplitterFetch extends Thread { Hfw*\=p  
Ac'0  
e{*-_j "I  
String sURL; //File URL =gYKAr^p5  
long nStartPos; //File Snippet Start Position YH 5jvvOI  
long nEndPos; //File Snippet End Position cKbjW  
int nThreadID; //Thread's ID n&4 4Acs[  
boolean bDownOver = false; //Downing is over oQ=v:P]  
boolean bStop = false; //Stop identical ^Qx qv  
FileAccessI fileAccessI = null; //File Access interface ."u-5r<O  
{4%B^+}T  
LMF@-j%  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )rqb<O  
{ tcm?qro)  
this.sURL = sURL; $0f(Gc|  
this.nStartPos = nStart; ^^O @ [_  
this.nEndPos = nEnd; 5Wyo!pRi  
nThreadID = id; zHEH?xZ6sD  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "Q>gQKgL  
} LxcC5/@\~(  
}#0i1]n$D  
\m\E*c ):  
public void run() qVvQ9?  
{ 6hW ~Q  
while(nStartPos < nEndPos && !bStop) VX;br1$X  
{ g$(<wWsU  
AxsTB9/  
,?OWwm&J  
try{ fs:%L  
URL url = new URL(sURL); - s}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,/XeG`vk  
httpConnection.setRequestProperty("User-Agent","NetFox"); s\CZ os&  
String sProperty = "bytes="+nStartPos+"-"; A$H;2T5N  
httpConnection.setRequestProperty("RANGE",sProperty); Q^|ZoJS  
Utility.log(sProperty); I 19 /  
S1!X;PP/  
z;#DX15Rj  
InputStream input = httpConnection.getInputStream(); g ss 3e&  
//logResponseHead(httpConnection); L355uaj  
TVVr<r  
^iHwv*ss  
byte[] b = new byte[1024]; 9}=]oX!+V  
int nRead; ;F/yS2p  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 323zR*\m  
{ cg]\R1Gm  
nStartPos += fileAccessI.write(b,0,nRead); n.323tNY  
//if(nThreadID == 1) " 0:&x n8L  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T&ECGF;Y/  
} >Z\{P8@k0  
8n[6BF);  
 wh A  
Utility.log("Thread " + nThreadID + " is over!"); EGY'a*]cU  
bDownOver = true; G~ldU: ?  
//nPos = fileAccessI.write (b,0,nRead); Q7~9~  
} w,,QXJe{Z_  
catch(Exception e){e.printStackTrace ();} /CE]7m,7~K  
} vq.~8c1  
} _N-.=86*  
C,;hNg[  
06Irx^n  
//打印回应的头信息 t=K;/ 1  
public void logResponseHead(HttpURLConnection con) } ^}fx [  
{ #TXN\YNP  
for(int i=1;;i++) v}Gpw6   
{ 1&Fty'p  
String header=con.getHeaderFieldKey(i); 4GiHp7Y&A  
if(header!=null) sp2"c"_+  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :FUefW m  
Utility.log(header+" : "+con.getHeaderField(header)); }Sxuc/%:  
else BJ c'4>  
break; {Xc^-A[~  
} FRSz3^Aw  
} iPD5 KsAOA  
&?#,rEw<x  
mr4W2Z@L  
public void splitterStop() lJ'. 1Z&  
{ Q?Y\WD  
bStop = true; 2i~tzo  
} =)2sehU/  
\e=Iw"yd  
nO ^m  
} R.Plfm06Ue  
<3 b|Sk:T  
 wfecM(  
/* 7M|!N_ $  
**FileAccess.java $RFy9(>  
*//文件访问(定位,写) DR d|m<Z  
package NetFox; 5`!Bj0Uf  
import java.io.*; ^tw\F7  
3!&PI  
yR`X3.:*]  
public class FileAccessI implements Serializable{ 9L`5r$/  
 c"pI+Q  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 F7FUoew<  
RandomAccessFile oSavedFile; ]YO &_#  
long nPos; ]ZkR~?  
<~%e{F:[#  
,C=Lu9  
public FileAccessI() throws IOException e(5 :XHe  
{ :jJ;&t^^  
this("",0); #[Z1W8e  
} (P+TOu-y\  
CJDnHuozc  
j o7`DDb  
public FileAccessI(String sName,long nPos) throws IOException S\,~6]^T  
{ %gd {u\h^  
oSavedFile = new RandomAccessFile(sName,"rw"); jGeil qPC  
this.nPos = nPos; a5)<roWQ  
oSavedFile.seek(nPos); up# R9 d|  
} \),DW)  
CQ4MQ<BJ.  
#:~MtV  
public synchronized int write(byte[] b,int nStart,int nLen) '=M4 (h  
{ I 3ZlKI  
int n = -1; %![%wI?  
try{ N=JZtf/i  
oSavedFile.write(b,nStart,nLen);  -L.U4x  
n = nLen; ![>j`i  
} *2? -6  
catch(IOException e) CTNeh%K;  
{ dGNg[  
e.printStackTrace (); 2"'<Yk9  
} E1=WH-iA0  
xw>\6VNt  
oHW:s96e  
return n; FLb Q#c\  
} ~]d3 f  
||}k99y +  
3pV^Oe^9  
} o_(@v2G`  
{\SJr:  
+9tm9<F8  
/* &=KNKE`  
**SiteInfoBean.java Hv>16W$_  
*/ *-zOQ=Y  
package NetFox; ".Z1CBM(  
<kmH^ viX  
(=T%eJ61  
public class SiteInfoBean { K KCzq |  
{mkD{2)KQ  
,?3)L   
private String sSiteURL; //Site's URL }.L\O]~{  
private String sFilePath; //Saved File's Path h@^d Vg  
private String sFileName; //Saved File's Name K [.*8  
private int nSplitter; //Count of Splited Downloading File o>#ue<Bc6  
"B$r{ vG  
,4OH9 -Q1  
public SiteInfoBean() ]"*sp  
{//nSplitter的缺省值为5 "1-gMob  
//default value of nSplitter is 5 (]Pr[xB  
this("","","",5); ++m^z` D  
} lCX*Q{s22  
77]6_  
HW@r1[Y  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) )Rlh[Y& r  
{ 3YFbT Z  
sSiteURL= sURL; ^z _m<&r  
sFilePath = sPath; #},4m  
sFileName = sName; kT=KxS{  
this.nSplitter = nSpiltter; 1 luRTI8^  
[yEH!7  
8+?|4'\`  
} ~vL`[JiK  
)~Pj 3  
TTfU(w%&P  
public String getSSiteURL() W/\M9  
{ W`d\A3v  
return sSiteURL; IHrG!owf  
} Gy3t   
Y\e8oIYu7  
HgY>M`U  
public void setSSiteURL(String value) m|c5X)}-  
{ b}C6/ zW  
sSiteURL = value; : U Yn  
} =8p *Ijs  
m,qMRcDF  
,~TV/l<  
public String getSFilePath() G|LJOq7QB  
{ n{@^ne4 m  
return sFilePath; U.kTdNSp  
} v=Y) A?  
U7(t >/  
fPj*qi  
public void setSFilePath(String value) >X$I:M<L  
{ ^=1:!'*3D  
sFilePath = value; ,5 A&  
} Vi5&%/Y  
4kr! Af  
*.2[bQL@v  
public String getSFileName() rmq^P;At  
{ ]rY3bG'&  
return sFileName; zfBaB0P  
} `Cv@16  
"(QI7:iM  
tnn,lWu|  
public void setSFileName(String value) zNo(|;19  
{ ,xzSFs>2  
sFileName = value; KsG>,# Q  
} s7(I  
,RYahu  
Li{R?Osx  
public int getNSplitter() 8K;wX%_,  
{ h88 IP:bo  
return nSplitter; Y;B#_}yF  
} Cr;d !=  
8A,="YIt  
t)62_nu  
public void setNSplitter(int nCount) l`' lqnhv  
{ /iwL$xQQ  
nSplitter = nCount; -|/kg7IO\  
} NA<6s]Cs.  
} % njcWVP;  
n?EL\B   
@0qDhv s  
/* |Ox !tvyr  
**Utility.java "KhVS  
*/ c8=@ s#  
package NetFox; =I6u*$9<  
M?FbBJ`sF  
`B GU  
public class Utility { a=%QckR*  
n~e#Y<IP\1  
:{tj5P!S  
public Utility() g 218%i  
{ BGSqfr1F  
M%#H>X\/  
|TE\]  
} iJsa;|2/  
LqOjVQxz  
//线程睡眠 OD~TWT_  
public static void sleep(int nSecond) wRLj>nc  
{ ` g5S  
try{ mm@)uV<\  
Thread.sleep(nSecond); zr1,A#BV  
} uV'w0`$y  
catch(Exception e) <Ky6|&!  
{ Ou'<9m!9  
e.printStackTrace (); 9>1 $Jv3  
} `tjH#W`  
} DdG*eKC  
ROfr  
//日志 wsg u# as|  
public static void log(String sMsg) G1`H H&  
{ F87aIJ.pGN  
System.err.println(sMsg); wwI'n*Q'$  
} }ippi6b:r  
h4 X>  
H>/LC* 8-  
public static void log(int sMsg) MY$-D+#/`  
{ U(t_uc5q  
System.err.println(sMsg); rdY/QvP0=  
} g'Id3 1r'  
} F#az&  
5uJ{#Zd  
Ov5 *&*P  
/* -Z/'kYj?U  
**TestMethod.java 6d% |yl  
*/ ~5xs$ub  
package NetFox; 6?X)'  
ue~?xmZg  
Jjgy;*hM  
public class TestMethod { N!hS`<}  
G;CB%qXI  
F]"Hs>  
public TestMethod() HxXCxI3  
{ ///xx/weblogic60b2_win.exe nP+]WUnY  
try{ zs_^m1t1s  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,aLdW,<6  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0k7kmDW  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~=pAy>oV  
fileFetch.start(); #!n"),3  
} +mqz)-x  
catch(Exception e){e.printStackTrace ();} 5{@Hpj/B  
xr<.r4  
 K#LG7faj  
} RlH~<|XK  
nLfITr|5  
]rs7%$ZW  
public static void main(String[] args) H |K}m,g  
{ =%Yw;% 0)Y  
new TestMethod(); yN Bb(!u  
} -UhGacw  
} IRxFcLk  
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