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http断点续传简单实现(java)

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/* V~! lY\  
**SiteFileFetch.java l`k""f69W  
*/ lZ>j:/R8^&  
package NetFox;  A4  
import java.io.*; $-ICTp  
import java.net.*; [JyhzYf\   
o~J~-$T{  
q88;{?T1  
public class SiteFileFetch extends Thread { {Ne5*HFV  
_(1Shm  
HBp$   
SiteInfoBean siteInfoBean = null; //文件信息Bean <7 R+p;y  
long[] nStartPos; //开始位置 ayK?\srw  
long[] nEndPos; //结束位置 q\]"}M 8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 vn(ji=  
long nFileLength; //文件长度 }Md5a%s<  
boolean bFirst = true; //是否第一次取文件 fs,]%g^  
boolean bStop = false; //停止标志 jhF&   
File tmpFile; //文件下载的临时信息 X5w_ }Nhe  
DataOutputStream output; //输出到文件的输出流 ])tUXU>  
}{y(&Oy3Y  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 7*I:cga  
public SiteFileFetch(SiteInfoBean bean) throws IOException )p!.V( ,  
{ V(c>1xLlz  
siteInfoBean = bean; =%Z5"];  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); odsLFU(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Z;M th#  
if(tmpFile.exists ()) %`)lCK)2  
{ Yx3ivjX.>  
bFirst = false; -.!+i8d>  
read_nPos(); :pXY/Pa  
} _-c1" Kl  
else 6haw\ *  
{ Ygs:Ox"[-G  
nStartPos = new long[bean.getNSplitter()]; a4E{7c  
nEndPos = new long[bean.getNSplitter()]; iRK&-wn  
} Xt9vTCox  
tRu j}n+x  
Uy98lv  
e~P4>3  
} mIh >8))E  
 hSgH;k  
A!uO7".E  
public void run() VqL#w<A %  
{ "J"RH:$v  
//获得文件长度 (\M#Ay t)  
//分割文件 Mfinh@K,  
//实例FileSplitterFetch l?<DY$H 0  
//启动FileSplitterFetch线程 < 19A=  
//等待子线程返回 _MLbJ  
try{ v9 *WM3  
if(bFirst) ?R":"*eu  
{ )\RG NJMC  
nFileLength = getFileSize(); M'|?* aNK  
if(nFileLength == -1) )j\9IdkU;y  
{ T-a [  
System.err.println("File Length is not known!"); XmAu n  
} h-+vN hH  
else if(nFileLength == -2) ?d' vIpzO!  
{ U+-R2w]#q_  
System.err.println("File is not access!"); E]dc4US  
} qe2@bG%2+F  
else /CXQ&nwY9=  
{ }Yargj_Gn  
for(int i=0;i<nStartPos.length;i++) \]|(w*C  
{ 0`KR8# A@  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); !D|c2  
} 6]NaP_\0  
for(int i=0;i<nEndPos.length-1;i++) rd1EA|T  
{ 3-v&ktD&N'  
nEndPos = nStartPos[i+1]; L}=t"y  
} 6`WI S4  
nEndPos[nEndPos.length-1] = nFileLength; '_B;e=v`  
} >qS2ha  
} Plj>+XRO  
Fk`|?pQm  
a3J' c  
//启动子线程 Nh[H[1"J  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; C Ef*:kr  
for(int i=0;i<nStartPos.length;i++) D%~"]WnZ\Q  
{ MGLcM&oR  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rH$M6S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), @~&1!  
nStartPos,nEndPos,i); ~?z u5,vb  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Aaug0X  
fileSplitterFetch.start(); S{jm4LZ  
} i6P'_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .2V?G]u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?h)T\z  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", WP5Vev9*+  
nEndPos = " + nFileLength); !:c_i,N  
// fileSplitterFetch[nPos.length-1].start(); >ud u~  
F/u i(4  
. L9n  
//等待子线程结束 ]]9 VI0   
//int count = 0; W4q |55  
//是否结束while循环 QB"+B]rV  
boolean breakWhile = false; Ij2T h]  
a"m-&mN  
3?Fe( !@  
while(!bStop) -unQ 4G  
{  %m##i  
write_nPos(); cJ#n<Rsz  
Utility.sleep(500); *r)dtI*  
breakWhile = true; I{i6e'.jP  
E<'V6T9bi  
5}TTf2&Xo#  
for(int i=0;i<nStartPos.length;i++) .^8rO ,H[  
{ c)Ne/E{!0  
if(!fileSplitterFetch.bDownOver) s\e b  
{ ?tkl cYB  
breakWhile = false; a7sX*5t{R  
break; yG2rAG_ G&  
} xbz O' C  
} wufQyT`  
if(breakWhile) n(#[[k9&Ic  
break; qOflvf  
4+:'$Nw  
vG:S(/\>  
//count++; Kf#iF*  
//if(count>4) {7Hc00FM  
// siteStop(); D*'sOB(  
} P6A##z  
hE7rnn{  
 0:$pJtx"  
System.err.println("文件下载结束!"); $!^C|,CS  
} ko"xR%Q  
catch(Exception e){e.printStackTrace ();} &q +l5L"  
} "gt1pf~y  
{E.A?yej9  
vCUbbQz  
//获得文件长度 K%UjPzPWw  
public long getFileSize() o|w w>m  
{ y"k %Wa`*  
int nFileLength = -1; K/_"ybR7  
try{ _<'?s>(U'  
URL url = new URL(siteInfoBean.getSSiteURL()); >z7 3uKA(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); X6=o vm  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6?a z  
 r}}2 Kl  
P 1  
int responseCode=httpConnection.getResponseCode(); JAy-N bb\  
if(responseCode>=400) tT+W>oA/M  
{ #e1iYFgS  
processErrorCode(responseCode); |uI~}pSG  
return -2; //-2 represent access is error `VF_rC[?  
} _ jH./ @G  
jhJ<JDJ?`  
FiSx"o  
String sHeader; mY]o_\`  
7~);,#[ky  
#Jt1AV  
for(int i=1;;i++) sRZ?Ilua6  
{ ([#'G+MC&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); G @EEh.s9  
//Utility.log(in.readLine()); ">Ms V/  
sHeader=httpConnection.getHeaderFieldKey(i); P9 y+rF.  
if(sHeader!=null) Dl,sl>{  
{ lMcO2006L  
if(sHeader.equals("Content-Length")) V+r&Z<&  
{ )l.AsfW%  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {R"mvB`  
break; f:6F5G  
}  FjMKb  
} F6}YM|  
else q>wO=qWx  
break; h!Y##_&&4  
} F'CJN$6Mw/  
} Wf-XH|j[  
catch(IOException e){e.printStackTrace ();} KK{_s=t%<  
catch(Exception e){e.printStackTrace ();} )2#q i/  
A 8-a}0Gh  
X&i;WI  
Utility.log(nFileLength); 6:AEg  
fs-LaV 0  
 \< dg  
return nFileLength; ";7/8(LBZ  
} 3177R>0  
;-BN~1Jg  
$$EEhy  
//保存下载信息(文件指针位置) 1Oq VV?oz  
private void write_nPos() KW3<5+w]c  
{ <L<^uFB  
try{ O#p_rfQ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9XKqsvdS  
output.writeInt(nStartPos.length); Ep:hObWG)  
for(int i=0;i<nStartPos.length;i++) %I{>H%CjE  
{ 6J@,bB jVz  
// output.writeLong(nPos); C%{2 sMJz  
output.writeLong(fileSplitterFetch.nStartPos); 78 ]Kv^l^_  
output.writeLong(fileSplitterFetch.nEndPos); ;?q}98-2  
} g4YlG"O[~  
output.close(); !aKu9SR^e  
} 2-jXj9kp`  
catch(IOException e){e.printStackTrace ();} f~/hsp~Hp  
catch(Exception e){e.printStackTrace ();} 7WY~v2SDF  
} 1Kr$JIcd  
agE-,  
|=KzQY|u  
//读取保存的下载信息(文件指针位置) f=VlO d  
private void read_nPos() <Q"G aqZ  
{ fK *l?Hr  
try{ s:_a.4&Y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); JYmYX-  
int nCount = input.readInt(); '.<c[Mp  
nStartPos = new long[nCount]; Gt _tL%  
nEndPos = new long[nCount]; q'4P/2)va  
for(int i=0;i<nStartPos.length;i++) fD3'Ye<R  
{ !Q5,Zhgr  
nStartPos = input.readLong(); hc3tzB  
nEndPos = input.readLong(); U@CAQ?  
} ob'" ^LO\  
input.close(); #XB3Wden2  
} *|y$z+g/  
catch(IOException e){e.printStackTrace ();} WRwx[[e6z  
catch(Exception e){e.printStackTrace ();} 87W!R<G  
} uqU&k@  
bsr]Z&9rrk  
:I7mM y*  
private void processErrorCode(int nErrorCode) `& h-+  
{ R*0mCz^+h  
System.err.println("Error Code : " + nErrorCode); ,zr,>^ v  
} 6 eu7&Kj'  
0rz1b6F5,  
*po o.Zz  
//停止文件下载 l'@!'  
public void siteStop() B3D}'<  
{ Yl lZ5<}  
bStop = true; MkjB4:"  
for(int i=0;i<nStartPos.length;i++) "'@D\e}  
fileSplitterFetch.splitterStop(); <SQR";  
 "\T-r2  
RgJbM\`} ?  
} h::(b,|f7  
} z^jmf_  
//负责部分文件的抓取 +P Dk>PdEt  
**FileSplitterFetch.java RAk"C!&^m  
*/ H V-;? 5  
package NetFox; I8% -ii  
HY1K(T  
8x LXXB  
import java.io.*; x}Lj|U$r<X  
import java.net.*; p Zlt4  
]z8/S!?  
Yw]$/oP`  
public class FileSplitterFetch extends Thread { 6R^32VeK($  
nw,.I [  
jDTG15_=  
String sURL; //File URL R4R\B  
long nStartPos; //File Snippet Start Position K*2s-,b *  
long nEndPos; //File Snippet End Position Mis B&Ok`k  
int nThreadID; //Thread's ID nTGZ2C)c<'  
boolean bDownOver = false; //Downing is over Vdefgq@<  
boolean bStop = false; //Stop identical =Ul"{T<  
FileAccessI fileAccessI = null; //File Access interface  S.B?l_d^  
nM:<l}~v{  
U`8Er48X  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException mMOgx   
{ XP0;Q;WF}  
this.sURL = sURL; R@s|bs?  
this.nStartPos = nStart; i+in?!@G:  
this.nEndPos = nEnd; !Q_Wbu\U  
nThreadID = id; qyFeq])  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 4c{j9mh  
} 7FyE?  
GnUD<P=I  
[KHlApL  
public void run() QV HI}3~  
{ @1&"S7@}u  
while(nStartPos < nEndPos && !bStop) ?u?mSO/  
{ iAk.pH]a  
m;hp1VO)  
&+A78I   
try{ I{>Z0+  
URL url = new URL(sURL); :_:)S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o _l_Yi  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3 yb]d5:U  
String sProperty = "bytes="+nStartPos+"-"; M% Rr=  
httpConnection.setRequestProperty("RANGE",sProperty); zh0T3U0D  
Utility.log(sProperty); >o{JG(Rn  
F[%k ;aJ  
\P9ms?((A  
InputStream input = httpConnection.getInputStream(); `''y,{Fs  
//logResponseHead(httpConnection); }uC]o@/  
UcD<vg"p  
Ayg^<)JWh  
byte[] b = new byte[1024]; SCe$v76p#  
int nRead; b=\chCRJJ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) WQ8 "Jj?k6  
{ WFV'^-4  
nStartPos += fileAccessI.write(b,0,nRead); *`wz  
//if(nThreadID == 1) ,%N[FZ`|  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xP9h$!  
} p=A, yGDV  
u/S>*E  
w xte  
Utility.log("Thread " + nThreadID + " is over!"); |[mmEYc  
bDownOver = true; <%% )C>l  
//nPos = fileAccessI.write (b,0,nRead); Qk>U=]U  
} !X$19"  
catch(Exception e){e.printStackTrace ();} Xx[,n-rA  
} }2e s"  
} cuumQQ  
rO.[/#p\  
f(blqO.@l  
//打印回应的头信息 u^|cG{i5"  
public void logResponseHead(HttpURLConnection con) 4vN:Kj  
{ 4ytdcb   
for(int i=1;;i++) <fDT/  
{ ^0cbN[~/ns  
String header=con.getHeaderFieldKey(i); D_JGbNigA  
if(header!=null) {47l1wV]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); EK[J!~  
Utility.log(header+" : "+con.getHeaderField(header)); `[#id@Z1  
else P7,g^:$  
break; Br}@Vvq@  
} M&29J  
} o3|4PAA/  
X<Cf y  
s !2Iui @  
public void splitterStop() NyRa.hgZ;  
{ t$Ff $(  
bStop = true; jVN06,3z  
} NQ[X=a8N  
ty#6%  
Zr2T^p5u  
} \<`oW>  
XR7v\rd  
0&I*)Zt9x  
/* Ly^bP>2i  
**FileAccess.java )D/ ,QWk  
*//文件访问(定位,写) w}OBp^V^  
package NetFox; cUG^^3!  
import java.io.*; l=l$9H,  
,lvG5B\0  
r"{jrBK$  
public class FileAccessI implements Serializable{ l-v m`-_#  
f -F}~S  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 b/R7 Mk1  
RandomAccessFile oSavedFile; {'wvb "b  
long nPos; =fnBE`Uc  
aN0 7\  
hbvcIGaT  
public FileAccessI() throws IOException uHZ4 @ w:  
{ 6.KEe^[-  
this("",0); ] L#c <0  
} Jh&DL8`  
P/1YN  
1|xe'w{  
public FileAccessI(String sName,long nPos) throws IOException D^m2iW;  
{ 0?/gEr  
oSavedFile = new RandomAccessFile(sName,"rw"); ^zO{Aks  
this.nPos = nPos; 'fb\t,  
oSavedFile.seek(nPos); FI?J8a  
} !i (V.A  
fi*b]a\'  
< B]qqqP  
public synchronized int write(byte[] b,int nStart,int nLen) j xkQ #Y  
{ &uO-h  
int n = -1; 9m2FH~  
try{ w*/@|r39  
oSavedFile.write(b,nStart,nLen); E%D.a=UX,  
n = nLen; .0xk},  
} <W8 %eRfU  
catch(IOException e) l P=I0A-  
{ e<1Ewml(]  
e.printStackTrace (); ?G',Qtz<K  
} tl!dRV92  
AQQa6Ce*  
gM;m{gXYK  
return n; DMch88W  
}  \SQ4yc  
^(C4Q?[2m  
3'0vLi  
} >]ux3F3\  
I)` +:+P  
^VMCs/g6  
/* j][&o-Ev  
**SiteInfoBean.java XPMUhozV  
*/ \C>IVz<O  
package NetFox; ;K8}Yq9p9  
rm3/R<  
{X?1}5ry  
public class SiteInfoBean { !<~.>5UQ  
+ <E zv  
:ZB.I(v  
private String sSiteURL; //Site's URL %regt{  
private String sFilePath; //Saved File's Path F4T!&E%6  
private String sFileName; //Saved File's Name N]/cBGy  
private int nSplitter; //Count of Splited Downloading File Km= Y^x0  
)b]wpEFl  
8g_kZ^<[  
public SiteInfoBean() g.`Ntsi$wI  
{//nSplitter的缺省值为5 sBI/`dGZV  
//default value of nSplitter is 5 qQDe'f~  
this("","","",5); 965x _ %  
} svEe@Kt`  
?32~%?m  
Myg;2.  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) g7hI9(8+  
{ m`8{arz2  
sSiteURL= sURL; J>T98y/))  
sFilePath = sPath; &XcPHZy'  
sFileName = sName; z)^.ai,:0  
this.nSplitter = nSpiltter; j~ds)dW%`&  
GEVDXx>@  
l\AdL$$Mb  
} r`Fs"n#^-4  
z;9D[ME#1  
3zKeN:w  
public String getSSiteURL() 6U8esPs,  
{ sj/k';#g  
return sSiteURL; Jv3G\9_  
} Gchs$^1`t  
1U/9=b  
qP;1LAX  
public void setSSiteURL(String value) RZ{O6~VH  
{ Lks+FW  
sSiteURL = value; [c1Gq)ht  
} pl@K"PRE  
G?,3Zn0  
%Ul,9qG+  
public String getSFilePath() .J @mpJdY  
{ 'Y ,2CN  
return sFilePath; T`]%$$1s  
} sDg1nKw(  
3p HI+a  
?nL,Otz  
public void setSFilePath(String value) L58H)V3Pn  
{ 5p~5-_JX  
sFilePath = value; G/3T0d+-  
} @,,G]4zZ!  
xWY\,'+Q  
;Q vQ fV4  
public String getSFileName() q#8\BOTP |  
{ L|#0CRiN  
return sFileName; zq$L[ X  
} uc"%uc'  
Ue;Z)}  
(r?hD*2r  
public void setSFileName(String value) G+2fmVB*X  
{ > fV "bj.  
sFileName = value; .6rbn8h  
} W-r^ME  
^vSSG5  :  
pV8tn!  
public int getNSplitter() -"'+#9{h  
{ o58c!44  
return nSplitter; "S'Yn-  
} +$>aT (q  
K5`*Y@  
g.62XZF@  
public void setNSplitter(int nCount) qk^/ &j  
{ fsEQ4xN'  
nSplitter = nCount; E6xdPjoWy  
} hfbu+w):  
} {0,6- dd5  
*wJz0ex7R/  
_(:$ :*@  
/* vc3r [mT  
**Utility.java "R)n1,0  
*/ 9L-jlAo<  
package NetFox; 1]0;2THx  
5Zhl@v,L%  
KCZ<#ca^  
public class Utility { zXlerQWUv  
jbZTlG  
I~~":~&  
public Utility() dJrUcZBr  
{ CflyK@  
6Ktq7'Z@  
+{;wOQ.  
} 1D [>oK\  
&CXk=Wj  
//线程睡眠 t&x\@p9  
public static void sleep(int nSecond) 3jW&S  
{ 4|cRYZj5  
try{ W<^t2j'  
Thread.sleep(nSecond); *6u2c%^  
} znWB.H  
catch(Exception e) TT3GGHR  
{ PvW4%A@0  
e.printStackTrace (); +CSv@ />3  
} )+,h}XqlX  
} $f+I#uJ  
+zDRed_]=_  
//日志 NB^Al/V@  
public static void log(String sMsg) DS@Yto  
{ RTg\c[=w  
System.err.println(sMsg); S^D@8<6GJ  
} <?DI!~  
4=y&}3om(0  
UB8n,+R  
public static void log(int sMsg) _~umE/tz  
{ 6q`)%"4k  
System.err.println(sMsg); 8n2;47 a  
} <f.Eog  
} .dxELSV  
>e-0A  
w9"~NK8xzM  
/* ;{R;lF,  
**TestMethod.java jHHCJOHB8  
*/ OA}; pQ9QN  
package NetFox; Ke:EL;*8k  
qvWi;  
eYkg4O'  
public class TestMethod { 5"1wz  
_e8v12s  
Hc|cA(9sh9  
public TestMethod() )OQ<H.X  
{ ///xx/weblogic60b2_win.exe ?0sTx6x@  
try{ %Q}(.h%M  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 74 )G.!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); X+u1p?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %`]!atH  
fileFetch.start(); 3PLA*n+%  
} ,|z zq@fk  
catch(Exception e){e.printStackTrace ();} Tz9 (</y  
pJl/d;Cyrb  
p0CPeH  
} Lq.2vfA>  
(IjM  
km^ZF<.@  
public static void main(String[] args) SS _6VE*sI  
{ .ej+?QYwC  
new TestMethod(); k5Q1.;fW76  
} d9jD?HgM(  
} sy4Nm0m  
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