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http断点续传简单实现(java)

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/* PXYo@^ 3  
**SiteFileFetch.java U$(AZ|0  
*/ (GdL(H#IL  
package NetFox; e7.!=R{6  
import java.io.*; ;MR(Eaep  
import java.net.*; RGim):1e  
"Aq-H g  
jFBnP,WQ  
public class SiteFileFetch extends Thread { o!+jPwEU  
R\wG3Oxol  
lx&ME#~  
SiteInfoBean siteInfoBean = null; //文件信息Bean &N! ;d E  
long[] nStartPos; //开始位置 [!E8C9Q#!  
long[] nEndPos; //结束位置 LMvsYc~]q  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +wwK#ocw  
long nFileLength; //文件长度 ` cgS yRD]  
boolean bFirst = true; //是否第一次取文件 Ag`:!*  
boolean bStop = false; //停止标志 sy|{}NkA!  
File tmpFile; //文件下载的临时信息 <v)Ai;l,  
DataOutputStream output; //输出到文件的输出流  !mX 2  
L>mv\D;o.  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) pPdOw K#  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~\z\f} w  
{ LAwl9YnG:  
siteInfoBean = bean; M/,jHG8v  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); &<P!o_+eb  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); v&EHp{8Qd  
if(tmpFile.exists ()) G*|2qX"o  
{ ? N|B,F  
bFirst = false; YrR}55V,  
read_nPos(); Uv06f+P(  
} @edi6b1W  
else >#RXYDd  
{ [yF4_UoF  
nStartPos = new long[bean.getNSplitter()]; =y/VrF.bV  
nEndPos = new long[bean.getNSplitter()]; Tl!}9/Q5E:  
} h.6yI  
WlnI`!)d  
U9KnW]O%"  
,&sBa{0  
} K6.*)7$#  
"(+ >#  
m*BtD-{  
public void run() K/y#hP  
{ *}\!&Zk"  
//获得文件长度 [lsr[`SJ<  
//分割文件 q lL6wzq,  
//实例FileSplitterFetch Iky'x[p,D  
//启动FileSplitterFetch线程 ,!f*OWnZ  
//等待子线程返回 shlL(&Py  
try{ j!;?=s  
if(bFirst) G!54 e  
{ PT|W{RlNl  
nFileLength = getFileSize(); SZCF db  
if(nFileLength == -1) L`ZH.fN  
{ wL2d.$?TEg  
System.err.println("File Length is not known!"); W)F2X0D>  
} Vl!Z|}z  
else if(nFileLength == -2) 7K`A2  
{ L44-: 3  
System.err.println("File is not access!"); 1_7}B4  
} <8Qa"<4f;  
else _AQ :<0/#  
{ u8*Uia*vwH  
for(int i=0;i<nStartPos.length;i++) AG#5_0]P~  
{ =S-'*F  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6M"]p  
} 6|05-x|  
for(int i=0;i<nEndPos.length-1;i++) $H/3t?6h`  
{ ~PUz/^^ s  
nEndPos = nStartPos[i+1]; w$7*za2  
} 33\{S$p  
nEndPos[nEndPos.length-1] = nFileLength; \HDRr*KO  
} )jp#|#h  
} 6P' m0  
<3QE3;4  
tWi@_Rlx;  
//启动子线程 }0T1* .Cz  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; i+&*W{Re  
for(int i=0;i<nStartPos.length;i++) =@m|g )  
{ .h^."+TJ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -O_5OT4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Od'!v&  
nStartPos,nEndPos,i); ?0+D1w  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); er}/~@JJ  
fileSplitterFetch.start(); 1dOVH7  
} ]7ROCJ;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), u|\Lb2Kb:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +"a . ,-f!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~) }npS;  
nEndPos = " + nFileLength); D:llGdU#2  
// fileSplitterFetch[nPos.length-1].start(); ;KmSz 1A  
POc< G^  
~l-Q0wg  
//等待子线程结束 "}|n;:r  
//int count = 0; Hq^sU%  
//是否结束while循环 >U9*  
boolean breakWhile = false; r9G<HKl  
TE0hV w0c  
g!<@6\RB  
while(!bStop) .8CR \-  
{ l?B\TA^  
write_nPos(); lC.Yu$O5  
Utility.sleep(500); @Q3aJ98)2  
breakWhile = true; &?*M+q34  
AFl]w'=  
iy8U rgG;l  
for(int i=0;i<nStartPos.length;i++) ekfD+X  
{ u9e A"\s  
if(!fileSplitterFetch.bDownOver) r9@W8](\  
{ b IcLMG s  
breakWhile = false; }(dhXOf\q  
break; lx~!FLn  
} Ud:v3"1  
} rU5gQq;  
if(breakWhile) .8l\;/o|  
break; \Btv76*,  
&D uvy#J  
u%#bu^4"  
//count++; Z*nC ;5Kd  
//if(count>4) ;]MHU/  
// siteStop(); $r9Sn  
} H(!)]dO  
 8OZc:/  
U=p,drF,A  
System.err.println("文件下载结束!"); A5+vzu^  
} PV>-"2n  
catch(Exception e){e.printStackTrace ();} .wx; !9  
} zO2Z\E'% .  
Zo22se0)  
nvxftbfE^D  
//获得文件长度 N9Yc\?_NU_  
public long getFileSize() Tul_/`An  
{ |~CN]N  
int nFileLength = -1; ;58l_ue  
try{ 7f'9Dm`  
URL url = new URL(siteInfoBean.getSSiteURL()); RT8xU;   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yEy} PCJ&  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2Q)"~3  
rFSLTbTf  
*8fnxWR   
int responseCode=httpConnection.getResponseCode(); @P4fR7  
if(responseCode>=400) Tl%#N"  
{ d5%A64?  
processErrorCode(responseCode); |SZRO,7x  
return -2; //-2 represent access is error @X"p"3V  
} a84^"GH7  
l[l('-f  
SPe Se/  
String sHeader; 6YQ&+4   
sE-E\+  
[(5;jUmF@  
for(int i=1;;i++) !t{3IE  
{ Ytc  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); D&/(Avx.  
//Utility.log(in.readLine()); ^~0\d;l_  
sHeader=httpConnection.getHeaderFieldKey(i); *n N;!*J  
if(sHeader!=null) $985q@pV0  
{ Ja| ! fT  
if(sHeader.equals("Content-Length")) ,-&ler~[  
{ VieC+Kk  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $[6:KV  
break; _LFZ0  
} !!b5vzyve  
} Ni'vz7j  
else #q%xJ[  
break; c</d1xT  
} OnC|9  
} ]ZelB,7q  
catch(IOException e){e.printStackTrace ();} amK?LDf]  
catch(Exception e){e.printStackTrace ();} A jr]&H4  
ce/Rzid  
bPAp0}{Fu  
Utility.log(nFileLength); :O{`!&[>L  
*{P"u(K  
,o]"G[Jk  
return nFileLength; v-3In\T=^  
} jmmm0,#D  
bg*4Z?[dd  
:kfHILi  
//保存下载信息(文件指针位置) 07DpvhDQ  
private void write_nPos() @|6n.'f+  
{ @>_`g=  
try{ B@Ez,u5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3 ~0Z.!O  
output.writeInt(nStartPos.length); G)';ucs:,  
for(int i=0;i<nStartPos.length;i++) &7!&]kA+  
{ ~&[Wqn@MZ  
// output.writeLong(nPos); 3gaijVN  
output.writeLong(fileSplitterFetch.nStartPos); <- Q=h?D  
output.writeLong(fileSplitterFetch.nEndPos); r ioNP(  
} 'xm_oGWE  
output.close(); b{=2#J-  
} 8 qt,sU  
catch(IOException e){e.printStackTrace ();} '^'vafs-/@  
catch(Exception e){e.printStackTrace ();} M%7{g"J*  
} 9Ruj_U  
;"hED:z6%  
+u#;k!B/>  
//读取保存的下载信息(文件指针位置) ,OsFv}v7  
private void read_nPos() Eg-3GkC  
{ B\wH`5/KW  
try{ 7c1xB.g   
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Gy hoo'<  
int nCount = input.readInt(); r`pg`ChHv  
nStartPos = new long[nCount]; zdrCr0Rx,  
nEndPos = new long[nCount]; &*B=5W;6^u  
for(int i=0;i<nStartPos.length;i++) 2--"@@  
{ 3 k py3z[%  
nStartPos = input.readLong(); jxU1u"WU  
nEndPos = input.readLong(); %Wkvo-rOq  
} ;t{Ew+s  
input.close(); dFFJw[$8w  
} Q<3=s6@T  
catch(IOException e){e.printStackTrace ();} XZLo*C!MG  
catch(Exception e){e.printStackTrace ();} @tWyc%t  
} cJd~UQ<k  
t8DyS FT  
 iUJqAi1o  
private void processErrorCode(int nErrorCode) {5QIQ  
{ IqJ7'X  
System.err.println("Error Code : " + nErrorCode); uIvy1h9m  
} 0tv"tA;  
ce{(5IC  
m_\w)  
//停止文件下载 S Cs@Q  
public void siteStop() T3,"g=  
{ 2`tdH|Z`  
bStop = true; "5"6mw?  
for(int i=0;i<nStartPos.length;i++) @r]wZ~@  
fileSplitterFetch.splitterStop(); x*Y&s<  
:p0|4g  
:'9%~q.D4  
} HpSmB[WF  
} o?$kcI4  
//负责部分文件的抓取 ]ppi962Z  
**FileSplitterFetch.java +dw$IMwb  
*/ tfW/Mf  
package NetFox; swJ3_WhbdT  
\Y&*sfQ  
OvqCuX  
import java.io.*; CB{% ~  
import java.net.*; ="<5+G  
6!bp;iLKy  
ifTMoC%  
public class FileSplitterFetch extends Thread { R]O!F)_/'  
kwU~kcM  
rxH*h`Xx@  
String sURL; //File URL 9otA5I^v  
long nStartPos; //File Snippet Start Position 23 j{bK  
long nEndPos; //File Snippet End Position SQhk)S  
int nThreadID; //Thread's ID w DswK "T  
boolean bDownOver = false; //Downing is over T+ey>[  
boolean bStop = false; //Stop identical ,ef"S r  
FileAccessI fileAccessI = null; //File Access interface }'mVD^<+  
WJbdsPs  
?K%&N99c!  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /fC@T  
{ M3c!SXx\  
this.sURL = sURL; KKP}fN  
this.nStartPos = nStart; f_a.BTtNO  
this.nEndPos = nEnd; Pj9n`LwM  
nThreadID = id; 8.FBgZh*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 )nmLgsg  
} ):OGhWq  
NSH20$A<  
}_93}e  
public void run() B?`n@/  
{ rqbX9M^  
while(nStartPos < nEndPos && !bStop) _9!*laR!2  
{ 8 #fzL7  
&$F4/2|b%  
2 g5Ft  
try{ ^HYmi\`  
URL url = new URL(sURL); UQ6UZd37   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [ fvip_Pt  
httpConnection.setRequestProperty("User-Agent","NetFox"); D-\WS^#  
String sProperty = "bytes="+nStartPos+"-"; M:x?I_JG8  
httpConnection.setRequestProperty("RANGE",sProperty); u&/[sq x  
Utility.log(sProperty); sk !92mQ  
v$c*3H.seM  
fq(r,h=|  
InputStream input = httpConnection.getInputStream(); 4Kjrk7GAx  
//logResponseHead(httpConnection); $MD|YW5  
g&9E>wT  
,0 +%ji^V  
byte[] b = new byte[1024]; H%N !;Jz=  
int nRead; par| j]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) gI8r SmH  
{ ^% y<7>%  
nStartPos += fileAccessI.write(b,0,nRead); #eSVFD5ZU  
//if(nThreadID == 1) q>:>f+4  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d'ddxT$GG  
} ;AyE(|U+  
W/_=S+CvK  
F[PIo7?K  
Utility.log("Thread " + nThreadID + " is over!"); [<SM*fQ>t  
bDownOver = true; 6v~` jS%3  
//nPos = fileAccessI.write (b,0,nRead); y,&.<Yc  
} pW ]+a0j  
catch(Exception e){e.printStackTrace ();} P \<dy?nZ  
} N2:};a[ui5  
} `L p3snS  
XQL"D)fw  
#?%akQ+w  
//打印回应的头信息 KWtLrZ(j  
public void logResponseHead(HttpURLConnection con) rmpx8C Y"  
{ k8fvg4  
for(int i=1;;i++) o=i)s2   
{ +E8 \g  
String header=con.getHeaderFieldKey(i); (2J_Y*N~>  
if(header!=null) n';"c;Ye)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |O0=Q,<m  
Utility.log(header+" : "+con.getHeaderField(header)); *:t]|$;E\  
else i!8 o(!I  
break; ~5Wr |qg%{  
} 'Gwa[ |6i  
} wn*<.s  
0l-m:6  
U 7mA~t2E  
public void splitterStop() mNkS!(L6  
{ L B`=+FD  
bStop = true; }G^Bc4@b  
} 0CXh|AU  
p\lS ) 9  
L~e\uP  
} 2q}M1-^  
_4qP0LCa  
|lH~nU.*  
/* A*l(0`aWq  
**FileAccess.java v_Om3i9$E  
*//文件访问(定位,写) +zodkB~)  
package NetFox; K"'W4bO#7  
import java.io.*; &8!* u3  
c%1 <O!c  
Q*wub9  
public class FileAccessI implements Serializable{ "=)i'x"0"  
W[S4s/)mg  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _r!''@B  
RandomAccessFile oSavedFile; o6f^DG3*  
long nPos; w)I!q&`Y  
=6j4_+5mnH  
Ao%E]M  
public FileAccessI() throws IOException 2`4'Y.Qf  
{ > Q1r^  
this("",0); ~F7 +R   
} ~doOt  
# Sfz^  
#fg RF  
public FileAccessI(String sName,long nPos) throws IOException @kU{  
{ ydp?%RB3w  
oSavedFile = new RandomAccessFile(sName,"rw"); HfN-WYiR  
this.nPos = nPos; 9/Q_Jv-Q  
oSavedFile.seek(nPos); Bkg/A;H  
} U" eP>HHp  
Id8^6FLw  
$Yfm>4  
public synchronized int write(byte[] b,int nStart,int nLen) EoLF7j<W  
{ lhZWL}l  
int n = -1; 1B~H*=t4h  
try{ [ bv>(a_,  
oSavedFile.write(b,nStart,nLen); oQJK}9QR  
n = nLen; 9vc3&r  
} arf`%9M  
catch(IOException e) 77/&M^0  
{ ) *:<3g!  
e.printStackTrace (); a&YD4DQ05  
} }>:v  
_2{i}L  
.S/W_R  
return n; dP0!?J Y  
} /|] %0B  
Ko%&~C_  
Alh"G6  
} b6=.6?H@4f  
k#k!AcC  
42:~oKiQ$"  
/* k,0RpE  
**SiteInfoBean.java (bH*i\W  
*/ [sG=(~BU  
package NetFox; WE$Pi;q1  
w?kdM1T  
Zcd!y9]#  
public class SiteInfoBean { 31mY]Jve"  
pE >~F  
e#`wshtN:  
private String sSiteURL; //Site's URL T 1m097  
private String sFilePath; //Saved File's Path !Dp4uE:Pq  
private String sFileName; //Saved File's Name YIs(Q  
private int nSplitter; //Count of Splited Downloading File Qg  
Y604peUF  
>*%ySlZbs  
public SiteInfoBean() l= 5kd.{  
{//nSplitter的缺省值为5 xy`aR< L  
//default value of nSplitter is 5 C/dqCUX:  
this("","","",5); lPm'>, }Y  
} _[h1SAJ  
Cec!{]DL&  
YBQO]3f  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) N(mhgC<O  
{ -[OGZP`8  
sSiteURL= sURL; }8 A]  
sFilePath = sPath; pLMki=.Ld  
sFileName = sName; eG26m_S=  
this.nSplitter = nSpiltter; @V)k*h3r+  
6TS+z7S81L  
ew B&PR  
} }S'+Ytea  
s9) @$3\  
WQ4:='(  
public String getSSiteURL() 4A0R07"  
{ e#L/  
return sSiteURL; 7dI+aJ  
} Sj{z  
VR5$[-E3  
$Hqm 09w  
public void setSSiteURL(String value) S:{hgi,T*  
{ [r_,BH\nu  
sSiteURL = value; m *8[I  
} O?NAbxkp  
lwPK^)|}  
I"*g-ji0  
public String getSFilePath() /HH5Mn*  
{ yNdtq\h  
return sFilePath; _7 .Wz7]b  
} Sai_rNRWB  
2;.7c+r0  
-fVeE<[  
public void setSFilePath(String value) lY!`<_Am  
{ l/;OC  
sFilePath = value; oH!sJ&"#_  
} Z 2Fm=88  
%b'ic  
ohusL9D  
public String getSFileName() 2H fP$.  
{ wG2lCv`d  
return sFileName; ON _uu]=  
} G\tTwX4  
%).phn"ij[  
<||F$t  
public void setSFileName(String value) i{PRjkR  
{ g;w4:k)U  
sFileName = value; ^#e:q  
} /lDW5;d  
i>r4Rz!  
^sd+s ~ xx  
public int getNSplitter() NS6Bi3~  
{ zAt!jP0E  
return nSplitter; CF>k_\/Bj  
} S(mJ;C  
Ta?#o  
5+:b #B  
public void setNSplitter(int nCount) ]"q[hF*PM  
{ ULMG"."IH  
nSplitter = nCount; Sj(uc#  
} sIdo(`8$  
} l*("[?>I  
N:[m,U9a  
^CI.F.#X|  
/* %k{~Fa  
**Utility.java g1muT.W]S  
*/ r Y|'<$wvg  
package NetFox; eV^@kI4  
O[y.3>l[s  
 IPa08/  
public class Utility { LslQZ]3MY  
`R0>;TdT  
L7_Mg{  
public Utility() U2/H,D  
{ 75wQH*  
`23&vGk}  
)y'`C@ijI  
} r vVU5zA4H  
e{U`^ao`F8  
//线程睡眠 IB /.i(  
public static void sleep(int nSecond) QkZT%!7  
{ =#n05*^  
try{ e"hm|'  
Thread.sleep(nSecond); Yi&;4vC  
} V\%;S  
catch(Exception e) f!e8xDfA  
{ #>O,w0<qM  
e.printStackTrace (); UP 1Y3  
} W"AWhi{h  
} 2:MB u5**  
3X*;.'#Z  
//日志 f( hK>H  
public static void log(String sMsg) fo&q/;l\  
{ !0c7nzjm  
System.err.println(sMsg); >BMJA:j  
} :aLShxKA  
gWqmK/.U.0  
)Ac8'{Tq/  
public static void log(int sMsg) j#Ly!%dp  
{ 5|x&Z/hL  
System.err.println(sMsg); 7!hL(k[  
} 6Bmv1n[X^h  
} }lML..((1  
7'7bIaJk  
3 l->$R]  
/* kI]i,v#F  
**TestMethod.java 5&v'aiWK  
*/ tz j]c  
package NetFox; 8|{:N>7  
X}0NeG^'O  
a2v UZhkR  
public class TestMethod { jWiZ!dtUZ  
,;;M69c[ x  
7 ;|jq39  
public TestMethod() N'Ywn}!js  
{ ///xx/weblogic60b2_win.exe F0o7XUt  
try{ +VDwDJ)lG  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); dP T)&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .hn{m9|U  
SiteFileFetch fileFetch = new SiteFileFetch(bean); pnca+d  
fileFetch.start(); )"|'=  
} (k6=o';y  
catch(Exception e){e.printStackTrace ();} /],:sS7  
;"!dq)  
44f8Hc1g  
} n0 _:!]k^  
eT[ ,k[#q  
f?#:@ zcL  
public static void main(String[] args) s#&jE GBug  
{ ?JzLn,&  
new TestMethod(); g?A4C`l6iy  
} J*U,kyYF  
} j7<`^OG  
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