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http断点续传简单实现(java)

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/* kj6H+@ {  
**SiteFileFetch.java H%>^_:h  
*/ Lrmhr3 w5  
package NetFox; `"o{MaFA  
import java.io.*; virt[5w  
import java.net.*; (\'$$  
zp5ZZcj_  
o=6 <?v7  
public class SiteFileFetch extends Thread { 6AoKuT;  
z,bK.KFSs  
ym+Ezb#o  
SiteInfoBean siteInfoBean = null; //文件信息Bean m>RtKCtP  
long[] nStartPos; //开始位置 `X)A$lLr  
long[] nEndPos; //结束位置 [b_qC'K[  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 o+.ySSBl+  
long nFileLength; //文件长度 `F]  
boolean bFirst = true; //是否第一次取文件 0 vYG#S  
boolean bStop = false; //停止标志 \ C>+ubF  
File tmpFile; //文件下载的临时信息 Zl{9G?abCT  
DataOutputStream output; //输出到文件的输出流 =dsEt\ j  
$N Mu  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) !K0 U..  
public SiteFileFetch(SiteInfoBean bean) throws IOException Lz!JLiMEET  
{ @|5B}%!  
siteInfoBean = bean; ioEjbqD<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); uEf=Vj}G  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &er,Wyc(  
if(tmpFile.exists ()) Y`(~eNX^%  
{ u:Ye`]~o  
bFirst = false; m'N8[ o|h  
read_nPos(); wa~zb!y<  
} (#Xs\IEVF  
else =z]rZSq*o  
{ &H P g>  
nStartPos = new long[bean.getNSplitter()]; t2YB(6w+xg  
nEndPos = new long[bean.getNSplitter()]; gVe]?Jva`  
} E-($Xc  
<EQaYZY=  
z;y{QO  
s;..a&C'  
} R7K`9 c1f6  
Fq_>}k@fI  
,L lYRj 5  
public void run() #oR`_Dm)P  
{ ^B%c3U$o  
//获得文件长度 g"k4Z  
//分割文件 2r ;h">  
//实例FileSplitterFetch a 9{:ot8,  
//启动FileSplitterFetch线程 _aBy>=2c$  
//等待子线程返回 u! &T}i:  
try{ RRpY%-8M  
if(bFirst) \yZVn6GVr  
{ hlZ{bO 'f  
nFileLength = getFileSize(); IC(:RtJ  
if(nFileLength == -1) H  XFY  
{ jm@,Ihz=wI  
System.err.println("File Length is not known!"); ];"40/X  
} ecQ{ePoU  
else if(nFileLength == -2) r d-yqdJ  
{ g{i= $xc  
System.err.println("File is not access!"); 5IOGH*'U8  
} ) <{u oH  
else .9WOT ti  
{ Bs`{qmbC  
for(int i=0;i<nStartPos.length;i++) =mF"D:s*  
{ /qMnIo  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); y:^o ._  
} /]_|uN)Q  
for(int i=0;i<nEndPos.length-1;i++) #"lb9. _ M  
{ /!^,+  
nEndPos = nStartPos[i+1]; *^Ges;5 $"  
} 9bM kP2w>  
nEndPos[nEndPos.length-1] = nFileLength; c9o]w8p/  
} \uZ|2WG`  
} ^,mN-.W  
WG@3+R>{  
MnZljB  
//启动子线程 /H"fycZ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; )Tp"l"(G  
for(int i=0;i<nStartPos.length;i++) F'sX ^/;  
{ 7(uz*~Z?`0  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), dP +wcl4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), U#]J5'i  
nStartPos,nEndPos,i); ,|3_@tUl  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?o$ t{AQ  
fileSplitterFetch.start(); OzD\* ,{7  
} W h)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7}y@VO6]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6wj o:I  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", u$C\#y7  
nEndPos = " + nFileLength); ]1XtV<  
// fileSplitterFetch[nPos.length-1].start(); B@NBN&Fr  
 }( CYok  
HfgTc h  
//等待子线程结束 1#%H!GKvTU  
//int count = 0; ot[ZFF\  
//是否结束while循环 AIY 1sSK  
boolean breakWhile = false; |JF,n~n  
*4NY"EwjN  
/]'&cD 1  
while(!bStop) :r ~iFP*  
{ J(@" 7RX  
write_nPos(); jf`w8*R  
Utility.sleep(500); =}kISh  
breakWhile = true; FU/:'/ L  
4w=v /WDo  
TfT^.p*  
for(int i=0;i<nStartPos.length;i++) ?jUgDwc(w  
{ 4H%#Sn#L^!  
if(!fileSplitterFetch.bDownOver) f<iK%  
{ <5}I6R;  
breakWhile = false; 3<"j/9;K'  
break; @&`^#pok  
} Xwdcy J!  
} i&^JG/a  
if(breakWhile) {Ji&rk}NP  
break; )B"{B1(  
d'ZB{'[8p  
/;d 5p  
//count++; x {Utf$|  
//if(count>4)  nOd;Zw  
// siteStop(); XHj%U  
} JbL3/h]  
Dy,MQIM|!  
8s2y!pn7Q  
System.err.println("文件下载结束!");  YTZ :D/  
} Zi+FIQ(  
catch(Exception e){e.printStackTrace ();} Gf3-%s xA  
} 1fMV$T==K  
%J9u?-~  
H v/5)  
//获得文件长度 fs;\_E[)  
public long getFileSize() V^R,j1*  
{ " "m-5PGYo  
int nFileLength = -1; )Z1&`rv  
try{ 9aLd!P uTN  
URL url = new URL(siteInfoBean.getSSiteURL()); gC(S(osF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4'dN7E1*f  
httpConnection.setRequestProperty("User-Agent","NetFox"); _s#]WyU1g  
)Sb-e(sl  
<mlN\BcX;  
int responseCode=httpConnection.getResponseCode(); &g&,~Y/z;  
if(responseCode>=400) JygJ4RI%j  
{ {l!{b1KJ  
processErrorCode(responseCode); j0~am,yZ  
return -2; //-2 represent access is error jT$J~M pHh  
} 6xtgnl#T  
uA[ :  
pTG[F  
String sHeader; ^.iRU'{  
RV_I&HD!  
O50<h O]l  
for(int i=1;;i++) _b&26!gl  
{ 8.. |-<w  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); J^yqu{  
//Utility.log(in.readLine()); X,aRL6>r  
sHeader=httpConnection.getHeaderFieldKey(i); 6`Y:f[VB  
if(sHeader!=null) }Vob)r{R@  
{ HVoP J!K3  
if(sHeader.equals("Content-Length")) 4)D~S4{E5  
{ "5<!   
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ><D2of|  
break; &8l?$7S"_/  
} keRLai7h  
} Y)F(-H)  
else \ui'~n_t]  
break; ,'HjL:r  
} RHn3\N  
} M0xhcU_  
catch(IOException e){e.printStackTrace ();} G.<0^q,  
catch(Exception e){e.printStackTrace ();} ,(Zxd4?y  
!;(Wm6~*ad  
(?8i^T?WP=  
Utility.log(nFileLength); %m f)BC  
9uWg4U  
G4 :\6fu  
return nFileLength; /"st sF  
} !ITM:%  
}=R0AKz!Cv  
4hxP`!<  
//保存下载信息(文件指针位置) K/Yeh<_&  
private void write_nPos() f!yl&ulKU  
{ -ak. wwx\  
try{ s<#BxN  
output = new DataOutputStream(new FileOutputStream(tmpFile)); O&aD]~|  
output.writeInt(nStartPos.length); !Whx^B:  
for(int i=0;i<nStartPos.length;i++) zn^7#$fC  
{ $`7Fk%#+e  
// output.writeLong(nPos); ?+7~ E8  
output.writeLong(fileSplitterFetch.nStartPos); T^#d;A  
output.writeLong(fileSplitterFetch.nEndPos); ibZ[U p?  
} 1)h<)  
output.close(); eq%cRd]u  
} /cx'(AT  
catch(IOException e){e.printStackTrace ();} .wq j  
catch(Exception e){e.printStackTrace ();} `3ha~+Goo!  
} AEnkx!o  
v&;JVai  
h_P  
//读取保存的下载信息(文件指针位置) oqh@ (<%  
private void read_nPos() -f ~1Id  
{ eDP&W$s#  
try{ G)[gLD{g?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); mD% qDKI  
int nCount = input.readInt(); c-&Q_lB  
nStartPos = new long[nCount]; >gL&a#<S  
nEndPos = new long[nCount]; .!L{yU,  
for(int i=0;i<nStartPos.length;i++)  "O9n|B  
{ r`sKe &  
nStartPos = input.readLong(); PR!0=E*}  
nEndPos = input.readLong(); +ug2p;<B  
} k=kkF"  
input.close(); =s*c(>  
} )K]p^lO  
catch(IOException e){e.printStackTrace ();} wAW{{ p  
catch(Exception e){e.printStackTrace ();} 8r"-3<*  
} w/ZP. B  
r*mSnPz\q  
YKU|D32  
private void processErrorCode(int nErrorCode) ;:oJFI#;  
{ {`*Fu/Upb  
System.err.println("Error Code : " + nErrorCode); +924_,zF  
} "2-D[rYZ  
MtPdpm6\  
l x5.50mI  
//停止文件下载 7_Te-i  
public void siteStop() Z?qLn6y1W  
{ 1>\V>g9  
bStop = true; |ITCw$T  
for(int i=0;i<nStartPos.length;i++) ^Tj{}<yT  
fileSplitterFetch.splitterStop(); 4zhh **]B  
2f%+1uU  
O>vCi&  
} %wru)  
} G?LC!9MB  
//负责部分文件的抓取 'lpCwH  
**FileSplitterFetch.java WQN`y>1#@_  
*/ ?8s$RYp14  
package NetFox; 5`e;l$ M`  
0/|Ax-dK  
 9S9j  
import java.io.*; YW~ 9N  
import java.net.*; N<4 nb  
Dpu?JF]  
1'p=yHw  
public class FileSplitterFetch extends Thread { *'H\`@L  
m*B4a9 f  
)f^^hEIS  
String sURL; //File URL M~`^deU1  
long nStartPos; //File Snippet Start Position IIGx+>  
long nEndPos; //File Snippet End Position `S4*~Xx  
int nThreadID; //Thread's ID 3:#6/@wQ  
boolean bDownOver = false; //Downing is over }.8yKj^p  
boolean bStop = false; //Stop identical \i-CTv6f  
FileAccessI fileAccessI = null; //File Access interface `ItoL7bi  
kzK9 .  
m##!sF^k~J  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException KrG,T5  
{ NhTJB7  
this.sURL = sURL; c V MRSp  
this.nStartPos = nStart; HrZX~JnTmf  
this.nEndPos = nEnd; SvkCx>6/G  
nThreadID = id; nIL67&  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3Ur_?PM+C  
} j@+$lU*r  
"Vl4=W)u  
`Xeiz'~f8  
public void run() IaO R%B g  
{ .w{Y3,dd>  
while(nStartPos < nEndPos && !bStop) s3@mk\?qMe  
{ P4{~fh(  
E8nj_ ^Z  
b+arnKo1fk  
try{ .I#_~C'\  
URL url = new URL(sURL); A1Uy|Dl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B1U!*yzG6  
httpConnection.setRequestProperty("User-Agent","NetFox"); GNrRc3dr$  
String sProperty = "bytes="+nStartPos+"-"; tEo-Mj5:  
httpConnection.setRequestProperty("RANGE",sProperty); NMhpKno  
Utility.log(sProperty); Pe\Obd8d  
2T?Y  
T fIOS]  
InputStream input = httpConnection.getInputStream(); LxWd_B  
//logResponseHead(httpConnection); c1a$J`  
a-F I`Dv  
\ %MsG  
byte[] b = new byte[1024]; [YODyf}M>\  
int nRead; :O&jm.2m  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) T2rBH]5  
{ iV#A-9  
nStartPos += fileAccessI.write(b,0,nRead); kQd|qZ=:w  
//if(nThreadID == 1) i0+e3!QU  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /|H9Gm  
} 7mXXMm  
^LB]  
z'1%%.r;FM  
Utility.log("Thread " + nThreadID + " is over!"); %*Mr ^=  
bDownOver = true; S|@/"?DC  
//nPos = fileAccessI.write (b,0,nRead); N`?/kubD  
} 0T(+z)Ki  
catch(Exception e){e.printStackTrace ();} id8QagJ  
} =)g}$r &<  
} @b.,pwZF  
4]p#9`j  
,:'JJZg@  
//打印回应的头信息 $-t@=N@vO?  
public void logResponseHead(HttpURLConnection con) /hVwrt(  
{ jC}HNiM78  
for(int i=1;;i++) E11C@%  
{ +Q);t,  
String header=con.getHeaderFieldKey(i); ns\I Y<Yo  
if(header!=null) M?}:N_9<J  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Hsv)] %p  
Utility.log(header+" : "+con.getHeaderField(header));  qbS6#7D  
else  |xg#Q`O  
break; {5c?_U  
} oq$#wiV"Q  
} 2.MUQ;OX  
[Y, L=p  
7j=KiiI  
public void splitterStop() _&s pMf  
{ 9c,/490Q  
bStop = true; =23@"ji@D  
} olxxs(  
ln8NcAEx  
/2/aMF(J  
} 5=#d#dDc  
emrA!<w!W  
p-EU"O  
/* VMJaL}J]  
**FileAccess.java k%O3\q  
*//文件访问(定位,写) -oUNK}>  
package NetFox; OUGkam0UK  
import java.io.*; ;]>)6  
]W2#8:i  
z^&$6c_  
public class FileAccessI implements Serializable{ Tl[*(| /C  
f#GMJ mCQs  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 hjFht+j1  
RandomAccessFile oSavedFile; @>~\So|  
long nPos; HB}rpiB  
RU6c 8>"  
sb8bCEm- \  
public FileAccessI() throws IOException 7_)38  
{ _TsN%)m  
this("",0); 1t?OD_d!8  
} A9K$:mL<2  
]a~sJz!  
n@;B_Bt7  
public FileAccessI(String sName,long nPos) throws IOException zG9D Ph  
{ =VZ_';b h  
oSavedFile = new RandomAccessFile(sName,"rw"); :@-yK8q's  
this.nPos = nPos; !P^Mo> "  
oSavedFile.seek(nPos); @sg.0GR  
} yOKzw~;0%  
a L+>XN  
x lqP%  
public synchronized int write(byte[] b,int nStart,int nLen) o'(BL:8s  
{ 6g" h}p\{S  
int n = -1; [' pO=ho  
try{ 0hGmOUO  
oSavedFile.write(b,nStart,nLen); U Xpp1/d|e  
n = nLen; vF'>?O?  
} ;sAGTq  
catch(IOException e) oxL<\4)WJ  
{ dc1Zh W4  
e.printStackTrace (); g<0K i^#  
} J!5b~8`v  
.7b%7dQ<\  
`Z5dRLrd  
return n; 9609  
} DQXcf*R  
Ny$3$5/  
GQ@mQ=i  
} /Qr`au  
I{[Z  
2YW;=n  
/* y1PyH  
**SiteInfoBean.java . o /uA  
*/ HZ Wt>f  
package NetFox; D^.  c:  
a*.#Zgy:lK  
7[qL~BT+  
public class SiteInfoBean { qA`@~\ qh"  
\6?a  
L;j++^p  
private String sSiteURL; //Site's URL L2EQ 9i'[  
private String sFilePath; //Saved File's Path C5TV}Bq\  
private String sFileName; //Saved File's Name @d 7V@F0d  
private int nSplitter; //Count of Splited Downloading File c$&({Z{1  
YOGj__:  
0\ (:y^X  
public SiteInfoBean() E JuTv%Y8  
{//nSplitter的缺省值为5 <y^_&9  
//default value of nSplitter is 5 @/^mFqr2  
this("","","",5); zN]%p>,)HB  
} _[Imwu}  
a4 N f\7  
][?J8F  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) QOg >|"KL  
{ `m<O!I"A  
sSiteURL= sURL; >|kD(}Axf  
sFilePath = sPath; `kQosQV  
sFileName = sName; 457{9k  
this.nSplitter = nSpiltter; 81s }4  
g([:"y?  
`=#jWZ.8m  
} A7+ZY,  
#*_!Xc9f  
0<~~0US  
public String getSSiteURL() ?-mOAHW0q  
{ \ DZ.#=d  
return sSiteURL; MSvZ3[5Io  
} s*yl& El/  
+#BOWz  
_r\M}lDh*  
public void setSSiteURL(String value) QNU~G3  
{ fpo{`;&F  
sSiteURL = value;  ]gcOMC  
} \2a;z<(  
8/dMvAB1So  
s[0`  
public String getSFilePath() o&%v"#H2  
{ 4^2>K C_  
return sFilePath; Q9O_>mZy  
} lm;hW&O9  
a0sz$u  
k"&o)*d  
public void setSFilePath(String value) TK\3mrEI  
{ ' :B;!3a0d  
sFilePath = value; -~ ~h1  
} Zc1x"j  
si6CWsb_f  
yFDeY PZP  
public String getSFileName() Z)E)-2U$@  
{ ,jis@]:  
return sFileName; =cjO]  
} ]Rxo}A  
X=]utn  
~r8<|$;  
public void setSFileName(String value) 0@cIj ]  
{ pIcg+~  
sFileName = value; ySO\9#Ho  
} 1a{3k#}  
&Z]}rn  
= N*Jis  
public int getNSplitter() pz['o  
{ /CsP@f_Gw  
return nSplitter; 1;=L] L?  
} %mT/y%&:  
<L qJg  
BK%B[f*[OA  
public void setNSplitter(int nCount) Dbn344s  
{ ye$_=KARP  
nSplitter = nCount; kpn|C 9r  
} 9Tt%~m^  
} pK3A/ry<  
@y;VV*  
.@OQ$ D<  
/* Pa3-0dUr  
**Utility.java !9/`PcNIpy  
*/ Q NMZR  
package NetFox; <>\|hno}  
%`5 (SC].  
raPOF6-_rH  
public class Utility { a&8K5Z%0  
>t cEx(  
;Y*K!iFWH  
public Utility() iXnXZ|M  
{ ftPps -  
I&La0g_E  
tf6m .  
} G:$kGzhJ  
15j5F5P   
//线程睡眠 VR>!Ch  
public static void sleep(int nSecond) t(*n[7e  
{ 6Oy:5Ps8a  
try{ 6;'[v}O^^  
Thread.sleep(nSecond); IVSC7SBiT  
} X|hYZR  
catch(Exception e) LQPQ !):;  
{ R'c dEoy  
e.printStackTrace (); M+ %O-B  
} (rBsh6@)  
} Zio! j%G  
cl^UFl f[  
//日志 V[/9?5pM  
public static void log(String sMsg) 06.%9R{  
{ N+c|0  
System.err.println(sMsg); q%;cu1^"M  
} X.4WVI  
G=17]>U  
; D<k  
public static void log(int sMsg) [#gm[@d,  
{ PDD2ouv4  
System.err.println(sMsg); `S|F\mI ~  
} $GRwk>N  
} 9abUh3  
a[~[l k=7  
GCN-T1HvA2  
/* Vp]7n!g4l  
**TestMethod.java | 9S8sfw  
*/ <h/q^|tZ{  
package NetFox; M{24MF   
g.9C>>tj  
_ $>);qIP4  
public class TestMethod { aF?_V!#cT  
vf3)T;X>  
geyCS3 :p  
public TestMethod() Lbz/M _G  
{ ///xx/weblogic60b2_win.exe @QmN= X5  
try{ Gxe)5,G  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); SnFyK5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ck] I?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); aYa`ex  
fileFetch.start(); -nNKUt.I  
} @3c'4O   
catch(Exception e){e.printStackTrace ();} im &N &A  
Zt9G[[]  
D*-  
} /W,hOv  
0j!<eN=  
_WWC8?6 U  
public static void main(String[] args) 3:jxr  
{ jnp~ACN,  
new TestMethod(); W'vekuM  
} $||WI}k3V  
} p4z4[=-:  
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