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http断点续传简单实现(java)

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/* &he:_p$x  
**SiteFileFetch.java = J]M#6N0  
*/ X&Sah}0V&  
package NetFox; 4vNH"72P  
import java.io.*; wFjQ1<s=  
import java.net.*; gSf >+|  
^z~drcR  
/2MZH  
public class SiteFileFetch extends Thread { 8~T=p:z'  
?y__ Vrw  
tI5*0  
SiteInfoBean siteInfoBean = null; //文件信息Bean s'OK])>`  
long[] nStartPos; //开始位置 EVE"F'Ww,_  
long[] nEndPos; //结束位置 &.PAIe.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 e_g&L)  
long nFileLength; //文件长度 ux,eY  
boolean bFirst = true; //是否第一次取文件 \rE] V,,2  
boolean bStop = false; //停止标志 U#<{RqY  
File tmpFile; //文件下载的临时信息 F`,Hf Cb\  
DataOutputStream output; //输出到文件的输出流 Nq|y\3]  
`?f<hIJoz  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) M1T.  
public SiteFileFetch(SiteInfoBean bean) throws IOException m"6K_4r]  
{ 'I:_}q  
siteInfoBean = bean; Bwu?DK  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); IkxoW:L  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `$FB[Z} &  
if(tmpFile.exists ()) qE VpkvEq  
{ P + C5 s  
bFirst = false; ?.n1t@sG&  
read_nPos(); \j &&o  
} ` k(Q:  
else nc1?c1s,f  
{ vZs~=nfi#|  
nStartPos = new long[bean.getNSplitter()]; vsQvJDna~  
nEndPos = new long[bean.getNSplitter()]; _>r (T4}]  
} jhBfy|Ftu  
*pABdP+  
 Z`|\%D%  
(cV1Pmn  
} -Owb@Nw  
7Jd&9&O U  
lHHx D  
public void run() px(~ZZB"  
{ N/<c;"o  
//获得文件长度 _H-Fm$Q  
//分割文件 PO^#G @  
//实例FileSplitterFetch (ak&>pk;  
//启动FileSplitterFetch线程 UUa@7|x  
//等待子线程返回 K$B~vy6E`  
try{ }lCQ+s!  
if(bFirst) bH:C/P<x  
{ hlz/TIP^N3  
nFileLength = getFileSize(); 4/v[ .5  
if(nFileLength == -1) Xq"Es  
{ 9l:[jsk<d  
System.err.println("File Length is not known!"); BB ::zBg  
} 8*|*@  
else if(nFileLength == -2) Dtyw]|L\H  
{ 8i<]$  
System.err.println("File is not access!"); c?aOX/C'  
} sGpAaGY>  
else fzAkUvo  
{ G>jC+0nkry  
for(int i=0;i<nStartPos.length;i++) /gex0 w  
{ O7 yj<  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); r=p^~tuyxr  
} AJ3Byb=.  
for(int i=0;i<nEndPos.length-1;i++) Xg\unUHa  
{ <7zz"R  
nEndPos = nStartPos[i+1]; _lRIS_^;eE  
} hzpl;Mj  
nEndPos[nEndPos.length-1] = nFileLength; (]10Z8"fJ  
} w'7J`n: {]  
} YPO24_B  
JNP6qM  
^t$uDQ[hA  
//启动子线程 ;Cjj_9e,:  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; dxH.  
for(int i=0;i<nStartPos.length;i++) y(E<MRd8V  
{ -Rr !J37  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {~G~=sC$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Ll VbY=EX7  
nStartPos,nEndPos,i); {<#b@=G  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jE8}Ho_#)  
fileSplitterFetch.start(); Vs Z7 n~e  
} qv4r !x  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -3 "<znv  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 563ExibH  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", N^k& 8  
nEndPos = " + nFileLength); 7{9M ^.}  
// fileSplitterFetch[nPos.length-1].start(); ic l]H  
=EU;%f  
zZey  
//等待子线程结束 d#W^S[[  
//int count = 0; Lf%}\0:  
//是否结束while循环 ,4B8?0sH|  
boolean breakWhile = false; }r;=<mc,O  
YN7`18u  
s?4nR:ZC}  
while(!bStop) #.C2_MN>  
{ A]drNFE  
write_nPos(); WLta{A?  
Utility.sleep(500); V ZtFgN$J  
breakWhile = true; 2]FRIy d  
tCPK_Wws?Z  
"5?1S-Vl  
for(int i=0;i<nStartPos.length;i++) _j*I\  
{ xVN!w\0  
if(!fileSplitterFetch.bDownOver) 3Wx\Liw,  
{ C@<gCMj,"  
breakWhile = false; #7}YSfm^6  
break; xr7M#n  
} F[W0gjUc  
} z+CX$.Z  
if(breakWhile) *O\lR-z!k  
break; wm9wnAy  
;:>q;%  
j *;.>akY7  
//count++; \~t!M~H  
//if(count>4) TmM~uc7mj  
// siteStop(); nHp(,'R/  
} H$pgzNL  
?IoA;GBg  
DF gM7if  
System.err.println("文件下载结束!"); 8U4In[4  
} ~[~#PO  
catch(Exception e){e.printStackTrace ();} Pv3G?u=4  
} :uC9 #H"b  
4^d).{&X  
(Jk[%_b>_  
//获得文件长度 b)E<b{'W  
public long getFileSize()  o|#F@L3i  
{ [,MK)7DU  
int nFileLength = -1; 0"ooHP$1  
try{ tF./Jx]_  
URL url = new URL(siteInfoBean.getSSiteURL()); pF8+< T3y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ELG9ts+5Uj  
httpConnection.setRequestProperty("User-Agent","NetFox"); G%= gCR  
NzeiGj  
Y]uVA`%"b  
int responseCode=httpConnection.getResponseCode(); 5r~hs6H  
if(responseCode>=400) (A=Z,ed  
{ $H]NC-\+>  
processErrorCode(responseCode); aygK$.wos  
return -2; //-2 represent access is error cRNVqMpg  
} GdrVH,j  
S 2W@;XvV  
^\Q%VTM  
String sHeader; r6:e 423  
Y> ~jho  
{Ve`VV5E  
for(int i=1;;i++) i->G {_gH  
{ i XGy*#>V  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); OPogH=vf  
//Utility.log(in.readLine()); rR#wbDr5  
sHeader=httpConnection.getHeaderFieldKey(i); _{eA8J(A<  
if(sHeader!=null) G-;EB  
{ mG0_&'"YIG  
if(sHeader.equals("Content-Length")) m&be55M;  
{ 3"k n5)x  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); BglbQ'6p  
break; {y%@1q%"  
} 5@I/+D  
} "}H2dn2n  
else a0Fq$  
break; -%{+\x2  
} 9U=6l]Np  
} =A$d)&  
catch(IOException e){e.printStackTrace ();} *19a\m=>oi  
catch(Exception e){e.printStackTrace ();} q9a6s {,  
sOS^  
TqOH(= {  
Utility.log(nFileLength); {k[dg0UV  
wx!2/I>  
wrK@1F9!  
return nFileLength; ZA@zs,o%  
} lLglF4  
GxC\Nj#  
raU_Z[  
//保存下载信息(文件指针位置) )p:+!sX(  
private void write_nPos() &n0Ag]$P  
{ =Mxu,A  
try{ /g!Xe]Ss  
output = new DataOutputStream(new FileOutputStream(tmpFile)); :m/qR74+"  
output.writeInt(nStartPos.length); eIN0 T;1T  
for(int i=0;i<nStartPos.length;i++) P7l3ZH( g  
{ C',uY7}<  
// output.writeLong(nPos); pr,1pqiAf  
output.writeLong(fileSplitterFetch.nStartPos); AI9922}*  
output.writeLong(fileSplitterFetch.nEndPos); kXlI *h  
} \|M[W~8  
output.close(); z3>4 xn{  
} ap"pQ[t;  
catch(IOException e){e.printStackTrace ();} [~`p~@\+  
catch(Exception e){e.printStackTrace ();} P4|A\|t  
} 141xi;o  
bUSa#pNO>  
l7IF9b$c  
//读取保存的下载信息(文件指针位置) 2pP"dX  
private void read_nPos() k5+ Fxf  
{ t'.:"H8BI  
try{ }"v#_vJfz7  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >}JEX]V  
int nCount = input.readInt(); }LLQ +  
nStartPos = new long[nCount]; 'SrDc'?  
nEndPos = new long[nCount]; 4nh0bIN1  
for(int i=0;i<nStartPos.length;i++) HYY+Fv5  
{ dNov= w  
nStartPos = input.readLong(); [6/8O  
nEndPos = input.readLong(); NZFUCD)  
} :()K2<E  
input.close(); \(`C*d  
} L&uPNcZ`-  
catch(IOException e){e.printStackTrace ();} IMzt1l =7  
catch(Exception e){e.printStackTrace ();} =e9<.{]S/  
} a( N;| <  
@uG/2'B(  
;z+}|>!  
private void processErrorCode(int nErrorCode) 78?cCj{e  
{ j8rxhToC  
System.err.println("Error Code : " + nErrorCode); Vh]=sd<F  
} X gtn}7N.  
L;+e)I]  
CUBL/U\=  
//停止文件下载 + [$Td%6  
public void siteStop() jyidNPLm4  
{ t2rZ%[O  
bStop = true; r@wE?hK  
for(int i=0;i<nStartPos.length;i++) %*IH~/Ld;]  
fileSplitterFetch.splitterStop(); `49!di[  
3Ljj|5.q  
Lc "{ePFh  
} ZU2D.Kf_:  
} wnQi5P+  
//负责部分文件的抓取 >enP~uW[#  
**FileSplitterFetch.java ,_=LV  
*/ Z^mQb2e.  
package NetFox; 4\uq$.f-  
~SsfkM"  
|t;Ktl  
import java.io.*; nB5^  
import java.net.*; g9d/nR X&  
D}-HWJQA3  
P*hYh5a  
public class FileSplitterFetch extends Thread { !FB2\hiM  
1CV ?  
9[`\ZGWD  
String sURL; //File URL XIl#0-E0X  
long nStartPos; //File Snippet Start Position {>TAnb?n  
long nEndPos; //File Snippet End Position N4{g[[ T  
int nThreadID; //Thread's ID A.r.tf}:  
boolean bDownOver = false; //Downing is over m2ph8KC  
boolean bStop = false; //Stop identical O(_f&a  
FileAccessI fileAccessI = null; //File Access interface :?i,!0#"  
F*N Hy.Y  
(/t{z =  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException vy>(?[  
{ gT,iH.  
this.sURL = sURL; r]wy-GT  
this.nStartPos = nStart; -OKXfN]  
this.nEndPos = nEnd; U<'z, Px6  
nThreadID = id; w[ )HQ1K  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 DQ0 UY  
} JxM32?Rm*w  
`/WOP`'zM  
r"\<+$ 7  
public void run() GW%!?mJ  
{ *GdJ<B$  
while(nStartPos < nEndPos && !bStop) %0 U@k!lP  
{ WM=)K1p0u  
$%ww$3  
L[Wi[S6=)g  
try{ FEBRUk6.h  
URL url = new URL(sURL); tlI]);iE,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k9VWyq__  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]J/;Xp  
String sProperty = "bytes="+nStartPos+"-"; 6k+tO%{~  
httpConnection.setRequestProperty("RANGE",sProperty); !L/.[:X  
Utility.log(sProperty); {`Mb),G  
)]m4FC:  
Uf?+oc'{  
InputStream input = httpConnection.getInputStream(); ?3v-ppw%  
//logResponseHead(httpConnection); QPvWdjf#mM  
)[yKO  
I^D*) z   
byte[] b = new byte[1024]; f&&Ao  
int nRead; C?6q ]k]r  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -:b<~S[  
{ 2t=&h|6EW  
nStartPos += fileAccessI.write(b,0,nRead); ?4Rq +  
//if(nThreadID == 1) LVL#qNIu  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); : >$v@d  
} (?.h<v1}  
EvA8<o  
" ;\EU4R  
Utility.log("Thread " + nThreadID + " is over!"); +hH7|:JQ  
bDownOver = true; &@PAv5iNf  
//nPos = fileAccessI.write (b,0,nRead); i A'p!l |P  
} 'p%w_VbI  
catch(Exception e){e.printStackTrace ();} 90wnwz  
} s;tI?kR>%  
} DnF|wS  
-YipPo"a  
0-d&R@lX.  
//打印回应的头信息 1d&Q E\2}  
public void logResponseHead(HttpURLConnection con) q s9r$o.\l  
{ ~BBh4t&  
for(int i=1;;i++) V9  EC@)  
{ NpA%7Q~B$,  
String header=con.getHeaderFieldKey(i); NpGz y`&b  
if(header!=null) |m$]I4Jr  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); PK_2  
Utility.log(header+" : "+con.getHeaderField(header)); Y)M-?|4  
else Ow-;WO_HQ  
break; wMM1Q/-#  
} /5\{(=0  
} &kH7_Lz  
oL9ELtb ]s  
Kf6D$}  
public void splitterStop() S7R*R}  
{ UK[+I]I p  
bStop = true; iciRlx.$c  
} z qd1G(tO  
MA7&fNjB  
#vPk XcP  
} 7? ="{;  
Ti#x62X{  
m x2Ov u  
/* 7~H$p X  
**FileAccess.java ;$4: &T  
*//文件访问(定位,写) QCfR2Nn}  
package NetFox; i \.&8  
import java.io.*; ^4{{ +G)j  
5ai$W`6  
yv> 6u7  
public class FileAccessI implements Serializable{ ]:4\ rBR3  
@ZcI]G%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !zfV (&  
RandomAccessFile oSavedFile; j<L!(6B  
long nPos; JS&;7Z$KX  
sWP_fb1  
#}UI  
public FileAccessI() throws IOException R ggZ'.\  
{ ~jC$C2A0  
this("",0); &Hl w2^  
} ZP.~Y;Ch;-  
+n|@'= ]  
tYUo;V  
public FileAccessI(String sName,long nPos) throws IOException 9}d^ll&  
{ AxCFZf5  
oSavedFile = new RandomAccessFile(sName,"rw"); asbFNJG{  
this.nPos = nPos; *+J`Yk7}  
oSavedFile.seek(nPos); O+~@ S~  
} \Oe8h#%  
o~VZ%B  
`Z (`  
public synchronized int write(byte[] b,int nStart,int nLen) Ja%isIdh  
{ X@~R<  
int n = -1; $oi8 <8Y  
try{ Ga;Lm?6-  
oSavedFile.write(b,nStart,nLen); $ Vsf? ID  
n = nLen; qwd T= H  
} v=YI%{tx)  
catch(IOException e) Gn% k#  
{ ,Aq |IH3j  
e.printStackTrace (); rX|{nb  
} W!a'KI'  
FOuPj+}F  
B)&z% +  
return n; 0-Wv$o[  
} v&"sTcS|  
tSunO-\y  
V:1_k"zQ  
} :U'Oc3l#Y  
c+UZ UgP  
~fz9PoC  
/* m =MM  
**SiteInfoBean.java -QQU>_  
*/ f5#VU7=1F2  
package NetFox; %){)/~e&  
Gg5>~"pb  
.[vYT.LE  
public class SiteInfoBean { Z7dVy8J  
)oMMDH w\  
M`|E)Y  
private String sSiteURL; //Site's URL lZD"7om  
private String sFilePath; //Saved File's Path C)ebZ3  
private String sFileName; //Saved File's Name -$(2Z[  
private int nSplitter; //Count of Splited Downloading File 9Ljd or  
{Ytqs(`   
v <E#`4{  
public SiteInfoBean() V}q=!zz  
{//nSplitter的缺省值为5 /6#i$\ j  
//default value of nSplitter is 5 p+:MZP -%(  
this("","","",5); `q?@ Ob&  
} sq}uq![?M  
]hY4 MS  
WNiM&iU  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) W%K=N-kE_  
{ ?qczMck_  
sSiteURL= sURL; j$khGR!  
sFilePath = sPath; f,8PPJ:,  
sFileName = sName; c.;<+dYsm*  
this.nSplitter = nSpiltter; ob7hNo#  
[vcSt5R=  
uSNlI78D  
} 8Y~\:3&1<  
~G8haN4  
*En4~;l  
public String getSSiteURL() I<$m%  
{ gPy}.g{tH$  
return sSiteURL; !F# ^Peb  
} e `IL7$  
&=v5M9GR]  
;C+ _KS  
public void setSSiteURL(String value) Q%_MO`<]$  
{ ROr|  <  
sSiteURL = value; 6Vy4]jdT5  
} wZ~eE'zx+  
nbSu|sX~r5  
HmRmZ3~  
public String getSFilePath() v'u}%FC  
{ XM?C7/^k  
return sFilePath; 3qrjb]E%}  
} a*Ng+~5)6  
p/Lk'h~  
Y q-7!  
public void setSFilePath(String value) )F%zT[Auph  
{ !+ ??3-q  
sFilePath = value; :.W</o~\s  
} v^1n.l %E  
4XArpKA  
u$y5?n|  
public String getSFileName() lgh+\pj  
{ 3b1%^@,ACy  
return sFileName; RRR=R]  
} G'6f6i|<I@  
"l 1z@  
C 4hvk'=  
public void setSFileName(String value) lxOUV?m^N  
{ p!2t/XIM  
sFileName = value; tcj3x<  
} 3Cl&1K #5  
420yaw/":  
3("E5lI(g:  
public int getNSplitter() r[RO"Ej"  
{ U7d05y'  
return nSplitter; 2B=+p83<  
} {#}?-X  
S)G*+)  
<+e&E9;>6  
public void setNSplitter(int nCount) q|N4d9/b  
{ ,PZ[CX;H@  
nSplitter = nCount; ]gB:ht  
} q%8Ck)xz  
} }y#aO  
9c=`Q5  
>d5L4&r  
/* km9@*@)  
**Utility.java ]d50J@W c  
*/ (, 2U?p  
package NetFox; _ }:#T8h  
e^Glgaf  
Ky6 d{|H  
public class Utility { VyxX5Lrj  
F=~LVaF/_  
g 9:V00^<  
public Utility() .0#{ ?R,  
{ Yjp*T:6  
k= oCpXq^  
s, ;L6nX"  
} 5D`!Tu3  
R(<_p"9(  
//线程睡眠 6gJc?+  
public static void sleep(int nSecond) gL6.,4q+1  
{ rJ fO/WK  
try{ Ihg1%.^V\  
Thread.sleep(nSecond); y_N h5  
} PW GN UNc  
catch(Exception e)  '' Pfs<!  
{ ?/^x)Nm  
e.printStackTrace (); C+Pw  
} lsRW.h,  
} +"Mlj$O  
HWi: CDgm  
//日志 H0Ck%5  
public static void log(String sMsg) ^ lM.lS>)  
{ wb/@g=` d  
System.err.println(sMsg);  eAbp5}B  
} m15> ^i^W  
wGAeOD  
m$bDWxm#e  
public static void log(int sMsg) ) >8k8E  
{ ,kw:g&A  
System.err.println(sMsg); m0+'BC{$u  
} Q(ec>+oi  
} 5u&hp  
"y$s`n4Mj  
d m$iiRY  
/* [rtMx8T  
**TestMethod.java k|[86<&[  
*/ geEETb} +y  
package NetFox; $' >|r]  
 Ts 1  
QeipfK+me  
public class TestMethod { 8VR! Y0`e  
k{w  
QKtVwsz +  
public TestMethod() )SsO,E+t=U  
{ ///xx/weblogic60b2_win.exe #FsoK*F  
try{ ,ku3;58O<  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); A!fRpN  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); TrmrA$5f  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0%>_fMaA  
fileFetch.start(); f l*O)r  
} H"J>wIuGX  
catch(Exception e){e.printStackTrace ();} Ur2) ];WZ  
3IDX3cM9  
!DNk!]|  
} LXx`Vk>ky  
e? n8S  
&<oDl _^  
public static void main(String[] args) #i0f}&  
{ QsH?qI&2jp  
new TestMethod(); eCXw8  
} :}p<Hq 8Z  
} NGOyd1$7N  
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