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http断点续传简单实现(java)

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/* Gefnk!;;  
**SiteFileFetch.java w%3Fg~Up  
*/ \E$1lc  
package NetFox; ,u}<Ws8N  
import java.io.*; OL=ET)Y  
import java.net.*; e&$p-0DmT|  
l:Dn3Q  
k,,!P""  
public class SiteFileFetch extends Thread { 731h ~x!u  
pbDw Lo]  
xH<'GB)  
SiteInfoBean siteInfoBean = null; //文件信息Bean +{xMIl_  
long[] nStartPos; //开始位置 d"H<e}D  
long[] nEndPos; //结束位置 _W0OM[  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 aKv[  
long nFileLength; //文件长度 50LHF %  
boolean bFirst = true; //是否第一次取文件 sDLS*467  
boolean bStop = false; //停止标志 :1aL9 fT  
File tmpFile; //文件下载的临时信息 %K h2E2Pe  
DataOutputStream output; //输出到文件的输出流 A\".t=+7  
~`t%M?l  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) qyg*n>nt  
public SiteFileFetch(SiteInfoBean bean) throws IOException -3.UE^W2  
{ 61/)l0 <;  
siteInfoBean = bean; ybZ}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); h?0F-6z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); g1ZV&X=2  
if(tmpFile.exists ()) eo1&.FQu  
{ XzT78  
bFirst = false; IQ3n@  
read_nPos(); @Ex;9F,Q  
} ?k{|Lk  
else gyi)T?uS)  
{ @Q;i.u{V  
nStartPos = new long[bean.getNSplitter()]; P*pbwV#|  
nEndPos = new long[bean.getNSplitter()]; r\(v+cd  
} S:ls[9G[3  
I"ca+4]  
=op`fn%  
!|B3i_n  
} u3]Uxy  
br0u@G  
p?Ed- S  
public void run() \n#]%X5c  
{ Hqvc7-c6  
//获得文件长度 QU:EY'2  
//分割文件 r4E`'o[  
//实例FileSplitterFetch ^vpIZjN  
//启动FileSplitterFetch线程 n`%2Mj c  
//等待子线程返回 bxAsV/j  
try{ ZB828T3  
if(bFirst) ZA0i)(j*Mn  
{ 5U%MoH  
nFileLength = getFileSize(); E;6~R M:  
if(nFileLength == -1) uie~'K\y  
{ np\st7&f6  
System.err.println("File Length is not known!"); dCE\^q[{  
} nO~b=qO  
else if(nFileLength == -2) dM Y 0K  
{ /D0RC  
System.err.println("File is not access!"); <EtUnj:qK8  
}  ]nUR;8  
else cTM$ZNin  
{ vYDSu.C@a  
for(int i=0;i<nStartPos.length;i++) &vCeLh:s  
{ eUt=n)*`  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); );nz4/V  
} "K,bH  
for(int i=0;i<nEndPos.length-1;i++) UP\C"\  
{ YMT8p\ #rp  
nEndPos = nStartPos[i+1]; "OO96F  
} U^[<  
nEndPos[nEndPos.length-1] = nFileLength; %JQ~!3  
} 6O9iEc,HM  
} czI{qi5N  
mj@31YW  
n@ 4@,  
//启动子线程 4r\*@rq  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; tQrS3Hz'nA  
for(int i=0;i<nStartPos.length;i++) .`,F  
{ / |GT\X4o  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), KbAR_T1n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &y7 0  
nStartPos,nEndPos,i); L\YKdUL  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G$C }?"l  
fileSplitterFetch.start(); ;7rd;zJ  
} 5SUN.%y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r} Lb3`'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Edw2W8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", QBoFpxh=  
nEndPos = " + nFileLength); -/>9c-F  
// fileSplitterFetch[nPos.length-1].start(); "V4Q2T T  
T7 {<arL$  
cGNvEM(4AV  
//等待子线程结束 7:>sc]Z  
//int count = 0; gE\b 982  
//是否结束while循环 I5qM.@%zB  
boolean breakWhile = false; 86%%n?"}  
~wOTjz  
["a"x>X&  
while(!bStop) ?6f7ld5  
{ 9@n diu[  
write_nPos(); |jT2W  
Utility.sleep(500); x? N.WABr;  
breakWhile = true; C/G]v*MBQ  
"(,2L,Zh  
f2yq8/J8.  
for(int i=0;i<nStartPos.length;i++) N5? IpE  
{ llq*T"7  
if(!fileSplitterFetch.bDownOver) gWOt]D&#/  
{ #{$1z;i?f  
breakWhile = false; T~Ly^|Ihz  
break; wiJRCH  
} 5 6DoO'  
} qbiK^g R  
if(breakWhile) X4wH/q^  
break; ZQAO"huk]  
,[isib3  
@'i+ff\  
//count++; ;F5"}x  
//if(count>4) <~{du ?4n  
// siteStop(); *%\mZ,s"  
} :"QfF@Z{  
NQX>Qh 2  
o0ZBi|U\4  
System.err.println("文件下载结束!"); v vq/  
} sb^mLH] 3  
catch(Exception e){e.printStackTrace ();} l!?yu]Yon  
} F2;:vTA>  
OQp, 3 M{_  
|0sPka/u16  
//获得文件长度 #G#g|x*V  
public long getFileSize() R,t$"bOd  
{ S2K#[mDG  
int nFileLength = -1; %2"J:0j  
try{ E!J=8C.:  
URL url = new URL(siteInfoBean.getSSiteURL()); PLA#!$c7q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _c2WqQ-05  
httpConnection.setRequestProperty("User-Agent","NetFox"); `G!M>h@  
~y /!fnv  
A]o4Mf0>I  
int responseCode=httpConnection.getResponseCode(); hJ*Ihwn|  
if(responseCode>=400) B=n[)"5fBO  
{ SV.z>p  
processErrorCode(responseCode); 5u$D/* Eb  
return -2; //-2 represent access is error &!L:"]=+  
} =']3(6*  
V`#.7uUP  
C\}/"  
String sHeader; 8 #}D : (  
tfYB_N  
|3shc,7  
for(int i=1;;i++) bgF^(T35  
{ BRS#Fl:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 'yY>as  
//Utility.log(in.readLine()); lCIDBBjy^  
sHeader=httpConnection.getHeaderFieldKey(i); XNehPZYS  
if(sHeader!=null) GZ3 ]N  
{ }Fa%%}  
if(sHeader.equals("Content-Length")) J?&l*_m;t  
{ +=BAslk  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;65D  
break; y(W|eBe  
} KxzYfH  
} `~# < &w  
else =0 qpVFvU  
break; {"S6\%=  
} D`yEwpV^  
} J2VTo: In  
catch(IOException e){e.printStackTrace ();} mr:CuqJ  
catch(Exception e){e.printStackTrace ();} W*N$'%  
IH9.F  
By)u-)g9  
Utility.log(nFileLength); y<:<$22O  
5/MKzoB  
^D{lPu 3  
return nFileLength; -/P\"c  
} .}B(&*9,v  
X4|4QgY  
\%0n}.A  
//保存下载信息(文件指针位置) r'GP$0rr9!  
private void write_nPos() j%IF2p2  
{ Oy57$  
try{ Yg9joNBh  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @FO) 0  
output.writeInt(nStartPos.length); *L4`$@l8  
for(int i=0;i<nStartPos.length;i++) Lel|,mc`k2  
{ QDx$==Fo  
// output.writeLong(nPos); )e|=mtp  
output.writeLong(fileSplitterFetch.nStartPos); uXjP`/R|  
output.writeLong(fileSplitterFetch.nEndPos); em{(4!W>  
} P{Lf5V9# <  
output.close(); ocz G|_  
} !C4!LZ0A  
catch(IOException e){e.printStackTrace ();} "N?+VkZEv  
catch(Exception e){e.printStackTrace ();} u #w29Pm  
} oU*45B`"  
G\de2Q"d:O  
v'!a\b`9  
//读取保存的下载信息(文件指针位置) ^T::-pN*  
private void read_nPos() iBTYY{-wF  
{ "A$!, PX6  
try{ t. ='/`!N  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); **3 z;58i  
int nCount = input.readInt(); 9iUrnG*  
nStartPos = new long[nCount]; vw,rF`LjZ  
nEndPos = new long[nCount]; "VG+1r+]4  
for(int i=0;i<nStartPos.length;i++) %D g0fL  
{ ^(HUGl_  
nStartPos = input.readLong(); }7E^ZZ]f  
nEndPos = input.readLong(); ~*A8+@ \R  
} 4)|8Eu[p7  
input.close(); kE9esC 3  
} !K f#@0E..  
catch(IOException e){e.printStackTrace ();} aFz5leD  
catch(Exception e){e.printStackTrace ();} Gs+3e8  
} Eow_&#WW;P  
a2'^8;U*_  
L|P5=/d  
private void processErrorCode(int nErrorCode) d?`ny#,GB  
{ aE;le{|!({  
System.err.println("Error Code : " + nErrorCode); eq(am%3~  
} 0j"8@<  
}X*Riu7gk  
D=m 'pL/pl  
//停止文件下载 #P l~R  
public void siteStop() Ms~{9?  
{ z|EEVNFd&  
bStop = true; Sz- J y:j  
for(int i=0;i<nStartPos.length;i++) $6OkIP.  
fileSplitterFetch.splitterStop(); WmY``  
~cTN~<{dq  
F *FwRj  
} 3RLFp\i"s  
} ^?7`;/  
//负责部分文件的抓取 ;r_F[E2z  
**FileSplitterFetch.java a,2'+Tlo  
*/ 8V^oP] Y  
package NetFox; x8S7oO7  
-gSUjP  
'EDda  
import java.io.*; h$4Hw+Yxs]  
import java.net.*; x=ul&|^7D  
qlL`jWJ  
TT =b79k  
public class FileSplitterFetch extends Thread { ]E\n9X-{  
F a'k0/_j  
T!Hb{Cg*  
String sURL; //File URL [0"'T[ok  
long nStartPos; //File Snippet Start Position Llr>9(|  
long nEndPos; //File Snippet End Position Vn*tp bz  
int nThreadID; //Thread's ID > ;/l)qk,  
boolean bDownOver = false; //Downing is over Zt.'K(]2h  
boolean bStop = false; //Stop identical Y. ,Kl~  
FileAccessI fileAccessI = null; //File Access interface xx[9~z=d  
ZI=%JU(  
sZx/Ee   
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException At-U2a#J{  
{ $ s9Vrw0Z  
this.sURL = sURL; 'nXl>  
this.nStartPos = nStart; C(00<~JC  
this.nEndPos = nEnd; T:5fc2Ngv  
nThreadID = id; Z .92y  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $2W%2rZ  
} (p2K36,9m  
:x tXQza"-  
:yUEkm8  
public void run() /YZr~|65  
{ xuqv6b.  
while(nStartPos < nEndPos && !bStop) a)wJT`xu  
{  ,%uo6%  
eeyHy"@  
i_j[?.?X}  
try{ ;kY(<{2  
URL url = new URL(sURL); &*+'>UEe5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "rx-_uK*  
httpConnection.setRequestProperty("User-Agent","NetFox"); C?lcGt!H  
String sProperty = "bytes="+nStartPos+"-"; mV3cp rRqv  
httpConnection.setRequestProperty("RANGE",sProperty); _lamn }(x0  
Utility.log(sProperty); V5UF3'3;}  
["h5!vj  
ogyTO|V=  
InputStream input = httpConnection.getInputStream();  Vh_P/C+  
//logResponseHead(httpConnection); i\,-oO  
3j\1S1  
,6-:VIHQ  
byte[] b = new byte[1024]; Wk)OkIFR  
int nRead; \O2Rhz  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 3B84^>U<  
{ U4d:] z  
nStartPos += fileAccessI.write(b,0,nRead); IZpP[hov  
//if(nThreadID == 1) vEJWFoeEFm  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 03q 5e  
} < jJ  
OX\A|$GS  
3yVMXK  
Utility.log("Thread " + nThreadID + " is over!"); 59h)-^!  
bDownOver = true; wB.&}p9p  
//nPos = fileAccessI.write (b,0,nRead); C{U?0!^  
} k?+?v?I =  
catch(Exception e){e.printStackTrace ();} .yz}ROmN^  
} E=nIRG|g  
} vSEuk}pk  
sS*3=Yh  
E7rDa1  
//打印回应的头信息 4 o Fel.o  
public void logResponseHead(HttpURLConnection con) <0Xf9a8>  
{ \W~ N  
for(int i=1;;i++) _h{C_;a[_  
{ sB7# ~p A  
String header=con.getHeaderFieldKey(i); Zy`m!]G]80  
if(header!=null) h2G$@8t}I  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 16 =sij%A  
Utility.log(header+" : "+con.getHeaderField(header)); Sc;BCl{=|  
else 4K\G16'$v  
break; 8Vr%n2M  
} o~`/_ +  
} nLXlU*ES  
\NPmym_ 6J  
VK m&iidU  
public void splitterStop() '=b/6@&  
{ {*G9|#[/@  
bStop = true; qLD ?juas  
} Q'=x|K#xj  
dYJ(!V&  
y [}.yyye  
} IG2r#N|C#  
F3On?x)  
Te"ioU?.  
/* $a.JSXyxL  
**FileAccess.java h9}+l  
*//文件访问(定位,写) v[1aW v:  
package NetFox; :D~DU,e'  
import java.io.*; -t!~%_WCv  
'jWr<]3  
| )K8N<n  
public class FileAccessI implements Serializable{ V% rzk*LA  
@>,^":`#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]cHgleHQ  
RandomAccessFile oSavedFile; >g1~CEMN#  
long nPos; q'T4w!V(V  
>mwlsL~X  
marQNZ  
public FileAccessI() throws IOException hOjk3 k  
{ j#!IuH\]  
this("",0); cr7 }^s  
} gb[5&> (#  
M?1Y,5  
f%][}NN)Xr  
public FileAccessI(String sName,long nPos) throws IOException 6]K_m(F  
{ %O|iE M  
oSavedFile = new RandomAccessFile(sName,"rw"); Ag-(5:  
this.nPos = nPos; 8\&X2[oAD  
oSavedFile.seek(nPos); "g5^_UP  
} <? q?Mn  
*#,7d"6W5  
"H'B*vc-  
public synchronized int write(byte[] b,int nStart,int nLen) J!dm-L  
{ D+lAhEN  
int n = -1; .s?L^Z^  
try{ #NEE7'&S  
oSavedFile.write(b,nStart,nLen); L>jY.d2w=K  
n = nLen; {'7B6  
} - YEZ]:"  
catch(IOException e) ha]VWt%}  
{ ]E5o1eeg  
e.printStackTrace (); xQ f*  
} BtkOnbz8X  
Ri<u/ ]oR"  
)1?y 8_B  
return n; X-bcQ@Oj  
} r8`ffH  
|mZxfI  
0"jY.*_EW  
} xG~P+n7t5$  
ER%^!xA  
.]8ZwAs=&  
/* d[iQ` YW5  
**SiteInfoBean.java bV^rsJm  
*/ x]}^v#  
package NetFox; S|Q@:r"  
uy>q7C  
lU8l}Ndz"  
public class SiteInfoBean { }7b%HTF=  
(~p< P+  
; 5*&xz  
private String sSiteURL; //Site's URL )3cAQ'w  
private String sFilePath; //Saved File's Path j`{?OYD  
private String sFileName; //Saved File's Name ">\?&0  
private int nSplitter; //Count of Splited Downloading File 'g}!  
<$D`Z-6  
sA+ }TNhq  
public SiteInfoBean() /:cd\A}  
{//nSplitter的缺省值为5 P\E<9*V  
//default value of nSplitter is 5 ]%;:7?5l  
this("","","",5); 9)l$ aBa  
} #|uCgdi  
tHU2/V:R  
U7?;UCmX  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #]\Uk,mhZB  
{ ^ gdaa>L  
sSiteURL= sURL; ) ;EBz  
sFilePath = sPath; tj'\tW+s'  
sFileName = sName;  on4HKeO  
this.nSplitter = nSpiltter; iDpSj!x/_  
mVj9, q0  
./\@Km?  
} y'3rNa]G1  
2R[:]-b  
sU=H&D99  
public String getSSiteURL() D(~U6SR  
{ Kew@&j~  
return sSiteURL; z}.e]|b^H  
} x'8x   
p'Y^ X  
})'B<vq  
public void setSSiteURL(String value) ,V7nzhA2  
{ M`0V~P`^  
sSiteURL = value; S;Fi?M  
} {B~QQMEow  
9=s<Ld  
N:^n('U&j  
public String getSFilePath() kXViWOXU^  
{ EfqX y>W  
return sFilePath; N"Z{5A  
} t$`r4Lb9/  
&j;wCvE4+  
ez7A4>/  
public void setSFilePath(String value) Mc)}\{J  
{ aEB_#1  
sFilePath = value; <;lkUU(WT2  
} [|v][Hwv  
\P[Y`LYL  
)j6~Wy@4  
public String getSFileName() ]>!K3kB  
{ }H53~@WP>  
return sFileName; Lw1Yvtn  
} %mW{n8W3{  
59LG{R2  
Usvl}{L[  
public void setSFileName(String value) d z|or9&  
{ 28-RC>,@}  
sFileName = value; {$oj.V 4  
} <NMEGit  
b 1c y$I  
#`^}PuQ  
public int getNSplitter() (&r. w  
{ [+^1.N  
return nSplitter; p:&8sO!m  
} "MeVE#O  
-abt:or  
*tA1az-jO  
public void setNSplitter(int nCount) a .#)G[*  
{ 9+|$$)  
nSplitter = nCount; Q3'llOx  
} +w`2kv  
} jRa43ck  
~g91Pr   
#<fRE"v:Q  
/* ZtNN<7  
**Utility.java (g]!J_Z"  
*/ 8\^R~K`sY  
package NetFox; Xg6Jh``  
9X6h  
Ov@gh kr  
public class Utility { 2Ah#<k-gC;  
{p2!|A&a  
cVv=*81\  
public Utility() `bq<$e  
{ w7L{_aom  
b! t0w{^w  
rI{; IDV  
} Z-%\ <zT  
ic:zsuEm  
//线程睡眠 G[PtkPSJ  
public static void sleep(int nSecond) ScOK)nL"  
{ s S+MqBh&I  
try{ }rUN_.n4z  
Thread.sleep(nSecond); |"}FXa O  
} "S[450%  
catch(Exception e) (MM]N=Tw4  
{ yZY\MB/  
e.printStackTrace (); qz_7%c]K[  
} LBeF&sb6  
} 6q\bB  
w{8xpAqm  
//日志 j^sg6.Z*  
public static void log(String sMsg) ;fTKfa  
{ q>_.[+6  
System.err.println(sMsg); I9A~Ye 5O&  
} P8:dU(nlW  
$S6`}3  
s[>,X#7 y  
public static void log(int sMsg) 7~h<$8Y(T  
{ C^Yb\N}S  
System.err.println(sMsg); -m zIT4  
} +HpA:]#Y  
}  tU5zF.%  
a=_g*OK}D  
@D[_}JE  
/* Y1\}5k{>  
**TestMethod.java &&8x%Pml  
*/ !qQl@j O  
package NetFox; #P9~}JB3,  
)u&|_&g{}J  
d'gfQlDny  
public class TestMethod { nF]W,@u"h  
R_cA:3qc~  
x;KOqfawv  
public TestMethod() AR%4D3Dma  
{ ///xx/weblogic60b2_win.exe Tk[ $5u*,  
try{ p$c6<'UqH  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Dj?> <@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [85spub&}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ( $MlXBI  
fileFetch.start(); @gEUm_#HTs  
} D/gw .XYL  
catch(Exception e){e.printStackTrace ();} .hb:s,0mP  
5 V~oIL  
?4}h&/  
} xIW3={b3  
wU36sCo  
Vm(y7}Aq{  
public static void main(String[] args) Ml{,  
{ p`dU2gV  
new TestMethod(); 2a)xTA#  
} s\(k<Ks  
} &BLJT9Frx  
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