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http断点续传简单实现(java)

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/* Q#zU0K*^  
**SiteFileFetch.java W<>R;~)  
*/ H @5dj}  
package NetFox; vOo-jUKs  
import java.io.*; NK6 ~qWsu  
import java.net.*; zx7A}rs3oX  
PwU<RKAE  
X8y :=k,E  
public class SiteFileFetch extends Thread { m2[]`Ir^@  
3L:SJskYR  
mwO9`AU;  
SiteInfoBean siteInfoBean = null; //文件信息Bean ujS C  
long[] nStartPos; //开始位置 w_#C8}2  
long[] nEndPos; //结束位置 ){*9$486  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 fLZ mQO  
long nFileLength; //文件长度 u4h.\ul8%  
boolean bFirst = true; //是否第一次取文件 = ( 4l  
boolean bStop = false; //停止标志 Vp&"[rC_z  
File tmpFile; //文件下载的临时信息 h?p!uQ  
DataOutputStream output; //输出到文件的输出流 N"s"^}M\  
mC} b>\  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) wizLA0W  
public SiteFileFetch(SiteInfoBean bean) throws IOException eI98J"h%?  
{ @*BVS'\  
siteInfoBean = bean; z||FmL{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ||Vx:(d7D&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Qt>Bvu Q  
if(tmpFile.exists ()) x27$h)R0v  
{ ;$3e pP  
bFirst = false; T_[  
read_nPos(); NZz^*Ela  
} hWi2S!*Y  
else m-]F]c=)w<  
{ p ^ ONJL  
nStartPos = new long[bean.getNSplitter()]; 80K"u[  
nEndPos = new long[bean.getNSplitter()]; eW;c 3<  
} r4Xaa<  
S 9|^VU  
Mavid kS  
\%_sL#?  
} b%7zu}F  
b9VI(s>  
}Z)YK}_1  
public void run() Q w)U  
{ w5=<}1`St  
//获得文件长度 )JY#8,{w  
//分割文件 ;@qQ^!g2  
//实例FileSplitterFetch ^%O$7*  
//启动FileSplitterFetch线程 <Ok7 -:OxA  
//等待子线程返回 }U?:al/m  
try{ o1thGttVDg  
if(bFirst) [9yd29pQ]  
{ ]e$n;tuW  
nFileLength = getFileSize(); .E;}.X  
if(nFileLength == -1) Ld 0j!II(  
{ `4wy *!]  
System.err.println("File Length is not known!"); 0-p %.}GE  
} 5t|$Yt[  
else if(nFileLength == -2) LI>Bl  
{ <?%49  
System.err.println("File is not access!"); :XOjS[wBm  
} %4})_h?j  
else KQ0f2?  
{ udPLWrPF\  
for(int i=0;i<nStartPos.length;i++) pm2]  
{ ra8AUj~RX  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); $3xDjiBb  
} h-fm)1S_  
for(int i=0;i<nEndPos.length-1;i++) }\1V%c  
{ Nz:p(X!  
nEndPos = nStartPos[i+1]; P!gY&>EU  
} |@VhR(^O$  
nEndPos[nEndPos.length-1] = nFileLength; $."F z x  
} #<G:&  
} ,{_56j^d,  
SeuDJxqopD  
!&5|:96o  
//启动子线程 89t"2|9 u  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; /Mj|Px%  
for(int i=0;i<nStartPos.length;i++) 2fXwJG'  
{ 8! /ue.T  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Zzmo7kFx3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7!;zkou  
nStartPos,nEndPos,i); V P(JV  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7Kpv fyL{  
fileSplitterFetch.start(); 2InM(p7j~K  
} u+c2 m  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z\YLO%Mm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Mm!;+bM%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >8&fFq  
nEndPos = " + nFileLength); n8JM 0 U-  
// fileSplitterFetch[nPos.length-1].start(); aSI%!Vg.  
i=&]%T6Qk  
)1 QOA  
//等待子线程结束 9A87vs4[  
//int count = 0; / S@iF  
//是否结束while循环 R G~GVf  
boolean breakWhile = false; di7cCn  
kOC0d,  
-j1]H"-  
while(!bStop) *?A!`JpJn  
{ 'j!n   
write_nPos(); ]W5p\(1g  
Utility.sleep(500); A\v53AT  
breakWhile = true; dF5y' R'  
|io)?`pj  
[zSt+K;  
for(int i=0;i<nStartPos.length;i++) PEaZ3{-  
{ :ciD!Ly  
if(!fileSplitterFetch.bDownOver) -Ir>pY\!  
{  bDD29  
breakWhile = false; E33WT{H&_'  
break; uo(LZUjPbN  
} 6$l?D^{  
} 24wr=5p]Q  
if(breakWhile) K[x=knFO  
break; KOoV'YSC[(  
8idIJm%y  
@LSX@V   
//count++; u|k_OUTq  
//if(count>4) y qK*E*  
// siteStop(); cucT |y  
} ?}= $zN  
jv6>7@<G  
1=e(g#Ajn\  
System.err.println("文件下载结束!"); lXEn m-_  
} ;|W:,a{kS  
catch(Exception e){e.printStackTrace ();} b|iIdDK  
} &VcO,7 A|  
K /%5\h  
0g; o6Fg  
//获得文件长度 I!Mkss xc  
public long getFileSize() 4N= gl(  
{ &wN}<G e6  
int nFileLength = -1; r%NzKPW'  
try{ Vv+ oq5hf  
URL url = new URL(siteInfoBean.getSSiteURL()); 4n1 g@A=y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {,?Gj@$  
httpConnection.setRequestProperty("User-Agent","NetFox"); +;=>&XR0m  
KHGUR(\Rd6  
)*Wz5x  
int responseCode=httpConnection.getResponseCode(); LI^D\  
if(responseCode>=400) j?g#8L;W\w  
{ QL2 `X2  
processErrorCode(responseCode); "xn,'`a  
return -2; //-2 represent access is error S~&9DQNj  
} "-j96 KD  
x(p/9$.#  
m\E=I5*/  
String sHeader; ^:,wk7  
ooP{Q r  
y=jZ8+M   
for(int i=1;;i++) RD;A  
{ UMT}2d%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); B\l0kiNT  
//Utility.log(in.readLine()); q(4Ny<=,'K  
sHeader=httpConnection.getHeaderFieldKey(i); .u`A4;;Gw  
if(sHeader!=null) {xOzxLB;  
{ \ Co Z+  
if(sHeader.equals("Content-Length")) i6y=3k  
{ e@S\7Ks  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); q8,,[R_  
break; 3#GIZ L}!x  
}  *I}_g4  
} qT&zg@m  
else oel?we6  
break; wD W/?lT&  
} <q Q@OUI   
} E>O@Bv  
catch(IOException e){e.printStackTrace ();} de[NIDA;`  
catch(Exception e){e.printStackTrace ();} 0-57_";%Q  
;%cW[*Dw  
25r3[gX9`  
Utility.log(nFileLength); '@IReMl  
B__e*d:)!m  
.9Dncsnf,`  
return nFileLength; 5@ Hg 4.  
} 9xE_Awlc85  
D9hq$?  
TI0=nfj  
//保存下载信息(文件指针位置) 4 Lz[bI  
private void write_nPos() H+@?K6{h  
{ ~:|V,1  
try{ /b/  6*&  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Og?GYe^_  
output.writeInt(nStartPos.length); NRspi_&4J  
for(int i=0;i<nStartPos.length;i++) Y{Lxo])e  
{ $vn)(zn+  
// output.writeLong(nPos); ;ZMIYFXRqh  
output.writeLong(fileSplitterFetch.nStartPos); P{Q$(rOe  
output.writeLong(fileSplitterFetch.nEndPos); *i!t&s  
} 1u(n[<WtT_  
output.close(); {Z Ld_VGW  
} Hw6 2'%  
catch(IOException e){e.printStackTrace ();} k![H;}W  
catch(Exception e){e.printStackTrace ();} 2 MW7nIEs  
} Z|)1ftcC  
{~G~=sC$  
Ll VbY=EX7  
//读取保存的下载信息(文件指针位置) {<#b@=G  
private void read_nPos() l-x-  
{ |CQ0{1R1  
try{ ]86*k %A  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); H\a\xCP3  
int nCount = input.readInt(); +At0V(  
nStartPos = new long[nCount]; '+'h^  
nEndPos = new long[nCount]; @hrIu" '!  
for(int i=0;i<nStartPos.length;i++) 2OqEyXh  
{ |$+/IxDP  
nStartPos = input.readLong(); @=Dc(5`[  
nEndPos = input.readLong(); `DM)tm3&m  
} W1ndb:  
input.close(); rj?c   
} Ug4o2n0sk  
catch(IOException e){e.printStackTrace ();} 1Tev&J  
catch(Exception e){e.printStackTrace ();} C~. T[Mlu  
} &5G@YQD1e  
q]*jTb  
Md8<IFi9]Q  
private void processErrorCode(int nErrorCode) P8;1,?ou  
{ A]drNFE  
System.err.println("Error Code : " + nErrorCode); WLta{A?  
} 0O-"tP8o  
( )f)  
tCPK_Wws?Z  
//停止文件下载 "5?1S-Vl  
public void siteStop() rhly.f7N=A  
{ 'tU\~3k  
bStop = true; (.L?sDQ</z  
for(int i=0;i<nStartPos.length;i++) >p" U|  
fileSplitterFetch.splitterStop(); p _3xW{I  
'/AX 'U8Y  
)_?h;wh 84  
} 17 0r5  
} 7#7|+%W0  
//负责部分文件的抓取 x"cB8bZ!$  
**FileSplitterFetch.java IYH4@v/#  
*/ 5g$>J)Ry  
package NetFox; 1'8-+?r  
mgM"u94-]  
oTcf[<   
import java.io.*; ;d_<6|*M  
import java.net.*; <=w!:   
!4 lN[  
@O-\s q  
public class FileSplitterFetch extends Thread { ]1W]  
)r)ZmS5O  
8#o2qQ2+  
String sURL; //File URL <aI}+  
long nStartPos; //File Snippet Start Position Cb.M  
long nEndPos; //File Snippet End Position */K]sQZa  
int nThreadID; //Thread's ID (v? rZv  
boolean bDownOver = false; //Downing is over B7'yc`)H  
boolean bStop = false; //Stop identical Q&"oh  
FileAccessI fileAccessI = null; //File Access interface BMV\@Sg  
|sP0z !)b  
6BM$u v4  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException * X}2  
{ ASr@5uFR  
this.sURL = sURL; aygK$.wos  
this.nStartPos = nStart; W"CG&.  
this.nEndPos = nEnd; GdrVH,j  
nThreadID = id; S 2W@;XvV  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 UIht`[(z  
} r6:e 423  
W/~q%\M {  
)UVekkq>Q  
public void run() i->G {_gH  
{ |`{$Ego:  
while(nStartPos < nEndPos && !bStop) i XGy*#>V  
{ OPogH=vf  
>l=^3B,j  
IY mkZ?cW  
try{ _{eA8J(A<  
URL url = new URL(sURL); G-;EB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?du*ITim  
httpConnection.setRequestProperty("User-Agent","NetFox"); m&be55M;  
String sProperty = "bytes="+nStartPos+"-"; 3"k n5)x  
httpConnection.setRequestProperty("RANGE",sProperty);  3SPXJa\i  
Utility.log(sProperty); P:3o}CB1I  
r}:U'zlC{  
5@I/+D  
InputStream input = httpConnection.getInputStream(); "}H2dn2n  
//logResponseHead(httpConnection); a0Fq$  
-%{+\x2  
peOoZdJd  
byte[] b = new byte[1024]; 5P 5Tgk  
int nRead; )e6sg]#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *~b~y7C  
{ {MDM=;WP_  
nStartPos += fileAccessI.write(b,0,nRead); FP*kA_z$  
//if(nThreadID == 1) FT-=^VA\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9RkNRB)8  
} t)~$p#NS  
V{x[^+w7X~  
3a=\$x@  
Utility.log("Thread " + nThreadID + " is over!"); LX=v _}l J  
bDownOver = true; o=xMaA  
//nPos = fileAccessI.write (b,0,nRead); 0<fQjXn  
} BlcsDB =ka  
catch(Exception e){e.printStackTrace ();} ziM@@$ .F  
} kmtkh "  
} Z5EII[=$o  
b@K1;A! S  
}qZ^S9  
//打印回应的头信息 tAujm*|&  
public void logResponseHead(HttpURLConnection con) aH8]$e8_,\  
{ ;W FiMM\  
for(int i=1;;i++) ez5>V7Y  
{ yMD0Tj5ZQ  
String header=con.getHeaderFieldKey(i); L 7LUy$M-<  
if(header!=null) :C,}DyZy  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -pQ?ybQ  
Utility.log(header+" : "+con.getHeaderField(header)); giW9b_  
else =ReSlt  
break; 2pP"dX  
} Q:b0!  
} HNlW.y"  
$'<$:;4b3  
VRSBf;?  
public void splitterStop() *m`x/_y+  
{ M 8(w+h{  
bStop = true; Dqd2e&a\  
} |_ U!i  
q]SH'Wd  
Z$6B}cz<  
} ];N/KHeZ  
PpF`0w=1%l  
|)*!&\Ch  
/* jJ,y+o  
**FileAccess.java ,wv>G]v  
*//文件访问(定位,写) hPCSAo!|  
package NetFox; #MiO4zXgd  
import java.io.*; 8+32hg@^F  
we@*;k@_  
B7o US}M  
public class FileAccessI implements Serializable{ 2=1qmQE  
kqq1;Kd  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 s ;]"LD@  
RandomAccessFile oSavedFile; gi)C5J4  
long nPos; :7(d 6gEL  
7| j rk  
w"O;: `|n  
public FileAccessI() throws IOException ;M\Cw.%![  
{ 5Kk}sxol  
this("",0); L%-ENk  
} +"~*L,ken0  
0 wDhX  
1(% 6X*z  
public FileAccessI(String sName,long nPos) throws IOException Ub4)x  
{ 8H8Q  
oSavedFile = new RandomAccessFile(sName,"rw"); \]\h,Y8  
this.nPos = nPos; ?`6Mfpvj96  
oSavedFile.seek(nPos); &>K|F >7q  
} IMpL+W.  
Ke~!1S8=  
|t;Ktl  
public synchronized int write(byte[] b,int nStart,int nLen) T| R!Aw.  
{ rL?{+S]&^)  
int n = -1; n0%S: (  
try{ 3x z z* <  
oSavedFile.write(b,nStart,nLen); `1y@c"t  
n = nLen; |It{L0=U  
} !d[]Qt%mA  
catch(IOException e) ,JPDPI/a  
{ HW"5MZ8E  
e.printStackTrace (); s:z  
} _)4zm  
BIg2`95F|  
x@pzgqi3  
return n; =CCddLO  
} s5MG#M 9  
'RNj5r  
&lxMVynL  
} LJt5?zQKrW  
,">CPl]  
}wEt=zOJ  
/* 0G+ qF96  
**SiteInfoBean.java 7ks!0``  
*/ /1=x8Sb  
package NetFox; n^l5M^.  
%%h.`p1  
m93{K7O2e  
public class SiteInfoBean { )5o6*(Y  
uOZSX.o^  
XSx'@ qH  
private String sSiteURL; //Site's URL 0$U\H>r  
private String sFilePath; //Saved File's Path l^$U~OB8k  
private String sFileName; //Saved File's Name M.C`nI4  
private int nSplitter; //Count of Splited Downloading File zW.Ltz  
aghlYcPg  
y'JJ#7O=  
public SiteInfoBean() zhyf}Ta'  
{//nSplitter的缺省值为5 2j1HN  
//default value of nSplitter is 5 4e?cW&  
this("","","",5); :&E~~EUW  
} eQqCRXx  
VjZb\ d4  
#ZHKq7  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 6r[pOl:  
{ I^D*) z   
sSiteURL= sURL; 5D3&6DCH  
sFilePath = sPath; M[_Ptqjb  
sFileName = sName; 'l-VWqR-  
this.nSplitter = nSpiltter; ?4Rq +  
LVL#qNIu  
(?.h<v1}  
} ?b(DDQMf  
M,Lq4bz  
+hH7|:JQ  
public String getSSiteURL() &@PAv5iNf  
{ RGY#0.Z}  
return sSiteURL; Y$qjQ1jF+  
} Ct3+ga$  
"# Q"gC.K  
ER4#5gd  
public void setSSiteURL(String value) 7EL0!:Pp3  
{ X'2%'z<  
sSiteURL = value; *2YWvGc  
} 0zA:?}  
'6T  *b  
5xH*&GpL7  
public String getSFilePath() i2LN`5k  
{ |(Xxi  
return sFilePath; HEK?z|Ne  
} Y`xAJ#= ,i  
i}))6   
_e|-O>#pl  
public void setSFilePath(String value) B5;94YIN  
{ eYv+tjIF  
sFilePath = value;  BfW@f  
} ksYPF&l  
A=*6|1w;  
$! g~pV  
public String getSFileName() nyG5sWMpe  
{ q1/mp){  
return sFileName; hm1.UE  
} ;*20b@  
~AF' 6"A  
T 7M];@q  
public void setSFileName(String value) obgO-d9l  
{ Ti#x62X{  
sFileName = value; X: Be'  
} Maiyd  
a]I~.$G   
M%Q_;\?]  
public int getNSplitter() AJP-7PPD  
{ gO]8hLT  
return nSplitter; :1#$p  
} cZw_^@!  
2d&HSW  
>R\!Qk  
public void setNSplitter(int nCount) 6%&w\<(SG  
{ 8%b-.O:_$  
nSplitter = nCount; z7Z!wIzJ  
} pWb8X}M  
} l!}7GWj  
(IAR-957pN  
YD5mJ[1t"2  
/* os+ ]ct  
**Utility.java tA K=W$r  
*/ :,'.b|Tl.b  
package NetFox; U a1Z,~ *  
c{i\F D  
q6P5:@  
public class Utility { D:N\K/p  
NRe=O*O  
36 ]?4, .  
public Utility() z_Pq5  
{ qqu ]r  
LO)QEUG  
zR}vR9Ls  
} tz%H1 `  
z*N%kcw"  
//线程睡眠 Z$K[e  
public static void sleep(int nSecond) $rQi$w/  
{ $oi8 <8Y  
try{ Ga;Lm?6-  
Thread.sleep(nSecond); $ Vsf? ID  
} qwd T= H  
catch(Exception e) Dh9C9<Ta:  
{ s>ZlW:jY  
e.printStackTrace (); XeAH.i<  
} rX|{nb  
} q9(hn_X@/  
1_)Y{3L  
//日志 0-Wv$o[  
public static void log(String sMsg) v&"sTcS|  
{ 4/&.N]  
System.err.println(sMsg); er>@- F7w  
} x\5\KGw16  
QV=|' S  
<T$rvS  
public static void log(int sMsg) en16hd>^W:  
{ AD"L>7  
System.err.println(sMsg); h{e?Fl  
} twql)lbx  
} qB3=wFI  
d-#yN:}0  
&t74T"(d  
/* q&: t$tSS  
**TestMethod.java !f# [4Xw  
*/ b*cVC^{Dy  
package NetFox; 6 $+b2&V  
B|- W  
8?t}S2n2  
public class TestMethod { l'"Ici#7Ls  
ztV%W6  
^FK-e;J  
public TestMethod() /6#i$\ j  
{ ///xx/weblogic60b2_win.exe 2S-z$Bi}]  
try{ h x hl  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Cvtz&dH  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); bO+L#Kf  
SiteFileFetch fileFetch = new SiteFileFetch(bean); N-Sjd%Z  
fileFetch.start(); 2?c%<_jPA  
} jp#/]>(9Z  
catch(Exception e){e.printStackTrace ();} fZ  pUnc  
B..> *Xb  
zR }vw{  
} @}A3ie'w  
lFc^y  
@)3orH  
public static void main(String[] args) ~@'DYZb- H  
{ jN sM&s,  
new TestMethod(); I<$m%  
} Dmn{ppfyb  
} ]{pH,vk-  
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