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http断点续传简单实现(java)

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/*  @Iy&Qo  
**SiteFileFetch.java G;3N"az  
*/ 3A.T_mGCs  
package NetFox; 1W +QcK4k  
import java.io.*; D/-$~u_o  
import java.net.*; L H`z '7&/  
Td6"o&0A!  
Fz4g:8qdA  
public class SiteFileFetch extends Thread { KcQe1mT!+  
:F`yAB3  
-<tfbaA  
SiteInfoBean siteInfoBean = null; //文件信息Bean N^{+1u7  
long[] nStartPos; //开始位置 ,HLgb}~  
long[] nEndPos; //结束位置 z(&~O;;N#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 I,xV&j+<  
long nFileLength; //文件长度 2E":6:Wsw  
boolean bFirst = true; //是否第一次取文件 m@){@i2.  
boolean bStop = false; //停止标志 J< U,~ra\  
File tmpFile; //文件下载的临时信息 !3'&_vmG$  
DataOutputStream output; //输出到文件的输出流 yl[6b1  
bM"crRG"  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ZeyA bo  
public SiteFileFetch(SiteInfoBean bean) throws IOException `vPc&.-K  
{ w,QO!)j!  
siteInfoBean = bean; 'P^6H$0  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %>G(2)Fb\\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >1n[Y- r  
if(tmpFile.exists ()) _ X* A  
{ L'?0*t  
bFirst = false; R2[-Q"|Ra  
read_nPos(); u \zP`Y  
} .j)f'<;%  
else b:w {7  
{ mt(2HBNoz  
nStartPos = new long[bean.getNSplitter()]; .s !qf!{V`  
nEndPos = new long[bean.getNSplitter()]; T1Q c?5K^  
} !w9w{dtW=  
?A4t &4  
hh<Es|v  
oJEUNgY&  
} 41[1_p(  
xrPC  
 qg+bh  
public void run() /{9"O y7E  
{ _a 40lcP  
//获得文件长度 Z1gZn)7  
//分割文件 =7U_ jDME  
//实例FileSplitterFetch VTt{ 0 ~  
//启动FileSplitterFetch线程 QP {V  
//等待子线程返回 +$F_7Hx  
try{ WI$MT6  
if(bFirst) , 9C~%c0Pw  
{ U- a+LS  
nFileLength = getFileSize(); hi30|^l-  
if(nFileLength == -1) RvPC7,vh  
{ }H4Z726  
System.err.println("File Length is not known!"); Rn-RMD{dh  
} TEK]$%2  
else if(nFileLength == -2) eaxp(VX?oy  
{ /M1 /  
System.err.println("File is not access!"); NJ;D Qv  
} LPNJuz  
else _K?{DnTb  
{ 8sG0HI$f+  
for(int i=0;i<nStartPos.length;i++) rI E m  
{ 2yyJ19Iul  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1eZ759PoO  
} VHlN;6Qlff  
for(int i=0;i<nEndPos.length-1;i++) Oa'DVfw2J  
{ ,L"1Ah  
nEndPos = nStartPos[i+1]; h!L/ZeRaV  
} w<ol$2&B  
nEndPos[nEndPos.length-1] = nFileLength; m*d {pX  
} $bd&$@sA  
} azxGUS_i<  
J AK+v  
f2JeXsOI  
//启动子线程 cq=ker zQ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];  Nx8~Rn  
for(int i=0;i<nStartPos.length;i++) ~P47:IZf  
{ QD}'2{M!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \NEXtr`Th  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), SeC[,  
nStartPos,nEndPos,i); 1$*ZN4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "0(H! }D  
fileSplitterFetch.start(); V u/{Hr  
} <&+\X6w[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,p,$(V  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); J\BTrN7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ;e>pu"#  
nEndPos = " + nFileLength); hw@ `Q@  
// fileSplitterFetch[nPos.length-1].start(); e7(iMe  
6Ch [!=p{  
DO#!ce  
//等待子线程结束 D[7+xAwS  
//int count = 0; )NoNgU\7!  
//是否结束while循环 R3;,EL{H&  
boolean breakWhile = false; J m5).  
fR& ;E  
6,707h  
while(!bStop) b6FC  
{ `n*e8T  
write_nPos(); <Oi65O_X  
Utility.sleep(500); %q~YJ*\  
breakWhile = true; e-Xr^@M*Q  
=peodj^  
fr\"MP  
for(int i=0;i<nStartPos.length;i++) Qd %U(|  
{ w$X"E*~>8  
if(!fileSplitterFetch.bDownOver) DcO$&)Eb  
{ Y-Zw'  
breakWhile = false; L*Gk1'  
break; wN|;_~h2  
} T=EHue$  
} `Dck$  
if(breakWhile) DHUK_#!  
break; |# _F  
'UYxVh9D  
%yj z@  
//count++; 5 (Lw-_y#  
//if(count>4) _</>`P[  
// siteStop(); *kmD/J  
} \i*QKV<  
i;u#<y{E  
*Vbf ;=Mb  
System.err.println("文件下载结束!"); >tmv3_<=  
} A)2eo<ij4  
catch(Exception e){e.printStackTrace ();} Ej\M e  
} k$kOp *X  
4@iMGYR9!s  
=N62 ){{  
//获得文件长度 e ej:  
public long getFileSize() lo1<t<w`  
{ D#=$? {w  
int nFileLength = -1; }#u.Of`6"  
try{  b6`_;Z  
URL url = new URL(siteInfoBean.getSSiteURL()); =RA8^wI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D%=VhKq  
httpConnection.setRequestProperty("User-Agent","NetFox"); B_gzpS]  
kqebU!0-  
lUL6L 4m  
int responseCode=httpConnection.getResponseCode(); m W/6FC  
if(responseCode>=400) [MQU~+]  
{ eHQS\n  
processErrorCode(responseCode); t",=]k  
return -2; //-2 represent access is error  iI!MF1  
} f,jN"  
\jkMnS6FvL  
?06+"Z  
String sHeader; SBf8Ipe  
9!``~]G2  
x1@`\r#0  
for(int i=1;;i++) u8w4e!rKo6  
{ `X["Bgk$!T  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %kHeU=  
//Utility.log(in.readLine()); 0eGz|J*7  
sHeader=httpConnection.getHeaderFieldKey(i); ;?{N=x8  
if(sHeader!=null) *%3%Zj,{  
{ IL]Js W  
if(sHeader.equals("Content-Length")) #j+0jFu  
{ 8|z@"b l)  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); lU`}  
break; {Rm N1'%  
} ;JD/4:  
} lYF~CNvE  
else m@Q%)sc)  
break; d)R7#HLZ7  
} CeZ+!-lG  
} Y"n$d0%  
catch(IOException e){e.printStackTrace ();} 1edeV48{:  
catch(Exception e){e.printStackTrace ();} IO@Ti(,  
0SHF 8kek  
z]twh&^1L  
Utility.log(nFileLength); TtWE:xE  
6h5,XcO4  
0b)q,]l]  
return nFileLength; 5DI&pR1eZ  
} <>Nq ]WqA  
?o D]J  
mRECd Gst  
//保存下载信息(文件指针位置) 6EX_IDb  
private void write_nPos() N wISf  
{ i$z).S?1  
try{ ^$D2fS  
output = new DataOutputStream(new FileOutputStream(tmpFile)); /c&;WlE/n  
output.writeInt(nStartPos.length); r(VGdG  
for(int i=0;i<nStartPos.length;i++) |z+K]R8_  
{ sTb@nrRxH  
// output.writeLong(nPos); oEuV&m|yX  
output.writeLong(fileSplitterFetch.nStartPos); :L6,=#  
output.writeLong(fileSplitterFetch.nEndPos); ru#CywK{{;  
} b9%G"?~Zz  
output.close(); X!AD]sK  
} DNyU]+\L[l  
catch(IOException e){e.printStackTrace ();} >Oz~j>jL  
catch(Exception e){e.printStackTrace ();} ?BEO(;'  
} xoYaL  
U WU PY  
3G.-JLhs  
//读取保存的下载信息(文件指针位置) s|O4 >LsG  
private void read_nPos() <5xlP:Cx  
{ eyIbjgpV  
try{ PCcI(b>?l  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -Wt (t2  
int nCount = input.readInt(); ?xT ^9  
nStartPos = new long[nCount]; sN8)p%'Lg  
nEndPos = new long[nCount]; >T)#KQ1t  
for(int i=0;i<nStartPos.length;i++) *#| lhf'  
{ VGVb3@  
nStartPos = input.readLong(); ?r%kif)  
nEndPos = input.readLong(); :~ ; 48m  
} H6vO}pq) r  
input.close(); 6+iZJgwAy  
} k ^:+Pp  
catch(IOException e){e.printStackTrace ();} &~ .n}h&  
catch(Exception e){e.printStackTrace ();} 2Sha&Z*CE  
} K]Rb~+a<  
? kBX:(g  
X%lk] &2  
private void processErrorCode(int nErrorCode) ]iHSUP  
{ xV+cX*4h  
System.err.println("Error Code : " + nErrorCode); V-N`R-FSr  
} 1oSU>I_i  
|{j\7G*5  
{I9<W'k{  
//停止文件下载 ro8c-[V  
public void siteStop() GX@=b6#-  
{ LV6BSQyQ  
bStop = true; ^*@D%U  
for(int i=0;i<nStartPos.length;i++) G,,7.%eib=  
fileSplitterFetch.splitterStop(); UVlXDebl  
6z3`*B  
!hc#il'g].  
} _]"uq/UWp  
} q Xj]O3 mm  
//负责部分文件的抓取 ?Dn 6  
**FileSplitterFetch.java k "Qr  
*/ j3$\+<m]  
package NetFox; Ae3=o8p  
Pg%k>~i  
3$#=* Zp  
import java.io.*; +j!$88%Z{  
import java.net.*; $Ao iH{f  
&XF@Dvv  
|-zefzD|  
public class FileSplitterFetch extends Thread { {@*l,[,5-  
rIRkXO)  
'6zk> rN  
String sURL; //File URL ^a #  
long nStartPos; //File Snippet Start Position U_oei3QP  
long nEndPos; //File Snippet End Position CeD(!1V G  
int nThreadID; //Thread's ID k>W}9^ cK  
boolean bDownOver = false; //Downing is over Q!`  
boolean bStop = false; //Stop identical !`S61~gE  
FileAccessI fileAccessI = null; //File Access interface X6 SqOb\(a  
{u@w^ hZ$  
O[|prk,  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException i^_?C5  
{ h5p,BRtu  
this.sURL = sURL; `ZELw=kLL  
this.nStartPos = nStart; rpn&.#KS  
this.nEndPos = nEnd; -D^.I  
nThreadID = id; +|c1G[Jh  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 K=Y{iHn  
} ~H\1dCW  
=Dc9|WuHN  
C[2LP$6*/  
public void run() vWq/A.  
{ G W~ZmK  
while(nStartPos < nEndPos && !bStop) s& Lyg>>`  
{ w7"&\8a  
$geDB~ 2>  
nZP%Z=p7  
try{ 2y` :#e`x1  
URL url = new URL(sURL); 9Lp[y%{GP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); FF'Ul 4y  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q2jl61d_9  
String sProperty = "bytes="+nStartPos+"-"; .~Y% AI  
httpConnection.setRequestProperty("RANGE",sProperty); r;'Vy0?AL  
Utility.log(sProperty); 1Uf8ef1,  
m>8tA+K)+)  
.N~YVul[a*  
InputStream input = httpConnection.getInputStream(); 6SVh6o@]  
//logResponseHead(httpConnection); { cMf_qQ  
r]yI5 ;  
YH-+s   
byte[] b = new byte[1024]; oaMh5 FPy  
int nRead; P d)<Iw^<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;UoXj+Z  
{ F ?.J1]  
nStartPos += fileAccessI.write(b,0,nRead); g6l&;S40  
//if(nThreadID == 1) q%\rj?U_  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jdW#; ]7+y  
} V(6GM+  
u .R   
_^Yav.A=  
Utility.log("Thread " + nThreadID + " is over!"); y - Ge"mY  
bDownOver = true; ; +%|!~  
//nPos = fileAccessI.write (b,0,nRead); ]~J.YX9ST  
} Qu6Q)dZ<  
catch(Exception e){e.printStackTrace ();} u8sK~1CPf  
} 3oE3bBj  
} :j4i(qcF  
q A?j-H  
01AzM)U3"m  
//打印回应的头信息 DY'1#$;  
public void logResponseHead(HttpURLConnection con) * u{CnH  
{ BzyzOtBp3L  
for(int i=1;;i++) 0$e]?]X6  
{ y+K21(z.  
String header=con.getHeaderFieldKey(i);  EWn\ ]f|  
if(header!=null) <h<4R Rj  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); B%^ $fJ|  
Utility.log(header+" : "+con.getHeaderField(header)); ]xf|xs  
else ,.PW qfb  
break; zm`^=cV  
}  {xS\CC(g  
} #M5[TN!  
.X(*mmH  
DX)T}V&mP  
public void splitterStop() Z2soy-  
{ &] euL:C  
bStop = true; \5=fC9*G  
} 'l`T(_zL\%  
+jIE,N  
q)E J?-  
} y*fU_Il|!  
`Z!NOC  
J^]Y`Q`  
/* FdVWj 5 $a  
**FileAccess.java +5C*i@v  
*//文件访问(定位,写) )Og,VXEB  
package NetFox; '@Q aeFm  
import java.io.*; M+q|z0U  
]'a9>o  
_m8JU  
public class FileAccessI implements Serializable{ *q/oS8vavd  
v\gCgx=%j  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -+#g.1UL/  
RandomAccessFile oSavedFile; 7<?~A6  
long nPos; tzFgPeo$;  
b6E,u*)"  
B\z4o\am%  
public FileAccessI() throws IOException SOPQg?'n=V  
{ %`Q<_LTU  
this("",0); -A A='s  
} Axtf,x+lH  
,0=@cJ  
3"OD"  
public FileAccessI(String sName,long nPos) throws IOException B U^3Ux$  
{ ,'69RL?-Wg  
oSavedFile = new RandomAccessFile(sName,"rw"); u  teI[Q  
this.nPos = nPos; (&x#VmDL  
oSavedFile.seek(nPos); K[( h2&  
} &v#*  
#[a+m  
1*!`G5c,}  
public synchronized int write(byte[] b,int nStart,int nLen) {Noa4i  
{ ua -cX3E  
int n = -1; WV'FW)%  
try{ G()- NJ{  
oSavedFile.write(b,nStart,nLen); aH1mW;,1u  
n = nLen; fGD#|a;,  
} b1A8 -![  
catch(IOException e) Zk.LGYz  
{ 'nFqq:2Xa  
e.printStackTrace (); ZJxUv {J  
} (|PxR#{l<  
%kg%ttu7  
7TC=$y ,  
return n; O)tZ`X;  
} >/DyR+?>4  
2@ <x%T  
8R6!SB  
} JRC+>'}Xj  
}"'^.FG^_  
yn[^!GuJ_  
/* |W/_S^C  
**SiteInfoBean.java ci@U a}T  
*/ m-Uq6_e  
package NetFox; LI&+5`  
o!3-=<^  
YAIDSZ&l[  
public class SiteInfoBean { +##b}?S%  
&.Jp,Xt)  
H?P:;1A]c  
private String sSiteURL; //Site's URL C NNyz$  
private String sFilePath; //Saved File's Path mGXjSWsd  
private String sFileName; //Saved File's Name ^]$x/1I;  
private int nSplitter; //Count of Splited Downloading File  wv2  
( *(#;|m  
^fLePsmd  
public SiteInfoBean() J/j?;qx]j  
{//nSplitter的缺省值为5 Xw=>L#Q  
//default value of nSplitter is 5 R18jju>Zr  
this("","","",5); ov=[g l  
} Fvy__ qcHi  
n0T\dc~  
u(7PtmV[!  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @}K'Ic  
{ McgTTM;E  
sSiteURL= sURL; %r0yBK2uOp  
sFilePath = sPath; _91g=pM   
sFileName = sName; !po8[fz~x  
this.nSplitter = nSpiltter; <|M cE  
0@yHT-Dy  
J>YwMl  
} !79^M  
8Vkw vc  
gsn3]^X  
public String getSSiteURL() :t6 w+h  
{ 5'/Ney9N  
return sSiteURL; SsDe\"?Q  
} ThX%Uzd"[;  
?v>!wuiP  
M ]dS>W%U  
public void setSSiteURL(String value) {q%wr*  
{ b8QA>]6A  
sSiteURL = value; %pNK ?M+  
} !_VKJZuH  
Lt+ Cm$3  
ngprTMO$&  
public String getSFilePath() h&+dIk\[3  
{ Ji_3*(  
return sFilePath; 3[E3]]OVa  
} OAMsqeWYA  
{$,e@nn  
9Xt5{\PJ  
public void setSFilePath(String value) ErK5iTSD  
{ -aDGXQM{~  
sFilePath = value;  u%<Je  
} ty|E[Ez1  
Ll%CeP  
5Xu2MY=  
public String getSFileName() %nQii? 1`i  
{ c(. 2D  
return sFileName; wRn]  
} [];*9vxW  
VLuhURI)  
>(s)S[\  
public void setSFileName(String value) 31 \l0Jg  
{ :b[ [}'  
sFileName = value; 8<C u S  
} 5:%xuJD  
37DyDzW)'  
5A,@$yp+  
public int getNSplitter() sas}k7m"  
{ 7*8R:X+^r  
return nSplitter; m$ZPQ0X  
} @U CGsw  
=7@N'xX  
{ZiJnJX  
public void setNSplitter(int nCount) *2ZX*w37  
{ /s"mqBXCG  
nSplitter = nCount; w yP|#Z\  
} rmS.$h@7 m  
} n`Pwo &  
HV-c DL  
eAh~ `  
/* `LU[+F8<  
**Utility.java Eg&xIyRmm  
*/ -&JUg o=  
package NetFox; ;LRY h?  
S"ZH5O(  
JsohhkJNGi  
public class Utility { U}ei2q\  
F.2<G.9  
G. Z:00x  
public Utility() _KBN  
{ BbEWa  
"c8 -xG  
T 22tZp  
} yOwo(+ 2  
Umx~!YL!  
//线程睡眠 hh/C{ l  
public static void sleep(int nSecond) kH'LG!O  
{ I8;xuutc  
try{ QOA7#H-m9  
Thread.sleep(nSecond); `)Z"||8K  
}  J jRz<T;  
catch(Exception e) f%fD>a  
{ `yYoVu*  
e.printStackTrace (); U.]5UP:a  
} JDcc`&`M  
} e 4-  
#9-qF9M  
//日志 u~WBu|  
public static void log(String sMsg) npC:SrI%  
{ FCL7Tn  
System.err.println(sMsg); &)[?D<  
} N>kY$*  
1h uU7xuf  
THC7e>P4  
public static void log(int sMsg) G`H4#@]  
{ "M#A `b  
System.err.println(sMsg); jdz]+Q`jq  
} GCaiogiBg  
} }+/j/es{]  
9u6GeK~G  
jc rLUs+\  
/* Jg} w{,  
**TestMethod.java 'sb&xj`d  
*/ O# n<`;W  
package NetFox; !C13E lf  
ZfMDyS$.  
{m%]`0  
public class TestMethod { }7?n\I+n"  
P1cI]rriW  
?'>pfU  
public TestMethod() 9)P-<  
{ ///xx/weblogic60b2_win.exe #aHPB#  
try{ }eKY%WU>O  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Tvp~~Dk  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); d\c?sYLv  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3|++2Z{},  
fileFetch.start(); |E]`rfr  
} 73C7g< Mx  
catch(Exception e){e.printStackTrace ();} M N-j$-y}  
Sq<ds}o'8l  
;og[ q  
} olA 1,8  
m2sf]-?Y  
^@91BY  
public static void main(String[] args) Hs9; &C  
{ {"rYlN7,  
new TestMethod(); {&u`d.Lk2p  
} 2!@ER i  
} hYvWD.c}  
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