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http断点续传简单实现(java)

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/* o2|(0uN'  
**SiteFileFetch.java m3WV<Cbz  
*/ ~3%3{a a  
package NetFox; 3(&.[o Z  
import java.io.*; K]u|V0c  
import java.net.*; Lg?'1dg  
}ot _k-  
YNXk32@j@e  
public class SiteFileFetch extends Thread { Om^/tp\  
O7\s1 V;  
BNy"YK$  
SiteInfoBean siteInfoBean = null; //文件信息Bean 4W?<hv+k7*  
long[] nStartPos; //开始位置 WAa?$"U2  
long[] nEndPos; //结束位置 Y; w]u_  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 5;{Bdvcv  
long nFileLength; //文件长度 nT12[@:Tr  
boolean bFirst = true; //是否第一次取文件 q>[% C5  
boolean bStop = false; //停止标志 :9#`| #uh  
File tmpFile; //文件下载的临时信息 Zb 2  
DataOutputStream output; //输出到文件的输出流 J v#^GNm  
Lm?*p>\Q  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) G4}q*&:k  
public SiteFileFetch(SiteInfoBean bean) throws IOException Q*8-d9C  
{ g@2.A;N0  
siteInfoBean = bean; V!P3CNK  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); V9 VP"kD  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =l(JJ  
if(tmpFile.exists ()) j+9 S  
{ 64lEB>VNm  
bFirst = false; W'jXIO  
read_nPos(); ETOc4hMO  
} [!le 9aNg  
else jE#8&P~  
{ sV<4^n7  
nStartPos = new long[bean.getNSplitter()]; w b[(_@eZ  
nEndPos = new long[bean.getNSplitter()]; k)s 7Ev*  
} =5`@:!t7  
/)1-^ju  
dO[4}FZ$  
gp)ds^  
} `VsGa  
;N\?]{ L  
S:YL<_oI|  
public void run() wDO5Zew!  
{ q?L(V+X  
//获得文件长度 /6zpVkV  
//分割文件 t {"iIz_S  
//实例FileSplitterFetch m3!M L>nLt  
//启动FileSplitterFetch线程 GU3/s&9  
//等待子线程返回 bY~v0kg  
try{ F 29AjW86  
if(bFirst) 1%"` =$q%  
{ ^rwSbM$  
nFileLength = getFileSize(); lc-|Q#$3$  
if(nFileLength == -1) Xt =bc  
{ |esjhf}H>v  
System.err.println("File Length is not known!"); fO^6q1a  
} QNXxpoS#  
else if(nFileLength == -2) 8~E)gV+v  
{ W~3tQ!  
System.err.println("File is not access!"); K]8wW;N4  
} l*Ei7 |Z  
else BA-nxR  
{ 14!J\`rI  
for(int i=0;i<nStartPos.length;i++) =on!&M  
{ %, et$1`g  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3+3m`%G  
} Ra5'x)m36)  
for(int i=0;i<nEndPos.length-1;i++) ~ fEs!hl  
{ s RQh~5kM  
nEndPos = nStartPos[i+1]; fR4l4 GU?)  
} M7R&J'SAY  
nEndPos[nEndPos.length-1] = nFileLength; 7[BL 1HI*  
} |nN/x<v  
} n-3j$x1Ne  
wG5RN;`V  
)V3(nZY  
//启动子线程 h(Ed%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =jc8=h[F<  
for(int i=0;i<nStartPos.length;i++) V1)P=?%(US  
{ lmKq xs4  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), I&8SP$S>J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2j7d$y*'  
nStartPos,nEndPos,i); %J7mZB9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); SRN9(LN  
fileSplitterFetch.start(); ]t)M}^w  
} *g4Cy 8$  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ""3m!qn#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); PbUcbb17  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", :ZS 8Zm"  
nEndPos = " + nFileLength); |.O!zRm  
// fileSplitterFetch[nPos.length-1].start(); 9jGuelwN  
n/oipiYx  
d[e:}1  
//等待子线程结束 |$w={N^4  
//int count = 0; FJ~_0E#L  
//是否结束while循环 :$i:8lz  
boolean breakWhile = false; MW$H/:3  
@:+n6  
U?fN3  
while(!bStop) H r^15  
{ )_*a7N!  
write_nPos(); |sqo+E  
Utility.sleep(500); H! r Kz  
breakWhile = true; =+}}Sv2  
BrH;(*H)8  
I.+)sB?5  
for(int i=0;i<nStartPos.length;i++) ClMtl59  
{ *C@[5#CA2z  
if(!fileSplitterFetch.bDownOver) P!+nZXo  
{ A?D"j7JD=L  
breakWhile = false; 0tCOb9  
break; .(7C)P{ .0  
} x56 F  
} r@[VY g~  
if(breakWhile) xSDE6]  
break; x*&&?nV Iz  
#VdI{IbW  
M=[q+A  
//count++; PR@4' r|a  
//if(count>4) 7s8<FyFsjd  
// siteStop(); R #3Q$   
} m>+,^`0  
R g0 XW6  
4nII/cPG  
System.err.println("文件下载结束!"); z[\W\g*|ri  
} FW)^O%2s  
catch(Exception e){e.printStackTrace ();} I0w@S7  
} ?[ S >&Vq  
@SC-vc  
sb|3|J6=  
//获得文件长度 Q;XHHk  
public long getFileSize() O<dZA=Oez  
{ p~q_0Pg%  
int nFileLength = -1; RUk<=! U  
try{ ()C^ta_]  
URL url = new URL(siteInfoBean.getSSiteURL()); g)9JO6]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Krr?`n  
httpConnection.setRequestProperty("User-Agent","NetFox"); $}^\=p}X  
I*W9VhIOV  
@ojg`!,  
int responseCode=httpConnection.getResponseCode(); h76NR  
if(responseCode>=400) Dl zmAN  
{ Sz|Y$,  
processErrorCode(responseCode); 8 5%Pq:E  
return -2; //-2 represent access is error u1;e*ty  
} X(!AI|6Bt  
we\b]  
2JA&{ch  
String sHeader; %<wQ  
u3M` 'YCb  
^\ vfos  
for(int i=1;;i++) zY+t,2z  
{ | 3N.5{  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); v$)@AE  
//Utility.log(in.readLine()); /=muj9|+s  
sHeader=httpConnection.getHeaderFieldKey(i); D]pK=247  
if(sHeader!=null) s-GleX<  
{ b#p~F}qT  
if(sHeader.equals("Content-Length")) S:p.W=TAB  
{ q: Bt]2x  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); //X e*0  
break; ti{H(;;@  
} ?)?IZ Qj  
} V#zhG AMy.  
else kJurUDo  
break; 3{Ek-{ 9  
} JA?,0S  
} a(}VA|l  
catch(IOException e){e.printStackTrace ();} +q #Xy0u  
catch(Exception e){e.printStackTrace ();} A]Q1&qM%  
mEB2RLCM  
|5O >>a()  
Utility.log(nFileLength); Et}C`vZ+Ve  
~mXZfG/D  
l:zU_J6  
return nFileLength; .#=j <&  
} 23}BW_m  
(o x4K{  
2vqmsl ?  
//保存下载信息(文件指针位置) *Z]5!$UpC  
private void write_nPos() (#j2P0B  
{ t+=12{9;f  
try{ Ad]<e?oN=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ']d!?>C@o  
output.writeInt(nStartPos.length); jiA5oX^g  
for(int i=0;i<nStartPos.length;i++) 4Vu'r?  
{ _W@,@hOH  
// output.writeLong(nPos); fa!3/X+  
output.writeLong(fileSplitterFetch.nStartPos); lFp!XZ!  
output.writeLong(fileSplitterFetch.nEndPos); f MY;  
} ).0V%}>  
output.close(); *? K4!q'  
} a%7"_{s1  
catch(IOException e){e.printStackTrace ();} 1<LC8?wt  
catch(Exception e){e.printStackTrace ();} ;[{:'^n  
} 9RG\UbX)^|  
N,j>;x3xT  
s{(ehP.Dd  
//读取保存的下载信息(文件指针位置) -1jjB1  
private void read_nPos() `e'G.@  
{ .k# N7[q=  
try{ -yX.Jv  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); CRZi;7`*1  
int nCount = input.readInt(); -`zG_]=-  
nStartPos = new long[nCount]; 0Jm]f/iZ  
nEndPos = new long[nCount]; do:QH.q8)  
for(int i=0;i<nStartPos.length;i++) CS~=Z>6EjA  
{ uY&=eQ_Cb  
nStartPos = input.readLong(); >DDQ'W!  
nEndPos = input.readLong(); !lR0w|  
} E$]a?uA:  
input.close(); m >]>$=%  
} gCv"9j<j  
catch(IOException e){e.printStackTrace ();} Dk)@>l:gI,  
catch(Exception e){e.printStackTrace ();} `fQM  
} :D"@6PC]  
;Y Dv.I  
Ms.PO{wb  
private void processErrorCode(int nErrorCode) R#Y50h zT  
{ IXGW2z;  
System.err.println("Error Code : " + nErrorCode); [ 3$.*   
} =E;=+eqt  
jA4PDHf+  
2Ryp@c&r^  
//停止文件下载 xK$}QZ)  
public void siteStop() /a@ kS  
{ Y3-]+y%l  
bStop = true; q{a#HnZo"  
for(int i=0;i<nStartPos.length;i++) e{,!|LhpQ  
fileSplitterFetch.splitterStop(); Z:I*y7V-  
}Q/G &F  
B }6Kd  
} ~_ *H)|  
} $Llta,ULE  
//负责部分文件的抓取 .D+RLO z  
**FileSplitterFetch.java F|ETug n  
*/ 3H1Pp*PH  
package NetFox; .|T2\M  
*Y8XP8u/  
jMK3T  
import java.io.*; %/P=m-K  
import java.net.*; 0;}Aj8Fle  
KuA>"X  
6dF$?I&  
public class FileSplitterFetch extends Thread { D ~Z=0yD  
?#?e(mpo  
g<f P:/  
String sURL; //File URL $np=eT)  
long nStartPos; //File Snippet Start Position T}UT 7W|  
long nEndPos; //File Snippet End Position 7nm}fT z7  
int nThreadID; //Thread's ID &kb\,mQ  
boolean bDownOver = false; //Downing is over ^rL ,&rk  
boolean bStop = false; //Stop identical v#zPH5xo  
FileAccessI fileAccessI = null; //File Access interface !]yQ1@)*'  
rqF"QU=l  
f:xUPH?+  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [1NaH  
{ i#k-)N _$  
this.sURL = sURL; u0xQ;BQ  
this.nStartPos = nStart; *]5z^> q;7  
this.nEndPos = nEnd; ]K7`-p~T  
nThreadID = id; x7f:F.  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1:_=g#WH  
} USprsaj  
~u! gUJ:  
j5zFDh1(  
public void run() o"RJ.w:dn  
{ T$u~E1  
while(nStartPos < nEndPos && !bStop) 9x(}F<L  
{ pL~=Z?(B  
JfkTw~'R  
2sUbiDe-  
try{ q?yMa9ZZky  
URL url = new URL(sURL); ?!H)zz6y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :.DI_XN`  
httpConnection.setRequestProperty("User-Agent","NetFox"); @YCv  
String sProperty = "bytes="+nStartPos+"-"; 82|q7*M*.  
httpConnection.setRequestProperty("RANGE",sProperty); 2\5cjdy  
Utility.log(sProperty); 85} ii{S  
bjlkX[{}I  
PT+c&5AS  
InputStream input = httpConnection.getInputStream(); <9`?Z-lJP  
//logResponseHead(httpConnection); H-Pq!9[DB  
+5-]iKh  
 [@<G+j  
byte[] b = new byte[1024]; Ih()/(  
int nRead; ?ZaD=nh$mK  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )=Zsv40O  
{ Q&gPa]z]}  
nStartPos += fileAccessI.write(b,0,nRead); 847 R   
//if(nThreadID == 1) rCE;'? Y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -1CEr_(P^  
} tn{8u7  
~5ubh2{  
O ^0"  
Utility.log("Thread " + nThreadID + " is over!"); pisB,wP$2  
bDownOver = true; v J-LPTB  
//nPos = fileAccessI.write (b,0,nRead); 6|^0_6_  
} 7 WP%J-   
catch(Exception e){e.printStackTrace ();} \6:>{0\  
} q`[K3p   
} .gq(C9<B[  
k}zd' /b  
xg} ug[  
//打印回应的头信息 \yG`Sfu2  
public void logResponseHead(HttpURLConnection con) <m0{'xw  
{ Oqmg;\pm  
for(int i=1;;i++) U*qNix  
{ sMm/4AY]  
String header=con.getHeaderFieldKey(i); 7@IFp~6<qK  
if(header!=null) EE]=f=3  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); .'/l'>  
Utility.log(header+" : "+con.getHeaderField(header)); b_=8!Q.:  
else f>z`i\1oO  
break; zKxvN3!  
} { 5-zyE  
} *NlpotW,f  
&6/%k kv  
-`Q}tg>cT  
public void splitterStop() AK*N  
{ HIGNRm  
bStop = true; m?;$;x~Dj  
} %2D17*eK  
ej52AK7  
jo_ sAb  
} E:w:4[neh  
Qn.[{rw  
P"F{=\V1`<  
/* q}wj}t#  
**FileAccess.java c 0-w6  
*//文件访问(定位,写) A,BEKjR~J  
package NetFox; -72j:nk  
import java.io.*; Yj|]Uff8O  
x2k*| =$  
JUQg 'D  
public class FileAccessI implements Serializable{ HabzCH  
@Tr&`Hi  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 M3(k'q7&:  
RandomAccessFile oSavedFile; h$ Da&$uyI  
long nPos; >zmzK{A=  
a4&:@`=  
gvyT-XI  
public FileAccessI() throws IOException 8Z#21X>  
{ O@jqdJu  
this("",0); S;=_;&68?  
} =j~Q/-`EC0  
=Ndli>x}1  
+O+<Go@a  
public FileAccessI(String sName,long nPos) throws IOException V"#Jk!k9k  
{ Au5rR>W  
oSavedFile = new RandomAccessFile(sName,"rw"); 6peyh_  
this.nPos = nPos; ZJ(rG((!  
oSavedFile.seek(nPos); os$nL'sq  
} O?ktWHUx  
=& -[TPW  
OOB^gf}$'  
public synchronized int write(byte[] b,int nStart,int nLen) zZ=$O-&%  
{ YH\j@ ^n  
int n = -1; |pW\Ec#(  
try{ {Q~7M$  
oSavedFile.write(b,nStart,nLen); Hm9<fQuM  
n = nLen; A-wRah.M  
} [w+Q^\%bN  
catch(IOException e) hNbIpi=  
{ >]&X ^V%Q#  
e.printStackTrace (); |^GyH$.  
} XP?*=Z]  
</s,pe79B  
maC>LBa2/  
return n; >"("*3AO  
} w`gyE 6A  
r,xmEj0E  
G{RTH_p  
} Mw^ *yW  
M35Ax],:^  
Bo r7]#  
/* y3IWfiz>/d  
**SiteInfoBean.java ssl&5AS  
*/ 8h.V4/?  
package NetFox; ^%#grX#  
'Kz9ygZy  
{'R)4hL  
public class SiteInfoBean { 'jvpNn  
JsQ6l%9  
kX2d7yQZz  
private String sSiteURL; //Site's URL l,d, T  
private String sFilePath; //Saved File's Path 6RK\}@^=K  
private String sFileName; //Saved File's Name "!L kp2\  
private int nSplitter; //Count of Splited Downloading File :a3 xvN-l  
[B9;?G  
- k`.j  
public SiteInfoBean() "C74  
{//nSplitter的缺省值为5 =|SdVv   
//default value of nSplitter is 5 4# )6.f~  
this("","","",5); &ao(!/im  
} @Zm J z  
;>ozEh#8w  
s".HEP~]=  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,W*H6fw+  
{ 1 Z[f {T)  
sSiteURL= sURL; kMxjS^fr  
sFilePath = sPath; Gvx[ 8I  
sFileName = sName; _x %1F  
this.nSplitter = nSpiltter; *Km7U-BG  
w>979g  
'*R%^RK  
} 4%_M27bu[  
R^8{bP  
^}>/n. %  
public String getSSiteURL() [,g~m9  
{ &mkpJF/  
return sSiteURL; ;/sHWI f+Z  
} Cs1>bpY*R6  
n&!+wcJ;Yt  
SSmHEy*r)  
public void setSSiteURL(String value) JP'= UZ'  
{ ^oeJKjJ  
sSiteURL = value; %Q4i%:Qi  
} ngUHkpYS5  
m{(+6-8|m  
NP_?f%(  
public String getSFilePath() K ,isjh2  
{ `|Fp^gM  
return sFilePath; ;n*J$B  
} =2 jhII  
J?Iq9f  
$f-hUOuyo  
public void setSFilePath(String value) edpW8eND  
{ (3%t+aqq  
sFilePath = value; 5 Op_*N{V  
} 3!#/k+,C  
EW(J5/mn  
`9 [i79U  
public String getSFileName() 'uC59X4l  
{ !O)qYmK]|  
return sFileName; y0IK,W'&?  
} $[(d X!]F  
?L|yaC~  
+AI`R`Tm  
public void setSFileName(String value) 0I%: BT  
{ QK <\kVZ8  
sFileName = value; ]WL|~mG  
} h-XY4gq/  
NFyMY#\]  
>K:u ?YD[  
public int getNSplitter() F ?=9eISLJ  
{ !%S4 n  
return nSplitter; }ug xN0  
} d2jr8U  
5*G%IR@@LK  
Qv{,wytyO  
public void setNSplitter(int nCount) >*qQ+_  
{ , =y#m- 9  
nSplitter = nCount; ClQe4uo{  
} -%m3-xZA  
} 5PiOH"!19  
W{Z^n(f4  
;l!`C':'  
/* jP=Hf=:$  
**Utility.java qd6fU^)i  
*/ JYmAn?o-  
package NetFox; GyC)EFd  
+5X DF  
\l,rpVv5m  
public class Utility { 5%i:4sMx *  
Oh; Jw  
<kc# thL  
public Utility() =G${[V \  
{ .SS<MDcqIt  
r>|-2}{N/  
@;)PSp*j  
} ;y1Q6eN  
=8JB8ZFP  
//线程睡眠 p 2 !FcFi  
public static void sleep(int nSecond) YpmYxd^  
{ HW6.O|3  
try{ ..qd,9H  
Thread.sleep(nSecond); r>n" 51*  
} a.kbov(  
catch(Exception e) &ab|2*3?X  
{ +%#8k9Y  
e.printStackTrace (); l-O$m  
} l]!B#{  
} pv# 2]v  
0A[esWmP  
//日志 #kcSQ'  
public static void log(String sMsg) >k(MUmhX  
{ s~L</Xvo  
System.err.println(sMsg); 7P**:b  
} <$i4?)f(  
<bUe/m  
,+1m`9}  
public static void log(int sMsg) X.#oEmA ,P  
{ NiSO'=y$n  
System.err.println(sMsg); Xe1P- 6 0  
} ^&[+H8$  
} ")UwkF  
~[W#/kd1n  
s"~5']8  
/* P LR0#).n  
**TestMethod.java &|o$=Ad  
*/ *l+Cl%e  
package NetFox; wpo1  
1mgLX_U9  
hYg'2OG  
public class TestMethod { kfrY1  
elO<a]hX  
W>-B [5O&[  
public TestMethod() 4na8  
{ ///xx/weblogic60b2_win.exe x]4Kkpqm  
try{ ?J!3j{4e  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *yaw$oB  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); QU5Sy oL[  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >fs2kha  
fileFetch.start(); ukAKFc^)k  
} q{' ~+Nq  
catch(Exception e){e.printStackTrace ();} < n?=|g  
cy3Td28,  
EbK0j?  
} &t}?2>:  
\~DM   
p]gT&[iJ  
public static void main(String[] args) :E_a 0!'  
{ j,-C{ K  
new TestMethod(); /iQ(3F  
} }*wLEa  
} {^ec(EsO#  
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