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http断点续传简单实现(java)

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/* OvX&5Q5  
**SiteFileFetch.java e(8hSVcl4  
*/ sG u.G  
package NetFox; M1/d7d  
import java.io.*; B5z'Tq1  
import java.net.*; t.9s49P  
=VD],R)  
TTVmm{6  
public class SiteFileFetch extends Thread { X9Ch(nWX  
`7=$I~`  
/"Vd( K2Z  
SiteInfoBean siteInfoBean = null; //文件信息Bean #'Y lO -C  
long[] nStartPos; //开始位置 QR&e~rks  
long[] nEndPos; //结束位置 %'iJVFF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 r'*$'QY-N  
long nFileLength; //文件长度 YCDH0M  
boolean bFirst = true; //是否第一次取文件 %nZ:)J>kz  
boolean bStop = false; //停止标志 E]mm^i`|  
File tmpFile; //文件下载的临时信息 5pJe`}O4  
DataOutputStream output; //输出到文件的输出流 <Z%=lwtX  
*tUOTA 3L  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) V?M (exN  
public SiteFileFetch(SiteInfoBean bean) throws IOException SZKYq8ZA)V  
{ tB4mhX|\  
siteInfoBean = bean; vxmX5.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); $2a"Ec!7  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); q!c=f!U?\l  
if(tmpFile.exists ()) 5_;-Qw  
{ {U;yW)  
bFirst = false; Nm"P8/-09  
read_nPos(); /JS_gr@DK  
} C 7C4 eW8  
else Rn?JMM]  
{ ,m{R m0  
nStartPos = new long[bean.getNSplitter()]; e#*3X4<\K  
nEndPos = new long[bean.getNSplitter()]; (u&x.J  
} 3:iEt (iCI  
H7Q$k4\l  
R,BJr y  
 )kWxp  
} r-y;"h'  
e{E\YEc  
E:K4k <  
public void run() i%FC lMF  
{ MDF_Xr-hZ  
//获得文件长度 O(/~cQ  
//分割文件 }&vD(hX  
//实例FileSplitterFetch yP{ 52%|+  
//启动FileSplitterFetch线程 r]!#v{#.  
//等待子线程返回 &x1A {j_  
try{ xq((]5Py  
if(bFirst) ^.6yzlY  
{ hP)Zm%@0f  
nFileLength = getFileSize(); JN/=x2n.  
if(nFileLength == -1) 4  eLZ  
{ y$%oR6 K7-  
System.err.println("File Length is not known!"); \8xSfe  
} BzfR8mD  
else if(nFileLength == -2) BaQyn 6B  
{ E4% -*n  
System.err.println("File is not access!"); 5f7id7SI  
} ^t})T*hM0  
else Oo :Dt~Ib  
{ d3c.lD)L9  
for(int i=0;i<nStartPos.length;i++) Tow=B  
{ Rt?CE jy  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Pg8.RvmQ  
} 4;AF\De  
for(int i=0;i<nEndPos.length-1;i++) $bG*f*w  
{ Br!;Ac&N  
nEndPos = nStartPos[i+1]; HS <Jp44  
} )Jjp^U3Ub  
nEndPos[nEndPos.length-1] = nFileLength; ?SNacN@r  
} 8H4NNj Oy  
} _[R(9KyF0f  
jkL=JAcf~  
bJIYe ld  
//启动子线程 q5_zsUR=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :XhF:c[.:  
for(int i=0;i<nStartPos.length;i++) Es+I]o0K  
{ (?Mn_FNE|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1L*[!QT4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), b WNa6x  
nStartPos,nEndPos,i); )YAa7\Od  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vcFR Td  
fileSplitterFetch.start(); 'd~(=6J  
} VZt%cq  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), e8<}{N0,n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); CK[8y&  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 1gV?}'jq  
nEndPos = " + nFileLength); 3*<@PXpK&  
// fileSplitterFetch[nPos.length-1].start(); \1Y|$:T/  
kf'(u..G  
ESB^"|9  
//等待子线程结束 &)OI!^ (  
//int count = 0; Zye04&x9k  
//是否结束while循环 "Ol:ni1  
boolean breakWhile = false; zwV!6xG  
\ UrD%;sq  
08xo_Oysq  
while(!bStop) ?XY'<]o E  
{ HDV-qYD|O~  
write_nPos(); R5ra*!|L)  
Utility.sleep(500); 7<)H?;~;  
breakWhile = true; z0rYzn?MR  
cjN)3L{  
F\r"Y)|b=  
for(int i=0;i<nStartPos.length;i++) "d)Yq Q  
{ #ELe W3 S}  
if(!fileSplitterFetch.bDownOver) b\0>uU  
{ B2kZ_4rB  
breakWhile = false; fx|d"VF[  
break; t}k:wzZ@  
} b@CjnAZ  
} f,yl'2{  
if(breakWhile) dE"_gwtX  
break; uaO.7QSwN  
"Vq= Ph  
J>v[5FX+  
//count++; Md~SzrU  
//if(count>4) Z|C,HF+m.  
// siteStop(); )>1}I_1j)  
} +UDt2  
{`D]%eRO  
~Y`ys[Z m  
System.err.println("文件下载结束!"); Ibz9j uY  
} yo[Sh6r/9b  
catch(Exception e){e.printStackTrace ();} |^-D&C(Eu  
} 7nT|yL?  
`+n0a@BVB  
&j:e<{@  
//获得文件长度 :O413#8  
public long getFileSize() Pp } Z"  
{ 9;LjM ~Ct  
int nFileLength = -1; 4wSZ'RTSR  
try{ |aLK_]!  
URL url = new URL(siteInfoBean.getSSiteURL()); ~+1mH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nx%As  
httpConnection.setRequestProperty("User-Agent","NetFox"); bdWdvd:  
%JBLp xnq  
(H uvo9  
int responseCode=httpConnection.getResponseCode(); ~u$ cX1M  
if(responseCode>=400) \'Ca1[y@B  
{ b|-)p+ba  
processErrorCode(responseCode); kS_#8 I  
return -2; //-2 represent access is error 68P'<|u?  
} ,+df=>$W  
Z$J-4KN  
FQ 0&{ulb  
String sHeader; s/hgWW$  
*KNfPh#wi}  
u)Kiwa  
for(int i=1;;i++) }kt%dDU  
{ i&H^xgm  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());  jfK&CA  
//Utility.log(in.readLine()); C5^WJx[  
sHeader=httpConnection.getHeaderFieldKey(i); eW 4[2Q  
if(sHeader!=null) iA{q$>{8  
{ WD\Yx~o  
if(sHeader.equals("Content-Length")) ]*=!lfrV  
{ p^ (Z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); G~y:ZEnN[  
break; Rw `ezC#  
} /TsXm-g#  
} i tNuY<"  
else gw"SKp!]  
break; IT:WiMDQ}  
} 1|8Bv0-b  
} +pgHCzwJE  
catch(IOException e){e.printStackTrace ();}  \xp0n  
catch(Exception e){e.printStackTrace ();} Y7+c/co  
;+ C$EJw-  
:ILpf+`yY  
Utility.log(nFileLength); %J-:%i  
&Ih }"  
@+t|Aa^g  
return nFileLength; W*s=No3C  
} 517"x@6Q  
nGWy4rY2S  
Vaf,  
//保存下载信息(文件指针位置) oJNQdW[  
private void write_nPos() e46`"}r  
{ Y[)mHs2  
try{ 00D.Jn  
output = new DataOutputStream(new FileOutputStream(tmpFile)); GU`q^q@Ea  
output.writeInt(nStartPos.length); 4tUoK[p  
for(int i=0;i<nStartPos.length;i++) ;{0alhMZ  
{ 3mofp`e  
// output.writeLong(nPos); U}:+Hz9  
output.writeLong(fileSplitterFetch.nStartPos); 4jDi3MMU9  
output.writeLong(fileSplitterFetch.nEndPos); jNx{*2._r  
} E4o{Z+C  
output.close(); ~D5FnN9  
} } *) l  
catch(IOException e){e.printStackTrace ();} N`7OJ)l  
catch(Exception e){e.printStackTrace ();} esZhX)dS  
} _;^x^  
HOu$14g  
5"40{3  
//读取保存的下载信息(文件指针位置) \i[N ";K  
private void read_nPos() 72RTEGy  
{ >0:3CpO*  
try{ ea @ H  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); w5y.kc;  
int nCount = input.readInt(); #t Uhul/O  
nStartPos = new long[nCount]; NG3:=  
nEndPos = new long[nCount]; <(TAA15Xol  
for(int i=0;i<nStartPos.length;i++) |FT.x9e-  
{ ^m D$#  
nStartPos = input.readLong();  Q'cWqr  
nEndPos = input.readLong(); D@ sMCR  
} ueU"v'h\  
input.close(); h*KDZ+{)  
} 8?m=Vw<kIZ  
catch(IOException e){e.printStackTrace ();} (&)uWjq `  
catch(Exception e){e.printStackTrace ();} r9(c<E?,h  
} SF:{PgGMi  
V6ECL6n  
fh_:ung  
private void processErrorCode(int nErrorCode) ;W+1 H !  
{ 9`/ywt3Y  
System.err.println("Error Code : " + nErrorCode); c|m?f  
} =&-.]| t  
gjK: a@{  
8KP   
//停止文件下载 9\Rk(dd  
public void siteStop() ( Ygy%O%  
{ OmK0-fa/  
bStop = true; >~_>.R+{  
for(int i=0;i<nStartPos.length;i++) S=< ]u  
fileSplitterFetch.splitterStop(); $h k_v~zM  
*WzPxQ_  
s#0m  
} N/0Q`cQ-  
} -"^"& )  
//负责部分文件的抓取 ]Zay9jD}c-  
**FileSplitterFetch.java <;b  
*/ \sVzBHy d  
package NetFox; S)2Uoj  
>i1wB!gc8  
xU.Ymq& 5  
import java.io.*; rY6bc\?`x  
import java.net.*; Q3)[ *61e  
Bt\V1)  
jP3~O  
public class FileSplitterFetch extends Thread { =>TXo@rVN  
6NFLk+kqN  
.d)H2X  
String sURL; //File URL mp]UUpt  
long nStartPos; //File Snippet Start Position <C*%N;F5R  
long nEndPos; //File Snippet End Position jI}{0LW&F&  
int nThreadID; //Thread's ID QmPHf*w[  
boolean bDownOver = false; //Downing is over k|_ >I  
boolean bStop = false; //Stop identical ON_G D"  
FileAccessI fileAccessI = null; //File Access interface ^dhtc% W>  
#0qMYe>Y  
9JC8OSjJ  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException T:j!a{_|  
{ rlDJHR6  
this.sURL = sURL; c*> SZ'T\  
this.nStartPos = nStart; yF&?gPh&  
this.nEndPos = nEnd; g5&,l  
nThreadID = id; fAR0GOI  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %eqL)pC]  
} >\!>CuU  
5HbPS%^.  
5adB5)`  
public void run() x(88Y7o.t  
{ o{QPW  
while(nStartPos < nEndPos && !bStop) k{$Mlt?&-  
{ ] i\a[3  
9=^4p=1J  
gI~jf- w  
try{ *8QGv6*vQ  
URL url = new URL(sURL); +4p gPv  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B,dKpz;kFg  
httpConnection.setRequestProperty("User-Agent","NetFox"); s%qK<U4@;Q  
String sProperty = "bytes="+nStartPos+"-"; 5/{gY{  
httpConnection.setRequestProperty("RANGE",sProperty); '| |),>~  
Utility.log(sProperty); IC7S +v  
HPR*:t  
?l<u%o  
InputStream input = httpConnection.getInputStream(); ddD $ 4+  
//logResponseHead(httpConnection); ! =c&U.B  
rRZ ,X%  
.@ElfPP(L  
byte[] b = new byte[1024]; )TcW.d6  
int nRead; rj].bGQ,+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) (yel  
{ G" Fd]'  
nStartPos += fileAccessI.write(b,0,nRead); V<!E9/4rS  
//if(nThreadID == 1) xem:#>&r  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \YBY"J  
} Gv}h/zu-  
=r:-CRq(  
;2;Kq)j_=  
Utility.log("Thread " + nThreadID + " is over!"); )#dP:  
bDownOver = true; b1;80P/:D  
//nPos = fileAccessI.write (b,0,nRead); s],+]<qX  
} Gx GZxf*(  
catch(Exception e){e.printStackTrace ();} r`L$[C5I  
} RSY{IY  
} LPk85E  
~WJEH#  
%!HmtpS  
//打印回应的头信息 q*<Df=+B  
public void logResponseHead(HttpURLConnection con) HBL)_c{/O  
{ Q[y75 [  
for(int i=1;;i++) NTVdSK7z~H  
{ ET`;TfqM  
String header=con.getHeaderFieldKey(i); !R WX1Z  
if(header!=null) z rt8ze=Su  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); HzT"{N9  
Utility.log(header+" : "+con.getHeaderField(header)); fO.gfHI  
else , c/\'k\K)  
break; Oav^BhUO  
} mMw&{7b:  
} (+9_nAgZ,  
?/~7\ '|Z  
>b0e"eGt  
public void splitterStop() 928szUo:  
{ b#.hw2?a`  
bStop = true; h?DMrYk_%#  
} F#Oqa^$(  
R)#D{/#FW  
#oi4!%*M  
} JF_\A)<ki  
Sj}@5 X6 C  
Z| +/Wl-h  
/* V2'(}k  
**FileAccess.java >=i47-H  
*//文件访问(定位,写) >0SF79-RE  
package NetFox; | 9!3{3  
import java.io.*; HlY4%M5q/  
V D.p"F(]  
6lq7zi}'w  
public class FileAccessI implements Serializable{ ^C@uP9g  
VD +8j29  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 =[?2'riI  
RandomAccessFile oSavedFile; ALwkX"AN  
long nPos; 2:/'  
%dS7u$Rnh  
}jfU qqFd  
public FileAccessI() throws IOException L;5j hVy  
{ <0R7uH  
this("",0); iH( K[F /  
} VE6T&fz`  
_d]w)YMO  
jfS?#;T)  
public FileAccessI(String sName,long nPos) throws IOException lVXgp'!#j  
{ }` Q'!_`  
oSavedFile = new RandomAccessFile(sName,"rw"); <k5FlvE2  
this.nPos = nPos; hn.9j"  
oSavedFile.seek(nPos); N*lq)@smq  
} o]}b#U8S  
4G@vO {$  
%7O`]ik:  
public synchronized int write(byte[] b,int nStart,int nLen) =1^Ru*G  
{ -t?S:9 [w  
int n = -1; <hdR:k@ #  
try{ g84~d(\?  
oSavedFile.write(b,nStart,nLen); NV*aHci  
n = nLen; :I F&W=?9  
} X&^t 8  
catch(IOException e) mh.0% 9`9  
{ gUL`)t\}*  
e.printStackTrace (); "a5?cX;  
} M$%aX,nk'  
A]BG*  
s3_i5,y  
return n; |j^>6nE  
} jLD=EJ  
F]z xx  
05DK-Wh?  
} z mrk`o~  
A7+eWg{  
N~\1yQT  
/* zL3~,z/o  
**SiteInfoBean.java E} Uy-  
*/ WsJ3zZc  
package NetFox; ~Rk6@&ZS}  
H]UM2.  
V{{b^y  
public class SiteInfoBean { 'e7<&wm ia  
l K}('7\  
eO (VSjo'`  
private String sSiteURL; //Site's URL G}BO!Z6  
private String sFilePath; //Saved File's Path +S^Uw'L$=T  
private String sFileName; //Saved File's Name GLnj& Ve  
private int nSplitter; //Count of Splited Downloading File -7'>Rw  
mZ7.#R*}  
Rc0OEs%7P  
public SiteInfoBean() `Kpn@Xg  
{//nSplitter的缺省值为5 f@[q# }6  
//default value of nSplitter is 5 !wJ~p:vRdY  
this("","","",5); 9N5 &N3  
} r$=iM:kERC  
{]Nvq9?  
$khWu>b  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) z1T.\mzfX  
{ (t>BO`,  
sSiteURL= sURL; zK k;&y|{  
sFilePath = sPath; 1 c3gHc7{t  
sFileName = sName; 3"6lPUS  
this.nSplitter = nSpiltter; u~bk~ 3.I  
,kpk XK  
,m8l /wG  
} nP0|nPWz#  
n0>#?ek12  
s34{\/'D+  
public String getSSiteURL() Wf-i)oc4I  
{ .,o=#  
return sSiteURL; BCJo/m  
} :JV= Kt  
rs]%`"&=  
|XtN\9V.  
public void setSSiteURL(String value) g"`BNI]Qp  
{ x5.H dKV  
sSiteURL = value; brl(7_ 2  
} Xg^`fRg =T  
!)?n n3  
/[q6"R!uMz  
public String getSFilePath() \5_+6  
{ M`q>i B  
return sFilePath; `J'xVq#O  
} g1@zk $  
o:.={)rX  
COH0aNp;  
public void setSFilePath(String value) P6u9Ngay  
{ ['~3"lK^O  
sFilePath = value; }TzMWdT  
} ?T3zA2  
({v$!AAv  
(+`pEDD{X  
public String getSFileName() Q>8F&p?R  
{ $A;jl`ng  
return sFileName; DJVH}w}9_P  
} )a AKO`  
5=WzKM  
!8lG"l|,l  
public void setSFileName(String value) cY8X A6  
{ Hbu8gqu  
sFileName = value; Bi;D d?.  
} Ebw1 %W KC  
X; I:i%-  
m \o<a|  
public int getNSplitter() NRN3*YGo  
{ 9>yLSM,!rS  
return nSplitter; V T8PV5z  
} ` Fnl<C<  
_0N=~`'  
)hs"P%Zg  
public void setNSplitter(int nCount) Ir&rTGFN  
{ $0$'co"  
nSplitter = nCount; ^0)Mc"&{  
}  yY_(o]k  
} R[KF${X4  
 ,5!&}  
,I6jfXI4  
/* c%y(Z5  
**Utility.java ).U\,@[A{  
*/ rQmDpoy=  
package NetFox; qTSyy=  
G"k.sRKu  
8Na.H::cZ  
public class Utility { "NEg]LB5  
4/KGrY! ck  
Yc~(W ue  
public Utility() [v47_ 5O  
{ & -r^Q  
#b~B 0:U  
h?_Cv*0q  
} w O H{L  
9mE6Cp.Wv  
//线程睡眠 zT<fTFJ1  
public static void sleep(int nSecond) grD[7;1~:)  
{ "PgVvm#w'  
try{ @*?)S{8  
Thread.sleep(nSecond); /ILj}g'  
} /q| r!+  
catch(Exception e) G5WQTMzf&  
{ 5(wmy-x\  
e.printStackTrace (); 7 bV(eV  
} 8Z&M}Llk  
} Vz.G!*>Dg  
Wd`*<+t]  
//日志 1`hmD1d  
public static void log(String sMsg) FOPfo b[  
{ [^Z)f<l  
System.err.println(sMsg); 5!QT }Um  
} In[rxT~K}Q  
J#.f%VJ  
]ilQq~X  
public static void log(int sMsg) ]I,(^Xq3a(  
{ A<h^.{  
System.err.println(sMsg); jJY{np  
} ?F6L,  
} ,`Keqfx  
p< Y-b,&  
c,2OICj  
/* eA{ nwtN  
**TestMethod.java a8WWFAC[  
*/ [psZc'q  
package NetFox; Pz^C3h$5_  
t[e]AU[}  
0OXl`V`w  
public class TestMethod { Ucx"\/"  
+\doF  
ZveNe~D7C  
public TestMethod() TU6(Q,Yi|  
{ ///xx/weblogic60b2_win.exe MY60%  
try{ 2tb+3K1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); o)bKs>` U  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); yV~TfTJ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >\!G43Q=  
fileFetch.start(); 3PjX;U|  
} 2 \<u;9  
catch(Exception e){e.printStackTrace ();} mm9uhlV8  
4tEAi4H|`@  
Pn,>eD*g  
} vX7U|zy  
d,b]#fj  
)oALB vX  
public static void main(String[] args) #bJp)&LO  
{ 74 W Ky  
new TestMethod(); D^QL.Du,  
} qSDn0^y  
} N%,zME  
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