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http断点续传简单实现(java)

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/* \lY26'  
**SiteFileFetch.java lcUL7  
*/ ^3r2Q?d\  
package NetFox; lT(MywNsg  
import java.io.*; pkxW19h*0  
import java.net.*; 0&mz'xra  
[e*8hbS  
\}<nXn!  
public class SiteFileFetch extends Thread { Ql\GL"  
/\=g;o'  
L^0jyp  
SiteInfoBean siteInfoBean = null; //文件信息Bean `Zk?.1*2/  
long[] nStartPos; //开始位置 leyX: +  
long[] nEndPos; //结束位置 ml3]CcKn  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9xWeVlfQ  
long nFileLength; //文件长度 a]ftE\99  
boolean bFirst = true; //是否第一次取文件 `GSfA0?  
boolean bStop = false; //停止标志 qQ|v~^  
File tmpFile; //文件下载的临时信息 =UYc~VUYnT  
DataOutputStream output; //输出到文件的输出流 "1l d4/  
^ 5UIbA(  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) qvab >U`  
public SiteFileFetch(SiteInfoBean bean) throws IOException \.*aC)  
{ aIm\tPbb  
siteInfoBean = bean; r<~1:/F|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); YxsW Y7J  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); e <IT2tv>u  
if(tmpFile.exists ()) JM!o(zbt  
{ Y=Bk;%yT=  
bFirst = false; S(rA96n  
read_nPos(); BGUP-_&  
} jLZ~9FXF2  
else fc&4e:Ve  
{ 8Y&(o-R0  
nStartPos = new long[bean.getNSplitter()]; ;up89a-,9  
nEndPos = new long[bean.getNSplitter()]; q5QYp  
} VV?KJz=,W=  
\E0Uj>9+[  
s K s D  
^OYar(  
} Qs*g)Yr  
b~cN#w #  
4egq Y0A  
public void run() 4GaF:/  
{ !R4`ihi1  
//获得文件长度 qL3*H\9N  
//分割文件 \/'u(|G  
//实例FileSplitterFetch ,qt9S0 QS  
//启动FileSplitterFetch线程 DmPp&  
//等待子线程返回 347p2sK>  
try{ Ga$+x++'*  
if(bFirst) `|Tr"xavf  
{ `2U zJ~  
nFileLength = getFileSize(); MSsboSxA  
if(nFileLength == -1) p]IF=~b  
{ A=E1S{C  
System.err.println("File Length is not known!"); hesL$Z [  
} vJ }^ p }  
else if(nFileLength == -2) c`AtK s)u  
{ L)J0T Sh  
System.err.println("File is not access!"); }"%tlU!}  
} mq su8ti  
else (*BQd1Z  
{ x.~Z9j  
for(int i=0;i<nStartPos.length;i++) ErHbc 2  
{ Mb uD8B  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .[ NB"\<q  
} {Jwh .bJ  
for(int i=0;i<nEndPos.length-1;i++) !z$.Jcr1  
{ K1]H~'  
nEndPos = nStartPos[i+1]; J9zSBsp_  
} (%YFcE)SRS  
nEndPos[nEndPos.length-1] = nFileLength; iE!\)7y  
} j"9bt GX  
} O4S~JE3o  
vzd1:'^t  
?ep93:j  
//启动子线程 lqTTTk  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; bO8g#rO  
for(int i=0;i<nStartPos.length;i++) &2d^=fih  
{ -uHD| }  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -O:+?gG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), N p$pz  
nStartPos,nEndPos,i); (:4N#p  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 67wY_\m9I  
fileSplitterFetch.start(); s=h  
} rzsb(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o['HiX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); LJt#c+]Li  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", imv[xBA(d  
nEndPos = " + nFileLength); YIvJN  
// fileSplitterFetch[nPos.length-1].start(); XXBN Nr_CK  
y1GVno  
wt0^R<28  
//等待子线程结束 meA=lg?  
//int count = 0; lTBPq?4{  
//是否结束while循环 K[!OfP  
boolean breakWhile = false; Ri=>evx  
mtSOygd  
ACxOC2\n  
while(!bStop) `xMmo8u4  
{ {4SwCN /  
write_nPos(); >~8;H x].d  
Utility.sleep(500); pC2ZN  
breakWhile = true; BQu_)@  
aw&:$twbM  
e33j&:O  
for(int i=0;i<nStartPos.length;i++) J6r"_>)z  
{ uu@Y]0-  
if(!fileSplitterFetch.bDownOver) %xF j;U?  
{ 1RpTI7  
breakWhile = false; ufyqfID  
break; 4=!SG4~o  
} 6;6a.iZ  
} Fr_esx  
if(breakWhile) bL soKe  
break; o!!";q%DX  
-e0C Bp  
3NAU|//J  
//count++; ~b;l08 <  
//if(count>4) Z^5j.d{e$  
// siteStop(); golr,+LSo  
}  O_^O1  
3 r4QB  
-;9pZ'r  
System.err.println("文件下载结束!"); AT Dm$ *  
} `7_=2C  
catch(Exception e){e.printStackTrace ();} 65X31vU  
} &U q++f6  
v0hr~1  
/^ *GoB  
//获得文件长度 banie{ e  
public long getFileSize() 2ED^uc: 0S  
{ y Nb&;E7 H  
int nFileLength = -1; juOOD   
try{ DE"KbA0}  
URL url = new URL(siteInfoBean.getSSiteURL()); DwM4/m  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [GKSQt{)  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7 +A-S9P)  
AdBF$nn[  
;m6Mm`[i<  
int responseCode=httpConnection.getResponseCode(); l*]9   
if(responseCode>=400) jCdKau&9  
{ p_h)|*W{  
processErrorCode(responseCode); 8qwc]f$.w  
return -2; //-2 represent access is error <q Z"W6&&  
} _\yrR.HIa  
XgY( Vv  
2y; |6`  
String sHeader; 7+] T}4;  
86d *  
.gUceXWH3  
for(int i=1;;i++) ,])@?TJb@  
{ "h.}o DS  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); VU,\OOp  
//Utility.log(in.readLine()); il^SGH  
sHeader=httpConnection.getHeaderFieldKey(i); : sIZ+3  
if(sHeader!=null) i(.c<e{v~  
{ ,Ie~zZE&  
if(sHeader.equals("Content-Length")) xo{f"8}^  
{ EFeGxM  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); x)<5f|j  
break; v8g3]MVj3  
} y@g{:/cmO  
} _DfI78`(  
else Yjz'lWg  
break; AfvTStwr  
} j}YZl@dYV  
} o:C:obiQbu  
catch(IOException e){e.printStackTrace ();} @'[w7HsJ  
catch(Exception e){e.printStackTrace ();} b7fP)nb695  
~h-G  
p}uT qI  
Utility.log(nFileLength); 2^Gl;3  
M"F?'zTkJ  
#I9|>XE1  
return nFileLength; Lc^nNUzPo  
} /b@0HL?  
:j$K.3n  
THQ W8 V  
//保存下载信息(文件指针位置) 4@#1G*OO  
private void write_nPos() 7-Rn{"5  
{ ZTd_EY0q  
try{ tjkY[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); aq"E@fb  
output.writeInt(nStartPos.length); i2b\` 805  
for(int i=0;i<nStartPos.length;i++) 9.e?<u*-z  
{ d%9I*Qo0,  
// output.writeLong(nPos); Wf_aEW&n  
output.writeLong(fileSplitterFetch.nStartPos); 0<{/T*AU:  
output.writeLong(fileSplitterFetch.nEndPos); O60jC;{F  
} tZ>>aiI3  
output.close(); aGp <%d  
} -a3+C,I8g  
catch(IOException e){e.printStackTrace ();} _wM[U`H}s  
catch(Exception e){e.printStackTrace ();} b7v] g]*  
} ?>q=Nf^Q.  
i#lvt#2J0  
8q7KqYu  
//读取保存的下载信息(文件指针位置) doc5;?6   
private void read_nPos() psRm*,*O  
{ SfJ/(q  
try{ &\sg~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); i40r}?-  
int nCount = input.readInt(); dG7sY O@U  
nStartPos = new long[nCount]; pRc(>P3;  
nEndPos = new long[nCount]; pzU">)  
for(int i=0;i<nStartPos.length;i++) d;lp^K M  
{ R$,`}@VqZ3  
nStartPos = input.readLong(); (]1le|+  
nEndPos = input.readLong(); yF0,}  
} 1b3Lan_2  
input.close(); (/"T=`3t  
} ]CC~Eo-%-  
catch(IOException e){e.printStackTrace ();} 3{MIBMA  
catch(Exception e){e.printStackTrace ();} e7#=F6  
} 8x,;B_Zu  
I]SR.Yp%  
h:bs/q+-  
private void processErrorCode(int nErrorCode) D4#,9?us  
{ T>f-b3dk  
System.err.println("Error Code : " + nErrorCode); 8QC:ro  
} ,7%(Jj$ ^  
Bl`e+&b  
P\zi:]h[Gh  
//停止文件下载 k}T~N.0  
public void siteStop() 3'/wRKl  
{ <Isr  
bStop = true; eHnC^W}|s  
for(int i=0;i<nStartPos.length;i++) A5H[g`&  
fileSplitterFetch.splitterStop(); ;4qalxzu  
|um)vlN;9  
Be]o2N;J  
} \17)=W  
} $^ >n@Q@&L  
//负责部分文件的抓取 ^E:;8h4$9  
**FileSplitterFetch.java :sA-$*&x  
*/ -5>g 0o2  
package NetFox; >LLzG  
*n[Fl  
I" j7  
import java.io.*; R,^FJ  
import java.net.*; 6|jE3rHw  
Xif`gb6`  
F H%yyT  
public class FileSplitterFetch extends Thread { SfR!q4b=  
ljf9L:L  
DHJnz>bE  
String sURL; //File URL @%fkW"y:  
long nStartPos; //File Snippet Start Position Z'j<wRf  
long nEndPos; //File Snippet End Position jyT(LDsS  
int nThreadID; //Thread's ID &WRoNc  
boolean bDownOver = false; //Downing is over m76]INq  
boolean bStop = false; //Stop identical 2 rBF<z7  
FileAccessI fileAccessI = null; //File Access interface &a(w0<  
iH$N HfH  
D@ lJ^+  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @v'<~9vG  
{ #]'V#[;~  
this.sURL = sURL; Pb`sn5;  
this.nStartPos = nStart; v m$v[  
this.nEndPos = nEnd; F3f>pK5  
nThreadID = id; wvYxL c#p0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 >L(F{c:  
} qqAsh]Z  
jGWLYI=V2  
s1FBz)yCY=  
public void run() *Xo f;)Z^  
{ 8]L.E  
while(nStartPos < nEndPos && !bStop) GJ$,@  
{ 3_>1j  
. =5Jpo  
Qp54(`  
try{ *~"`&rM(  
URL url = new URL(sURL); !(~>-;A8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @88 efF  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0T5>i 0/  
String sProperty = "bytes="+nStartPos+"-"; 7lpVK]  
httpConnection.setRequestProperty("RANGE",sProperty); |)_R bqZ  
Utility.log(sProperty); GwycSb1  
P&YaJUq.u  
w\ :b(I  
InputStream input = httpConnection.getInputStream(); aVb]H0  
//logResponseHead(httpConnection); Rt|Hma  
Yp)U'8{h c  
aFym&n\  
byte[] b = new byte[1024]; a8 1%M  
int nRead; ]4yvTP3[Rm  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 6b|`[t  
{ l.juys8s  
nStartPos += fileAccessI.write(b,0,nRead); ""d>f4,S  
//if(nThreadID == 1) yd~fC:_ ]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \2,18E  
} $yAfs3/%)s  
abnd U,s  
w-$w  
Utility.log("Thread " + nThreadID + " is over!"); o0L#39`' g  
bDownOver = true; ar|[D7Xrq\  
//nPos = fileAccessI.write (b,0,nRead); S+G)&<a^  
} Anv8)J!9u  
catch(Exception e){e.printStackTrace ();} d@tr]v5 B  
} Yn>zR I  
} q1Sm#_7  
F21[r!3  
r<v%Zp  
//打印回应的头信息 5XI*I( .%/  
public void logResponseHead(HttpURLConnection con) >G2-kL_  
{ %#9~V  
for(int i=1;;i++)  uN 62>  
{ \<B6>  
String header=con.getHeaderFieldKey(i); [r8 d+  
if(header!=null) VWy:U#;+8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,d>~='  
Utility.log(header+" : "+con.getHeaderField(header)); QtQ^"d65  
else v s|6w w  
break; 9Oyi:2A  
} 8 -;ZPhN&  
} ;|QR-m2/  
+c`C9RXk  
SsX05>  
public void splitterStop() xm5FQ) T  
{ FM"BTA:C  
bStop = true; t[,T}BCy.  
} gsWlTI  
y%bqeo L~  
>5Oy^u6Ly  
} r/sRXM:3cZ  
!a(qqZ|s  
 jnzz~:  
/* MVP)rugU  
**FileAccess.java Y~hd<8 ~  
*//文件访问(定位,写) rqe_zyc&  
package NetFox; k`mrRs  
import java.io.*; 2G5!u)  
'3UIriY6  
nQ!#G(_nO  
public class FileAccessI implements Serializable{ O\F^@;] F6  
1qKxg  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _<F@(M5  
RandomAccessFile oSavedFile; f9XO9N,hE:  
long nPos; r]EZ)qp^@  
2]RH)W86;  
obc^<ZD]  
public FileAccessI() throws IOException j X!ftm2  
{ pkV\D  
this("",0); k&_u\D"^"%  
} B0XBI0w^Y  
i~Ob( YIH  
e9hVX[uq  
public FileAccessI(String sName,long nPos) throws IOException QRZTT qG  
{ OK2/k_jXN'  
oSavedFile = new RandomAccessFile(sName,"rw"); q'AnI$!  
this.nPos = nPos; :f !=_^}  
oSavedFile.seek(nPos); - Zoo)  
} ny_ kr`$42  
@1SKgbt>  
%)hIpxOrX  
public synchronized int write(byte[] b,int nStart,int nLen) )>X|o$2  
{ k5%0wHpk=  
int n = -1; ]^6y NtLK  
try{ 3|'#n[3  
oSavedFile.write(b,nStart,nLen); C(1A8  
n = nLen; >[%.h(h/%  
} PxVI {:Uz  
catch(IOException e) )3`  
{ ?(NT!es  
e.printStackTrace (); fF9oYOh|  
} z1SMQLk  
<j1d~XU}  
~ut& U  
return n; B-ri}PA  
} @F(3*5c_Y  
J.e8UQ@=5  
qp~4KukL  
} \l=KWa3Q  
$YGIN7_Gg  
jQ_|z@OV  
/* %X9:R'~sP  
**SiteInfoBean.java ahi57r[  
*/ RqN_vk\  
package NetFox; X.T\=dm%v  
QC\g%MVG  
v1"g!%U6  
public class SiteInfoBean { x,w`OMQ}c  
{Z?$Co^R  
rz[uuY7  
private String sSiteURL; //Site's URL iQm.]A  
private String sFilePath; //Saved File's Path %+7T9>+  
private String sFileName; //Saved File's Name BudWbZ5>Ep  
private int nSplitter; //Count of Splited Downloading File I"F .%re  
)S wG+k,  
=ve*g&  
public SiteInfoBean() =_?pOq  
{//nSplitter的缺省值为5 GEe 0@q#YA  
//default value of nSplitter is 5 Q0L@.`~  
this("","","",5); 7{K i;1B[w  
} b5n]Gp  
I4o =6ts  
dY4k9p8  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^ =/?<C4  
{ 9Ew:.&d  
sSiteURL= sURL; q2S!m6!  
sFilePath = sPath; \&\_>X.,  
sFileName = sName; Ha=_u+@  
this.nSplitter = nSpiltter; u^aFj%}]L  
EZ%w=  
{w |dM#  
} ==h|+NFa  
l}Q"Nb)  
EI=Naq  
public String getSSiteURL() 9k=U0]!ch  
{ B0b[p*g Il  
return sSiteURL; 68koQgI[^  
} "'z,[v 50&  
(b/A|hl  
tT@w%Sz57N  
public void setSSiteURL(String value) nOAJ9  
{ tb:,Uf>E  
sSiteURL = value; Ci7P%]9  
} i}/e}s<-6  
`1E|PQbWc  
%Y cxC0S[  
public String getSFilePath() V>b2b5QAH,  
{ T~i%j@Q.6  
return sFilePath; ]>R`;"(  
} e2]4a3  
PGPISrf  
HE#,(;1i  
public void setSFilePath(String value) GBH_r 0  
{ EJf#f  
sFilePath = value; g>2aIun_Q  
} sU) TXL'_!  
S  ~@r  
v! 7s M  
public String getSFileName() ?QCmSK=L  
{ NFk}3w:  
return sFileName; o&(wg(Rv  
} T>}0) s  
Q~Ay8L+  
&+mV7o  
public void setSFileName(String value) v8ba~  
{ ;B&^yj&;  
sFileName = value; x(L(l=^"  
} ShQ|{P9  
Fi mN?s  
ojHhT\M`  
public int getNSplitter() K&=D-50%  
{ `/#f?Hk=  
return nSplitter; o^3FL||P#r  
} <f N; xIB  
Zp?4uQ)[W  
4-mVB wq  
public void setNSplitter(int nCount) 3sH\1)Zz  
{ 9YB2 e84j  
nSplitter = nCount; l , ..5   
} .%q$d d>>  
} ^YGTh0$W  
8{dEpV*  
PgMbMH  
/* X0`j-*,FX  
**Utility.java ; e@gO  
*/ Yu'a<5f  
package NetFox; Y9F)`1 7  
nX|Q~x]  
2 nv[1@M  
public class Utility { jpRBER_X  
2-~|Z=eGW  
Gqb])gXpl  
public Utility() we3tx{j  
{ (&jW}1D  
?~J i-{#X  
l _+6=u  
} CK0l9#g  
8-m 3e  
//线程睡眠  FZ F @  
public static void sleep(int nSecond) ef=K_, _  
{ 4:7mK/Z  
try{ ?7 \\e;j}  
Thread.sleep(nSecond); jfD1  
} d|XmasGN  
catch(Exception e) iib  
{ +L0w;wT  
e.printStackTrace (); +`B'r '  
} d H? ScXM=  
} r3qf[?3`6  
y500Xs[c  
//日志 :P$#MC  
public static void log(String sMsg) D'b#,a;V  
{ ]5' d&f  
System.err.println(sMsg); +H_MV=A^  
} .$&Q[r3Lu  
(u hd "  
{^}0 G^  
public static void log(int sMsg) <@G8ni  
{ `]=oo%(h  
System.err.println(sMsg); ,lt8O.h-l  
} maNW{"1  
} t P"\J(x  
AVl~{k|  
Hp Vjee  
/* k`\R+WK$  
**TestMethod.java \( )# e  
*/ @F~LW6K  
package NetFox; /KCPpERk{  
e5?PkFV^a1  
qQ0C?  
public class TestMethod { x%N\5 V1  
`.%JjsD<  
k |YWOy@D~  
public TestMethod() amWD-0V  
{ ///xx/weblogic60b2_win.exe cXnKCzSxZq  
try{ QA#3bFZt1n  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); lFSe?X^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); dRi5hC$  
SiteFileFetch fileFetch = new SiteFileFetch(bean); EW<kI+0D  
fileFetch.start(); 8RW&r  
} ?GA&f2]a  
catch(Exception e){e.printStackTrace ();} FV39QG4b4  
@n&<B`/  
O#a6+W"U  
} 23!;}zHp  
ZR0r>@M3v<  
en F:>H4  
public static void main(String[] args) O81X ;JdP3  
{ ^].jH+7i*  
new TestMethod(); .@q-B+Eg  
} G oM ip8'u  
} h}`!(K^;3  
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