请教java批量更新mysql，为什么update进程会sleep呢？？？那个数据库只有我一个人在用的，只执行一个select，然后依次根据id进行update,有时候update进程就sleep了.importjava.sql.Co...

请教java批量更新mysql，为什么update进程会sleep呢？？？那个数据库只有我一个人在用的，只执行一个select，然后依次根据id进行update,有时候update进程就sleep了.

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.SQLException;

import java.util.ArrayList;

import java.util.concurrent.ArrayBlockingQueue;

public class DBwriteThread implements Runnable {

private volatile ArrayBlockingQueue queue2;

private volatile ArrayBlockingQueue flag;

public DBwriteThread(ArrayBlockingQueue queue2,

ArrayBlockingQueue flag) {

this.queue2 = queue2;

this.flag = flag;

}

public void run() {

String driver = "com.mysql.jdbc.Driver";

String url = "jdbc:mysql://localhost:3306/dev";

String user = "user";

String password = "password";

Connection conn = null;

PreparedStatement stmt = null;

try {

Class.forName(driver);

conn = DriverManager.getConnection(url, user, password);

conn.setAutoCommit(false);

while ((flag.size() < 2) || (!(queue2.isEmpty()))) {

try {

String sql = "update SINA_LEARN_SAMPLE set PARSE_LINE=?,WORD=?,TIMES=?,FEATURE=? where document_id=";

Documents newDocument = queue2.take();

String sql1 = sql + (newDocument.getDocumentID());

String word;

String times;

String feature;

stmt = conn.prepareStatement(sql1);

word = ArrayListToString(newDocument.getWord());

times = ArrayListToString(newDocument.getTime());

feature = ArrayListToString(newDocument.getFeature());

stmt.setString(1, newDocument.getParseLine().get(0));

stmt.setString(2, word);

stmt.setString(3, times);

stmt.setString(4, feature);

stmt.executeUpdate();

conn.commit();

} catch (InterruptedException e1) {

break;

}

}

flag.put(5);

} catch (ClassNotFoundException e1) {

System.err.println("装载JDBC失败");

e1.printStackTrace();

} catch (SQLException e2) {

System.err.println("SQL异常");

e2.printStackTrace();

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} finally {

if (stmt != null) {

try {

stmt.close();

} catch (SQLException e) {

e.printStackTrace();

}

}

if (conn != null) {

try {

conn.close();

} catch (SQLException e) {

e.printStackTrace();

}

}

}

}

public String ArrayListToString(ArrayList newArray) {

String result = null;

for (int i = 0; i < newArray.size(); i++) {

if (result == null) {

result = newArray.get(i);

} else {

result = result + "," + newArray.get(i);

}

}

return result;

}

}

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