jdbc 更新 测 并发

用到 junitperf-1.9.1.jar 这个包

用到 junit4

package com.bingfa;
import java.sql.Connection;

public final class JDBCUtils {
  private JDBCUtils() {
  }

  private static String url = "jdbc:mysql://localhost:3306/test";
  private static String user = "root";
  private static String password = "root";

  static {
    try {
      Class.forName("com.mysql.jdbc.Driver");
    } catch (ClassNotFoundException e) {
      throw new ExceptionInInitializerError(e);
    }
  }

  public static Connection getConnection() throws SQLException {
    return DriverManager.getConnection(url, user, password);
  }

  public static void freePs(ResultSet rs, PreparedStatement ps, Connection conn) {
    try {
      if (rs != null)
        rs.close();
    } catch (SQLException e) {
      e.printStackTrace();
    } finally {
      try {
        if (ps != null)
          ps.close();
      } catch (SQLException e) {
        e.printStackTrace();
      } finally {
        try {
          if (conn != null)
            conn.close();
        } catch (SQLException e) {
          e.printStackTrace();
        }
      }
    }
  }
  
  
  public static void freeSt(ResultSet rs, Statement st, Connection conn) {
    try {
      if (rs != null)
        rs.close();
    } catch (SQLException e) {
      e.printStackTrace();
    } finally {
      try {
        if (st != null)
          st.close();
      } catch (SQLException e) {
        e.printStackTrace();
      } finally {
        try {
          if (conn != null)
            conn.close();
        } catch (SQLException e) {
          e.printStackTrace();
        }
      }
    }
  }
}

更新表，里面有用Statement和PreparedStatement两种方式

package com.bingfa;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;

public class UploadCC {
  

  public static void JDBCStatment() throws Exception {
    Connection conn = null;
    Statement st = null;
    ResultSet rs = null;
    try {
      conn = (Connection) JDBCUtils.getConnection();
      conn.setAutoCommit(false);
      
      String sql = "";
      sql = "SELECT cc FROM test WHERE id=1 ";
      st = conn.createStatement();
      rs = st.executeQuery(sql);
      int c = 0;
      while (rs.next()) {
        c = rs.getInt(1);
      }
      c = c + 1;
//用cc=cc+1，不会有并发问题，如果用c=c+1，则有问题
      sql = "UPDATE test SET cc = cc+1 WHERE id =1 ";
      st=(Statement) conn.createStatement();
      st.execute(sql);
      conn.commit();
      
    } finally {
      JDBCUtils.freeSt(rs, st, conn);
    }
  }
  
  
  
  public static void JDBCPrepare() throws Exception {
    Connection conn = null;
    PreparedStatement ps = null;
    ResultSet rs = null;
    try {
      conn = (Connection) JDBCUtils.getConnection();
      conn.setAutoCommit(false);
      String sql = "";
      sql = "SELECT cc FROM test WHERE id=1 ";
      ps = conn.prepareStatement(sql);
      rs = ps.executeQuery();
      int c = 0;
      while (rs.next()) {
        c = rs.getInt(1);
      }
      c = c + 1;
      sql = "UPDATE test SET cc = ? WHERE id =1 ";
      ps = conn.prepareStatement(sql);
      ps.setInt(1, c);
      ps.execute();
      conn.commit();
    } finally {
      JDBCUtils.freePs(rs, ps, conn);
    }
  }

}

测试类，注意，测试并发并不用直接使用此类

package test;

import junit.framework.TestCase;

public class UploadCCTest extends TestCase {

  public UploadCCTest(String name) {
    super(name);
  }

  @org.junit.Test
  public void testJdbcStatment() {
    try {
      UploadCC.JDBCStatment();
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
  
  
  @org.junit.Test
  public void testJdbcPrepare() {
    try {
      UploadCC.JDBCPrepare();
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

}

用这个类进行并发测试

package test;

import com.clarkware.junitperf.LoadTest;
import com.clarkware.junitperf.TestMethodFactory;

import junit.framework.Test;

public class TestSuite {
  public static Test suite() {
    Test suite = new TestMethodFactory(UploadCCTest.class, "testJdbcStatment");
    Test loadTest = new LoadTest(suite, 20, 10);
//如果正常，cc的值应为200,但如果用c=c+1，值肯定小于200
    return loadTest;
  }
  
//  public static Test suite() {
//    Test suite = new TestMethodFactory(UploadCCTest.class, "testJdbcPrepare");
//    Test loadTest = new LoadTest(suite, 20, 10);
//    return loadTest;
//  }
}

• ​​junitperf-1.9.1.jar​​ (34.8 KB)
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