java.sql.ResultSet.next()方法的使用及代码示例

x33g5p2x  于2022-01-28 转载在 其他  
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本文整理了Java中java.sql.ResultSet.next方法的一些代码示例，展示了ResultSet.next的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。ResultSet.next方法的具体详情如下：
包路径：java.sql.ResultSet
类名称：ResultSet
方法名：next

ResultSet.next介绍

[英]Shifts the cursor position down one row in this ResultSet object.

Any input streams associated with the current row are closed and any warnings are cleared.
[中]在此ResultSet对象中将光标位置下移一行。
与当前行关联的所有输入流都将关闭，所有警告都将清除。

代码示例

canonical example by Tabnine

public void runQuery(String url, String sql) {
  try (Connection connection = DriverManager.getConnection(url);
     PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
    // ... add parameters to the SQL query using PreparedStatement methods:
    //     setInt, setString, etc.
    try (ResultSet resultSet = preparedStatement.executeQuery()) {
      while (resultSet.next()) {
        // ... do something with result set
      }
    }
  } catch (SQLException e) {
    // ... handle SQL exception
  }
}

代码示例来源：origin: prestodb/presto

private static String getSessionProperty(Connection connection, String key, String valueType)
    throws SQLException
{
  try (Statement statement = connection.createStatement()) {
    ResultSet rs = statement.executeQuery("SHOW SESSION");
    while (rs.next()) {
      if (rs.getString("Name").equals(key)) {
        return rs.getString(valueType);
      }
    }
  }
  return null;
}

代码示例来源：origin: stackoverflow.com

Statement stmt = conn.createStatement();
try {
  ResultSet rs = stmt.executeQuery( "SELECT FULL_NAME FROM EMP" );
  try {
    while ( rs.next() ) {
      System.out.println( "Name: " + rs.getString("FULL_NAME") );
    }
  } finally {
    try { rs.close(); } catch (Exception ignore) { }
  }
} finally {
  try { stmt.close(); } catch (Exception ignore) { }
}

代码示例来源：origin: com.h2database/h2

/**
 * Get the user name for this id.
 * This method is called by the database.
 *
 * @param conn the connection
 * @param id the user id
 * @return the user name
 */
public static String getUserById(Connection conn, int id) throws SQLException {
  PreparedStatement prep = conn.prepareStatement(
      "SELECT NAME FROM INFORMATION_SCHEMA.USERS WHERE ID=?");
  prep.setInt(1, id);
  ResultSet rs = prep.executeQuery();
  if (rs.next()) {
    return rs.getString(1);
  }
  return null;
}

代码示例来源：origin: prestodb/presto

private static void assertConnectionSource(Connection connection, String expectedSource)
      throws SQLException
  {
    String queryId;
    try (Statement statement = connection.createStatement();
        ResultSet rs = statement.executeQuery("SELECT 123")) {
      queryId = rs.unwrap(PrestoResultSet.class).getQueryId();
    }

    try (PreparedStatement statement = connection.prepareStatement(
        "SELECT source FROM system.runtime.queries WHERE query_id = ?")) {
      statement.setString(1, queryId);
      try (ResultSet rs = statement.executeQuery()) {
        assertTrue(rs.next());
        assertThat(rs.getString("source")).isEqualTo(expectedSource);
        assertFalse(rs.next());
      }
    }
  }
}

代码示例来源：origin: spring-projects/spring-framework

@Test
public void testStringQueryWithoutResults() throws SQLException {
  given(resultSet.next()).willReturn(false);
  StringQuery query = new StringQuery(dataSource, SELECT_FORENAME_EMPTY);
  String[] results = query.run();
  assertThat(results, is(equalTo(new String[0])));
  verify(connection).prepareStatement(SELECT_FORENAME_EMPTY);
  verify(resultSet).close();
  verify(preparedStatement).close();
  verify(connection).close();
}

代码示例来源：origin: spring-projects/spring-framework

@Test
public void testStringQueryWithResults() throws Exception {
  String[] dbResults = new String[] { "alpha", "beta", "charlie" };
  given(resultSet.next()).willReturn(true, true, true, false);
  given(resultSet.getString(1)).willReturn(dbResults[0], dbResults[1], dbResults[2]);
  StringQuery query = new StringQuery(dataSource, SELECT_FORENAME);
  query.setRowsExpected(3);
  String[] results = query.run();
  assertThat(results, is(equalTo(dbResults)));
  verify(connection).prepareStatement(SELECT_FORENAME);
  verify(resultSet).close();
  verify(preparedStatement).close();
  verify(connection).close();
}

代码示例来源：origin: iluwatar/java-design-patterns

/**
 * {@inheritDoc}
 */
@Override
public Optional<Customer> getById(int id) throws Exception {
 ResultSet resultSet = null;
 try (Connection connection = getConnection();
   PreparedStatement statement = 
     connection.prepareStatement("SELECT * FROM CUSTOMERS WHERE ID = ?")) {
  statement.setInt(1, id);
  resultSet = statement.executeQuery();
  if (resultSet.next()) {
   return Optional.of(createCustomer(resultSet));
  } else {
   return Optional.empty();
  }
 } catch (SQLException ex) {
  throw new CustomException(ex.getMessage(), ex);
 } finally {
  if (resultSet != null) {
   resultSet.close();
  }
 }
}

代码示例来源：origin: prestodb/presto

@Test(timeOut = 10_000)
public void testPartialCancel()
    throws Exception
{
  try (Connection connection = createConnection();
      Statement statement = connection.createStatement();
      ResultSet resultSet = statement.executeQuery("SELECT count(*) FROM blackhole.test.slow")) {
    statement.unwrap(PrestoStatement.class).partialCancel();
    assertTrue(resultSet.next());
    assertEquals(resultSet.getLong(1), 0);
  }
}

代码示例来源：origin: spring-projects/spring-framework

@Test
public void testCloseConnectionOnRequest() throws Exception {
  String sql = "SELECT ID, FORENAME FROM CUSTMR WHERE ID < 3";
  given(this.resultSet.next()).willReturn(false);
  given(this.connection.createStatement()).willReturn(this.preparedStatement);
  RowCountCallbackHandler rcch = new RowCountCallbackHandler();
  this.template.query(sql, rcch);
  verify(this.resultSet).close();
  verify(this.preparedStatement).close();
  verify(this.connection).close();
}

代码示例来源：origin: stackoverflow.com

public void create(User user) throws SQLException {
  try (
    Connection connection = dataSource.getConnection();
    PreparedStatement statement = connection.prepareStatement(SQL_INSERT,
                   Statement.RETURN_GENERATED_KEYS);
  ) {
    statement.setString(1, user.getName());
    statement.setString(2, user.getPassword());
    statement.setString(3, user.getEmail());
    // ...

    int affectedRows = statement.executeUpdate();

    if (affectedRows == 0) {
      throw new SQLException("Creating user failed, no rows affected.");
    }

    try (ResultSet generatedKeys = statement.getGeneratedKeys()) {
      if (generatedKeys.next()) {
        user.setId(generatedKeys.getLong(1));
      }
      else {
        throw new SQLException("Creating user failed, no ID obtained.");
      }
    }
  }
}

代码示例来源：origin: spring-projects/spring-framework

@Test
public void testQueryForObjectWithString() throws Exception {
  String sql = "SELECT AGE FROM CUSTMR WHERE ID = 3";
  given(this.resultSet.next()).willReturn(true, false);
  given(this.resultSet.getString(1)).willReturn("myvalue");
  assertEquals("myvalue", this.template.queryForObject(sql, String.class));
  verify(this.resultSet).close();
  verify(this.statement).close();
}

代码示例来源：origin: gocd/gocd

private static Long executeScalar(PreparedStatement ps, Long defaultValue) throws SQLException {
  ResultSet rs = null;
  try {
    rs = ps.executeQuery();
    if (rs.next()) {
      return rs.getLong(1);
    }
    return defaultValue;
  } finally {
    closeQuietly(rs);
  }
}

代码示例来源：origin: prestodb/presto

private void checkRepresentation(String expression, int expectedSqlType, ResultAssertion assertion)
    throws Exception
{
  try (ResultSet rs = statement.executeQuery("SELECT " + expression)) {
    ResultSetMetaData metadata = rs.getMetaData();
    assertEquals(metadata.getColumnCount(), 1);
    assertEquals(metadata.getColumnType(1), expectedSqlType);
    assertTrue(rs.next());
    assertion.accept(rs, 1);
    assertFalse(rs.next());
  }
}

代码示例来源：origin: elasticjob/elastic-job-lite

private String getOriginalTaskId(final String taskId) {
  String sql = String.format("SELECT original_task_id FROM %s WHERE task_id = '%s' and state='%s' LIMIT 1", TABLE_JOB_STATUS_TRACE_LOG, taskId, State.TASK_STAGING);
  String result = "";
  try (
      Connection conn = dataSource.getConnection();
      PreparedStatement preparedStatement = conn.prepareStatement(sql);
      ResultSet resultSet = preparedStatement.executeQuery()
  ) {
    if (resultSet.next()) {
      return resultSet.getString("original_task_id");
    }
  } catch (final SQLException ex) {
    // TODO 记录失败直接输出日志,未来可考虑配置化
    log.error(ex.getMessage());
  }
  return result;
}

代码示例来源：origin: com.h2database/h2

/**
 * Get the name of the current schema.
 * This method is called by the database.
 *
 * @param conn the connection
 * @return the schema name
 */
public static String getCurrentSchema(Connection conn) throws SQLException {
  ResultSet rs = conn.createStatement().executeQuery("call schema()");
  rs.next();
  return rs.getString(1);
}

代码示例来源：origin: spring-projects/spring-framework

@Before
public void setUp() throws SQLException {
  given(connection.createStatement()).willReturn(statement);
  given(connection.prepareStatement(anyString())).willReturn(preparedStatement);
  given(statement.executeQuery(anyString())).willReturn(resultSet);
  given(preparedStatement.executeQuery()).willReturn(resultSet);
  given(resultSet.next()).willReturn(true, true, false);
  given(resultSet.getString(1)).willReturn("tb1", "tb2");
  given(resultSet.getInt(2)).willReturn(1, 2);
  template.setDataSource(new SingleConnectionDataSource(connection, false));
  template.setExceptionTranslator(new SQLStateSQLExceptionTranslator());
  template.afterPropertiesSet();
}

代码示例来源：origin: spring-projects/spring-framework

@Test
public void testQueryForObjectWithMapAndInteger() throws Exception {
  given(resultSet.getMetaData()).willReturn(resultSetMetaData);
  given(resultSet.next()).willReturn(true, false);
  given(resultSet.getInt(1)).willReturn(22);
  Map<String, Object> params = new HashMap<>();
  params.put("id", 3);
  Object o = template.queryForObject("SELECT AGE FROM CUSTMR WHERE ID = :id",
      params, Integer.class);
  assertTrue("Correct result type", o instanceof Integer);
  verify(connection).prepareStatement("SELECT AGE FROM CUSTMR WHERE ID = ?");
  verify(preparedStatement).setObject(1, 3);
}

代码示例来源：origin: spring-projects/spring-framework

@Test
public void testQueryWithRowCallbackHandlerNoParameters() throws SQLException {
  given(resultSet.next()).willReturn(true, false);
  given(resultSet.getInt("id")).willReturn(1);
  given(resultSet.getString("forename")).willReturn("rod");
  final List<Customer> customers = new LinkedList<>();
  namedParameterTemplate.query(SELECT_NO_PARAMETERS, rs -> {
    Customer cust = new Customer();
    cust.setId(rs.getInt(COLUMN_NAMES[0]));
    cust.setForename(rs.getString(COLUMN_NAMES[1]));
    customers.add(cust);
  });
  assertEquals(1, customers.size());
  assertTrue("Customer id was assigned correctly", customers.get(0).getId() == 1);
  assertTrue("Customer forename was assigned correctly", customers.get(0).getForename().equals("rod"));
  verify(connection).prepareStatement(SELECT_NO_PARAMETERS);
  verify(preparedStatement).close();
  verify(connection).close();
}

代码示例来源：origin: alibaba/druid

public static List<Map<String, Object>> executeQuery(Connection conn, String sql, List<Object> parameters)
                                                     throws SQLException {
  List<Map<String, Object>> rows = new ArrayList<Map<String, Object>>();
  PreparedStatement stmt = null;
  ResultSet rs = null;
  try {
    stmt = conn.prepareStatement(sql);
    setParameters(stmt, parameters);
    rs = stmt.executeQuery();
    ResultSetMetaData rsMeta = rs.getMetaData();
    while (rs.next()) {
      Map<String, Object> row = new LinkedHashMap<String, Object>();
      for (int i = 0, size = rsMeta.getColumnCount(); i < size; ++i) {
        String columName = rsMeta.getColumnLabel(i + 1);
        Object value = rs.getObject(i + 1);
        row.put(columName, value);
      }
      rows.add(row);
    }
  } finally {
    JdbcUtils.close(rs);
    JdbcUtils.close(stmt);
  }
  return rows;
}

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