Руководство Spring JDBC

In this lesson, I am going to guide you for using JdbcTemplate class. This is a central class in the Spring JDBC, which includes the most common logics in using the JDBC API to access databases, for example, creating connections and query commands, deleting, editing and updating data ... This class can be found in the  org.springframework.jdbc.core package.
The objective of the lesson is to provide examples using the methods of  JdbcTemplate class.
  • JdbcTemplate.queryForList
  • JdbcTemplate.queryForRowSet
  • JdbcTemplate.query
  • JdbcTemplate.queryForObject
  • ...
Let's ensure that you may have created a project using  Spring JDBC to connect to a specific database. If not, you can refer to the following lesson:

1- Modal Classes

Department.java
package org.o7planning.springjdbc.model;

public class Department {

    private Long deptId;
    private String deptNo;
    private String deptName;

    public Department() {

    }

    public Department(Long deptId, String deptNo, String deptName) {
        this.deptId = deptId;
        this.deptNo = deptNo;
        this.deptName = deptName;
    }

    public Long getDeptId() {
        return deptId;
    }

    public void setDeptId(Long deptId) {
        this.deptId = deptId;
    }

    public String getDeptNo() {
        return deptNo;
    }

    public void setDeptNo(String deptNo) {
        this.deptNo = deptNo;
    }

    public String getDeptName() {
        return deptName;
    }

    public void setDeptName(String deptName) {
        this.deptName = deptName;
    }
    
    
}

2- JdbcTemplate.queryForList -> List

Первый и самый простой пример с Spring JDBC это запрос (query) на получение списка значений столбца.
QueryForListReturnListDAO.java
package org.o7planning.springjdbc.dao;

import java.util.List;

import javax.sql.DataSource;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.support.JdbcDaoSupport;
import org.springframework.stereotype.Repository;

@Repository
public class QueryForListReturnListDAO extends JdbcDaoSupport {

    @Autowired
    public QueryForListReturnListDAO(DataSource dataSource) {
        this.setDataSource(dataSource);
    }


    public List<String> getDeptNames() {

        String sql = "Select d.dept_name from Department d ";

        // queryForList(String sql, Class<T> elementType)
        List<String> list = this.getJdbcTemplate().queryForList(sql, String.class);

        return list;
    }

    public List<String> getDeptNames(String searchName) {

        String sql = "Select d.dept_name from Department d "//
                + " Where d.dept_name like ? ";

        // queryForList(String sql, Class<T> elementType, Object... args)
        List<String> list = this.getJdbcTemplate().queryForList(sql, String.class, //
                "%" + searchName + "%");

        return list;
    }


}
QueryForListReturnList_Test.java
package org.o7planning.springjdbc.demo;

import java.sql.SQLException;
import java.util.List;

import org.o7planning.springjdbc.config.AppConfiguration;
import org.o7planning.springjdbc.dao.QueryForListReturnListDAO;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class QueryForListReturnList_Test {

    public static void main(String[] args) throws SQLException {

        ApplicationContext context = new AnnotationConfigApplicationContext(AppConfiguration.class);

        QueryForListReturnListDAO dao = context.getBean(QueryForListReturnListDAO.class);

        List<String> names = dao.getDeptNames("A");

        for (String name : names) {

            System.out.println("Dept Name: " + name);
        }
    }

}
Запуск примера:

3- JdbcTemplate.queryForList -> List<Map>

// JdbcTemplate.queryForList methods, return List<Map<String,Object>>

public List<Map<String, Object>> queryForList(String sql,
               Object[] args, int[] argTypes) throws DataAccessException;


public List<Map<String, Object>> queryForList(String sql,
               Object... args) throws DataAccessException;
Пример:
QueryForListReturnListMapDAO.java
package org.o7planning.springjdbc.dao;

import java.sql.Types;
import java.util.Calendar;
import java.util.Date;
import java.util.List;
import java.util.Map;

import javax.sql.DataSource;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.support.JdbcDaoSupport;
import org.springframework.stereotype.Repository;

@Repository
public class QueryForListReturnListMapDAO extends JdbcDaoSupport {

    @Autowired
    public QueryForListReturnListMapDAO(DataSource dataSource) {
        this.setDataSource(dataSource);
    }

    // Map<String columnName, Object value>
    public List<Map<String, Object>> queryForList_ListMap() {

        String sql = "Select e.Emp_No, e.Emp_Name from Employee e ";

        // List<Map<String, Object>> queryForList(String sql)
        List<Map<String, Object>> list = this.getJdbcTemplate().queryForList(sql);

        return list;
    }

    // List<Map<String, Object>>
    // queryForList(String sql, Object[] args, int[] argTypes)

    public List<Map<String, Object>> queryForList_ListMap2() {

        String sql = "Select e.Emp_Id,e.Emp_No,e.Emp_Name From Employee e " //
                + " Where e.Hire_Date > ? and e.Salary > ? ";
        //
        Date hireDate = getDateByYear(1981);
        Object[] args = new Object[] { hireDate, 2800 };
        int[] argTypes = new int[] { Types.DATE, Types.DOUBLE };

        // List<Map<String, Object>> queryForList(String sql)
        List<Map<String, Object>> list = this.getJdbcTemplate().queryForList(sql, args, argTypes);

        return list;
    }

    private Date getDateByYear(int year) {
        java.sql.Date date = new java.sql.Date(System.currentTimeMillis());
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.YEAR, year);
        c.set(Calendar.MONTH, Calendar.JANUARY);
        c.set(Calendar.DAY_OF_YEAR, 1);
        return c.getTime();
    }

}
QueryForListReturnListMap_Test.java
package org.o7planning.springjdbc.demo;

import java.sql.SQLException;
import java.util.List;
import java.util.Map;

import org.o7planning.springjdbc.config.AppConfiguration;
import org.o7planning.springjdbc.dao.QueryForListReturnListMapDAO;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class QueryForListReturnListMap_Test {

    public static void main(String[] args) throws SQLException {

        ApplicationContext context = new AnnotationConfigApplicationContext(AppConfiguration.class);

        QueryForListReturnListMapDAO dao = context.getBean(QueryForListReturnListMapDAO.class);

        // Map<String columnName, Object value)
        List<Map<String, Object>> list = dao.queryForList_ListMap2();

        for (Map<String, Object> map : list) {
            System.out.println("-----");
            for (String key : map.keySet()) {
                System.out.println("Key: " + key + " - value: " + map.get(key));
            }
        }
    }

}
Запуск примера:

4- JdbcTemplate.queryForRowSet

// JdbcTemplate.queryForRowSet methods ....

public SqlRowSet queryForRowSet(String sql,
                     Object[] args, int[] argTypes) throws DataAccessException;

public SqlRowSet queryForRowSet(String sql, Object... args)
                                                              throws DataAccessException;
QueryForRowSetReturnSqlRowSetDAO.java
package org.o7planning.springjdbc.dao;

import java.sql.Types;
import java.util.Calendar;
import java.util.Date;

import javax.sql.DataSource;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.support.JdbcDaoSupport;
import org.springframework.jdbc.support.rowset.SqlRowSet;
import org.springframework.stereotype.Repository;

@Repository
public class QueryForRowSetReturnSqlRowSetDAO extends JdbcDaoSupport {

    @Autowired
    public QueryForRowSetReturnSqlRowSetDAO(DataSource dataSource) {
        this.setDataSource(dataSource);
    }

    // SqlRowSet queryForRowSet(String sql, Object[] args, int[] argTypes)

    public SqlRowSet queryForRowSet_SqlRowSet() {

        String sql = "Select e.Emp_Id,e.Emp_No,e.Emp_Name From Employee e " //
                + " Where e.Hire_Date > ? and e.Salary > ? ";
        //
        Date hireDate = getDateByYear(1981);
        Object[] args = new Object[] { hireDate, 2800 };
        int[] argTypes = new int[] { Types.DATE, Types.DOUBLE };

        // SqlRowSet queryForRowSet(String sql, Object[] args, int[] argTypes)
        SqlRowSet rowSet = this.getJdbcTemplate().queryForRowSet(sql, args, argTypes);

        return rowSet;
    }

    private Date getDateByYear(int year) {
        java.sql.Date date = new java.sql.Date(System.currentTimeMillis());
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.YEAR, year);
        c.set(Calendar.MONTH, Calendar.JANUARY);
        c.set(Calendar.DAY_OF_YEAR, 1);
        return c.getTime();
    }

}
QueryForRowSetReturnSqlRowSet_Test.java
package org.o7planning.springjdbc.demo;

import java.sql.SQLException;

import org.o7planning.springjdbc.config.AppConfiguration;
import org.o7planning.springjdbc.dao.QueryForRowSetReturnSqlRowSetDAO;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.jdbc.support.rowset.SqlRowSet;

public class QueryForRowSetReturnSqlRowSet_Test {

    public static void main(String[] args) throws SQLException {

        ApplicationContext context = new AnnotationConfigApplicationContext(AppConfiguration.class);

        QueryForRowSetReturnSqlRowSetDAO dao = context.getBean(QueryForRowSetReturnSqlRowSetDAO.class);

        // SqlRowSet
        SqlRowSet rowSet = dao.queryForRowSet_SqlRowSet();

        while (rowSet.next()) {
           
            System.out.println("-----");
            Long empId = rowSet.getLong("Emp_Id"); // Index = 1
            String empNo = rowSet.getString(2); // Index = 2
            String empName = rowSet.getString("Emp_Name"); // Index = 3

            System.out.println("EmpID: " + empId + ", EmpNo: " + empNo + ", EmpName:" + empName);
        }

    }
   
}

5- JdbcTemplate.query & RowMapper

// query methods with RowMapper & returns List

public <T> List<T> query(String sql, Object[] args,
            int[] argTypes, RowMapper<T> rowMapper) throws DataAccessException; 


public <T> List<T> query(String sql, Object[] args,
           RowMapper<T> rowMapper) throws DataAccessException;


public <T> List<T> query(String sql, RowMapper<T> rowMapper,
           Object... args) throws DataAccessException;
JdbcTemplate shows some query methods and the return result is a list of Java objects. You need to provide a RowMapper defining mappings between columns and fields of class.
QueryWithRowMapperDAO.java
package org.o7planning.springjdbc.dao;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;

import javax.sql.DataSource;

import org.o7planning.springjdbc.model.Department;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.jdbc.core.support.JdbcDaoSupport;
import org.springframework.stereotype.Repository;

@Repository
public class QueryWithRowMapperDAO extends JdbcDaoSupport {

    @Autowired
    public QueryWithRowMapperDAO(DataSource dataSource) {
        this.setDataSource(dataSource);
    }

    private static final String BASE_SQL = //
            "Select d.Dept_Id, d.Dept_No, d.Dept_Name from Department d ";

    class DepartmentRowMapper implements RowMapper<Department> {

        @Override
        public Department mapRow(ResultSet rs, int rowNum) throws SQLException {
            Long deptId = rs.getLong("Dept_Id");
            String deptNo = rs.getString("Dept_No");
            String deptName = rs.getString("Dept_Name");
            return new Department(deptId, deptNo, deptName);
        }

    }

    public List<Department> queryDepartment() {
        String sql = BASE_SQL //
                + " Where d.Dept_Id > ? ";

        DepartmentRowMapper rowMapper = new DepartmentRowMapper();
        Object[] args = new Object[] { 20 };

        List<Department> list = this.getJdbcTemplate().query(sql, args, rowMapper);
        return list;
    }

}
Test:
QueryWithRowMapper_Test.java
package org.o7planning.springjdbc.demo;

import java.sql.SQLException;
import java.util.List;

import org.o7planning.springjdbc.config.AppConfiguration;
import org.o7planning.springjdbc.dao.QueryWithRowMapperDAO;
import org.o7planning.springjdbc.model.Department;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class QueryWithRowMapper_Test {

   
    public static void main(String[] args) throws SQLException {

        ApplicationContext context = new AnnotationConfigApplicationContext(AppConfiguration.class);

        QueryWithRowMapperDAO dao = context.getBean(QueryWithRowMapperDAO.class);

        List<Department> list = dao.queryDepartment() ;
       
        for(Department dept: list)  {
            System.out.println("DeptNo: "+ dept.getDeptNo()+" - DeptName: "+ dept.getDeptName());
        }
    }
   
}

6- JdbcTemplate.query & RowCallbackHandler

JdbcTemplate предоставляет вам несколько методов для запроса данных и интеракции с данными через ResultSet. Ниже являются эти методы:
// JdbcTemplate.query methods & RowCallbackHandler.

public void query(PreparedStatementCreator psc,
           RowCallbackHandler rch) throws DataAccessException;

public void query(String sql, PreparedStatementSetter pss,
           RowCallbackHandler rch) throws DataAccessException;


public void query(String sql, Object[] args, int[] argTypes,
           RowCallbackHandler rch) throws DataAccessException;

public void query(String sql, Object[] args,
           RowCallbackHandler rch) throws DataAccessException;

public void query(String sql, RowCallbackHandler rch,
           Object... args) throws DataAccessException;
RowCallbackHandler interface:
** RowCallbackHandler **
public interface RowCallbackHandler {

   void processRow(ResultSet rs) throws SQLException;

}
Пример:
QueryWithRowCallbackHandlerDAO.java
package org.o7planning.springjdbc.dao;

import java.sql.ResultSet;
import java.sql.SQLException;

import javax.sql.DataSource;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.RowCallbackHandler;
import org.springframework.jdbc.core.support.JdbcDaoSupport;
import org.springframework.stereotype.Repository;

@Repository
public class QueryWithRowCallbackHandlerDAO extends JdbcDaoSupport {

    @Autowired
    public QueryWithRowCallbackHandlerDAO(DataSource dataSource) {
        this.setDataSource(dataSource);
    }

    public void queryEmployee() {
        String sql = "Select e.Emp_Id, e.Emp_No, e.Emp_Name,e.Salary from Employee e "//
                + " Where e.Salary > ? ";

        RowCallbackHandler handler = new RowCallbackHandler() {

            @Override
            public void processRow(ResultSet rs) throws SQLException {
                Long empId = rs.getLong("Emp_Id");
                String empNo = rs.getString(2);
                System.out.println(" ---------------- ");
                System.out.println("EmpId:" + empId);
                System.out.println("EmpNo:" + empNo);
            }

        };
        // query(String sql, RowCallbackHandler rch, Object... args)
        this.getJdbcTemplate().query(sql, handler, 2800);
    }

}
QueryWithRowCallbackHandler_Test.java
package org.o7planning.springjdbc.demo;

import java.sql.SQLException;

import org.o7planning.springjdbc.config.AppConfiguration;
import org.o7planning.springjdbc.dao.QueryWithRowCallbackHandlerDAO;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class QueryWithRowCallbackHandler_Test {

   
    public static void main(String[] args) throws SQLException {

        ApplicationContext context = new AnnotationConfigApplicationContext(AppConfiguration.class);

        QueryWithRowCallbackHandlerDAO dao = context.getBean(QueryWithRowCallbackHandlerDAO.class);

        dao.queryEmployee();
    }
   
}

7- JdbcTemplate.query & ResultSetExtractor

// JdbcTemplate.query methods with ResultSetExtractor.

public <T> T query(PreparedStatementCreator psc,
                ResultSetExtractor<T> rse) throws DataAccessException;


public <T> T query(String sql, PreparedStatementSetter pss,
                ResultSetExtractor<T> rse) throws DataAccessException;


public <T> T query(String sql, Object[] args, int[] argTypes,
                ResultSetExtractor<T> rse) throws DataAccessException;


public <T> T query(String sql, Object[] args,
                ResultSetExtractor<T> rse) throws DataAccessException;


public <T> T query(String sql, ResultSetExtractor<T> rse,
                Object... args) throws DataAccessException;
Пример:
QueryWithResultSetExtractorDAO.java
package org.o7planning.springjdbc.dao;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import javax.sql.DataSource;

import org.o7planning.springjdbc.model.Department;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.ResultSetExtractor;
import org.springframework.jdbc.core.support.JdbcDaoSupport;
import org.springframework.stereotype.Repository;

@Repository
public class QueryWithResultSetExtractorDAO extends JdbcDaoSupport {

    @Autowired
    public QueryWithResultSetExtractorDAO(DataSource dataSource) {
        this.setDataSource(dataSource);
    }

    private static final String BASE_SQL = //
            "Select d.Dept_Id, d.Dept_No, d.Dept_Name from Department d ";

    class DepartmentListResultSetExtractor implements ResultSetExtractor<List<Department>> {

        @Override
        public List<Department> extractData(ResultSet rs) throws SQLException, DataAccessException {
            List<Department> list = new ArrayList<Department>();
            while (rs.next()) {
                Long deptId = rs.getLong("Dept_Id");
                String deptNo = rs.getString("Dept_No");
                String deptName = rs.getString("Dept_Name");
                list.add(new Department(deptId, deptNo, deptName));
            }
            return list;
        }

    }

    class DepartmentResultSetExtractor implements ResultSetExtractor<Department> {

        @Override
        public Department extractData(ResultSet rs) throws SQLException, DataAccessException {
            if (rs.next()) {
                Long deptId = rs.getLong("Dept_Id");
                String deptNo = rs.getString("Dept_No");
                String deptName = rs.getString("Dept_Name");
                return new Department(deptId, deptNo, deptName);
            }
            return null;
        }

    }

    public List<Department> queryDepartments() {
        String sql = BASE_SQL //
                + " Where d.Dept_Id > ? ";

        DepartmentListResultSetExtractor rse = new DepartmentListResultSetExtractor();

        // <T> T query(String sql, ResultSetExtractor<T> rse, Object... args)
        List<Department> list = this.getJdbcTemplate().query(sql, rse, 40);
        return list;
    }

    public Department findDepartment(Long deptId) {
        String sql = BASE_SQL //
                + " Where d.Dept_Id = ? ";

        DepartmentResultSetExtractor rse = new DepartmentResultSetExtractor();

        // <T> T query(String sql, ResultSetExtractor<T> rse, Object... args)
        Department dept = this.getJdbcTemplate().query(sql, rse, 40);
        return dept;
    }

}

8- JdbcTemplate.queryForObject

// JdbcTemplate.queryForObject methods:

public <T> T queryForObject(String sql, Object[] args,
                int[] argTypes, RowMapper<T> rowMapper)
        throws DataAccessException; 


public <T> T queryForObject(String sql, Object[] args,
                RowMapper<T> rowMapper) throws DataAccessException;

public <T> T queryForObject(String sql, RowMapper<T> rowMapper,
                Object... args) throws DataAccessException;


public <T> T queryForObject(String sql, Object[] args,
                int[] argTypes, Class<T> requiredType)
        throws DataAccessException;


public <T> T queryForObject(String sql, Object[] args,
                Class<T> requiredType) throws DataAccessException;


public <T> T queryForObject(String sql, Class<T> requiredType,
                Object... args) throws DataAccessException;
Пример:
QueryForObjectDAO.java
package org.o7planning.springjdbc.dao;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;
import java.util.Date;

import javax.sql.DataSource;

import org.o7planning.springjdbc.model.Department;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.dao.EmptyResultDataAccessException;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.jdbc.core.support.JdbcDaoSupport;
import org.springframework.stereotype.Repository;

@Repository
public class QueryForObjectDAO extends JdbcDaoSupport {

    @Autowired
    public QueryForObjectDAO(DataSource dataSource) {
        this.setDataSource(dataSource);
    }

    private static final String BASE_SQL = //
            "Select d.Dept_Id, d.Dept_No, d.Dept_Name from Department d ";

    class DepartmentRowMapper implements RowMapper<Department> {

        @Override
        public Department mapRow(ResultSet rs, int rowNum) throws SQLException {
            Long deptId = rs.getLong("Dept_Id");
            String deptNo = rs.getString("Dept_No");
            String deptName = rs.getString("Dept_Name");
            return new Department(deptId, deptNo, deptName);
        }

    }

    public Department getDepartment(String deptNo) {
        try {
            String sql = BASE_SQL //
                    + " Where d.Dept_No = ? ";

            DepartmentRowMapper rowMapper = new DepartmentRowMapper();
            Object[] args = new Object[] { deptNo };

            Department dept = this.getJdbcTemplate().queryForObject(sql, args, rowMapper);
            return dept;
        } catch (EmptyResultDataAccessException e) {
            return null;
        }
    }

    public String getDeptNameById(Long deptId) {
        try {
            String sql = "Select d.Dept_Name from Department d "//
                    + " Where d.Dept_Id = ?";
            Object[] args = new Object[] { deptId };

            String deptName = this.getJdbcTemplate().queryForObject(sql, String.class, args);
            return deptName;
        } catch (EmptyResultDataAccessException e) {
            return null;
        }
    }

    public Date getEmpHireDateById(Long empId) {
        try {
            String sql = "Select e.Hire_Date from Employee e "//
                    + " Where e.Emp_Id = ?";
            Object[] args = new Object[] { empId };
            int[] argTypes = new int[] { Types.BIGINT };

            Date hireDate = this.getJdbcTemplate().queryForObject(sql, args, argTypes, Date.class);
            return hireDate;
        } catch (EmptyResultDataAccessException e) {
            return null;
        }
    }

}
Test:
QueryForObject_Test.java
package org.o7planning.springjdbc.demo;

import java.sql.SQLException;
import java.util.Date;

import org.o7planning.springjdbc.config.AppConfiguration;
import org.o7planning.springjdbc.dao.QueryForObjectDAO;
import org.o7planning.springjdbc.model.Department;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class QueryForObject_Test {

    public static void main(String[] args) throws SQLException {

        ApplicationContext context = new AnnotationConfigApplicationContext(AppConfiguration.class);

        QueryForObjectDAO dao = context.getBean(QueryForObjectDAO.class);

        System.out.println(" ------------- ");
        Department dept = dao.getDepartment("D20");

        if (dept != null) {
            System.out.println("DeptNo: " + dept.getDeptNo() + " - DeptName: " + dept.getDeptName());
        } else {
            System.out.println("Department not found!");
        }
        System.out.println(" ------------- ");

        String deptName = dao.getDeptNameById(30L);
        System.out.println("Dept Name by Id 30: " + deptName);

        System.out.println(" ------------- ");

        Date hireDate = dao.getEmpHireDateById(7839L);
        System.out.println("HireDate by EmpId 7839: " + hireDate);

    }

}

9- TODO ..