一文解析Spring JDBC Template的使用指导

<dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>

JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());

import com.zjq.javabase.base27.domain.Emp;
import com.zjq.javabase.base27.utils.JDBCUtils;
import org.junit.Test;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import java.sql.Date;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
import java.util.Map;
/**
 * JdbcTemplate入门
 *
 * @author zjq
 */
public class JdbcTemplateDemo2 {
 //1. 获取JDBCTemplate对象
 private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());
 /**
     * 1. 修改1号数据的 salary 为 10000
     */
 @Test
 public void test1() {
 //2. 定义sql
 String sql = "update emp set salary = 10000 where id = 1";
 //3. 执行sql
 int count = template.update(sql);
 System.out.println(count);
 }
 /**
     * 2. 添加一条记录
     */
 @Test
 public void test2() {
 String sql = "insert into emp(name,dept_id) values(?,?)";
 int count = template.update(sql, "郭靖", 1);
 System.out.println(count);
 }
 /**
     * 3.删除刚才添加的记录
     */
 @Test
 public void test3() {
 String sql = "delete from emp where id = ?";
 int count = template.update(sql, 7);
 System.out.println(count);
 }
 /**
     * 4.查询id为1的记录，将其封装为Map集合
     * 注意：这个方法查询的结果集长度只能是1
     */
 @Test
 public void test4() {
 String sql = "select * from emp where id = ? ";
 Map<String, Object> map = template.queryForMap(sql, 1);
 System.out.println(map);
 //{id=1, ename=孙悟空, job_id=4, mgr=1004, joindate=2000-12-17, salary=10000.00, bonus=null, dept_id=20}
 }
 /**
     * 5. 查询所有记录，将其封装为List
     */
 @Test
 public void test5() {
 String sql = "select * from emp";
 List<Map<String, Object>> list = template.queryForList(sql);
 for (Map<String, Object> stringObjectMap : list) {
 System.out.println(stringObjectMap);
 }
 }
 /**
     * 6. 查询所有记录，将其封装为Emp对象的List集合
     */
 @Test
 public void test6() {
 String sql = "select * from emp";
 List<Emp> list = template.query(sql, new RowMapper<Emp>() {
 @Override
 public Emp mapRow(ResultSet rs, int i) throws SQLException {
 Emp emp = new Emp();
 int id = rs.getInt("id");
 String ename = rs.getString("NAME");
 String gender = rs.getString("gender");
 Date joindate = rs.getDate("join_date");
 double salary = rs.getDouble("salary");
 int dept_id = rs.getInt("dept_id");
 emp.setId(id);
 emp.setName(ename);
 emp.setGender(gender);
 emp.setJoindate(joindate);
 emp.setSalary(salary);
 emp.setDept_id(dept_id);
 return emp;
 }
 });
 for (Emp emp : list) {
 System.out.println(emp);
 }
 }
 /**
     * 6. 查询所有记录，将其封装为Emp对象的List集合
     */
 @Test
 public void test6_2() {
 String sql = "select * from emp";
 List<Emp> list = template.query(sql, new BeanPropertyRowMapper<Emp>(Emp.class));
 for (Emp emp : list) {
 System.out.println(emp);
 }
 }
 /**
     * 7. 查询总记录数
     */
 @Test
 public void test7() {
 String sql = "select count(id) from emp";
 Long total = template.queryForObject(sql, Long.class);
 System.out.println(total);
 }
}