黑马学习连接池 druid JdbcTemplate c3p0 池技术
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1 package cn.itcast.jdbctemplate; 2 3 4 import org.junit.Test; 5 import org.springframework.jdbc.core.BeanPropertyRowMapper; 6 import org.springframework.jdbc.core.JdbcTemplate; 7 8 import java.math.BigDecimal; 9 import java.util.Date; 10 import java.util.List; 11 import java.util.Map; 12 13 /* 14 * 1. 要求 JdbcTemplate 15 * 2. jdbcUtils工具类直接拿来用(druid.properties) 16 * 3. 插入员工数据(完整的) 17 * 4. 删除员工数据(按照员工编号删除) 18 * 5. 修改员工数据(修改李逵的工资、奖金、部门) 19 * 6. 查询所有工资大于20000万的员工, 按工资降序排列 20 * 7. 查询所有在 2007-5-1 之后入职的员工 21 * 8. 按部门分组,统计每组的人数 22 * 23 * 分析: 24 * 1.使用jdbctemplate+druid来进行测试,准备一个DataSource对象,来创建JdbcTemplate对象 25 * 26 * */ 27 public class JdbcTemplate_Test { 28 private JdbcTemplate jdbcTemplate = new JdbcTemplate(DruidJdbcUtils.getDataSource()); 29 /** 30 * 插入员工数据(完整的) 31 */ 32 @Test 33 public void test1(){ 34 Employee emp = new Employee(); 35 emp.setId(1015); 36 emp.setEname("小白龙"); 37 emp.setJobId(4); 38 emp.setMgr(1004); 39 emp.setJoindate(new Date()); 40 emp.setSalary(new BigDecimal(3000)); 41 emp.setBonus(new BigDecimal(8000)); 42 emp.setDeptId(20); 43 44 String sql = "insert into emp(id, ename, job_id, mgr, joindate, salary, bonus, dept_id) values(?,?,?,?,?,?,?,?)"; 45 46 int rows = jdbcTemplate.update(sql, emp.getId(), emp.getEname(), emp.getJobId(), emp.getMgr(), 47 emp.getJoindate(), emp.getSalary(), emp.getBonus(), emp.getDeptId()); 48 System.out.println(rows); 49 } 50 51 /** 52 * 删除员工数据(按照员工编号删除) 53 */ 54 @Test 55 public void test2(){ 56 String sql = "delete from emp where id = ?"; 57 int rows = jdbcTemplate.update(sql, 1015); 58 System.out.println(rows); 59 } 60 61 /** 62 * 修改员工数据(修改李逵的工资、奖金、部门) 63 */ 64 @Test 65 public void test3(){ 66 String sql = "update emp set salary = ?, bonus = ?, dept_id = ? where ename = ? "; 67 int rows = jdbcTemplate.update(sql, 2000, 2000, 20, "李逵"); 68 System.out.println(rows); 69 } 70 71 /** 72 * 查询所有工资大于20000万的员工, 按工资降序排列 73 */ 74 @Test 75 public void test4(){ 76 // TimeZone.setDefault(TimeZone.getTimeZone("GMT+10:00"));数据库是Date类型的,这里修改默认时区根本不影响结果。 77 String sql = "select id, ename, job_id as jobId, mgr, joindate, salary, bonus, dept_id as deptId from emp where salary > ? "; 78 List<Employee> employeeList = jdbcTemplate.query(sql, new BeanPropertyRowMapper<>(Employee.class), 20000); 79 employeeList.forEach(System.out::println); 80 } 81 82 /** 83 * 按部门分组,统计每组的人数 84 */ 85 @Test 86 public void test5(){ 87 String sql = "select\n" + 88 "\tcount(t1.id) as employee_num, t2.id as id, t2.dname as dname\n" + 89 "FROM\n" + 90 "emp as t1\n" + 91 "right join \n" + 92 "dept as t2\n" + 93 "on \n" + 94 "t1.dept_id = t2.id\n" + 95 "GROUP BY\n" + 96 "t2.id"; 97 List<Map<String, Object>> mapList = jdbcTemplate.queryForList(sql); 98 mapList.forEach(System.out::println); 99 } 100 }
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1 package cn.itcast.jdbctemplate; 2 3 import com.alibaba.druid.pool.DruidDataSourceFactory; 4 5 import javax.sql.DataSource; 6 import java.io.IOException; 7 import java.sql.Connection; 8 import java.sql.ResultSet; 9 import java.sql.SQLException; 10 import java.sql.Statement; 11 import java.util.Properties; 12 13 public class DruidJdbcUtils { 14 //DataSource对象 15 private static DataSource dataSource; 16 17 static { 18 try { 19 //加载配置 20 Properties props = new Properties(); 21 props.load(DruidJdbcUtils.class.getClassLoader().getResourceAsStream("druid.properties")); 22 23 //创建德鲁伊连接池 24 dataSource = new DruidDataSourceFactory().createDataSource(props); 25 } catch (IOException e) { 26 e.printStackTrace(); 27 } catch (Exception e) { 28 e.printStackTrace(); 29 } 30 } 31 32 //获取连接池 33 public static DataSource getDataSource(){ 34 return dataSource; 35 } 36 37 //获取连接 38 public static Connection getConnection() throws SQLException { 39 return dataSource.getConnection(); 40 } 41 42 //DML语句释放资源 43 public static void release(Statement stmt, Connection conn){ 44 /* if(stmt != null){ 45 try { 46 stmt.close(); 47 } catch (SQLException e) { 48 e.printStackTrace(); 49 } 50 } 51 if(conn != null){ 52 try { 53 conn.close(); 54 } catch (SQLException e) { 55 e.printStackTrace(); 56 } 57 }*/ 58 release(null, stmt, conn); 59 } 60 61 //查询语句释放资源 62 public static void release(ResultSet rs, Statement stmt, Connection conn){ 63 if(rs != null){ 64 try { 65 rs.close(); 66 } catch (SQLException e) { 67 e.printStackTrace(); 68 } 69 } 70 if(stmt != null){ 71 try { 72 stmt.close(); 73 } catch (SQLException e) { 74 e.printStackTrace(); 75 } 76 } 77 if(conn != null){ 78 try { 79 conn.close(); 80 } catch (SQLException e) { 81 e.printStackTrace(); 82 } 83 } 84 } 85 }
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1 package cn.itcast.jdbctemplate; 2 3 import java.math.BigDecimal; 4 import java.util.Date; 5 6 /* 7 CREATE TABLE emp ( 8 id INT PRIMARY KEY, -- 员工id 9 ename VARCHAR(50), -- 员工姓名 10 job_id INT, -- 职务id 11 mgr INT , -- 上级领导 12 joindate DATE, -- 入职日期 13 salary DECIMAL(7,2), -- 工资 14 bonus DECIMAL(7,2), -- 奖金 15 dept_id INT, -- 所在部门编号 16 ); 17 */ 18 public class Employee { 19 private Integer id; 20 private String ename; 21 private Integer jobId; 22 private Integer mgr; 23 private Date joindate; 24 private BigDecimal salary; 25 private BigDecimal bonus; 26 private Integer deptId; 27 28 public Employee() { 29 } 30 31 public Integer getId() { 32 return id; 33 } 34 35 public void setId(Integer id) { 36 this.id = id; 37 } 38 39 public String getEname() { 40 return ename; 41 } 42 43 public void setEname(String ename) { 44 this.ename = ename; 45 } 46 47 public Integer getJobId() { 48 return jobId; 49 } 50 51 public void setJobId(Integer jobId) { 52 this.jobId = jobId; 53 } 54 55 public Integer getMgr() { 56 return mgr; 57 } 58 59 public void setMgr(Integer mgr) { 60 this.mgr = mgr; 61 } 62 63 public Date getJoindate() { 64 return joindate; 65 } 66 67 public void setJoindate(Date joindate) { 68 this.joindate = joindate; 69 } 70 71 public BigDecimal getSalary() { 72 return salary; 73 } 74 75 public void setSalary(BigDecimal salary) { 76 this.salary = salary; 77 } 78 79 public BigDecimal getBonus() { 80 return bonus; 81 } 82 83 public void setBonus(BigDecimal bonus) { 84 this.bonus = bonus; 85 } 86 87 public Integer getDeptId() { 88 return deptId; 89 } 90 91 public void setDeptId(Integer deptId) { 92 this.deptId = deptId; 93 } 94 95 @Override 96 public String toString() { 97 return "Employee{" + 98 "id=" + id + 99 ", ename='" + ename + '\'' + 100 ", jobId=" + jobId + 101 ", mgr=" + mgr + 102 ", joindate=" + joindate + 103 ", salary=" + salary + 104 ", bonus=" + bonus + 105 ", deptId=" + deptId + 106 '}'; 107 } 108 }
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1 package utils; 2 3 import java.io.FileReader; 4 import java.io.IOException; 5 import java.net.URL; 6 import java.sql.*; 7 import java.util.Properties; 8 9 public class JDBCUtils { 10 //连接参数 11 private static String driver; 12 private static String url; 13 private static String user; 14 private static String password; 15 16 static{ 17 try { 18 //读取配置 19 Properties props = new Properties(); 20 //方式一 21 // props.load(JDBCUtils.class.getClassLoader().getResourceAsStream("jdbc.properties")); 22 //方式二 23 ClassLoader cl = JDBCUtils.class.getClassLoader(); 24 URL resource = cl.getResource("jdbc.properties"); 25 //D:/Code/IdeaProject/IdeaCode/javaweb-T1/out/production/jdbc-day01/jdbc.properties 26 System.out.println(resource.getPath()); 27 props.load(new FileReader(resource.getPath())); 28 29 //赋值 30 driver = props.getProperty("driver"); 31 url = props.getProperty("url"); 32 user = props.getProperty("user"); 33 password = props.getProperty("password"); 34 35 //加载驱动 36 Class.forName(driver); 37 } catch (IOException e) { 38 e.printStackTrace(); 39 } catch (ClassNotFoundException e) { 40 e.printStackTrace(); 41 } 42 } 43 44 //获取连接 45 public static Connection getConnection() throws SQLException { 46 return DriverManager.getConnection(url, user, password); 47 } 48 49 50 //释放资源 51 public static void release(Statement stmt, Connection conn){ 52 release(null, stmt, conn); 53 } 54 55 public static void release(ResultSet rs, Statement stmt, Connection conn){ 56 if(rs != null){ 57 try { 58 rs.close(); 59 } catch (SQLException e) { 60 e.printStackTrace(); 61 } 62 } 63 if(stmt != null){ 64 try { 65 stmt.close(); 66 } catch (SQLException e) { 67 e.printStackTrace(); 68 } 69 } 70 if(conn != null){ 71 try { 72 conn.close(); 73 } catch (SQLException e) { 74 e.printStackTrace(); 75 } 76 } 77 } 78 }
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1 package conn; 2 3 import utils.JDBCUtils; 4 5 import java.sql.Connection; 6 import java.sql.PreparedStatement; 7 import java.sql.SQLException; 8 9 public class ConnAndSql { 10 public static void main(String[] args) throws SQLException { 11 long start = System.currentTimeMillis(); 12 Connection conn = JDBCUtils.getConnection(); 13 long end = System.currentTimeMillis(); 14 15 System.out.println("获取连接:" + (end - start)); 16 17 start = System.currentTimeMillis(); 18 String sql = "select * from account"; 19 PreparedStatement pstmt = conn.prepareStatement(sql); 20 pstmt.executeQuery(); 21 end = System.currentTimeMillis(); 22 23 System.out.println("执行sql:" + (end - start)); 24 25 /* 26 获取连接:543 27 执行sql:18 28 */ 29 } 30 }
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1 package pro01.service; 2 3 import pro01.dao.EmployeeDao; 4 import pro01.domain.Employee; 5 6 import java.math.BigDecimal; 7 import java.sql.SQLException; 8 import java.util.List; 9 import java.util.Scanner; 10 11 public class EmployeeMain { 12 private static EmployeeDao employeeDao = new EmployeeDao(); 13 14 private static final String prompt = "user>"; 15 16 public static void main(String[] args) { 17 //显式主界面,并给出提示 18 showMain(); 19 20 Scanner sc = new Scanner(System.in); 21 while(true){ 22 23 System.out.print(prompt); 24 25 String line = sc.nextLine(); 26 switch (line.trim().toLowerCase()){ 27 case "1" : 28 findAllProc();break; 29 case "2" : 30 deleteProc();break; 31 case "3" : 32 insertProc();break; 33 case "4" : 34 updateProc();break; 35 case "5" : 36 showMain();break; 37 case "exit" : 38 return; 39 default: 40 System.out.println("输入有误,请重新输入!"); 41 } 42 } 43 } 44 45 private static void showMain() { 46 System.out.println("1 查询所有员工信息"); 47 System.out.println("2 删除员工"); 48 System.out.println("3 新增员工"); 49 System.out.println("4 修改员工信息"); 50 System.out.println("5 显示主界面"); 51 System.out.println("exit 退出程序"); 52 } 53 54 private static void updateProc() { 55 //请输入要修改的员工编号 56 Scanner sc = new Scanner(System.in); 57 System.out.println("请输入要修改的员工编号"); 58 System.out.print(prompt); 59 60 //获取id 61 String idStr = sc.nextLine(); 62 Integer id = null; 63 try{ 64 id = Integer.parseInt(idStr); 65 } catch (NumberFormatException e){ 66 System.out.println("输入有误"); 67 return; 68 } 69 70 //根据id,查找用户,判断是否存在 71 Employee employee = employeeDao.findById(id); 72 if(employee == null){ 73 System.out.println("员工不存在"); 74 return; 75 } 76 77 //封装修改条件 78 employee = new Employee(); 79 employee.setId(id); 80 81 //姓名 82 System.out.println("请输入员工姓名"); 83 System.out.print(prompt); 84 String name = sc.nextLine(); 85 if(!"".equals(name.trim())){ 86 employee.setName(name); 87 } 88 89 //薪水 90 System.out.println("请输入员工薪水"); 91 System.out.print(prompt); 92 String salaryStr = sc.nextLine(); 93 if(!"".equals(salaryStr.trim())){ 94 try{ 95 BigDecimal salary = new BigDecimal(salaryStr); 96 employee.setSalary(salary); 97 }catch (NumberFormatException e){ 98 System.out.println("输入的薪水应该是数字"); 99 return; 100 } 101 } 102 103 boolean isSuccess = false; 104 try { 105 isSuccess = employeeDao.updateById(employee); 106 } catch (SQLException e) { 107 System.out.println("数据库错误"); 108 return; 109 } 110 if(isSuccess){ 111 System.out.println("更新成功"); 112 }else{ 113 System.out.println("更新失败"); 114 } 115 } 116 117 private static void insertProc() { 118 Scanner sc = new Scanner(System.in); 119 //员工编号 120 System.out.println("请输入员工编号:"); 121 System.out.print(prompt); 122 String idStr = sc.nextLine(); 123 int id; 124 try{ 125 id = Integer.parseInt(idStr); 126 } catch (NumberFormatException e) { 127 System.out.println("员工编号输入错误,只能是正数"); 128 return; 129 } 130 //员工姓名 131 System.out.println("请输入员工姓名:"); 132 System.out.print(prompt); 133 String name = sc.nextLine(); 134 //员工薪资 135 System.out.println("请输入员工薪资:"); 136 System.out.print(prompt); 137 String salaryStr = sc.nextLine(); 138 BigDecimal salary = null; 139 try{ 140 salary = new BigDecimal(salaryStr); 141 }catch (NumberFormatException e){ 142 System.out.println("工资必须为有效的数字"); 143 return; 144 } 145 146 Employee employee = new Employee(); 147 employee.setId(id); 148 employee.setName(name); 149 employee.setSalary(salary); 150 151 boolean isSuccess = false; 152 try { 153 isSuccess = employeeDao.add(employee); 154 } catch (SQLException e) { 155 System.out.println("数据库错误"); 156 return; 157 } 158 if(isSuccess){ 159 System.out.println("添加成功"); 160 }else{ 161 System.out.println("添加失败"); 162 } 163 } 164 165 private static void deleteProc() { 166 //请输入要删除的员工编号 167 Scanner sc = new Scanner(System.in); 168 System.out.println("请输入要删除的员工编号"); 169 System.out.print(prompt); 170 171 //获取id 172 String idStr = sc.nextLine(); 173 int id; 174 try{ 175 id = Integer.parseInt(idStr); 176 } catch (NumberFormatException e){ 177 System.out.println("输入有误"); 178 return; 179 } 180 181 //根据id,查找用户,判断是否存在 182 Employee employee = employeeDao.findById(id); 183 if(employee == null){ 184 System.out.println("员工不存在"); 185 return; 186 } 187 188 //如果用户存在,则删除用户 189 boolean isSuccess = employeeDao.deleteById(id); 190 if(isSuccess){ 191 System.out.println("删除成功"); 192 }else{ 193 System.out.println("删除失败"); 194 } 195 } 196 197 private static void findAllProc() { 198 List<Employee> list = employeeDao.findAll(); 199 200 System.out.println("员工编号\t员工姓名\t员工薪资"); 201 list.forEach(e->{ 202 System.out.println(e.getId() + "\t\t" + e.getName() + "\t\t" + e.getSalary()); 203 }); 204 } 205 }
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1 package pro01.domain; 2 3 import java.math.BigDecimal; 4 5 /* 6 create table employee( 7 id int primary key auto_increment, 8 name varchar(50), 9 salary DECIMAL 10 ); 11 */ 12 public class Employee { 13 private Integer id; 14 private String name; 15 private BigDecimal salary; 16 17 public Employee() { 18 } 19 20 public Integer getId() { 21 return id; 22 } 23 24 public void setId(Integer id) { 25 this.id = id; 26 } 27 28 public String getName() { 29 return name; 30 } 31 32 public void setName(String name) { 33 this.name = name; 34 } 35 36 public BigDecimal getSalary() { 37 return salary; 38 } 39 40 public void setSalary(BigDecimal salary) { 41 this.salary = salary; 42 } 43 }
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1 package pro01.dao; 2 3 import pro01.domain.Employee; 4 5 import java.sql.*; 6 import java.util.ArrayList; 7 import java.util.List; 8 9 public class EmployeeDao { 10 /** 11 * 查询全部员工信息 12 * @return 13 */ 14 public List<Employee> findAll() { 15 String driver = "com.mysql.jdbc.Driver"; 16 String url = "jdbc:mysql://localhost:3307/jdbc_db"; 17 String user = "root"; 18 String password = "root"; 19 20 Connection conn = null; 21 PreparedStatement pstmt = null; 22 ResultSet rs = null; 23 24 List<Employee> employeeList = new ArrayList<>(); 25 try { 26 //连接 27 conn = DriverManager.getConnection(url, user, password); 28 //语句 29 String sql = "select * from employee"; 30 pstmt = conn.prepareStatement(sql); 31 //执行 32 rs = pstmt.executeQuery(); 33 while(rs.next()){ 34 //读取记录数据,封装为Employee对象 35 Employee emp = new Employee(); 36 emp.setId(rs.getInt("eid")); 37 emp.setName(rs.getString("ename")); 38 emp.setSalary(rs.getBigDecimal("salary")); 39 40 //将员工添加到集合 41 employeeList.add(emp); 42 } 43 } catch (SQLException e) { 44 e.printStackTrace(); 45 } finally{ 46 if(rs != null) { 47 try { 48 rs.close(); 49 } catch (SQLException e) { 50 e.printStackTrace(); 51 } 52 } 53 if(pstmt != null) { 54 try { 55 pstmt.close(); 56 } catch (SQLException e) { 57 e.printStackTrace(); 58 } 59 } 60 if(conn != null) { 61 try { 62 conn.close(); 63 } catch (SQLException e) { 64 e.printStackTrace(); 65 } 66 } 67 } 68 return employeeList; 69 } 70 71 public Employee findById(int id) { 72 String driver = "com.mysql.jdbc.Driver"; 73 String url = "jdbc:mysql://localhost:3307/jdbc_db"; 74 String user = "root"; 75 String password = "root"; 76 77 Connection conn = null; 78 PreparedStatement pstmt = null; 79 ResultSet rs = null; 80 81 Employee employee = null; 82 try { 83 //连接 84 conn = DriverManager.getConnection(url, user, password); 85 //语句 86 String sql = "select * from employee where eid = ? "; 87 pstmt = conn.prepareStatement(sql); 88 pstmt.setInt(1, id); 89 //执行 90 rs = pstmt.executeQuery(); 91 if(rs.next()){ 92 //读取记录数据,封装为Employee对象 93 employee = new Employee(); 94 employee.setId(rs.getInt("eid")); 95 employee.setName(rs.getString("ename")); 96 employee.setSalary(rs.getBigDecimal("salary")); 97 } 98 } catch (SQLException e) { 99 e.printStackTrace(); 100 } finally{ 101 if(rs != null) { 102 try { 103 rs.close(); 104 } catch (SQLException e) { 105 e.printStackTrace(); 106 } 107 } 108 if(pstmt != null) { 109 try { 110 pstmt.close(); 111 } catch (SQLException e) { 112 e.printStackTrace(); 113 } 114 } 115 if(conn != null) { 116 try { 117 conn.close(); 118 } catch (SQLException e) { 119 e.printStackTrace(); 120 } 121 } 122 } 123 return employee; 124 } 125 126 public boolean deleteById(int id) { 127 String driver = "com.mysql.jdbc.Driver"; 128 String url = "jdbc:mysql://localhost:3307/jdbc_db"; 129 String user = "root"; 130 String password = "root"; 131 132 Connection conn = null; 133 PreparedStatement pstmt = null; 134 try{ 135 //获取连接对象 136 conn = DriverManager.getConnection(url, user, password); 137 //获取语句 138 String sql = "delete from employee where eid = ? "; 139 pstmt = conn.prepareStatement(sql); 140 pstmt.setInt(1, id); 141 //执行 142 int count = pstmt.executeUpdate(); 143 //如果条数大于0,表示删除成功 144 return count > 0 ? true : false; 145 } catch (SQLException e) { 146 e.printStackTrace(); 147 } finally{ 148 if(pstmt != null) { 149 try { 150 pstmt.close(); 151 } catch (SQLException e) { 152 e.printStackTrace(); 153 } 154 } 155 if(conn != null) { 156 try { 157 conn.close(); 158 } catch (SQLException e) { 159 e.printStackTrace(); 160 } 161 } 162 } 163 return false; 164 } 165 166 167 public boolean add(Employee employee) throws SQLException { 168 String driver = "com.mysql.jdbc.Driver"; 169 String url = "jdbc:mysql://localhost:3307/jdbc_db"; 170 String user = "root"; 171 String password = "root"; 172 173 Connection conn = null; 174 PreparedStatement pstmt = null; 175 try{ 176 //获取连接对象 177 conn = DriverManager.getConnection(url, user, password); 178 //获取语句 179 String sql = "insert into employee(eid, ename, salary) values(?,?,?)"; 180 pstmt = conn.prepareStatement(sql); 181 pstmt.setInt(1, employee.getId()); 182 pstmt.setString(2,employee.getName()); 183 pstmt.setBigDecimal(3, employee.getSalary()); 184 //执行 185 int count = pstmt.executeUpdate(); 186 //如果条数大于0,表示删除成功 187 return count > 0 ? true : false; 188 } finally{ 189 if(pstmt != null) { 190 try { 191 pstmt.close(); 192 } catch (SQLException e) { 193 e.printStackTrace(); 194 } 195 } 196 if(conn != null) { 197 try { 198 conn.close(); 199 } catch (SQLException e) { 200 e.printStackTrace(); 201 } 202 } 203 } 204 } 205 206 public boolean updateById(Employee employee) throws SQLException { 207 String driver = "com.mysql.jdbc.Driver"; 208 String url = "jdbc:mysql://localhost:3307/jdbc_db"; 209 String user = "root"; 210 String password = "root"; 211 212 Connection conn = null; 213 PreparedStatement pstmt = null; 214 try{ 215 //获取连接对象 216 conn = DriverManager.getConnection(url, user, password); 217 //获取语句 218 ArrayList<Object> args = new ArrayList<>(); 219 StringBuilder sb = new StringBuilder(); 220 221 if(employee.getName() != null){ 222 sb.append(",ename=? "); 223 args.add(employee.getName()); 224 } 225 if(employee.getSalary() != null){ 226 sb.append(",salary=? "); 227 args.add(employee.getSalary()); 228 } 229 230 int argsNum = args.size(); 231 if(argsNum == 0){ 232 return false; 233 } 234 String sql = "update employee set " + sb.deleteCharAt(0).toString() + "where eid=? "; 235 236 pstmt = conn.prepareStatement(sql); 237 238 for (int i = 0; i < argsNum; i++) { 239 pstmt.setObject(i + 1, args.get(i)); 240 } 241 pstmt.setObject(argsNum + 1, employee.getId()); 242 //执行 243 int count = pstmt.executeUpdate(); 244 //如果条数大于0,表示删除成功 245 return count > 0 ? true : false; 246 } finally{ 247 if(pstmt != null) { 248 try { 249 pstmt.close(); 250 } catch (SQLException e) { 251 e.printStackTrace(); 252 } 253 } 254 if(conn != null) { 255 try { 256 conn.close(); 257 } catch (SQLException e) { 258 e.printStackTrace(); 259 } 260 } 261 } 262 } 263 }