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【转载】JdbcTemplate学习笔记

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原文:http://it.oyksoft.com/post/234/

1、使用JdbcTemplate的execute()方法执行SQL语句

java代码

jdbcTemplate.execute(

"CREATE TABLE USER (user_id integer, name varchar(100))");

 jdbcTemplate.execute("CREATE TABLE USER (user_id integer, name varchar(100))");

 

2、如果是UPDATE或INSERT,可以用update()方法。

java代码

jdbcTemplate.update("INSERT INTO USER VALUES('" 
+ user.getId() + "', '" 
+ user.getName() + "', '" 
+ user.getSex() + "', '" 
+ user.getAge() + "')"); 
jdbcTemplate.update("INSERT INTO USER VALUES('" 
+ user.getId() + "', '" 
+ user.getName() + "', '" 
+ user.getSex() + "', '" 
+ user.getAge() + "')"); 

 

3、带参数的更新

java代码

jdbcTemplate.update("UPDATE USER SET name = ? WHERE user_id = ?", new Object[] {name, id});   
jdbcTemplate.update("UPDATE USER SET name = ? WHERE user_id = ?", new Object[] {name, id}); 

java代码

jdbcTemplate.update("INSERT INTO USER VALUES(?, ?, ?, ?)", new Object[] {user.getId(), user.getName(), user.getSex(), user.getAge()});   
jdbcTemplate.update("INSERT INTO USER VALUES(?, ?, ?, ?)", new Object[] {user.getId(), user.getName(), user.getSex(), user.getAge()});

4、使用JdbcTemplate进行查询时,使用queryForXXX()等方法
Java代码
    int count = jdbcTemplate.queryForInt("SELECT COUNT(*) FROM USER");   
    int count = jdbcTemplate.queryForInt("SELECT COUNT(*) FROM USER"); 

 


Java代码
    String name = (String) jdbcTemplate.queryForObject("SELECT name FROM USER WHERE user_id = ?", new Object[] {id}, java.lang.String.class);   
   String name = (String) jdbcTemplate.queryForObject("SELECT name FROM USER WHERE user_id = ?", new Object[] {id}, java.lang.String.class); 

 

Java代码
    List rows = jdbcTemplate.queryForList("SELECT * FROM USER");   
    List rows = jdbcTemplate.queryForList("SELECT * FROM USER"); 

 

Java代码
    List rows = jdbcTemplate.queryForList("SELECT * FROM USER"); 
    Iterator it = rows.iterator(); 
    while(it.hasNext()) { 
    Map userMap = (Map) it.next(); 
    System.out.print(userMap.get("user_id") + "\t"); 
    System.out.print(userMap.get("name") + "\t"); 
    System.out.print(userMap.get("sex") + "\t"); 
    System.out.println(userMap.get("age") + "\t"); 
    } 
     
    List rows = jdbcTemplate.queryForList("SELECT * FROM USER"); 
     
    Iterator it = rows.iterator(); 
    while(it.hasNext()) { 
    Map userMap = (Map) it.next(); 
    System.out.print(userMap.get("user_id") + "\t"); 
    System.out.print(userMap.get("name") + "\t"); 
    System.out.print(userMap.get("sex") + "\t"); 
    System.out.println(userMap.get("age") + "\t");
    } 

 

JdbcTemplate将我们使用的JDBC的流程封装起来,包括了异常的捕捉、SQL的执行、查询结果的转换等等。spring大量使用Template Method模式来封装固定流程的动作,XXXTemplate等类别都是基于这种方式的实现。

 

除了大量使用Template Method来封装一些底层的操作细节,spring也大量使用callback方式类回调相关类别的方法以提供JDBC相关类别的功能,使传统的JDBC的使用者也能清楚了解spring所提供的相关封装类别方法的使用。

 

JDBC的PreparedStatement

 


Java代码
   final String id = user.getId();   
   final String name = user.getName();   
   final String sex = user.getSex() + "";   
   final int age = user.getAge(); 
    
   jdbcTemplate.update("INSERT INTO USER VALUES(?, ?, ?, ?)", 
    
   new PreparedStatementSetter() {   
   public void setValues(PreparedStatement ps) throws SQLException {   
   ps.setString(1, id); 
   ps.setString(2, name); 
   ps.setString(3, sex); 
   ps.setInt(4, age); 
   } 
   }); 
    
   final String id = user.getId(); 
   final String name = user.getName(); 
   final String sex = user.getSex() + ""; 
   final int age = user.getAge(); 
      
   jdbcTemplate.update("INSERT INTO USER VALUES(?, ?, ?, ?)", 
      
   new PreparedStatementSetter() {     
   public void setValues(PreparedStatement ps) throws SQLException {   
   ps.setString(1, id);   
   ps.setString(2, name);     
   ps.setString(3, sex);   
   ps.setInt(4, age);     
   }   
   });        
Java代码
   final User user = new User();     
   jdbcTemplate.query("SELECT * FROM USER WHERE user_id = ?",   
   new Object[] {id},   
   new RowCallbackHandler() {   
   public void processRow(ResultSet rs) throws SQLException {   
   user.setId(rs.getString("user_id")); 
   user.setName(rs.getString("name")); 
   user.setSex(rs.getString("sex").charAt(0));   
   user.setAge(rs.getInt("age"));   
   } 
   }); 
    
   final User user = new User(); 
      
   jdbcTemplate.query("SELECT * FROM USER WHERE user_id = ?",   
   new Object[] {id},     
   new RowCallbackHandler() { 
    
    
   public void processRow(ResultSet rs) throws SQLException {   
   user.setId(rs.getString("user_id"));   
   user.setName(rs.getString("name"));   
   user.setSex(rs.getString("sex").charAt(0));   
   user.setAge(rs.getInt("age"));   
   }   
   }); 
Java代码
  class UserRowMapper implements RowMapper { 
   
  public Object mapRow(ResultSet rs, int index) throws SQLException { 
   
  User user = new User(); 
  user.setId(rs.getString("user_id"));     
  user.setName(rs.getString("name"));   
  user.setSex(rs.getString("sex").charAt(0));     
  user.setAge(rs.getInt("age"));     
  return user;        
  }        
  } 
     
  public List findAllByRowMapperResultReader() {      
   
  String sql = "SELECT * FROM USER"; 
   
  return jdbcTemplate.query(sql, new RowMapperResultReader(new UserRowMapper())); 
   
  } 
   
  class UserRowMapper implements RowMapper { 
   
  public Object mapRow(ResultSet rs, int index) throws SQLException { 
  User user = new User();   
  user.setId(rs.getString("user_id"));   
  user.setName(rs.getString("name"));   
  user.setSex(rs.getString("sex").charAt(0));   
  user.setAge(rs.getInt("age"));   
  return user;   
  }   
  } 
   
  public List findAllByRowMapperResultReader() {     
  String sql = "SELECT * FROM USER";   
  return jdbcTemplate.query(sql, new RowMapperResultReader(new UserRowMapper())); 
  } 

 

在getUser(id)里面使用UserRowMapper

 


Java代码
   public User getUser(final String id) throws DataAccessException {   
   String sql = "SELECT * FROM USER WHERE user_id=?";   
   final Object[] params = new Object[] { id };   
   List list = jdbcTemplate.query(sql, params, new RowMapperResultReader(new UserRowMapper()));     
   return (User) list.get(0);   
   }
    
   public User getUser(final String id) throws DataAccessException { 
   String sql = "SELECT * FROM USER WHERE user_id=?";     
   final Object[] params = new Object[] { id };     
   List list = jdbcTemplate.query(sql, params, new RowMapperResultReader(new UserRowMapper()));     
   return (User) list.get(0);     
   }

 

网上收集
org.springframework.jdbc.core.PreparedStatementCreator 返回预编译SQL 不能于Object[]一起用
Java代码
   public PreparedStatement createPreparedStatement(Connection con) throws SQLException {   
   return con.prepareStatement(sql);   
   } 
    
   public PreparedStatement createPreparedStatement(Connection con) throws SQLException {   
   return con.prepareStatement(sql);   
   } 

 

1.增删改
org.springframework.jdbc.core.JdbcTemplate 类(必须指定数据源dataSource)
Java代码
   template.update("insert into web_person values(?,?,?)",Object[]);   
   template.update("insert into web_person values(?,?,?)",Object[]); 

Java代码
    template.update("insert into web_person values(?,?,?)",new PreparedStatementSetter(){ //匿名内部类 只能访问外部最终局部变量   
    public void setValues(PreparedStatement ps) throws SQLException {   
    ps.setInt(index++,3);   
    }); 
     
    template.update("insert into web_person values(?,?,?)",new PreparedStatementSetter(){ //匿名内部类 只能访问外部最终局部变量 
     
    public void setValues(PreparedStatement ps) throws SQLException {   
    ps.setInt(index++,3);   
    }); 
     
    org.springframework.jdbc.core.PreparedStatementSetter //接口 处理预编译SQL       
    public void setValues(PreparedStatement ps) throws SQLException {   
    ps.setInt(index++,3);   
    } 
     
    public void setValues(PreparedStatement ps) throws SQLException {   
    ps.setInt(index++,3);   
    } 

 

2.查询JdbcTemplate.query(String,[Object[]/PreparedStatementSetter],RowMapper/RowCallbackHandler)

 

org.springframework.jdbc.core.RowMapper 记录映射接口 处理结果集
Java代码
   public Object mapRow(ResultSet rs, int arg1) throws SQLException { //int表当前行数   
   person.setId(rs.getInt("id"));   
   }   
   List template.query("select * from web_person where id=?",Object[],RowMapper);   
   public Object mapRow(ResultSet rs, int arg1) throws SQLException { //int表当前行数   
   person.setId(rs.getInt("id"));   
   }   
   List template.query("select * from web_person where id=?",Object[],RowMapper); 

 

org.springframework.jdbc.core.RowCallbackHandler 记录回调管理器接口 处理结果集
Java代码
   template.query("select * from web_person where id=?",Object[],new RowCallbackHandler(){   
   public void processRow(ResultSet rs) throws SQLException {   
   person.setId(rs.getInt("id"));   
   }); 

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