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Java JDBC操作Mysql数据库增删改查，分页查询实例详解(源码)

江山如画 • • 编程开发 • 阅读 4067

查询操作

1.查询结果以list返回

/**
   * 查询结果以list返回
   * @param pageIndex 页数
   * @param pageSize 每页记录条数
   * @param attachTableName 在结果集中是否给key值附加表名，例如：user.id,与id
   * @param sql 查询语句 例如："select u.id,u.name,u.sex,u.depart_id AS departId,d.* from user u,depart d where u.depart_id=d.id"
   * @param values
   * @throws SQLException 
   */
  private List<Map<String, Object>> queryList(int pageIndex,int pageSize,boolean attachTableName,String sql,Object... values) throws SQLException{
    Connection conn = null;
    PreparedStatement pStmt = null;
    List<Map<String, Object>> dataList = null;
    //校验参数
    if(pageIndex <= 0){
      pageIndex = 1;
    }
    if(pageSize <= 0){
      pageSize = Config.PAGE_SIZE_DEFAULT;
    }
    conn = this.getConnection(conn);
    pStmt = conn.prepareStatement(sql);
    //设置参数
    if(pStmt != null && values != null && values.length > 0){
      for (int i = 0; i < values.length; i++) {
        pStmt.setObject(i+1, values[i]);
      }
    }
    //设置最大查询到第几条记录
    pStmt.setMaxRows(pageIndex*pageSize);
    ResultSet rs = pStmt.executeQuery();
    //游标移动到要输出的第一条记录
    rs.relative((pageIndex-1)*pageSize);
    if(rs != null){
      try {
        dataList = new ArrayList<Map<String,Object>>();
        ResultSetMetaData md = rs.getMetaData(); //得到结果集(rs)的结构信息，比如字段数、字段名等 
        //遍历结果集
        while(rs.next()){
          Map<String, Object> map = new LinkedHashMap();
          for (int i = 1; i <= md.getColumnCount(); i++) {
            map.put(attachTableName?(formatTableName(md.getTableName(i))+"."+md.getColumnLabel(i)):(md.getColumnLabel(i)), rs.getObject(i));
          }
          dataList.add(map);
        }
      }finally{
        if(rs != null){
          rs.close();
        }
        if(pStmt != null){
          pStmt.close();
        }
        if (conn != null) {
          this.closeConnection(conn);
        }
      }
    }
    return dataList;
  }

调用list查询

public static void queryList(){
    String sql = "select u.*,d.* from user u,depart d where u.depart_id=d.id";
    try {
      List<Map<String, Object>> dataList = baseImp.queryForListAttachTableName(2,2,sql, null);
//     List<Map<String, Object>> dataList = baseImp.queryForList(2,2,sql, null);
      for (Map<String, Object> map : dataList) {
        for (String key : map.keySet()) {
          System.out.print(key+"="+map.get(key)+" ");
        }
        System.out.println();
      }
    } catch (SQLException e) {
      e.printStackTrace();
    }
  }

结果

Java JDBC操作Mysql数据库增删改查，分页查询实例详解(源码)

2.查询结果以jsonArray返回

/**
   * 查询结果以ArrayList返回
   * @param 在结果集中是否给key值附加表名，例如：user.id,与id
   * @param sql 查询语句 例如："select u.id,u.name,u.sex,u.depart_id AS departId,d.* from user u,depart d where u.depart_id=d.id"
   * @param values
   * @throws SQLException 
   */
  private JSONArray queryJsonArray(int pageIndex,int pageSize,boolean attachTableName,String sql,Object... values) throws SQLException{
    JSONArray jsonArray = null;
    Connection conn = null;
    PreparedStatement pStmt = null;
    //校验参数
    if(pageIndex <= 0){
      pageIndex = 1;
    }
    if(pageSize <= 0){
      pageSize = Config.PAGE_SIZE_DEFAULT;
    }
    conn = this.getConnection(conn);
    pStmt = conn.prepareStatement(sql);
    //设置参数
    if(pStmt != null && values != null && values.length > 0){
      for (int i = 0; i < values.length; i++) {
        pStmt.setObject(i+1, values[i]);
      }
    }
    //设置最大查询到第几条记录
    pStmt.setMaxRows(pageIndex*pageSize);
    ResultSet rs = pStmt.executeQuery();
    //游标移动到要输出的第一条记录
    rs.relative((pageIndex-1)*pageSize);
    if(rs != null){
      try {
        jsonArray = new JSONArray();
        ResultSetMetaData md = rs.getMetaData(); //得到结果集(rs)的结构信息，比如字段数、字段名等 
        //遍历结果集
        while(rs.next()){
          JSONObject jsonObject = new JSONObject();
          for (int i = 1; i <= md.getColumnCount(); i++) {
            jsonObject.put(attachTableName?(formatTableName(md.getTableName(i))+"."+md.getColumnLabel(i)):(md.getColumnLabel(i)), rs.getObject(i)+"");
          }
          jsonArray.add(jsonObject);
        }
        }finally{
          if(rs != null){
            rs.close();
          }
          if(pStmt != null){
            pStmt.close();
          }
          if (conn != null) {
            this.closeConnection(conn);
          }
        }
    }
    return jsonArray;
  }

调用jsonArray查询

public static void queryJsonArray(){
//   String sql = "select * from user u";
    String sql = "select u.*,d.* from user u,depart d where u.depart_id=d.id";
//   String sql = "select u.id AS uid,u.name,u.sex,u.depart_id AS departId,d.name from user u,depart d where u.depart_id=d.id";
//   String sql = "select u.id,u.name,u.sex,u.depart_id AS departId,d.* from user u,depart d where u.depart_id=d.id";
    try {
      JSONArray jsonArray = baseImp.queryForJsonArrayAttachTableName(2,2,sql, null);
//     JSONArray jsonArray = baseImp.queryForJsonArray(sql, null);
      System.out.println(jsonArray.toString());
      for (int i = 0; i < jsonArray.size(); i++) {
        JSONObject jsonObject = jsonArray.getJSONObject(i);
        Iterator<?> iterator = jsonObject.keys();
        Object key = null;
        while (iterator.hasNext()) {
          key = iterator.next();
          System.out.print(key+" "+jsonObject.get(key)+" ");
        }
        System.out.println();
      }
    } catch (SQLException e) {
      e.printStackTrace();
    }
  }

结果

Java JDBC操作Mysql数据库增删改查，分页查询实例详解(源码)

[{"user.id":"4","user.name":"王五","user.sex":"0","user.depart_id":"3","depart.id":"3","depart.name":"研发部","depart.desc":"这是研发部"},{"user.id":"5","user.name":"赵六","user.sex":"1","user.depart_id":"1","depart.id":"1","depart.name":"测试部","depart.desc":"这是测试部"}]
user.id 4 user.name 王五 user.sex 0 user.depart_id 3 depart.id 3 depart.name 研发部 depart.desc 这是研发部 
user.id 5 user.name 赵六 user.sex 1 user.depart_id 1 depart.id 1 depart.name 测试部 depart.desc 这是测试部

3.查询总记录条数

/**
   * 查询记录条数
   * @param sql 例如："select count(*) from user where xxx"
   * @param values
   * @throws SQLException 
   */
  public int queryCount(String sql,Object... values) throws SQLException{
    int count = -1;
    Connection conn = null;
    PreparedStatement pStmt = null;
    conn = this.getConnection(conn);
    pStmt = conn.prepareStatement(sql);
    //设置参数
    if(pStmt != null && values != null && values.length > 0){
      for (int i = 0; i < values.length; i++) {
        pStmt.setObject(i+1, values[i]);
      }
    }
    ResultSet rs = pStmt.executeQuery();
    if(rs != null){
      try {
        while(rs.next()){
          count = rs.getInt(1);
        }
      }finally{
        if(rs != null){
          rs.close();
        }
        if(pStmt != null){
          pStmt.close();
        }
        if (conn != null) {
          this.closeConnection(conn);
        }
      }
    }
    return count;
  }

调用查询总记录条数

public static void queryCount(){
    String sql = "select count(*) from user u";
    try {
      System.out.println("count="+baseImp.queryCount(sql, null));
    } catch (SQLException e) {
      e.printStackTrace();
    }
  }

结果

Java JDBC操作Mysql数据库增删改查，分页查询实例详解(源码)

这就是Java中JDBC对mysql数据库进行增删改查操作与分页查询的全部内容，希望对你有所帮助。

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