第一步，從.csv文件讀取數據，轉成JSON格式
1 import com.fasterxml.jackson.dataformat.csv.CsvMapper; 2 import com.fasterxml.jackson.dataformat.csv.CsvSchema; 3 import com.google.gson.Gson; 4 5 public static String readFile(String filename) throws Exception { 6 7 String filetype = filename.substring(filename.lastIndexOf(".") + 1); 8 String filepath = "src/main/java/"+ filename; 9 String json = null; 10 11 if (filetype.equals("csv")) { 12 13 File input = new File(filepath); 14 CsvSchema csvSchema = CsvSchema.builder().setUseHeader(true).build(); 15 CsvMapper csvMapper = new CsvMapper(); 16 17 // Read data from CSV file 18 List<Object> readAll = csvMapper.readerFor(Map.class) 19 .with(csvSchema).readValues(input).readAll(); 20 Gson objJson = new Gson(); 21 json = objJson.toJson(readAll, List.class); 22 } 23 return json; 24 }
第二步，建立Object類
1 import com.fasterxml.jackson.annotation.JsonProperty; 2 3 public class User { 4 5 @JsonProperty("Userid") 6 private String Userid; 7 8 @JsonProperty("FirstName") 9 private String FirstName; 10 11 @JsonProperty("LastName") 12 private String LastName; 13 14 public String getUserId() { 15 return Userid; 16 } 17 18 public String getFirstName() { 19 return FirstName; 20 } 21 22 public String getLastName() { 23 return LastName; 24 } 25 26 public void setUserId(String Userid) { 27 this.Userid = Userid; 28 } 29 30 public void setFirstName(String FirstName) { 31 this.FirstName = FirstName; 32 } 33 34 public void setLastName(String LastName) { 35 this.LastName = LastName; 36 } 37 }
第三步，將JSON字符串轉化爲Object List
1 import com.fasterxml.jackson.databind.ObjectMapper; 2 3 public static List<User> jsonToUserEntity(String json) { 4 ObjectMapper objectMapper = new ObjectMapper(); 5 6 try { 7 return objectMapper.readValue( 8 json, 9 objectMapper.getTypeFactory().constructCollectionType(List.class, User.class) 10 ); 11 12 } catch (IOException e) { 13 e.printStackTrace(); 14 } 15 return new ArrayList<User>(); 16 }
補充：
若是CSV文件的第一行是Column名，而你想要自定義它們，能夠用下面的方法
1 CsvSchema csvSchema = CsvSchema.builder().setSkipFirstDataRow(true) 2 .addColumn("userId") 3 .addColumn("firstName") 4 .build()
若是CSV文件自己沒有分列，只是按行存放了數據內容（第一行仍是Column名)，則能夠用下面的方法
1 CsvSchema schema = CsvSchema.builder().setColumnSeparator(',').setSkipFirstDataRow(true).build(); 2 MappingIterator<String[]> it = csvMapper.readerFor(String[].class).with(schema).readValues(input); 3 4 List<String> recordList = new ArrayList<String>(); 5 6 while (it.hasNext()) { 7 String[] arr = it.next(); 8 String record = ""; 9 for (int i=0; i<arr.length; i++) { 10 //arr[i]存放了一個單元格的內容，把一行中全部的單元格連起來就是一個完整的record 11 if (arr[i] != "") { 12 record = record + arr[i]; 13 } 14 } 15 recordList.add(record); 16 }