使用Jackson美化输出json数据

转: https://javarevisited.blogspot.com/2015/05/how-to-print-json-string-in-java-jackson-example.html

1. 引入依赖

<dependency>
     <groupId>org.codehaus.jackson</groupId>
     <artifactId>jackson-xc</artifactId>
     <version>1.9.12</version>
</dependency>

2. 代码

public static void main(String[] args) {

    Map<String, Integer> m = new HashMap<>();
    m.put("0021", 1);
    m.put("0022", 2);

    org.codehaus.jackson.map.ObjectMapper mapper = new ObjectMapper();
    try {
        System.out.println("Default JSON String:" + mapper.writeValueAsString(m));
        System.out.println("formatted JSON String:" + mapper.writerWithDefaultPrettyPrinter().writeValueAsString(m));
    } catch (Exception e) {
        e.printStackTrace();
    }
}

3. 输出

Default JSON String:{"0022":2,"0021":1}
formatted JSON String:{
  "0022" : 2,
  "0021" : 1
}